- This topic has 9 replies, 2 voices, and was last updated 5 years, 3 months ago by
.
-
Posts
-
Hi all, 99 wj that has been having stalling problems. I’ve been testing pretty much everything and I’ve got it down to a reproduceable symptom.
I’ll start it in my driveway and it runs good, sitting in park, can redline it, whatever, runs good. Put in reverse and “roll” a cars length down my slightly declined driveway and it sputters. Stop, put into 1st, (automatic) and let off brake and roll forward down street (very slightly decline). As soon as it starts “moving” it starts to sputter. Put on brakes, comes back. Reverse back to driveway same symptoms, put into 1st and let idle hold position on incline and it sits, in gear, motionless, no issues, slight gas to move, sputters…
Cannot wait to get this solved.
Thanks to anyone who can help!
Jeff
check your fuel pressure. 44-54psi key on engine off. key off engine off, psi should stay the same and not drop more than 1psi is 15-30min. engine running at idle, snap the throttle, psi should go up then down just below static psi and then level off at static psi. if psi goes down instead of up you have a pressure regulator or fuel pump issue.
is the computer throwing any codes?
Hi, pressure was steady around 50 psi, held good for a check valve test. Replaced IAC, cleaned throttle body, replaced crankshaft position sensor today, seemed to run good for a few minutes after that but then went right back to shuddering when it flips from open to closed loop and, for the first time ev, threw a code, P0132 o2 sensor high voltage. The fact that it started to run like crap as soon as it reached temp and started to read the sensors seemed like a tell. I’ve got two NTK on order for Friday.
P.S. The crankshaft position sensor is easy to remove, a pain in the you know what to get the bolt started…Disconnected upstream o2 sensor and runs great. Doesn’t even seem too rich, going to install new one today. So, either o2 sensor was bad or was good but something else was so bad the o2 couldn’t compensate for it with adjustments like a massive vacuum leak. Whatever was wrong, if anything, is still there, so, simply running a little rich is working, so must not be too bad (I.E. Spark, injection, air, etc…) I’m leaning towards the o2 was bad… Thoughts? Bets?
first, respectfully, stop firing that parts canon… that’s what this site is about. Use scan data to diagnose the problem.
What are the STFT and LTFT fuel trims for both banks and the voltage reading for the 02’s.
By unplugging the 02 the ecm is compensating by running the engine rich. unplugging the 02 will setoff more codes.
Because the 02’s are in closed loop, that tells me that one or both are not reaching operating temp (600 degrees). if an 02 voltage stays or goes above 450mv for over 2min, the P0132 or P0136 will set. Most likely B1S1 02 has failed. Check your wiring first before buying a new 02. If the wiring failed or shorted the new 02 will not work.
While I understand the premise of the group, sometimes we do not have the complete set of diagnostic tools or the time or the space to take the time, etc… I did a fair bit of diagnostic work and, in the end, had to trust a little common sense. A 30 dollar o2 sensor wasn’t going to break me and it seemed pretty logical based on everything else I had tested or diagnosed positively. I replaced the o2 sensor and it’s running well, knock on wood. I’ll report back if anything changes. Side note, the new o2 seems to be reading much better, I think it was slow and likely off too.
I only have a DVOM and basic Autoenginuity.
Is it a fix with the new 02? no more codes fuel trims Ok?
- You must be logged in to reply to this topic.