2000 xj 4.0 144k.. runs excellent, or it did until i ran out of gas the other day.. still performs excellent but now after full warm up it stalls at idle, no othr issues and no cel.. now conventional theory says i burned the fuel pump.. so i replaced it. still stalls at idle, stopped in drive, neutral or park.. stock fuel pressure. any thoughts?
-
Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.
dd xj stalling after ran out of gas..
- Thread starter skidj2x
- Start date
birchlakeXJ
NAXJA Forum User
- Location
- Melrose, MN
One of the most common causes of stalling at idle is a marginal battery. And yes, you can have a battery strong enough to start the engine, but marginal enough to give the engine management system fits and stall the engine.
While there certainly are other options, I would recommend you start with having your battery "load tested". Any parts stores will do this for you for free.
Good luck and keep us updated!
While there certainly are other options, I would recommend you start with having your battery "load tested". Any parts stores will do this for you for free.
Good luck and keep us updated!
funny you should mention.. had to jump it that morning....
but, im not entirely convinced. the voltage regulator in the alt should keep the system turning, you can run most any vehicle indefinitly without a battery, so long as the alternator is good.. the battery acts as a buffer from the rest of the system to absorbs spikes in voltage to help protect the ecm, as well as the fuses..
usually in the moring i can hear the evap pump ticking against the firewall doing its cold startself test.. but i dont recall hearing it the last few times i stareted it cold..
so, at closed loop, the ecm should be purging off of the evap canister, but whats the connection between running out of gas, once in 144k, and the evap not working?
sprayed all the vac lines/elbows and found nothing..
but, im not entirely convinced. the voltage regulator in the alt should keep the system turning, you can run most any vehicle indefinitly without a battery, so long as the alternator is good.. the battery acts as a buffer from the rest of the system to absorbs spikes in voltage to help protect the ecm, as well as the fuses..
usually in the moring i can hear the evap pump ticking against the firewall doing its cold startself test.. but i dont recall hearing it the last few times i stareted it cold..
so, at closed loop, the ecm should be purging off of the evap canister, but whats the connection between running out of gas, once in 144k, and the evap not working?
sprayed all the vac lines/elbows and found nothing..
birchlakeXJ
NAXJA Forum User
- Location
- Melrose, MN
Humor me and load test your battery. Or temporarily swap in a different battery.
You might be surprised. I can't tell you how many stalling issues I've resolved that have been positively caused by the battery. VERY common.
You might be surprised. I can't tell you how many stalling issues I've resolved that have been positively caused by the battery. VERY common.
yeah, so i checked the batt.. specific graviy of 1275, and good load test..
so i was wondering if the higher than normal vacuum by such slow rpms would have sucked a hole in one of the softer lines maybe.. and started to pull them off one by one to see wich one made no change.. and with the first one, it ran better.. hmm so its starving for air.. so im assuming that when it wanted to stall the first time, due to a lack of gas, the iac was trying to do what it could to balance the mixture, beyond its normal range, and may have moved some carbon on the pintle, so under a normal idle situation, the pintle couldnt respond properly. so i sprayed some cleaner through the throttle body into the slot for the air to get to the iac.. then ran it.. runs and idles fine now
so i was wondering if the higher than normal vacuum by such slow rpms would have sucked a hole in one of the softer lines maybe.. and started to pull them off one by one to see wich one made no change.. and with the first one, it ran better.. hmm so its starving for air.. so im assuming that when it wanted to stall the first time, due to a lack of gas, the iac was trying to do what it could to balance the mixture, beyond its normal range, and may have moved some carbon on the pintle, so under a normal idle situation, the pintle couldnt respond properly. so i sprayed some cleaner through the throttle body into the slot for the air to get to the iac.. then ran it.. runs and idles fine now
- Location
- on the beach in Ocean View, VA
as a side note for future searchers--
the ECU can "forget" the idle position of the IAC if battery voltage drops too low. The result of this can be seen as and engine that will run with throttle, but stall when it should be idling. This can continue for a few minutes if the ECU cannot find the correct position for the IAC to maintain idle RPM. Eventually, it "figures it out" and idle speed is again maintained.
