From 1 crank to 2, and sometimes 3

[Mudderoy]

Well for years she cranked on the first twist of the key. Then it took two but no more. Now she's taking three start attempts.

In addition the engine runs rough, sort of like a miss, for about 15 seconds. Doesn't matter if I give it throttle or not. It usually only does this after sitting off over night. Little or no miss after 9 hours sitting in the parking garage.

Seafoam seems to cure the start problem, and rough idle, but only for a couple of days, if that.

Somethings dirty boys!

Was that enough information for a diagnosis?

[4.3LXJ]

Muddy, first guess is fuel pressure is going down after shut down. Hook up a gauge and check it as someone tries to start it.

[ice_cold]

I'm with 4.3LXJ on this one. Cooler evenings, and the fuel is creeping back...sitting in the nice sun....heat helps keep everything pressurized.
Had this problem on a Intrepid I had. As it got colder it got worse...did a reg. change and she was perky again.

[Mudderoy]

I'm with 4.3LXJ on this one. Cooler evenings, and the fuel is creeping back...sitting in the nice sun....heat helps keep everything pressurized.
Had this problem on a Intrepid I had. As it got colder it got worse...did a reg. change and she was perky again.

Well I do need to check the pressure to be sure ($30 for a gauge) but turning the key on and waiting 30 seconds, or on and off 3 times, blah blah blah makes no difference in the cranking times.

[xj4life2]

According to my crystal ball ...... I would blame the IAC motor getting jiggy.

[Mudderoy]

According to my crystal ball ...... I would blame the IAC motor getting jiggy.

I meant to clean that damn thing ages ago. Thanks.

[msmoorenburg]

Fuel pressure reg is where I would look. The first few mins of running sounds like it maybe getting air in the fuel system

[Mudderoy]

Fuel pressure reg is where I would look. The first few mins of running sounds like it maybe getting air in the fuel system

Thanks. Two minor points. The problem goes away after a good Seafoam-ing and it runs rough for about 15 seconds.

[brandonlp]

i did some research on your injectors, fords run on a 39psi system, your injectors are 24lbs at 39 psi unless they changed it sometime after 2005, the way i figure it you running at 25.5 lbs/hr and the injectors are 14.5 ohms which stock injectors are 12 ohm its harder for the ecu to control them maybe try a different set and see if that helps,

also when did the misfiring and rough idle start happening? a good time frame would help

[xj4life2]

I meant to clean that damn thing ages ago. Thanks.

I would just replace it there not expensive at all $45.00 or so , however be sure to clean the passage very well q-tip and carb cleaner.Then blow it out with air.

[Mudderoy]

i did some research on your injectors, fords run on a 39psi system, your injectors are 24lbs at 39 psi unless they changed it sometime after 2005, the way i figure it you running at 25.5 lbs/hr and the injectors are 14.5 ohms which stock injectors are 12 ohm its harder for the ecu to control them maybe try a different set and see if that helps,

also when did the misfiring and rough idle start happening? a good time frame would help

The starting issue was prior to the injector swap, I was hoping for better fuel mileage and normal one try starts. I didn't change anything...

[steph74]

get a renix engine, and experience the 4 second crank before it starts.... then you'll know it is normal and will not worry about it ;)

[Mudderoy]

Afternoon start...

http://www.youtube.com/watch?v=pr2UzpS71HA

[4.3LXJ]

Muddy, I would check that fuel pressure on that first crank. You might find it low.

[xj4life2]

get a renix engine, and experience the 4 second crank before it starts.... then you'll know it is normal and will not worry about it ;)

You must have a fancy renix or something only 4 seconds huh???:smiley-laughing021:

[steph74]

ahah yeah maybe I was a bit optimistic on that one...

[default83]

dude that parking garage looks like mine, are you in the galleria area?

[XJ4IV]

no he is in champions forest area... kinda tomball-ish I guess.
thats odd tony after doing my swap on injectors i have had no issues at all
Mine always starts on the first shot ( when my battery is good). Id say fuel delivery which is what everyone else has said...

[gary63]

you might check your fuel injector cold start valve.

[XJ Rat]

My 98 has the cranking issue also. Overnite it might take 4, 5, or 6 cranks to fire, but turn it off and let it sit during the day she fires right up in about 1/2 to 1 crank. I was leaning towards a fuel pressure issue.

