Rough idle

[420a dsm kid]

I got a 90 eagle talon tsi awd. I got a rough idle. I try looking for vacuum leak and dint find nothing I recently converted the 1g maf to a 2g maf thinking it would chance idle but nothing happen and today I notice white smoke coming from the muffler just for a minute or two. Please help.

 

[laser_92]

Well the smoke could be the engine burning coolant, or oil, the idle issue would be something different. First place I always look is the ISC sensor, if no boost leaks as you say.

 

[iaintmaci]

I'm hoping that when you changed to a 2g MAF you also changed the injectors to 550s or have some way to tune it. If not, I believe you will lean the car way out. Some one correct me if I am wrong please. I would start with checking your timing, plugs and wires and such before messing with too many sensors. Also, check to see if you have any major boost leaks.

 

[turbotom]

White smoke could be antifreeze burning, check your spark plugs to see if they are clean. If they are black with carbon (black soot) then your good. If not, then head gasket problem or your turbo is leaking coolant into the exhaust causing it to blow white smoke. See the funny thing is the ISC, doesn't effect much because the ECU doesn't even know if it's working or not, it just assume that it is. I could remove the ISC with a FIAV and it would run the same as if it was there. Yeah sure you need to hold the throttle for a few seconds but after that, your good.

Check your oil to make sure it isn't coffee colored.

Check compression, because uneven compression could cause run idle if example: 130/140/60/145 will cause idle issue.

Do a boost leak test? (Boost leak tells all!!)

BIS screw leaking? (O ring replacement)

iaintmaci, yes your right, you could use 450s though with a SAFC. But I do recommend 420a dsm kid to get a SAFC or 550s if not you will be breaking up on full throttle.

 

[420a dsm kid]

Ok I tried putting the 1g maf sensor back on but it just seems that makes it worse like every time I connect it I try and give it gas but it dosent rev it takes a while to rev. I change my spark plugs, the oil looks good and the antifreeze looks like is not leaking. So I was just wondering could my tps sensor cause the problem with my car not reving good.

 

[undefined0000]

Have you tried running the car with the MAF unplugged?

 

[Chucky_D]

Does it stay on and running when it cold starts? Might have something to do with the o2 sensor if it runs worse as it warms up.

But definitely check the ISC, and possibly order a new BISS.

[ame=http://www.youtube.com/watch?v=KibYz21IMA0]DSM ISC motor testing & Replacement - YouTube[/ame]

 

[undefined0000]

Does it stay on and running when it cold starts? Might have something to do with the o2 sensor if it runs worse as it warms up.

But definitely check the ISC, and possibly order a new BISS.

DSM ISC motor testing & Replacement - YouTube

That's what I was getting at.

 

[Chucky_D]

oh-and one more thing dont keep starting it untill you know you have a working ISC, im fairly sure I fried my ecu by trying to figure out what was wrong with my car while I had a bad ISC.

 

[TopGun8818]

Have you checked the Fuel Filter? I remember when my fuel filter needed replacing I had a rough idle and it would sputter and bog when I tried giving it full throttle.

 

[420a dsm kid]

Yea I tried running the car with the maf unplug it runs a lil better with it unplug but I just have to change gears at 2000 rpm. am gonna try and test my o2 and my isc tomorrow how do you check for a good o2 sensor and also am gonna look into replacing my fuel filter.

 

[Chucky_D]

Yea I tried running the car with the maf unplug it runs a lil better with it unplug but I just have to change gears at 2000 rpm. am gonna try and test my o2 and my isc tomorrow how do you check for a good o2 sensor and also am gonna look into replacing my fuel filter.

Are you throwing a check engine light? If your car runs better with the maf unplugged you got a bad maf.

 

[420a dsm kid]

The check engine light turns on when the maf is unplug. And how do you test a maf sensor..

 

[Chucky_D]

The check engine light turns on when the maf is unplug. And how do you test a maf sensor..

Mine threw a cel, i just swapped it out with a working one not sure if theres a way to test besides yanking it and running the car. If you can borrow or pick up a cheap working maf give it a shot, as for o2 sensor i just ordered mine from oxygensensors.com it was 45$ i think

 

[RallyEclipse98]

Check to make sure your throttle body is coated inside with oil. That could cause a rough idle. Oil could be in your tb if your head gasket is leaking..

 

[ChiTownHussla]

does the car run great once its moving? no hesitation or stuttering?

 

[420a dsm kid]

Alright I test out the isc and it came out good no bad cel, when I was checking the spark plugs I found out that cylinder 2&3 where missfiring so I test the ignition coil pack and it came out good so my other guess is my ignition control module. Does any body know how to test the ignition control module.

 

[Simadowna119]

It will be on vfaq. My 90 talon acted the same way. Boggy really slow to rev, shitty idle, and it was the ignition power transistor.

Invest in DSMlink. Advice to every DSMr!

 

[420a dsm kid]

does the car run great once its moving? no hesitation or stuttering?

Alright I bought myself a new ignition control module and I switch back to my 2g maf ### my 1g was bad. I also but some RC 550cc injectors. So my only problem is that the car turns on with a bad idle when it's cold but after it worms up it starts to idle at 1100 rpm and when am driving it starts to hesitate when am giving it gas but not for a long time. So I was just wondering if I had to tune the car with the 550cc injectors, or if I have to check the timing?

 

[420a dsm kid]

Alright am getting tire of this problem my I have bought a wideband, 255 walbro fuel pump apexi safc2 and a downpipe a new throttle bodie with new sensors on it 550cc injectors an I can't still not find the problem with my bad idles at cold start and am just getting frustrated with this problem that I just wanna sell it and buy me a new car. So what else could I check for the bad idle at cold start