Won't start on 1st crank

[eastcoastclimber]

Hello Everyone,

Hoping some of you guys can help me figure out my starting issue. She's a 98 4.0, auto. I bought this XJ about 4 months ago. It always starts but would have to mess with Shifter in park position so I removed/cleaned NSS also fuel gauge didn't work consistently, so I replaced fuel pump and found the old filter inside the bottom of the tank. Fuel gauge works now and NSS looks like new. I also removed injectors and gave them a good cleaning, cleaned IAC and TB, new plugs, wires, coil. Also cleaned/re-greased starter as well as all wires to/from battery/coil.

It did throw a code po455, but engine light has been off for some time now. Vacuum lines up top look good. It did come on when I unhooked my CPS, which I still think could be the problem, but other than that CEL has been off. It will start right up when its hot, but cold will need a good 3 sec crank than let off key then crank again and it fires up. I checked fuel pressure at the rail and it read 10 psi on first prime, and 30 psi on second prime and idled at steady 50psi. After shutting off engine it died down to 10psi within 3 seconds and then slowly drained to about 5psi within 5 secs after shutting off engine.

Not sure if this is fuel related, or could be old/worn Crank Pos Sensor which I've been reading alot of threads about. But it never stalls, and always starts. No CEL currently on. It does idle a little rough, but tach doesn't dip down. Just has this slight shutter every 3 seconds. Acceleration is good.

Thanks,
ECC

[NW99XJ]

The regular oscillating "shutter" leads me to believe it's something in the distributor maybe. Could POTENTIALLY even be the crankshaft position sensor (or whatever one is in the bottom of the dist.)
Cam position sensor could lead to similar symptoms i suppose, but usually those things just go out, and dont give you wonky issues before they do (in my experience)
With as many fuel issues as you've had, i'm wondering if it aint something there...
The po455 code is Evap control.
FROM www.OBDCODES.COM:
"This indicates a fuel vapor leak or lack of purge flow in the EVAP control system. It means a large leak has been detected. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine."

A code p0455 most likely means one or more of the following has happened: A loose or improperly affixed gas cap A non-conforming gas cap (i.e. not factory/original brand) Other leak or damaged piece in EVAP system...

Having mentioned you replaced the fuel pump makes me think of all the "new artex fuel pumps gone bad" threads i've read over the years... but then your fuel pressure readings are right where they need to be (IIRC)

SOME of the symptoms you're mentioning make me think of leaky injectors... not necessarily the injector itself, but maybe one of the o-rings that's supposed to seal them.

[eastcoastclimber]

Is there anyway to test the distributor? All points looked clean, but I did not replace. I know the camshaft position sensor is located under the dist. I believe it can be adjusted, not positive tho.

It's strange because I don't notice any issues at all while accelerating. Just cranking the engine over.

Anyway to test injectors to see if they are leaking?

[cpttuna]

check valve bad?

[eastcoastclimber]

sounds like it could be a bad check valve or possibly a leaky injector. When engine shuts off I immediately start heading towards 10psi then under 10psi way before 30 seconds.

Is there a way to replace check valve, which im assuming is in the tank?

[XJ Wheeler]

Mine has taken a few revs to crank when cold since i got it over ten years ago. Does fine after its been driven and start up warm though. Personally, i've considered it being a slow starter. But mine has never given me much problem.

The way you can test for a bad check valve is to prime the fuel system by turning the key to the "On" position and back a couple times then crank. If its fires right up, you know your problem. Mine didn't, that's why i don't suspect it on mine. And since it has done it for so long and so consistent i don't think its something failing or after ten years it would have been toast.

Sent via messenger pigeon - i talk, he types.

[JeepFreak]

The testing you're seeing on the PSI gauge is known in the auto industry as a "leak down" test. Leak down happens when an injector or multiple injectors or the fuel pressure regulator have gone bad or are leaking. Your pressure shouldn't drop that quickly and certainly not that much. First thing that gets me is it drops so fast. Your fuel pressure regulator may be bad. If it is it will cycle backwards through gas tank pressure back into the gas tank and drain your fuel lines to the engine. The rest of the pressure beyond the regulator would be leak down from a leaking injector or injectors. Most injectors can be cleaned with a simple Lucas injector cleaner in one tank. Fuel regulator can be replaced fairly easily. Just be sure to remove the gas pressure.

[eastcoastclimber]

Pulled fuel rail out today and primed jeep, didn't see any leaks coming from injectors. 1 clip looked out of place on one injector, which accidentally made injector pop out of the rail. Fuel went everywhere, but now I know the rail is gunk free. It did seem to start easier when I got it back together. I will check pressure again and see if I can clamp the fuel line to verify bad regulator.