But I do not have the rough idle for the period you described.

Maybe you have two unrelated issues that coincidentally surfaced at the same time.

[default83]

try turning the key on and waiting about 10 seconds, turn it off then turn it on again then start it. see if it helps.

[Mudderoy]

try turning the key on and waiting about 10 seconds, turn it off then turn it on again then start it. see if it helps.

Sorry I should have mentioned it previously, I've already tried all the various "voodoo" methods for getting the fuel pump to pressurize the fuel rail. No change.

[Mudderoy]

It actually started up pretty quick today!

http://www.youtube.com/watch?v=X4qQVeGtNxQ

[ice_cold]

Pour some coffee into the tank. Maybe it just doest want to get going in the morning like alot of us, without our coffee!! ;)

[Mudderoy]

Gas mileage seems to be down. When I start it I smell a funny burned and fuel smell, not like raw fuel, hard to describe. Also it used to start right up after running it and then restarting it just 30 minutes an hour later. Not any more, requires more cranking time.

I checked under the hood today at work just to make sure not of the injectors were leaking. I was just being careful but again it really didn't smell like raw fuel. The smell goes away quickly. It's almost like a smell you get when you flood the carburetor on the older 350 and 327 Chevy's.

[TeXJ]

like was said seems like you are loosing pressure. Could you rent a tool from autozone or oreillys to check and see if the pressure is going down? or you can release the pressure yourself and take note of how much/less fuel comes out before starting and just after.

[Mudderoy]

like was said seems like you are loosing pressure. Could you rent a tool from autozone or oreillys to check and see if the pressure is going down? or you can release the pressure yourself and take note of how much/less fuel comes out before starting and just after.

I believe I already checked about the gauge as a loaner, and they said no (but I'll ask again to be sure). I have drained fuel before (when I changed the injectors) A lot came out and it took a while for it to stop. I really don't believe it is fuel pressure.

[TeXJ]

since you think it isnt the fuel pressure, then you have spark and air to consider. Spark plugs in good condition? Coil ok?

[Mudderoy]

since you think it isnt the fuel pressure, then you have spark and air to consider. Spark plugs in good condition? Coil ok?

3 coils, original, new, and high voltage coil about 3 months old.

spark plugs are relatively new, but problem has been there with the last several sets of plugs.

The ignition system is actually the FireWire ($200) system that I put on a few months ago. High voltage coil, plug wires rotor and cap. Problem before and after this installation.

[pvt.tadpolxj]

Hey Muddy, Sorry to hear about the starting thing. If there is anything that has caused me issue's on my street XJ. It would be IGN. COIL'S. I had to make a real nice heat shield for mine because i did not want to relocate. I used lot's of the heat insulation i removed under my hood when i cut it out for the cowl piece, and some flashing. Believe me it has to be really good. If you have not done this already I bet you it is your IGN. COIL. And with a relocate or a good heat shield I bet you will run just fine with a good stock IGN. KIT... I hope this help's.:driving:

[Mudderoy]

Hey Muddy, Sorry to hear about the starting thing. If there is anything that has caused me issue's on my street XJ. It would be IGN. COIL'S. I had to make a real nice heat shield for mine because i did not want to relocate. I used lot's of the heat insulation i removed under my hood when i cut it out for the cowl piece, and some flashing. Believe me it has to be really good. If you have not done this already I bet you it is your IGN. COIL. And with a relocate or a good heat shield I bet you will run just fine with a good stock IGN. KIT... I hope this help's.:driving:

So I'm assuming that the heat makes them go bad? Keep in mind that the engine and bay is cold in the morning when I first start the engine. No heat to effect the coil at that time and it runs great once started.

