anomaly on the Jeep + reward

D

dabeersboys

NAXJA Forum User
Location
Colorado Springs
My girlfriend bought an 87 pioneer 4.0 4x4. I can't figure out the problem. I've tested every thing and nearly replaced everything.
What it is doing:
While driving it will buck, and jolt. and some times on turns Dies... It just shuts off and most of the time starts right back up. It doesn't matter if it is hot or cold.
I've done grounds, replaced sensors, and I don't know what to do... Faricy said the TPS wasn't adjusted and fixed it. didn't work came in again and said it was unsafe to drive because a pop in the steering (that was there on the first visit)
My girl friend is misruable not having a vehicle and going to school which is brought down on me making me misruable. and I can't figure the thing out!
If some one in the springs wants to take a look and make an opinion, That would e great.
I don' really have the money but who ever can give me the opinion that fixes our problem I'll give them 100 bucks.

What Ive done
replaced coil, tps (and Adjusted), cps, tightened exhaust, fixed any bad grounds, tested, tested and tested....
I'm going to replace the computer next i think...
Please I need to get this fixed.
Were on the verge of selling it... and we both don't want to at all!!!
-Matt
 
I'm betting on fuel as well. Fuel filter may need replacing, fuel pump may be going bad, in-tank fuel filter may have deteriorated, injectors may be clogged, etc.
 
Replaced fuel filter, I was thinking pump as well but I've never heard of a pump slowly going bad. And I don't want it to be the pump cause shes been telling me that the whole time...
It Idles beautifully, but when you drive it problems arise... I can bring the idle up and down with throtle and no problems... I've checked fuel pressure also and it checks perfectally.
 
Sometimes a low fuel level can cause an aging pump to overheat. Does it seem to run better with 1/2 a tank or more?

On my 96, it would hesitate and buck going up hills at part throttle. After 2+ years of off and on trouble shooting, I traced it to a corroded wire on the fuel pump.
 
A friend just went through a lot of trouble shooting for an ignition module that bench tested just fine. He and his wife were looking for the socket to plug in a stick of dynamite when I asked how the auto parts "tested" the module. What she described didn't sound anything like an engine bay under full electrical load.

He lives in Aurora, so he hit the Pull-N-Save. They had a few RENIX rigs to that probably ran great when they crashed. One more used part presto-chango gave them a running Heep again. They might still have that dynamite. LOL
 
I'm gonna also go with a fuel delivery problem. The fuel pressure regulator is vacuum activated. At idle and when in Park or neutral, the vacuum is stable. Put it into gear and/or under a load and vacuum can be very finicky. Ensure ALL vacuum lines are pliable, seal tight to the connections, etc. The fuel pressure regulator - IIRC - connects directly to manifold vacuum but may have some sort of thermo valve in line.

Take a fresh length of vac. line and connect it directly between the manifold and the regulator. Drive it and see if that cures the problem.

If not, then I'm thinking that the fuel pump is going bad. I've had them go out all at once, and I've had them run for long periods of time with fluctuating pressure.
 
Israel said:
in-tank fuel filter...
Click to expand...

My guess too.

It's actually called a strainer and is attached to the bottom of the pump. Take out the pump and replace the strainer.

Note: if the strainer is missing or clogged up, it may have damaged the pump itself.

.
 
If you can get it up here to Loveland, I will diagnose it for you no charge. I have a knack for these PIA problems. I even have a spare fuel pump we can swap in if need be.
 
I had the same issue and it ended up that the harness connector on the firewall next to the brake booster. I was not getting a good connection, you might take it off and put some dielectric grease in there and see if that helps.
 
xjnik said:
I had the same issue and it ended up that the harness connector on the firewall next to the brake booster. I was not getting a good connection, you might take it off and put some dielectric grease in there and see if that helps.
Click to expand...

X2 on the bulkhead connector at the firewall. Not saying it's YOUR problem, but a very problematic area.

Just out of curiosity what spark plugs are in it? Brand?
 
Check the firewall connector and the fuel pump. I'd definately be willing to be its the pump. Do you here a high-pitched whining coming from the tank?

Also, check out ALL your vacuum lines. Bad vacuum lines are one of the biggest problems with engine power/performance on older vehicles.
 
Not sure on plugs... We'll be trying all that this weekend. Thanks guys and I'll let you know our findings....
If any body else has any ideas let me know...
Thanks.

OldMan, Thanks for the offer but no way in hell it would make it to Loveland. We've tried to get it to denver and it was a long bumpy ride resulting in needing a tow back to the springs...
 
dabeersboys said:
Not sure on plugs... We'll be trying all that this weekend....
Click to expand...

What are you planning on installing for spark plugs? If it's got Bosch Platinum's in it, they could be causing problems like you're describing. Put standard Champion plugs in it.

J
 
Frank Z said:
Huh? I'm running Bosch Pltinum IV's and have never experienced any problems as a result. Care to go into detail on this?
Click to expand...

And according to your profile, your XJ is a '97, so they wouldn't be a problem. The Bosch Platinum incompatibility issue is ONLY an issue in Renix equipped 4.0's (1987-1990 model years).

J
 
Frank Z said:
Link?
Click to expand...

I found this one here real quick:
http://www.naxja.org/forum/showthread.php?t=26322&highlight=bosch+platinum+renix

It's not much, but I know it's been covered more in depth in the past. This also comes from my personal experience as an independent repair shop owner for 11+ years and LOTS of Jeep experience. It just has something to do /w the Renix ignition system and the Bosch plat. plugs, they don't get along well together. I've seen it numerous times on customers vehicles here, although it doesn't cause driveability issues in ALL renix rigs.

John
 
Ok so it won't be next week. I can't get the fuel pump and sending unit until next friday. And i leave for chicago next friday.. So it will have to wait... But I'll keep you guys updated.
 
I think it is the vss on the tranny just above the tcase shifter linkage
just my 2cents worth
 
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