Hard to start, then runs fine.

[PhotoDoctor]

I have a 1994 Cherokee 4.0 that has trouble starting but once started runs fine.

So far I have new plugs, wires, rotor button, and cap. The spark is fine. Next I have tried the key to prime the system in-case of a bad fuel pressure valve as in turning the key to the run position hold 3 seconds and repeat 4 times. The hard starting remained the same.

Any thoughts on where to go from here? Cam senors test? (I've not read up on how to test but thought I would check for some help from long time owners here to get some thoughts on what to check next)

Thanks for any thoughts in advance.

[Mudderoy]

I have a 1994 Cherokee 4.0 that has trouble starting but once started runs fine.

So far I have new plugs, wires, rotor button, and cap. The spark is fine. Next I have tried the key to prime the system in-case of a bad fuel pressure valve as in turning the key to the run position hold 3 seconds and repeat 4 times. The hard starting remained the same.

Any thoughts on where to go from here? Cam senors test? (I've not read up on how to test but thought I would check for some help from long time owners here to get some thoughts on what to check next)

Thanks for any thoughts in advance.

Try disconnecting and then reconnecting the CPS and see if that makes any difference. Does it matter if the engine has been running or not?

[4.3LXJ]

Might want to check the fuel pressure while starting. Borrow a gauge if you don't have one

[PhotoDoctor]

It does not matter if it's hot or cold - although in Tampa, FL during June it will never be Cold!

I unplugged and sprayed some contact cleaner in the CPS connection. It started on the 2nd try.......I'll know in a day or two if that is the cure!

Thanks - I'll keep you posted.

[PhotoDoctor]

MuddeRoy - It does not matter if the engine has been running or not. I can drive it then shut the motor off and it's still hard to restart. I will give it a day or so to see if unplugging the CPS and cleaning helps. Thanks for the tip.

4.3 LXJ - I lined up the pressure gauge as the next step.

[msmoorenburg]

MuddeRoy - It does not matter if the engine has been running or not. I can drive it then shut the motor off and it's still hard to restart. I will give it a day or so to see if unplugging the CPS and cleaning helps. Thanks for the tip.

4.3 LXJ - I lined up the pressure gauge as the next step.

give this a go, turn the key to the on position and listen for the pump to start then stop then turn the key off and back on again when the pump stops (you should hear it load up by this time) try and start it and see if it kicks off first try.

[PhotoDoctor]

So far I've yet to hear the fuel pump run. The jeep is new to me so I don't have a history of being able to hear the fuel pump in the past. (I've put only 500 miles on it, I bought it a few months ago from a friend and drove it 200 miles home without this starting problem. Then I let it mostly sit for two months while I did a dyi paint job. The starting issue is new)

I'll continue to listen maybe from the outside via having a friend turn the key. Although once it starts it runs fine.

[PhotoDoctor]

I checked the fuel pressure and sure enough it bleeds down to zero in about 20 minutes.

[msmoorenburg]

I checked the fuel pressure and sure enough it bleeds down to zero in about 20 minutes.

Looking up testing specs in Alldata they state this

http://i1135.photobucket.com/albums/m639/sellitx/fpwarning_zps4d95e176.jpg (http://s1135.photobucket.com/user/sellitx/media/fpwarning_zps4d95e176.jpg.html)

[ArmyGuy45]

Starter....

[Mudderoy]

I checked the fuel pressure and sure enough it bleeds down to zero in about 20 minutes.

Mine would bleed down to 0 in about 15 seconds. Took 2 or 3 cranks to start, but that took less that maybe 10 seconds. In other words normal crank time, stop, try again, start.

I bet you have a CPS going out.

[Mudderoy]

Starter....

Yeah I had a started problem about the same time as well, but my resolution was the fuel pump assembly that goes in the fuel tank on the 97+ models.

[PhotoDoctor]

Since the jeep will still start - via turning key to run position a few times then all the way to start position - I think I'll do the fuel pressure test again with another gauge before I start replacing parts.

The starting is much better now that I know about priming the system via key on and off. Thus one more test and I'll move forward with parts and see what happens.

Thanks and I'll follow up with the next results.

[Mudderoy]

http://youtu.be/pr2UzpS71HA

[bigmike441]

check the voltage to the fuel pump, make sure its the proper one for that year, figure out the proper pressure then get one just a lb or 2 higher see if it helps, it sounds like it is loosing pressure fast and not building fast enough

[silver_xj]

I was having hard start problems before my starter went out. My fuel pressure was fine and the XJ had new plugs. The prime method works well for me, even with the new starter.

[PhotoDoctor]

Oddly, while I have not made any repairs, the jeep is now starting fine. So, I have a rehab project on a house that is getting all my time. As long as the jeep starts fine ....... we shall see if it continues to do so.....


Thanks - I'll update the results.

[JeepFreak]

You may want to try something simple such as the fuel FILTER lol if that is plugged up then it might take a few tries to get the gas to reach the engine. Try replacing it and see if that helps and you'll know if it's clogged (full) because the weight of it will feel quite heavier than the new one coming straight from the box. If this doesn't solve it then try replacing the pump as that may be going bad.

[PhotoDoctor]

I installed a fuel pressure gauge on the fuel injector rail per the instructional article. The fuel pressure is about 30 psi and bleeds down to zero in about 30 minutes. I also pulled the fuel relay and swapped it with the AC relay – now every time I turn the key I do hear the fuel pump kick in and the jeep starts and runs fine. (I should replace the fuel pump but it starts every time)
However, a more pressing problem is the jeep is running hot on longer runs of 30 miles or more. (The jeep is not my daily driver but do want to get it all sorted)

[JeepFreak]

I installed a fuel pressure gauge on the fuel injector rail per the instructional article. The fuel pressure is about 30 psi and bleeds down to zero in about 30 minutes. I also pulled the fuel relay and swapped it with the AC relay – now every time I turn the key I do hear the fuel pump kick in and the jeep starts and runs fine. (I should replace the fuel pump but it starts every time)
However, a more pressing problem is the jeep is running hot on longer runs of 30 miles or more. (The jeep is not my daily driver but do want to get it all sorted)

About how hot is it running? Mine usually ran just under the middle tick mark which is about 210 degrees for me. It slowly started creeping higher and higher over the last few months and I thought "Eh I'm replacing it soon anyway" so I didn't think much of it. Well last week my poor XJ blew her radiator. If it's having a problem with overheating I would suggest having a look at the water pump and the radiator itself for defects. Check the hoses as well. If there's a bulge, crack, tear, or squishiness in any of the hoses, you need to have them replaced. If there's anything odd looking about your coolant then you need to have that looked at as well. Unfortunately I didn't have the money to replace my radiator until this week (go figure) so it's now gonna cost me more money than it would if I had just been able to do it a week ago. My suggestion is not to wait. Figure out what's wrong and nip it in the bud before it gets to be a problem.

[4x4Dalton]

Try flushing the system out. May be something floating round somewhere that sooner or later blocks a line or hose. Plus check yer thermo and like said before water pump.