[pvt.tadpolxj]

Yea Muddy I understand your theory it's just that during month's of operation the heat start's breaking down thr perfprmance of the IGN. Coil's..I have never had a IGN. COIL just stop working all at once. It just get's harder and harder to start, and start's running worse. But eventually it will not start. I hope this help's....:driving::driving::driving:

[Mudderoy]

Yea Muddy I understand your theory it's just that during month's of operation the heat start's breaking down thr perfprmance of the IGN. Coil's..I have never had a IGN. COIL just stop working all at once. It just get's harder and harder to start, and start's running worse. But eventually it will not start. I hope this help's....:driving::driving::driving:

I really appreciate the information but in my case 3 coils all doing same thing, I don't think this is my issue. If it stops running I'll try changing it out though! :thumbsup:

[pvt.tadpolxj]

O.K. Muddy.. By the way I replaced exactly 3 Ignition Coil's before i made a heat shield...:patriot::patriot::patriot:

[Jeepster19]

Well for years she cranked on the first twist of the key. Then it took two but no more. Now she's taking three start attempts.

In addition the engine runs rough, sort of like a miss, for about 15 seconds. Doesn't matter if I give it throttle or not. It usually only does this after sitting off over night. Little or no miss after 9 hours sitting in the parking garage.

Seafoam seems to cure the start problem, and rough idle, but only for a couple of days, if that.

Somethings dirty boys!

Was that enough information for a diagnosis?

I had the same problem with my 98Xj.Have you replaced the fuel pump?If so did you use a Mopar O.E.M. replacement pump?If not that is surely the problem?Been there,did that Mudderoy.The new pump is expensive but "well" worth the cash!:thumbsup:

[Mudderoy]

I had the same problem with my 98Xj. Have you replaced the fuel pump? If so did you use a Mopar O.E.M. replacement pump? If not that is surely the problem? Been there, did that Mudderoy. The new pump is expensive but "well" worth the cash! :thumbsup:

No.
n/a

Yeah I'm thinking it's the pump too (just hoping it's something else).

[gary63]

have you check your comprision if it is low it will be hard to start some of the time and it will run hotter at high rpm.also the ignition will work harder.

[Mudderoy]

have you check your comprision if it is low it will be hard to start some of the time and it will run hotter at high rpm.also the ignition will work harder.

lol no, that's another gauge I'd have to buy. All makes great sense to check these things of course, but you have to have the things that check them.

As good as it runs, and still over 100 mph with 4.56 gears I doubt compression is very low, still I've been wrong before. I'm not sure if you read about how well it starts after I seafoam it, then it goes back to normal after a couple of days. I probably need to replace the last sensor the IAC. I just hate throwing money at a problem.

[pvt.tadpolxj]

Hey Muddy I forgot to mention. One of the three Ign. Coil's that started failing before i made a heat shield was one of those firepower Ign. Kit's. I think the coil was called a Dirt Devil.....I hope this help's....:cool:

[gary63]

the firepower coil must have a bad batch or something I know 3 people who
had them and they went out on them too.As for it running good after you seafoam it could be removing the glaze off the cylndrs wall so the rings can stick to the walls and removing corbin fom around the valves. But with low comb. it can't blow off the corben and ext. oil so then is dosen't fire as well.
if you do a comb. test do 1 dry and 1wet and then do a leak down test.all so
it can run 100 mph on low comb. it just has to work harder.

[pvt.tadpolxj]

Muddy! Buddy!..... All you need is a Ign. Coil...:cool:

[BlueXJ]

I have looked over this thread and find no place where you say you pulled and cleaned or replaced the IAC. Did I miss that or does it still need to be done? That little motor can get the pintle on it dirty and cause many of the symptoms you are describing until the system is at normal operating temperatures.
If you clean it be very careful as the pintle is quite delicate. Use Q-tips to clean the orifice and carb cleaner to flush it out. HTH

[Mudderoy]

I have looked over this thread and find no place where you say you pulled and cleaned or replaced the IAC. Did I miss that or does it still need to be done? That little motor can get the pintle on it dirty and cause many of the symptoms you are describing until the system is at normal operating temperatures.
If you clean it be very careful as the pintle is quite delicate. Use Q-tips to clean the orifice and carb cleaner to flush it out. HTH

Thanks. Nope I had plans on doing this some time back but never did.

[modestmar00xj]

I'm with 4.3LXJ on this one. Cooler evenings, and the fuel is creeping back...sitting in the nice sun....heat helps keep everything pressurized.
Had this problem on a Intrepid I had. As it got colder it got worse...did a reg. change and she was perky again.


havent though about that! good post!

