Car has horrible idle tps ok t.b. screw tight what else to check?

[bobby180360]

my 95 tsi awd will not idle right, it will stay running though unless i put to much of a load on it when my foot is not on the gas, i thought that it may have been the tps, i ohmed it out and it was with in specs. i checked the idle screw to begin with hoping it was lose or just bad gas, i ran about 2 tanks though it and it did not get any better, and its only the idle, when i nail the gas i still have full power its not doggin idk, its probley an easy fix of something that iam not thinking of so if anyone has an idea please let me know. thanks

 

[turbodsm_125]

look for a vacuum leak. they will create all kinds of problems. are you idle surgeing or will it just not idle?

 

[smellmyface686]

Did you change anything or remove/replace anything when it started to happen? I was having the same problem last week, but i had just missed replacing a vac line on the intake (it was like 3am after my rear conversion, using my phone for a flash light )

 

[tbonitz301]

If you are surging i would check the isc motor. You will find it on the back side of the TB its down low. This is the pins numbered with the two tongues on the isc facing up.They should all be between 28-32 ohms. Test 1-2,then3-4,and lastly5-6

1 2 3
4 5 6

 

[bobby180360]

the idle is lower then usually but when i put it in gear, that is when it starts to surge. i don't know if that helps narrow anything down or not

 

[Hollywood77]

Have you recently installed a new clutch and/or bled your clutch hydraulics?

I just installed new clutch, flywheel, and RRE SS clutch line the other day. Soon as I started the car to take it for a test-drive, it wouldn't idle properly. It wouldn't ever die, but as soon as I push the clutch pedal in to shift, or at a stop light, the idle drops to around 100 rpms or so. After maybe 5 seconds, the idle stabilizes and goes back to normal. I'm told that my clutch M/C is causing this problem.

Maybe that'll help you, maybe I'm just rambling.
This is my first DSM; all my other cars have been Audis, so I'm still learning as I go along.

 

[nfernotalon]

Try running some seafoam through it, I did and my car idles much better.

 

[bobby180360]

Have you recently installed a new clutch and/or bled your clutch hydraulics?

I just installed new clutch, flywheel, and RRE SS clutch line the other day. Soon as I started the car to take it for a test-drive, it wouldn't idle properly. It wouldn't ever die, but as soon as I push the clutch pedal in to shift, or at a stop light, the idle drops to around 100 rpms or so. After maybe 5 seconds, the idle stabilizes and goes back to normal. I'm told that my clutch M/C is causing this problem.

Maybe that'll help you, maybe I'm just rambling.
This is my first DSM; all my other cars have been Audi's, so I'm still learning as I go along.

Mine is an automatic, but thanks for the ideas

 

[Dave532]

Buy or borrow a vacuum guage. If it is lower than 15-18 hg you have a vac leak of some kind. Verify the outside 10 mm studs and nuts on the intake are tight. Spray some carb cleaner around the intake manifold and see if it affects the idle. if so, it is a intake gasket leak (or loose). First usual suspect of a vac leak on a turbo car is hoses, second is the intake gasket.
If the vac reads good, go after ignition, fuel pressure, etc.

-Dave
#532
NASA PTC
Rally America PGT

 

[tbonitz301]

IF you have a faulty master cylinder it can cause stumbling idle. Check for leaks.Duh, im an idiot. he's auto

 

[VETTE_50_TH]

Buy or borrow a vacuum guage. If it is lower than 15-18 hg you have a vac leak of some kind. Verify the outside 10 mm studs and nuts on the intake are tight. Spray some carb cleaner around the intake manifold and see if it affects the idle. if so, it is a intake gasket leak (or loose). First usual suspect of a vac leak on a turbo car is hoses, second is the intake gasket.
If the vac reads good, go after ignition, fuel pressure, etc.

-Dave
#532
NASA PTC
Rally America PGT

Not quite. I pulled about 20-22 hg on my car up until today, money_pit and I replaced the isc stepper and a new gasket and now it idles perfectly. And i pull 20 hg. I dont why. But the car pulls enough vacuum. Obviously, check for boost leaks. That will kill your motor and idle. Secondly, take you isc and test for 43 ohms of resistance. If that is bad, go to dsmisc.com to replace. If not, check your MAF making sure that its it good working order. There is a bunch of shit that could be wrong.

