Car Stalls out in neutral when warm

[Brax93]

Well recently put in a transmission with 79k miles.
Thought everything was good until I drove it that night after replacing it and when the engine is warm and I go to neutral to go to 1st or stop the car will idle rough and die???? Have to keep giving it gas/ stay above 1k rpm or stalls out and takes a min to restart the car.

Didn't happen before I replaced transmission,the car did sit for about 4 months when I was in AIT.

So I checked the IAC checked out to be fine,replaced it just to see if it was the problem (spare IAC) same thing,Cleaned the throttle body, No obvious vacuum leaks (previous owner kinda ran his own) going to check with soapy water tomorrow. Even put some new fuel in just in case but still does it.

Im confused so any help would greatly be appreciated.

 

[SoDakGSX]

Not sure if it will help but heres a few things you can try..

Verify base timing
Check for spark in all cylinders (spark plugs, wires, etc)
Check TPS voltage
Double check for vacuum leaks
If you have a CEL getting thrown, that might point you in the right direction also

I'm sure there is more, but that's all I can think of right now haha, hope that helps.

Here's a couple of links you can check out that have helped me out.

http://www.dsmtuners.com/forums/articles-engine-fuel/191137-how-fix-your-idle-surge-problem.html

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

 

[jdezmit]

You mentioned it would run rough and then die. When you are applying throttle to keep it at 1k, does it still run rough? Does it clean up and you go through the gears? How old is the fuel?

 

[Brax93]

Alright well its not giving me a cel unfortunately and when its at 1k and I give it throttle I have to keep giving it throttle or it will die, it doesn't clean up if i just hit it once, and the fuel was like 5 months old but I put some new fuel in


It doesn't idle rough when I start the car runs fine, its when I drive it for a distance and I go to neutral acts like its not getting enough air?? and thats when the problem starts

 

[SoDakGSX]

I would check the ISC with a volt meter just to be sure that's not your problem.

Other things that can effect performance - exhaust leaks, bad o2 sensor, low coolant, bad thermostat sensor, bad oil pressure sensor, faulty FIAV, improper BISS adjustment, bad injector o-rings, etc..

It might run okay at idle because the car is supposed to idle high on cold startup, so maybe you could try to adjust the biss after you've made sure that the isc or tps isn't the problem, here's an article on proper biss adjustment.

1G BISS Adjustment

 

[Brax93]

well I checked the ISC/IAC again just plugging it in and turned to car to on and all it does is vibrate didn't move in or out so im assuming its out? i have a 420a so no biss screw...

 

[SoDakGSX]

Oh alright haha.

I would grab a voltmeter and test the coils, measuring resistance is the easiest way to check for a bad ISC.

It should vibrate in and out though when you turn the key on and off.

Here is a good video that jafromobile posted on how to test the ISC.

YouTube

Here's another good video that shows you what it's supposed to look like when you turn the key off and on.

YouTube

 

[Brax93]

Yeah I saw the video on how to test the coils the haynes manual said 38-52ohms so I tested both earlier 1st one was 51.8 and 52.0 ohms and other ISC was 52.6 and 53.2, so I used the one I thought was good
But I did the turn go to on and it just vibrated little bit didn't move in or out like that Im going to get a new one from autozone I think and test it with the car on to see if any different and I forgot to mention i don't have the vehicle speed sensor hooked up right now could that be causing it? (its cause wrong connecter)

 

[SoDakGSX]

I'm not sure if the VSS could be causing it..

And my knowledge on the 420a is very limited so hopefully someone else can chime in on this who knows what's up

 

[Brax93]

Alright well I ordered a new ISC/AIC so I will figure out if that is the problem it will be here Tuesday.... so I will have to wait till then

 

[Brax93]

Hey, If anyone is here now, I replaced the ISC/AIC and it did it again but now it has a idle surge right after I start the car so maybe TPS and also the coolant gauge isnt halfway when its at operating temp maybe coolant sensor but there is two on it for gauge and one for ecu correct?? so if the gauge one was off I wouldn't think that would do it?

going to clear codes still no engine light and take it up to advance auto to see if i can get any codes read off

 

[Kod]

BISS adjustment - turn the screw all the way in (don't bottom out) and back out 2 full turns 750 idle + / - a little usually (if still not there or not even close)

FIAV on the bottom of the throttle body (also causes idle surge I believe)

Bad EGR unless it's blocked off (can cause rough idle / hesitiation)

MAF / MAP good?

Bad MAF could cause stalling when warmed up (seen it happen my own car )

o2's I never had cause idle issues for me but could be possible.. usually just ran rich

 

[Brax93]

Alright Ill try to look at them this guy before me took out the check engine light bulb.............. I just swapped on of the non important bulbs out and going to drive it around next couple of days if i cant get it figured out to see if I can get one

hey on the MAP sensor this guy has this little black box connected to 2 of the wires going into the sensor anyone know what he was trying to do and if I should remove it?? probably so

 

[Kod]

you should just take it somewhere like autozone or something and get it scanned 96+ is scannable anywhere

 

[Brax93]

I did they didn't get any codes when I took it to them today so Im going to see if the light comes on (since I put a bulb in) when I drive it little bit then take it back to them.

 

[V8srslow]

The map sensor is manifold pressure differential sensor so it's only purpose is to verify that the egr is opening/closing properly.egr only opens when engine is warm and under light throttle.they can stick open and make a big intake leak.

 

[Brax93]

Alright the previous owner he has a little black box connected to the MAP sensor, then he has the egr solenoid like a constant vacuum because goes from the manifold vacuum to the egr solenoid then back to a vacuum line and he has a bolt on the opening on the engine where the egr solenoid goes with a clamp to block that off, He ran his own vacuum lines....

 

[Brax93]

OK if anyone is here, I have the codes now they are P0122-TPS, P0107-MAP Sensor voltage low,P0106- MAP sensor again out of range, P1390-camshaft sensor and last P1496-5 voltage low/low voltage.

The last code I think could be causing the all the other problems the night this all happened the electricity was being weird one headlight stopped working, radio didn't want to turn off, and HVAC was flickering when i messed with it.....So I think its something electrical and where i should look for bad connection/wire??? I checked the fuses none of them seemed to be blown. and battery connection seems to be fine any help will be appreciated.

 

[Brax93]

just for the records the problem was the crankshaft position sensor causing it to die in neutral in case some has this problem and see's this thread.