[Mudderoy]

I'm with 4.3LXJ on this one. Cooler evenings, and the fuel is creeping back...sitting in the nice sun....heat helps keep everything pressurized.
Had this problem on a Intrepid I had. As it got colder it got worse...did a reg. change and she was perky again.

Where is the regulator?

[Mudderoy]

Well this is interesting....

:link: (http://autorepair.about.com/library/a/1i/bl487i.htm)


The problem could very well be the combination Fuel Filter/Fuel Pressure Regulator. At 52,000 miles the filter is due for replacing and since the fuel pressure regulator is part of the filter, replaing it should take care of the problem. At this point it isn't very likely the fuel pump is a problem.

You will need to drop the fuel tank to replace the combination Fuel Filter/Fuel Pressure Regulator assembly.

[Mudderoy]

Well I don't know what he's talking about because all I can find is the fuel pump assembly...

http://www.jeep4x4center.com/images/5012953AC.jpg

:link: (http://www.jeep4x4center.com/product-information.asp?number=5012953AC)

[gary63]

The reg. is on the top but I have only found it all to gether in 1 unit.
I don't thing it comes apart or you can buy it in peace.I would just replace the hole thing and then take the old one apart.
The older one did come in 2 peaces I'm trying to work out a replacement becouse this thing go out in the worst time.
ether making a axes hole from the top or just replace it with a after market pump and reg. and filter.I just don't know why someone hasn't
yet must be some thing.

[Mudderoy]

The reg. is on the top but I have only found it all to gether in 1 unit.
I don't thing it comes apart or you can buy it in peace.I would just replace the hole thing and then take the old one apart.

Oh I agree, especially since you have to drop the tank, however at $194 sometimes it's worth it to drop the tank multiple times! :D

[gary63]

I have done one on a frieds we parked it on a hill and it had 1/2 tank. I steal think that I'm ether cutting a hole or changing mine out so it is not in the tank.

[Mudderoy]

I have done one on a frieds we parked it on a hill and it had 1/2 tank. I steal think that I'm ether cutting a hole or changing mine out so it is not in the tank.

I've heard, not sure if it applies to the XJ or not, that the fuel helps cool the pump. Taking it out of the fuel might cause problems. I guess you could always use an aftermarket external to the tank fuel pump!

[gary63]

yes the factory puts the pump in the tank to help keep it cool that is becouse they don't biuld the pump right it would cost more money.
I have replace some in other thing but not a jeep yet. the hart part is some tie in to ather parts so thing will change for thing like thiker gas (cold day and aditivs) and more pisher on every hot days. so far I have see any changes I did do a remote pump with a remote tank only I got was a low gas light.

[Mudderoy]

I finally cleaned the IAC (Idle Air Control) this weekend. Here is the first cold start after sitting over night.

http://youtu.be/nxFIFkH-OFM

[BlueXJ]

That sounds pretty strong. My multiple start problem turned out to be a vacuum leak at the MAP sensor. but mine is a Renix which is a whole different beast.

[Mudderoy]

http://youtu.be/6EOvPYOwyIM

[4.3LXJ]

Second one sounds good Tony. I have to clean mine now. It sticks on start up. It is your fault. You gave it ideas...

[Mudderoy]

Second one sounds good Tony. I have to clean mine now. It sticks on start up. It is your fault. You gave it ideas...

I've driven 40 miles so far and the needle is down to full. I probably just jinxed any mpg improvement that MIGHT have happened.

[4.3LXJ]

I've driven 40 miles so far and the needle is down to full. I probably just jinxed any mpg improvement that MIGHT have happened.

look on the bright side, you get better than some others:sign0181:

[Mudderoy]

http://youtu.be/EnWD5vewX9w

[TeXJ]

sorry to hear, do you have any check engine codes?

[Mudderoy]

sorry to hear, do you have any check engine codes?

nope, that would make it too easy.

[TeXJ]

What happened with mine. It would hessitate as i would hit the gas to speed up...turned out to be the fuse for the O2 sensor, it was giving the O2 sensor code, I went through 4 sensors till the mechanic found it was a fuse, after 3 O2 sensors I took it to a mechanic lol

[Mudderoy]

What happened with mine. It would hessitate as i would hit the gas to speed up...turned out to be the fuse for the O2 sensor, it was giving the O2 sensor code, I went through 4 sensors till the mechanic found it was a fuse, after 3 O2 sensors I took it to a mechanic lol

lol it just takes more than one try to start and idles rough for a few seconds, then everything is fine.

