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-   -   Yet Another ZJ Stall Problems Post - 5.2 V8 (http://www.jeepforum.com/forum/f13/yet-another-zj-stall-problems-post-5-2-v8-1599409/)

Tully Mars 09-18-2013 12:32 PM

Yet Another ZJ Stall Problems Post - 5.2 V8
 
Hello All,
I have a 94 Grand Cherokee Limited with 5.2 V8 - 185K miles
My saga started about 3 months ago or so when I failed the CA emissions. EVAP system leak and some emission out of spec at idle.
It had been running like sh*% for a few months and I pretty much knew it was probably a clogged cat. Converter.
It had not been a high priority to get it back on the road cause I have other vehicles. Anyway decided to drive to Colo. And have it there.
Got the cat. Replaced as it was indeed clogged. Ran much much better. But it had overheated a couple times and threw a 32 EGR CEL. The EGR was indeed cooked as a result of the cat I had overheated a couple of times. Replaced the EGR (Delphi ) which got rid of the CEL but then I had no fuel pump / stall / no start / no CEL at startup etc. Just like so many threads here.
So here is what I have done:
The 12 Things – ZeeJay’s great post.
#1- The Brain Replaced the Caps and cleaned the contacts. All seems well. Jiggling the harness does not affect anything as far I can tell
#2 – Grounds - Cleaned up the ground conx on the block by the Coil and on the fender near the battery. Is there a third one on the 5.2?
#3 – PDC - Replace the Relay for the Fuel pump. Everything else seems fine. No blown fuses. But I have not taken it apart.
#4 Battery and Cables - 12.46 volts on the battery not running. And 13.85V at idle 500-600 RPM) The battery is less than a year old. Contacts at posts are clean. Cables… are old but I don’t see a voltage problem so….?
#5 Fuel Quality - No Idea. Ran some Lucas last tank full. Don’t thin this is it. I usually buy ARCO here in CA.. I ran this guy in Mexico for 3 years and never had a problem with PEMEX. Fuel Filter is new this summer.
#6 Fuel Pressure - Borrowed the gauge from Autozone. Right on 32 PSI at idle. I am on my third fuel pump so I suspect it from the beginning but it seems to run fine until the stall. And when it stalled at idle, a could here it run for few seconds AFTER the stall.
#7 Ignition - Have not done this yet. I know I have at least 30K on this tune up. Pulled a couple of plugs and they looked okay. The car runs pretty good before the stall so I really don’t think this is causing the stall.
#8 Connections – Have not looked at every connection. But I have been diligent with everything that I have taken apart and reconnected.
Coil wire? Probably should take a look at this.
#9 Wiring – God knows I have moved harness wiring around a lot in the last couple of weeks. I am not sure about this one.
#10 Throttle Body - I have cleaned the TB and IAC. Throttle body only from the top. I guess I should take it off and do the whole deal.
#11 Vacuum Leaks - Have not spent too much time on this one. I do have a mityvac so I need to learn how to use it to check for leaks. I am sure there is write here on that one. I have only used mine to bleed hydraulic systems.
#12 Restricted Exhaust - Resolved. New cat and muffler only a year old.
What else have I done?
New Crankshaft sensor - Had to use a BWD because Mopar is on back order nationwide according to my local Jeep dealer.
New Throttle Position Sensor
New NTK O2 Sensor - What a pain to change this.
So my current status is that it starts and idles okay. After replacing the 02 sensor on Sat. I ran it at idle for 15 minutes and had no big problems. I rev it up and seems to run fine. When I let up on the gas the RPM goes way down to almost stall and then comes back to about 400 plus/minus rpm. Turn it off and starts back up fine. Usually it does. Stalled a few blocks away and I could not get it started. Fuel Pump was not priming and CEL not coming on with key. But, I came back the next morning and started at a few ons and offs with the key,
Now when I test drive, I immediately get CEL after going forward for just a little way. Reverse seems no problem. The code is 32 – EGR.
I am going to do the following:
Fully clean and check the PDC
Take off the throttle body and Clean.
Check for leaks in Vacuum System
New plugs, wires, dist. Cap, rotor
So, what should I do first?

Oldfrog 09-18-2013 01:39 PM

If it were a 4.0.....I'd say "Sounds like a PCM to me. It's time."
But I dont know your engine well enough to say it with conviction.

dusterdude 09-18-2013 03:40 PM

Its the bwd crank sensor,try factoryparts.com(i think) they're in new york(i think)thats where i got mine,65 bucks

Tully Mars 12-11-2013 10:00 AM

Hmmm. I don't really think it is the BWD Crank Sensor. The one I pulled out was a BWD and it was fine for many miles and many years.

WJ4x4LIFE 12-11-2013 12:14 PM

Sounds like an "open loop" stuck issue, I read that you replaced a 02 sensor. Which one, upstream or downstream?

Tully Mars 12-11-2013 03:08 PM

Hi Omar.
The 94 5.2 V8 only has one O2 sensor. Upstream of the cat. Open loop? Meaning when the o2 sensor heats up.. it does not cause the "Brain" to adjust the fuel mixture?

WJ4x4LIFE 12-11-2013 04:02 PM

Quote:

Originally Posted by Tully Mars (Post 18451666)
Hi Omar.
The 94 5.2 V8 only has one O2 sensor. Upstream of the cat. Open loop? Meaning when the o2 sensor heats up.. it does not cause the "Brain" to adjust the fuel mixture?



Oh, gotta ya on the 02 sensor. The 32 DTC shows a EGR issue and/or Air/fuel ratio issue as well, that is WHY I stated that. Besides the tell sign of issues when you move forward and get a CEL and at start-up when "cold."

The upstream or in this case the only 1 o2 sensor, adjusts the mixture, but if any issues may arise the computer may thrown up a code.

Rich93ZJ 12-12-2013 04:51 AM

Quote:

Originally Posted by Tully Mars (Post 16115713)
Now when I test drive, I immediately get CEL after going forward for just a little way. Reverse seems no problem. The code is 32 – EGR.
I am going to do the following:
Fully clean and check the PDC
Take off the throttle body and Clean.
Check for leaks in Vacuum System
New plugs, wires, dist. Cap, rotor
So, what should I do first?

Why not check out the EGR system first? :idea:

Tully Mars 12-21-2013 10:20 AM

Hello All,
In response to 1993ZJ, I have a new EGR Valve. So… do you think it is vacuum related?

I now have new plugs, wires, rotor.
Have cleaned the TB and IAC completely.
Cleaned up and replaced battery cables.
Replaced the vacuum lines coming off the Throttle body.
Cleaned all connections at the PDC. All the fuses etc.

Still stalling on me.

Threw up my hands and opened my wallet and took it down to a recommended mechanic. He has been going through all of my handiwork this week. Finally decided it had to be the Brain. The Powertrain control Module. Okay… stuck a rebuilt one in (Cardone) and he said it was running great.
Wrong… It stalled a couple times on way out of the parking lot. I was able to restart it and take it back to the garage… After starting, dying, restarting several times… it would not longer start. No spark to plugs.

So, we are now thinking it is the alternator. And/or the battery. The battery is actually 2 years 3 months old. He says that it is not charging adequately at idle speeds…. which is different form my voltage test.

But he has found that there is a intermittent short at the ignition switch. ? So he replacing that and the alternator right now. And we shall see….


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