1G Still stalling after i changed the ISC!

[Alex Bland]

Ok so first off ill list off what i have done to my car.
new spark plugs
re-built turbo
new ISC
new battery
and oil change

So this is whats going on. My car will start up fine when its cold, But when it gets warm and i drive it it will stall when i take my foot off the gas if i put the gas it will run fine. I herd that this sounds like the ISC so i bought a new one and nope. Still stalling. no jerking or anything. So now I'm thinking maybe scene i messed with the turbo and air and what not could this be because i didn't do anything with the BISS screw? 91 eagle talon tsi awd


Oh also when the isc is unplugged idk if this matters but the CEL does not turn on.

 

[sonik619]

Have you checked for boost leaks/bov vented?

 

[Alex Bland]

im gunna say...no..i have not.. but would that cause my car to stall?

 

[RayBan GST]

check for boost leaks and check your spark plugs wires ( did u gap your spark plugs?) which spark plugs are you running?


adjust also the BISS to read between 750-850 RPM ( when car is warm)

good luck

 

[Jeff99GS]

im gunna say...no..i have not.. but would that cause my car to stall?

YES a boost leak and/or vented blow off valve will cause the car to stall when the RPM's drop rapidly.

Do a boost leak test ASAP. Adjust the BISS screw

what does your VAC read at idle?

 

[steve]

What are your ISC steps when the car is warmed up?

What rpm does the car idle at?

What happens if you turn on the AC?

 

[Alex Bland]

I dont know what VAC is.

I dont know what plugs but i know the manager at one of the napas and he gives me the best with the best discount. yes there gaped
old spark plug wires (i dont know how old)

Im gunna go start it again right now and let it warm up and check the idle level

 

[snowborder714]

VAC is vacuum. It can only be read if you have an aftermarket boost gauge.

I would pull one of the spark plugs out and see what it is. The "best" spark plug is usually one that doesn't work well in our cars. You'll want to get NGK BPR6ES plugs (they're copper) and make sure they're gapped to .028". They come pre-gapped, but they're not always correct.

 

[Alex Bland]

Ok, here's what happens,
warm with nothing on (car sat for just a little sitting still) - between 650-700 solid
warm right after driving it (as soon as i parked it) 550-700 sways
warm with just A/C on - 500 solid
warm with headlights only 600-700 swayed
And after its warm it will keep its self alive with no gas on, but if i rev it up it will fall back down and die.

yeah I looked on the gap opener and by what i remember it it was not that small.

ok so i have NGK plugs they were gapped so..

 

[steve]

Your ISC is not working. Since you say you have a new one you are either not seeing the Idle Position Switch close, have wiring problems between the ISC and ECU, or your old ISC blew the drivers on the ECU board.

Since in most of those cases your idle speed is below 750 rpm I would expect that the ISC steps are maxed out if you log them which would tell you that the ISC isn't functioning correctly. But if the ECU never sees the IPS close it doesn't know to try and control the idle, so check that first. Could be as simple as the throttle body not being grounded cause somebody removed the strap.

 

[Alex Bland]

So what would be my first move into checking the wires..? is there a way to test the female plug in? and what do you mean by "you are either not seeing the Idle Position Switch close" Also shold the CEL come on if its unplugged?

 

[steve]

So what would be my first move into checking the wires..?
Is there a way to test the female plug in?
What do you mean by "you are either not seeing the Idle Position Switch close"
Also shold the CEL come on if its unplugged?

Your first move would be to get the diagrams and your multimeter and check each for continuity back to the ECU and for power on the two center pins.

What part don't you understand? What the IPS is or how to check that it grounds out the signal from the ECU?

I don't believe you get a CEL from the IPS unless it's stuck closed. I don't think it can tell if the wire gets disconnected.

 

[Alex Bland]

Oh im dumb i read it like 5 more times and i understand what you mean now =P.
So i dont need to go into my ecu to test anything? just need the female plug in?
what do i set the meter to for testing?

 

[Jeff99GS]

To test Contnuity you will need to set a digital volt ohm meter on LOGIC. When in this mode the meter will BEEP when the black and red probes are touched together. The BEEP means there is continuity of the circut. Touch the leads together to make sure its working before tesing the car.

Now to begin your test you will need to touch one probe of the meter to the first wire in the plug. NOTE the color of the wire going to that terminal. Now Find that same color wire at the ECU and touch the other probe of the meter to that end of the wire. If it beeps then the WIRE has Contunuity. If it doesn't BEEP then there is a break in the wire somewhere....or you're on the wrong wire.

When looking for the wire colors you have to notice BOTH colors. Like Blue with a white tracer....or Blue with a white DASHED tracer. Or Green with a pink tracer.

You are going to have to extend the wires on your meter for this one.

I circled the logic setting in red. Some meters will say LOGIC and some won't....Just touch the probes together and make sure they beep.

 

[Alex Bland]

Ok so there is 2 red ones (they beeped)
then there is a
black
blue
yellow
white

there all sold colors idk what to do with these because none of them beeped i tested all the ways i can with them.

yeah i did it mine had like a music note on it.

 

[Jeff99GS]

Did you test the 2 center pins for 12v like Steve said?

Also check for that groud strap on the intake manifold or throttle body...if its NOT there then run a fat gound wire from the firewall to the intake manifold.

 

[Alex Bland]

I tested the middle ones with the beeper and it worked and with the 12v thing
also with the ground is it the thing with the little black rubber boot over it? if thats it then its there.

 

[Jeff99GS]

SO you're puting one end of the meter on the plug in the engine bay and the other end on the ECU end of the wire?
If the coils in the old ISC shorted out then the drivers in your ECU are probably bad.

Did you ever answer us if you're venting your Blow off valve??

 

[Alex Bland]

Im have not vented my BOV and also im tryin to find a guide on how to get to the ECU as im typeing

The coils in the old ISC where fine i think it was the motor i tested and all the coils said 30 ohms

 

[Jeff99GS]

Well if you checked the coils and they weren't shorted out then the ECU is More than likely fine.

Look around for vacuum leaks, you may have unhooked a hose when you were putting the re-built turbo on.

That why I still say Do a BOOST leak test real quick. If a vacuum line is off it will make the idle whacky.

 

[Alex Bland]

is a book leak test something i can do fast. i sprayed contact cleaner on the vac's and nothing changed in idle.. Do you think this could possibly be injectors?

 

[Jeff99GS]

Man I don't know if contact cleaner is enough to change the tone of the engine. I've hard of people using starting fluid but I don't reccomend that either.

I don't think it's the injectors, but it could be a clogged fuel filter.

 

[Alex Bland]

oh shoot im dumb uh i wont even mention anything for why..

Uh so can you find me a good way to do a boost leak test got a air compressor, psi gauge, probly find some tubeing somewhere around here. Oh and thanks for all the help.

 

[Jeff99GS]

oh shoot im dumb uh i wont even mention anything for why..

Uh so can you find me a good way to do a boost leak test got a air compressor, psi gauge, probly find some tubeing somewhere around here. Oh and thanks for all the help.

Yeah if you have an air compressor you can make a boost leak tester with some couplers and a gauge. Or just set the air compressor to 15 psi disconnect a vacuum line and blow the compressed air into the vacuum line. Then listen for leaks anywhere. open the throttle blade up. spray soapy water on everything and look for bubbles. Put zipties or claps on the vacuum lines to seal them.

 

[Alex Bland]

Hey i talked to like a mechanic guy and he said scence i changed is ISC that he thinks it might be my high temperature sensor do you think that might be my problem?