I think I'll just get a new IAC.

[XJ4IV]

What happened with mine. It would hessitate as i would hit the gas to speed up...turned out to be the fuse for the O2 sensor, it was giving the O2 sensor code, I went through 4 sensors till the mechanic found it was a fuse, after 3 O2 sensors I took it to a mechanic lol:hmmmm2:

[4.3LXJ]

Hey Tony, I suspect you are having the fuel pressure bleed off when it sits. If you have a fuel pressure gauge, you might check that.

[Mudderoy]

Hey Tony, I suspect you are having the fuel pressure bleed off when it sits. If you have a fuel pressure gauge, you might check that.

I don't. And this doesn't make sense to me since it changes when I Seafoam and now clean the IAC. The results has been the same. An immediate change in starting, first start, then after a couple of days, back to 2 and 3 attempts before start.

Nothing was touched having to do with the fuel system, therefore low fuel pressure shouldn't be the issue.

I don't want to spend $30 on a fuel pressure gauge just to confirm there isn't a fuel pressure problem.

Check my logic here and correct as needed. ;)

[4.3LXJ]

It is not the logic here I am questioning. But generally, when there is a slow start after sitting, it is the fuel pressure that has bled off. Then it is reestablished and starts right up. How does it do if you turn on the key for a few seconds, turn it off then start?

[Mudderoy]

It is not the logic here I am questioning. But generally, when there is a slow start after sitting, it is the fuel pressure that has bled off. Then it is reestablished and starts right up. How does it do if you turn on the key for a few seconds, turn it off then start?

Well I'm talking about the logic of what I am doing and how it would effect (or not) the fuel pressure.

I've done the wait (which the remote start does automagically) and I've done the turn the key on and off several times, wait and try to start. Neither makes a difference.

This isn't a major deal, and frankly I started the post because I thought that I had fixed it.

I called the local dealership and a new IAC is $124. I think I'll be ordering one for $70 off the Internet. It just won't be a Chrysler part.

[bigjim350]

Mine does the same thing. Takes a couple cranks to start, then runs rough for a few seconds. On mine the culprit is one injector leaks down. Which in turn cause the hard start by losing pressure, and the rough running cause of the extra gas in that one cylinder.

[Mudderoy]

Mine does the same thing. Takes a couple cranks to start, then runs rough for a few seconds. On mine the culprit is one injector leaks down. Which in turn cause the hard start by losing pressure, and the rough running cause of the extra gas in that one cylinder.

Well I had the problem before and after changing the injectors, so unless I'm misunderstanding what the culprit is in the injector leak down...

Also the Ford Mustang injectors I installed were some that were removed from a dealership from a new Mustang, so they are used, but barely.

[Mudderoy]

So I think I'm going to try a new IAC. I have replaced the MAP and TPS so this is the original 170k miles IAC.

I checked and the dealership wants $124 for one, but I think I'm going to try an aftermarket for $70.

I wouldn't bother with it except it seems that messing with this little device has effected MPG.

[xj4life2]

After reading this entire post I have to agree with the logic behind your decision especially since its not a big enough issue to set a code, I'm thinking the IAC is gettin a little jiggy on the inside, mine had that isuue until the IAC got replaced but again I'm renix also

[Mudderoy]

After reading this entire post I have to agree with the logic behind your decision especially since its not a big enough issue to set a code, I'm thinking the IAC is gettin a little jiggy on the inside, mine had that isuue until the IAC got replaced but again I'm renix also

Thanks, I can't find anything about the IAC effecting mpg. Do you think it could?

[xj4life2]

theretically it could, but I have never heard or seen anything to make me lean (no pun intended) that way, its only function is to control air intake at idle (overfuel) so it will have enough fuel to start after that the 02 takes over. It tells the ECM how the fuel trim should be,a bad o2 will get into your pocket as far a MPG goes but I don't think the IAC would.