I'll agree that the IAC should always be cleaned if you are experiencing poor idle or inability to idle, but any time you have to jump start or change a battery in one of these things be prepared for the possibility that you could be doing the two "foot shuffle" to keep her running for a few minutes.
the ECU can "forget" the idle position of the IAC if battery voltage drops too low. The result of this can be seen as and engine that will run with throttle, but stall when it should be idling. This can continue for a few minutes if the ECU cannot find the correct position for the IAC to maintain idle RPM. Eventually, it "figures it out" and idle speed is again maintained.
I'll agree that the IAC should always be cleaned if you are experiencing poor idle or inability to idle, but any time you have to jump start or change a battery in one of these things be prepared for the possibility that you could be doing the two "foot shuffle" to keep her running for a few minutes.
- Location
- on the beach in Ocean View, VA
heyhar
NAXJA Forum User
- Location
- PA (near Poconos)
While on the subject of possible battery/charging problems, I once had a cracked negative terminal. Car started fine, but while driving, the volt meter was up and down, radio would alternately buzz then quiet down, torque converter was in and out of lock-up. On the way home, I stopped and pick up a new alternator, and when I was disconnecting the battery to change the alternator, that's when I found the cracked terminal. At 160k miles, I figured it wouldn't hurt anyway. And, I was glad it wasn't the TPS again...
it funny though.. in the twenty some odd years of working on cars trucks and busses, changing batteries, swapping parts and diagnosing charging systems, ive never ever ever ever ever heard of an idle air motor forgetting its job.. the only time an iac usually fails to do what it should is when its either dirty, faulty or its taken out and manaually moved, like on an older chey, where you can manually change the pintle depth by screwing it in or out..
- Location
- on the beach in Ocean View, VA
... right, same thing I said-- except that I said the ECU can forget where to position the IAC upon initial start up. The IAC never ever ever ever ever forgets it's job-- it's only as smart as the ECU that tells it what to do....
but, im not entirely convinced. the voltage regulator in the alt should keep the system turning regulator is actually located in the ECU and not in the alternator, you can run most any vehicle indefinitly without a battery, so long as the alternator is good.. and that's one of the best ways to induce voltage spikes in the system that will kill highly sensitive electronics. Not the best choice for anything that's computer controlled.:nono:
the point is, it will still run regardless.. like when you pop a clutch, the batt or the starter may be junk, but it ill run.. what i wanted to know, is how running out of gas is causing the issue of stalling at idle..
the point is, it will still run regardless.. like when you pop a clutch, the batt or the starter may be junk, but it ill run.. what i wanted to know, is how running out of gas is causing the issue of stalling at idle..
Talyn
NAXJA Forum User
- Location
- Radford, Communistwealth of Virginia
Have you checked the voltage at idle?
I would also reset the PCM. Maybe it learned something bad when it was low on gas.
I would also reset the PCM. Maybe it learned something bad when it was low on gas.
heyhar
NAXJA Forum User
- Location
- PA (near Poconos)
Or, the pick-up sucked some junk from the bottom of a thirteen year old tank. Maybe there's dirt obstructing fuel flow somewhere, giving the computer fits trying to compensate.
Or, the pick-up sucked some junk from the bottom of a thirteen year old tank. Maybe there's dirt obstructing fuel flow somewhere, giving the computer fits trying to compensate.
ah yes, see i had figured, under conventional wisdom, that i had burned the pump maybe, so i replaced it.. and then when i still had the same problem, i wondered if maybe something like this ocurred.. but the fuel sock at the base of the pump, was not only intact, but clean.. infact, the tank was very clean and debris free as well..
ah yes, see i had figured, under conventional wisdom, that i had burned the pump maybe, so i replaced it.. and then when i still had the same problem, i wondered if maybe something like this ocurred.. but the fuel sock at the base of the pump, was not only intact, but clean.. infact, the tank was very clean and debris free as well..
yeah, i had figured that, all things being equal, and the fuel sock being the only filter.. that i had prhaps screwed the pump.. and it was about time.. over this past summer id lose the prime on the fuel rail and would have to key the ign twice or id have a long start.. figured that after the pump ran a while it would get too hot or weak to keep up decent idle pressure. but i did resolve the issue with a little cleaner into the iac slit in the throttle assembly
Similar threads
