[e92_bron]

Currently trying to track down a problem on warm starts. The car will fire up just fine on a cold start but will fire up and immediately die when the car is started whenever it is warm. A second sometimes third start up will usually do the trick or I can keep the car alive the first time by feathering the throttle for a couple seconds; it will idle/drive as it should after it catches itself. It also doesn't trigger a code at all.

Could my injectors be leaking causing it to flood? I recently replaced all of the seals/de-couplers during my VC replacement and I am running PI. Also just replaced plugs, coils and both VANOS solenoids. Smoke tested through my TB BOV adapter port and it doesn't show any signs of a vacuum leak.

[e92_bron]

Originally Posted by TerminatorStout

I forgot to mention, usually the sign of a leaky injector is the opposite of what is happening to you. Short drives, car warm, no problems. Sits over night for cold start and injector has been leaking fuel all night long and causes a hard start or rough start condition.

Makes sense! I won't completely rule out the battery but it was replaced about a month ago, so possible but not probable. I replaced the alternator about 10k miles ago as well, the car will stall once or twice if I don't feather the throttle on both long and short drives; its when the car doesn't go into its "cold start" procedure where it stalls. I'm going to throw that one on the back burner for the meantime.

TB could be the culprit. I recently replaced the MAP sensor because it was completely gunked up with oil so I will definitely pull the TB off and give it a good look and check the TMAP sensor while I'm there. That was a great suggestion.

Just curious, why would a dirty TB cause it to stall during a warm start?

[Dave92N54]

Originally Posted by TerminatorStout

Well without getting into the crazy of sensors and computers, ill keep it basic, old school -

When the engine is cold the gas is harder to burn, and the air is denser so there is more oxygen. The reduced volatility of the fuel and increase in oxygen creates a lean condition so it is enriched with fuel to compensate so the Air Fuel Ratio - AFR is correct.

When the engine is warm if the throttle body is dirty there is a lack of airflow or rather a "dirty" or "buffeted" air flow which during the enriched cold start doesn't have the same effect. There is also the butterfly seating tolerances, but won't get in to that.

Without the enrichment the AFR will be off enough to play games, and when bad enough happens hot and cold. Maybe you know, but when you push the gas pedal you are actually adding air the mixture by opening the throttle body, so when you feather the throttle you are actually adding more air, which the brain then adds more fuel, but like I said without getting into the electricals, this is all controlled by big brains and sensors, IAT, MAF, MAP, O2, ETC....

Great explanation

One I always like to use is Toyotas as an example. A lot of times if you remove their battery, the car will stall out on first start up. Due to the dirty throttle body and the loss of adaptations due to battery disconnect, it doesn't know how to control idle for a moment.

[Dave92N54]

OP, do you have MHD or any method of data logging? If so i'd like for you to start logging warm starts and once you get a log of it happening, post it up here.

[e92_bron]

Originally Posted by Dave92N54

OP, do you have MHD or any method of data logging? If so i'd like for you to start logging warm starts and once you get a log of it happening, post it up here.

JB4 with a BEF. I'll have one up tonight if you can check it out for me that'd be great.

[Dave92N54]

Originally Posted by e92_bron

JB4 with a BEF. I'll have one up tonight if you can check it out for me that'd be great.

ill take a look, JB4 logs are weird but if it's fueling related at all should be obvious.

[e92_bron]

Originally Posted by Dave92N54

ill take a look, JB4 logs are weird but if it's fueling related at all should be obvious.

Wasn't able to catch a log today of it happening but I did manage to take the TB and TMAP sensor off to clean. Seemed to have helped a bit but a marginal difference at best. I also switched back to the pump BEF to see if it was tune related and it doesn't seem to be.

I have a gut feeling its fuel supply or o2 sensor related. Trims sit at high 20s-30 flat at idle, its more apparent when its cold outside but at certain points of a drive itll idle at 25 during a stop light. Recently started getting the 29E0, 29E1 codes as well but its intermittent, if I clear it the car runs perfectly fine until the next time it shows up again. Normal driving shifting from 1st to 2nd gear I would get a huge positive fuel trim spike and the car will jerk forward momentarily as well. I've reset all adaptions via INPA but it hasn't helped.

Could low fuel pressure at low RPMs, low load caused by running PI be a possible culprit? Maybe a clogged filter in the HPFP or its on its last leg? At WOT the HPFP holds well above 9 on my JB4 gauge, its partial throttle/idle where I'm seeing the most issues. It also blows a good amount of white smoke when its cold out during idle or reversing into a parking spot. I want to say some of it is condensation or steam but its highly unlikely all of it is that. Any ideas or inputs?

[e92_bron]

I'll go ahead and drive around the neighborhood and get a log. I may not be able to get the car to stall every single time but its definitely throwing the fuel mixture codes more often than not recently. I don't think its coolant but ive also never had the opportunity to smell coolant smoke out of an exhaust, my instinct tells me its running pig rich when its smoking. AFR also goes down to the high 13s then lean out to mid to high 14s then back down consistently, its like they're playing a game of pong.

[e92_bron]

Originally Posted by Dave92N54

ill take a look, JB4 logs are weird but if it's fueling related at all should be obvious.

First time posting a log, let me know if this will do.

https://datazap.me/u/bronson/log-166...10-14-18-24-35

Went on a short drive that hesitation at low rpm/low load jerk happened a few times.

[Dave92N54]

Yeah, JB4 logs are so weird to me. Currently looking at it but one thing I notice off the bat is WGDC? Any reason it's at 80% literally at idle? LOL

[e92_bron]

Originally Posted by Dave92N54

Yeah, JB4 logs are so weird to me. Currently looking at it but one thing I notice off the bat is WGDC? Any reason it's at 80% literally at idle? LOL

The default jb4 values set it at 60, I had suggestions to up it to 80 to see if it helped with that low load hesitation.

[e92_bron]

Really appreciate the detailed insight! I'll go ahead and change the WGDC to 30 and also do a log in 3rd like you suggest. Will check back in. Thanks!