[Mudderoy]

theretically it could, but I have never heard or seen anything to make me lean (no pun intended) that way, its only function is to control air intake at idle (overfuel) so it will have enough fuel to start after that the 02 takes over. It tells the ECM how the fuel trim should be,a bad o2 will get into your pocket as far a MPG goes but I don't think the IAC would.

Based on the name I didn't think it did, but I wasn't sure.

I'm going to replace mine, could you shoot me a PM with a price?

[TeXJ]

:hmmmm2:

not in that order... :out:

:smiley-taunt013:

[Mudderoy]

New IAC ordered!

Will it fix the hard start problem? Stay tuned...

[Mudderoy]

New IAC installed!

Still doing the two try start and running a little rough for 3 to 7 seconds.

I don't know. Very strange how it works great right after I clean the throttle body. I've cleaned in on the vehicle, off the vehicle and Seafoam'd it. All three times it started great and didn't run rough, only to go back after a couple of days.

Damned strange.

[LizardRunner]

Questions Tony, Do you turn the key on and let the fuel pump work for a few seconds before cranking the engine? Have you added seafoam to the gas tank to help keep the injectors clean? Changed the air filter lately? I had start problems like that but after seafoaming the injectors it went away. I have also gotten into the habit of letting the pressure build up in the fuel rail for a few seconds before I crank the engine and it starts right up everytime now.

[Mudderoy]

Questions Tony, Do you turn the key on and let the fuel pump work for a few seconds before cranking the engine? Have you added seafoam to the gas tank to help keep the injectors clean? Changed the air filter lately? I had start problems like that but after seafoaming the injectors it went away. I have also gotten into the habit of letting the pressure build up in the fuel rail for a few seconds before I crank the engine and it starts right up everytime now.

I've done...

key on wait
key on off 3 times
injectors have been changed with 19 mile "used" injectors
Seafoam NOT put in the tank only in throttle body.
Air filter has been changed several times in the 2 years this has been going on.

I have NOT measured fuel pressure, I haven't wanted to waste $30 or a gauge I may use once every 10 years.

[LizardRunner]

I don't and won't have a fuel pressure gauge either, seems to me that if you press the valve and it shoots out really hard, you have plenty of pressure. We aren't drag racing here, and if we were we would have inline gauges that you could see from the cockpit lol. I do run seafoam in my gas tank and use about two oz in the oil when I change it, seems to just help everything work right.

[Mudderoy]

I don't and won't have a fuel pressure gauge either, seems to me that if you press the valve and it shoots out really hard, you have plenty of pressure. We aren't drag racing here, and if we were we would have inline gauges that you could see from the cockpit lol. I do run seafoam in my gas tank and use about two oz in the oil when I change it, seems to just help everything work right.

I hate putting things in the gas tank, but I think I'll give it a try, thanks!

[LizardRunner]

I am not a big believer of "additives" either but when three mechanics told that seafoam would work in my bike, I tried it and son of a gun it worked like they said it would. So, it's the only "additive" I buy or use now. I've used it in the gas tank and the crank case oil for about 10 years now. Not really sure how it works but with 59k on the bike and no oil smoke (when buddies with less miles are leaving a blue trail) I will recomend this one product. Also when I pulled my heads for a little more porting this winter, I found a very clean engine.

[Mudderoy]

Ok bear with me here, because this is the first time checking the fuel pressure on my XJ.

On my 1998 I hooked up the pressure gauge and it read 0. I guess the Jeep has been off for about an hour at this point.

I turned the key on and it still read 0.

I started the engine (2 start attempts) and it read...

https://lh4.googleusercontent.com/-ieZyP0ptpjo/ThZQfH7Z96I/AAAAAAAABAE/X_1b9W22jq8/s800/2011-07-07%25252019.19.43.jpg

https://lh4.googleusercontent.com/-WjxAc20jeQU/ThZQXC1l4VI/AAAAAAAABAA/5SiZdRfa48A/2011-07-07%25252019.19.55.jpg

I turned the engine off and almost immediantly the pressure dropped. 30 seconds later the pressure was nearly 0.

https://lh3.googleusercontent.com/-3hQn3Jt7v8A/ThZSv6t1dLI/AAAAAAAABAY/W0_tGpX-hSI/s800/2011-07-07%25252019.21.07.jpg

Then just long enough to zoom in the camera...

https://lh4.googleusercontent.com/-95uA9GCUs2U/ThZSo2-GpEI/AAAAAAAABAU/T320_BUDAEE/s800/2011-07-07%25252019.21.30.jpg

Now did I misunderstand? I thought pressure was supposed to come up with the key on then after the engine was running it should maintain a much higher psi for longer than 30 seconds.

