Hey DF pals!

Still trying to diagnose this van after some time now. Runs rich, fuel trims leaning out, fumey, rough idle, misfires... I swear this one is possessed!

A new development in the caper:

Recently it has been stalling on sudden acceleration and when I just let it warm up it will stall out of nowhere at idle. I'm hoping this symptom can lead me to a solution finally.

I'm finding fuel pressure has become much shakier at idle, fluctuating between 35-55 at idle now, BUT is a steady 49 psi with throttle. (Previously it only fluctuated +/- 2psi at idle)

I'm thinking either
- a bad fuel regulator, filter, pump, or FP wiring issue
and/or
- fuel injector(s) stuck open or wiring (ground to ground).

First impressions? Thoughts? What would you test next?

Cheers y'all!

 

Should have constant 49 psi. Try it with out starting, Turn the key to on and let the pump prime the system. It should go up 49 psi and slowly drop over time. If it drops fast it's probably a stuck injector.

 

It definitely primes and holds pressure well with KOEO. The fluctuating fuel pressure problem is only when idling.
Stalling never happens mid throttle, only randomly during idle when warmed up, or at throttle off idle. The engine always starts right back up.

 

Another member had this issue, and it was the battery temp sensor causing the problem........

 

Thanks for chiming in! It seems this would throw a code but, Chrysler...

I wonder how this could cause the issues I'm having. Any theories? 5v ref circuit gets shorted causing computer shutdown?

Does anyone know how to best test the sensor and circuit or what resistance should measure on a 50 degree day?
I guess I'll check it out and start w some wiggle tests for short to ground.

 

Have you checked the fuel trims? Whaada they read? How about the intake air temp? Do you use mass air flow or map sensor? I'd start with unplugging the front O2 sensor/s n see if there's any difference.

 

Whoops, yeah, just saw fuel trim checked. What are they reading % AND voltage wise?

 

Thanks, yeah, trims are not the best. Leaning out heavy but not as bad as it once was after all sorts of improvements. I was going to bring this up in a separate thread, but here ya go:
LTFT ends up -10 to -15
STFT +/-3 once LT steadies there
IAT gets up to 150's
ECT at 195 at idle (195 thermostat installed)

My biggest concern now, other than the stalling and rough idle and rich condition is the condition of the cat as 02's are showing me something new, likely due to running with a misfires for a while.
Upstream oscillates like you'd expect but downstream is fixed rich (0.8-0.9V) when idling at around 0.86V
Here's the thing, downstream goes to fixed lean (less than 0.1V) with throttle.
The stalling may be due to a clogged cat but I need to know if this is behavior of a clogged cat, a bad cat, or good cat.


This starts off with idle and ends with acceleration. What does the downstream behavior say about the cat?

 

I just pulled the battery temp sensor and the circuit to pcm and sensor ground test good.
The sensor itself shows resistance and drops with temperature, though I'm unsure what kind of resistance the PCM is looking for.
Unless there's an intermittent ground issue, I don't know what else to test there.

 

Can you rev it almost to red line idling?