Dead in the lot.. fuel pump?

Hood297 · **Posted:** Mon Oct 17, 2011 11:10 am

Hey guys, Been a while since I've posted up on LOST, been a busy time in my life. Well now I am in need of some knowledge on the subject.

Cranked up this morning just fine, just like every morning, no hesitation, no issues. Made the 10 mile drive to the gas station to get a cokem, come back out and Crank-crank-crank-crank-crank. No fire. Sounds like one or two cylinders MAY be firing occasionally. not enough to get er going though. Hooked up the code reader, nothing. Thought the timing chain may have jumped or something but, No codes/DTC's. according to the guage, I have over a 1/2 tank, and my odometer reflects that. about 100 miles on my typical 220-230 miles to a tank. bled fuel rail and did get some air out of it, hooked up a fuel injector cleaner with some fuel and it tried to crank more than it did before. think I may try and put some gas in it, to see if the pickup has a pinhole in it.

Any ideas?

climber12 · **Joined:** Fri Oct 14, 2011 9:05 pm **Posts:** 5

In my experience, this is typically how the fuel pump dies. Everything will be running fine, and then all of a sudden the car will die. I had this happen while trying to climb an incline once. Generally, it's a pretty easy fix, but there aren't many other factors that could cause this that you haven't already eliminated. Has anyone used Angie's List for finding a mechanic? It might be time to get a deeper inspection if you find this to untrue.

Hood297 · **Posted:** Tue Oct 18, 2011 6:53 pm

Well last night i pulled the valve covers and timing chain was intact, unless it jumped somehow and screwed up the timing. Does anyone know what the fuel pressure at the rail is supposed to be? I had about 50ish psi. I pulled the rear cargo area out and took the inspection plate off, which was a royal PAIN ( the cake on about a 1/2" of some kind of bedliner type stuff, and opened up the tank and it all looked perfect. Took off the lines from pump to plate and it pumped away just like normal. Tank didnt have a bit of dirt and was over 1/2 full, pickup strainer looked great too. Very very lost on this one.

tjkj2002 · **Posted:** Tue Oct 18, 2011 7:47 pm

Your pump is fine with 50psi.

If you had a scope you could check the crank and cam sensors,one or the other is most likely your issue.If you have a scanner that shows some live data hook it up and crank the engine over while looking at the engine rpm's,if it shows 0 rpm's while your cranking I would be suspecting the crank sensor.

TheJawsOfDeath · **Joined:** Sun Nov 05, 2006 3:56 am **Posts:** 305

I just checked alldata, and depending how your jeep is equipped it should be between 50 and 60psi. Do you have spark?

tjkj2002 · **Posted:** Tue Oct 18, 2011 7:57 pm

TheJawsOfDeath wrote:

I just checked alldata, and depending how your jeep is equipped it should be between 50 and 60psi. Do you have spark?

From the FSM the correct fuel pressure for the 3.7 is 49.2psi +/- 5psi for all years,this only applies to the 3.7.

TheJawsOfDeath · **Joined:** Sun Nov 05, 2006 3:56 am **Posts:** 305

tjkj2002 wrote:

TheJawsOfDeath wrote:

I just checked alldata, and depending how your jeep is equipped it should be between 50 and 60psi. Do you have spark?

From the FSM the correct fuel pressure for the 3.7 is 49.2psi +/- 5psi for all years,this only applies to the 3.7.

I was kind of paraphrasing. What alldata literally says is:

If equipped with JTEC Powertrain Control Module using 3 electrical connectors: 339 kPa ±34 kPa (49.2 psi ±2 psi)
If equipped with NGC Powertrain Control Module using 4 electrical connectors: 400 kPa ±34 kPa (58 psi ±5 psi)

So if the factory manual says it's the first one, it seems like their second spec is for the 4 cylinder.

Hood297 · **Posted:** Tue Oct 18, 2011 9:15 pm

Not sure if i have spark. Tried to crank it a few times with the scanner hooked up and unhOoked to try and get a code out of it. If i give it a little pedal it will run, just terribly rough. When
I checked the pressure at the rail it did seem to have some air in it, but im not positive. I wouldve expected a sensor failure to show up on the DTC, no scanner said np saved or active dtc's were shown. Even enhanced dtc's there was nothing showin up.

tjkj2002 · **Posted:** Tue Oct 18, 2011 9:20 pm

Hood297 wrote:

Not sure if i have spark. Tried to crank it a few times with the scanner hooked up and unhOoked to try and get a code out of it. If i give it a little pedal it will run, just terribly rough. When
I checked the pressure at the rail it did seem to have some air in it, but im not positive. I wouldve expected a sensor failure to show up on the DTC, no scanner said np saved or active dtc's were shown. Even enhanced dtc's there was nothing showin up.

Generally the PCM will not store codes or even monitor sensors(for failures) when cranking as that is a very high amp draw period.If it was a intermittent issue or failed while the engine was running a DTC would be set in most cases.

No crank signal equals no spark or very eratic spark.

Liberty02sport · **Posted:** Sun Oct 23, 2011 2:02 am

Have you ran a compression check yet ?? Mine was doing somehting similar and it wound up that ti had dropped a valve seat on cyl #6. Showed no codes, did the same thing it sounds like yours is doing ...I stopped to put in some gas and when I started it back up it ran rough for about a fraction of a second and died. took it to stealership and was told bad PCM, so replaced PCM and still somehtig wasn't right so tey pulled the valve cover and lifter was froze as well as a rocker arm being off. They ran a compression check for that cylinder and it wasn't holding.....

This will be the third motor going into this '02. Any more problems and this thing is gone, I've never had any car I ever owned give me this level of problems. Best of luck with yours.

Dead in the lot.. fuel pump?

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