[4.3LXJ]

When you turn the key on, the pressure should come up within a few seconds. Within about 3 seconds it should be at about 50 psi. Then it should maintain it for at least ten minutes, but in reality much longer. I would say you have a bad pressure regulator or fuel pump check valve allowing the pressure to bleed completely down and not come up as fast as it should.

[Mudderoy]

When you turn the key on, the pressure should come up within a few seconds. Within about 3 seconds it should be at about 50 psi. Then it should maintain it for at least ten minutes, but in reality much longer. I would say you have a bad pressure regulator or fuel pump check valve allowing the pressure to bleed completely down and not come up as fast as it should.

Well swell. Ok with the gauge it's easier to see how things work.

I hooked the gauge back up, turned the key to run (not start) I ran around and checked the gauge. It was dropping fast from 20 psi.

I then tried the 3 on off, about a 1 sec delay between each cycle. I ran around and it was up close to 40 psi and dropping fast. It drops to 8 psi (the lowest measure on the gauge) after about 20 seconds.

I tried the 3 on and off again and saw the same 40+ psi.

I tried it one more time and this time I tried starting, the engine cranked up first try.

So even though I had done the 3 on off start before I didn't understand that it needed to be very quick, with in a second or two of that third on/off cycle.

Now it may just be because I have a problem here but I can make the 3 cycle thing work, or so it appears.

I was look at the FSM and it looks to me the pressure regulator is external to the tank, but I don't see it. Unless it's on the top of the tank.

[Mudderoy]

Yeah looks like it's in the tank...

http://www.4wd.com/images/hard-parts/XJ_Fuel.jpg

Well maybe ON top of the tank.

[4.3LXJ]

Tony, I believe on the 98 you have to drop the tank and pull the sending unit which is in the top. Somebody on Cherokee Talk found a pressure regulator seperate for not much money.

On the bright side, I can speculate you may have found your milage problem. Insufficient fuel pressure.

[Mudderoy]

Tony, I believe on the 98 you have to drop the tank and pull the sending unit which is in the top. Somebody on Cherokee Talk found a pressure regulator seperate for not much money.

On the bright side, I can speculate you may have found your milage problem. Insufficient fuel pressure.

I was hopeful for that as well, but it is running 49.5 psi when the engine is running. Plus O2 OBDII data is showing it is running rich, well according to have I've been told. I guess it doesn't matter really, there IS a problem with the fuel delivery system and fixing it shouldn't hurt the mpg...

[Mudderoy]

Ok guys help me decide...

SPECTRA PREMIUM Part # SP7121M More Info Includes Fuel Pump, Sender, Float, Strainer and Fuel Reservoir $126.79

AIRTEX Part # E7121MN In Tank Fuel Pump Assy-Module $152.79

http://info.rockauto.com/getimage/getimage.php?imageurl=http%3A%2F%2Finfo.rockauto.c om%2FAirtex%2FE7121MN-1.jpg&imagekey=1063693-0&width=450
:link: (http://www.rockauto.com/catalog/moreinfo.php?pk=1063693)

CARTER Part # P75040M Fuel Pump Module Assembly $208.79

BOSCH Part # 67658 Fuel Pump Module Assembly $316.79

OMIX-ADA Part # 1770919 $374.99

[Mudderoy]

Or perhaps a better choice?

[Mudderoy]

The problem could very well be the combination Fuel Filter/Fuel Pressure Regulator. At 52,000 miles the filter is due for replacing and since the fuel pressure regulator is part of the filter, replaing it should take care of the problem. At this point it isn't very likely the fuel pump is a problem.

:link: (http://autorepair.about.com/library/a/1i/bl487i.htm)

So it looks like a fuel pressure regulator is about $70 to $95 and a pump etc... is $200. Plus I'll still have to drop the tank to replace the regulator...

