1G Stalling after RPMs drop

[1gDSMtsi]

i have a 91 awd talon that i have rebuilt. i have all new internals, cams, big 16g, fmic, plugs, wires, computer, mpi, egr block off, evap gone. when i start it up when its cold it is hard to start but once its started it will idle fine. however when i try to drive the car it wants to stall after i let off the gas to come to a stop. i checked the fuel pump and it has 12.7 at the pump and the fuel is reaching the rail. it seems to rev up just fine in neutral and drop to the normal rpm without stalling. it is a stock fuel pump and stock blue top injectors. while the car is idling it smells like it is running rich. if anyone has any clue or tips please help!!

 

[yokotabrat]

Check to make sure your idle switch is working properly.

There's no good way to know if the car is really rich at idle unless you have access to a wideband or are looking at your fuel trims on a logger. Those will be great things to have when you move on to bigger injectors.

 

[1gDSMtsi]

could it possibly be the O2 sensor? i have a CEL but the diag port doesnt have a power supply to it to check it

 

[habitatguy187]

could it possibly be the O2 sensor? i have a CEL but the diag port doesnt have a power supply to it to check it

Definitely, could also be a loose coupler around the mas or a bad mas, often times this is caused by vacuum leaks.

 

[1bad95tsi]

Sounds like its vented to the atmosphere that will make it want to stall when the rpms come back down also

 

[BoostFrenzy]

could it possibly be the O2 sensor? i have a CEL but the diag port doesnt have a power supply to it to check it

1G Diag ports don't provide power.

Sounds like its vented to the atmosphere that will make it want to stall when the rpms come back down also

Either way, it sounds like it is running rich. If you are on a stock fuel setup then it is probably a boost leak, or your front o2 is dead/dieing. Because then your engine goes into a kind of safe mode and starts tossing in fuel to keep the motor from going lean.

If your BOV is vented, that would also cause it. Again, going rich.

Something you need to do: Check your oil. Pull the dipstick and smell it. If it smells like fuel, change your oil out before running the car again. This means you are DEFINANTLY running rich and it is comtaminating your oil. Of which, is very bad because it breaks it down and reduces its lubrication ability.

Do a BLT, and then get your OBD port fixed so you can get that CEL read.

 

[1gDSMtsi]

i figured it was running rich due to the smell of the oil as you said. i also have a vented BOV. is there anyway for it to run correct with a vented BOV? i now know i have a boost leak but havent tested it yet. i took it for a test drive and it wont make boost.

 

[stefanOst]

i figured it was running rich due to the smell of the oil as you said. i also have a vented BOV. is there anyway for it to run correct with a vented BOV? i now know i have a boost leak but havent tested it yet. i took it for a test drive and it wont make boost.

The easy way would be to recirculate it and fix all your problems. If you really want to vent it, you will need to switch to a GM MAF and a MAF-T

 

[1gDSMtsi]

ok so i now have the boost leaks fixed and the car running better...but when i tap the gas the rpms drop then pick back up..also after i get to about 4500 to 5k the car starts to misfire or hesitate real bad almost like running too lean

 

[ben's93talon]

i sort of had the same problem and mine is stock, all i had to do is just start it, let it idle for a bit and give it a couple of good revs and mine now juss starts right up

 

[1gDSMtsi]

the problem is not starting the car it is driving the car

 

[ben's93talon]

the problem is not starting the car it is driving the car

yea i forgot to put in after reving it mine would go down to like 300-400 rpm and almost stall but i dont know what to say about what ## car does

 

[1gDSMtsi]

ok no offense but can i get someone with a little more knowledge or experience to help me out here. WTF

 

[-red97rum-]

ok no offense but can i get someone with a little more knowledge or experience to help me out here. WTF

Did you do an actual boost leak test yet? Check the timing and properly set the idle per the vfaq instructions

This article may be of help

Also try searching a little as this is a pretty common problem with DSM's. Here's a couple threads I picked out based on the topic title:

Low idle (stall) after high RPM's??????

1g Idle/Stall Problem

You'll figure it out man, no biggie.

 

[1gDSMtsi]

yes i did and actual boost leak test with the real tester all leaks are fixed.

 

[yokotabrat]

Did you recirculate you BOV back into your intake? When is the misfiring happening? WOT? Cruising?

 

[1gDSMtsi]

a little of both mostly WOT. no the bov is still vented havent got the money yet to get the maft

 

[LandoAWD]

Fix the BOV. Report back.

 

[AlaskanDsm]

I would just try to recirculate the BOV until you HAVE the maft. Otherwise the car is going to run like crap. These cars on stock design are ment to run with a recirculation.

 

[zhjiln]

another stalling because vented BOV ... jesus...

read the tech articles/FAQS please

 

[1gDSMtsi]

another stalling because vented BOV ... jesus...

read the tech articles/FAQS please

sorry dude but no one told you to reply to this post either now did they. anyway its not stalling anymore its choking out around 4500. now i have more problems my oil filter housing pretty much just took a crap and i lost all oil.

 

[1gDSMtsi]

ok now i have the maft hooked up. car idles better and runs better but still cuts out at 5k. not sure if my bov is dumping too early or what