James

 

[Calan]

First of all, do you have any mods or is your car stock? (need to list them in your profile, or at least put "stock")

If you can monitor on a logger, what do your fuel trims look like? If low fuel trims are out of whack for some reason (vac leak, hacked maf, PCV valve, etc etc), your ECU can run out of idle adjustment with the ISC..causing all kinds of idle issues.

Done a boost leak test yet?

 

[meliketoball]

Check Engine Light come on? Maybe your timing is off; can you go through the RPMs?

 

[Icarus]

Honestly sounds like a vac leak, like everyone else says. But if you can't find any leaks, I just fixed a problem like this on one of my Diamante's. Though not very probable on a 2g, it turned out to be bad caps. It would idle poorly. It would misfire even backfire at partial throttle. Then it would seem to even out at 80%+ throttle. Long story short, repaired the ECU and it's fixed now.

 

[tbonitz301]

Not quite. I pulled about 20-22 hg on my car up until today, money_pit and I replaced the isc stepper and a new gasket and now it idles perfectly. And i pull 20 hg. I dont why. But the car pulls enough vacuum. Obviously, check for boost leaks. That will kill your motor and idle. Secondly, take you isc and test for 43 ohms of resistance. If that is bad, go to dsmisc.com to replace. If not, check your MAF making sure that its it good working order. There is a bunch of shit that could be wrong.

James

Im sorry,but your numbers are wrong it should be between 28-32 ohm's of resistance between 1-2, 3-4, 5-6. As stated earlier

 

[bobby180360]

No mods done just cold air intake and the boost being turned up. I have not yet done a boost leak test or vac test, i will as soon as i get my hands on the tools. No the check engine light is not on, and i dont belive i have a timing issue.

 

[tbonitz301]

Have you ruled out the ISC?

 

[VETTE_50_TH]

Im sorry,but your numbers are wrong it should be between 28-32 ohm's of resistance between 1-2, 3-4, 5-6. As stated earlier

We are both wrong.

You must be logged in to view this image or video.

James

 

[bobby180360]

Now i'am getting a PO125b code my second fuel bank or something like that says disabled on the computer and theres no voltage to the O2 sensor

 

[meliketoball]

Now i'am getting a PO125b code my second fuel bank or something like that says disabled on the computer and theres no voltage too the O2 sensor

Done deal.

 

[bobby180360]

Dumb question but would the o2 sensor cause all of these problems, because when i looked up the codes on our scan tool it said no voltage to the o2 so would that also cause the car to have the "Insufficient Coolant Temperature for Closed Loop Fuel Control ECT Excessive Time to Closed Loop Fuel Control", Code.

 

[blcknspo0ln]

Dumb question but would the o2 sensor cause all of these problems, because when i looked up the codes on our scan tool it said no voltage to the o2 so would that also cause the car to have the "Insufficient Coolant Temperature for Closed Loop Fuel Control ECT Excessive Time to Closed Loop Fuel Control", Code.

Does the scantool (just google the P code) say o2 sensor heater circuit 1 bank 1 or circuit 1 bank 2? bank 1 or 2 denote the front or rear o2.

For the second code, that most likely is your coolant temperature sensor crapping out on you, it's pretty common on our cars and if you're having trouble on cold starts, that also may be the culprit.

 

[bobby180360]

Does the scantool (just google the P code) say o2 sensor heater circuit 1 bank 1 or circuit 1 bank 2? bank 1 or 2 denote the front or rear o2.

For the second code, that most likely is your coolant temperature sensor crapping out on you, it's pretty common on our cars and if you're having trouble on cold starts, that also may be the culprit.

I believe the scan tool said that the 2nd bank was disabled or something to that effect, and iam 99% positive that it would be the down stream o2. I hope that helps

 

[turbotsi90]

any luck with your problem? BTW if I were to check my ICS what setting do I use on my multimeter? Thanks

 

[blcknspo0ln]

Just your regular good ol' ohms.