Since the pump is putting out 49.5 psi at idle I'm thinking the pump is working fine. What to do...

[4.3LXJ]

I guess one of the factors I would consider is who made them. You usually cannot go wrong with Bosch, but it is twice as much. I have also had good luck with carter fuel pumps

[4.3LXJ]

:link: (http://autorepair.about.com/library/a/1i/bl487i.htm)

So it looks like a fuel pressure regulator is about $70 to $95 and a pump etc... is $200. Plus I'll still have to drop the tank to replace the regulator...

Since the pump is putting out 49.5 psi at idle I'm thinking the pump is working fine. What to do...

Personally I would just get the regulator. It seems to be what fails in these assemblies.

[Mudderoy]

Personally I would just get the regulator. It seems to be what fails in these assemblies.

I'm thinking that way now that I went out and tested the 1999, and it does the same thing, just not as bad. The bright side is the 1999 doesn't have a skid on the tank :S :bang:

[Mudderoy]

I'll need to do more testing, but this morning I did the 3 on/off key and then on the third off I went directly to start. Started right up and I didn't have the slight miss that lasts about 5 to 10 seconds.

[4.3LXJ]

It is just taking that long to develop sufficient pressure.

[Mudderoy]

Part of the problem was the OEM starter was dragging. Replaced and now it spins really quick. Still takes two tries to start, but the fuel regulator will probably resolve that.

[pvt.tadpolxj]

Hey Muddy...I know you people have not heard from me in a while but I do check in from time to time...I want to say something in responce to this thread. I have been dealing with my 91 XJ for a couple years now and I still have a starting issue. But I should let you know I still drive this Jeep every day. As long as it start's it will go anywhere!...I have 2 theories...On my 91 I am eithier loosing fuel pressure as it sit's as many Jeeper's have said or Since these motor's have a preset timing once the valve train get's so many mile's on them you start losing the truness of your timing set. If I remember correctly this could mean it is getting a little retarded...I hope this will be a little food for thought....:sniper:

[Mudderoy]

This problem was SOLVED by replacing the fuel pump, filter, pressure regulator assymbly. I replaced it with a unit from the Chrysler dealership!

I found that the fuel pressure would drop from normal (45?) to 0 in about 15 seconds! Running the fuel pressure was good. So I think the fuel pump was fine and the fuel pressure regulator was bad.

I've had the new unit installed now for about a month and it cranks first time every time! Kudos to those of you that said it was the fuel pressure regulator from the beginning. I didn't want to believe you because of the expense and difficulty in changing the part. It wasn't that difficult to change, I just had never done it before. :D

[TeXJ]

Thats cool!

[Mudderoy]

I will add that my 170k mile starter was dragging prior to it going out and a new starter turned the engine over much more quickly.

Also I purchased a bunch of sensors at the same time as the fuel pump assembly. I replaced the CPS just prior to the fuel pump assy. The old CPS wasn't bad it was just very old.

I'm sure many of the things I have done improved the starting but I firmly believe it was the fuel pump assembly that fixed it.

[jeepxj95]

now ??? for the renix guys. is that why they take so long or are they just a slow starting set up???? my 95 takes a few secs but the 90 is like 10 secs.... hummm

[4.3LXJ]

The Renix needs three full cranks, plus proper fuel pressure before the ECM will allow the engine to start.

[jeepxj95]

thanks 4.3LXJ so what about the 95??? i know when i get the starter rebuilt will help and new cable to the starter. good fuel pressure and holds unlike tonys did. what else is there???

[4.3LXJ]

I always leave the key on for 2 seconds then start. Insures good fuel pressure. But you need to have good cranking that does not draw on the battery too much. What does your voltage look like when cranking?

[jeepxj95]

when it was on the scan tool last week in class. it was around 9.2 or so and thats when it would engage. its toast. i leave the key alone untill i cant hear the fuel pump run or until the seat buzzer stops

[4.3LXJ]

Your cranking voltage should be higher than that. Below 10 volts some ECMs will not work because they will not give sufficient voltage to controls and sensors to function. You might want to consider a new battery.

[jeepxj95]

its 6 months old. is usally takes 3-6 trys be4 the starter will grad the flex plate. guess we'll see after i get my check from school if it lasts that long.