bad idle, and wont stay running

[cgmtboarder]

my 91 tsi doesnt want to start very well. to get it to start i have to have the gas pedal to the floor and then as long as i keep the gas on it it will stay running. but if i let of the gas it dies. the idle is really rough also, until i rev up to about 2000 rpm then it smooths out. i checked for any vacuum lines unhooked and everythings connected. but sounds like vacuum leak or somethin. ideas anyone?

 

[wezzy785]

have you done a boost leak test ? if not do that

look at you're plugs and wires. plugs need to be gaped at .028". some good plugs are NGK.

may be a good fuel treatment, like lucas fuel injector cleaner

check all the grounds.

 

[Blaze2gDSM]

Check out the throttle body make sure its clean and nothing loose. Make sure throttle cables are hooked up correctly. Check out Vfaq.com and check your BISS settings see if that helps. MAS plugged in right? Check the connector, clean with some contact cleaner and make sure its plugged in tight. Between what Wezzy and myself said you should be able to figure this out.

 

[cgmtboarder]

plugs and wires im pretty sure r fine cause they came out of a running car. and im not exactly sure how to do a boost leak test. i think i may need a gasket in the throttle body and intercooler.

 

[Mr PopUps]

Sounds like ECU issues, along with possible voltage issues.

 

[cgmtboarder]

checked the ecu and its perfect. as for voltage im pretty sure its fine. but im not positive

 

[spaugh]

To check for a vacuum leak you can get a can of carb cleaner and spray around your vac lines and if the car revs up then you know you leak is in that area. As far as doing a boost leak test use the search feature (how to do a boost leak test) and you will find some helpful write ups on how to make a tester and how to do it. You may as want to find a different mas and swap it out. My 1g done about the same thing and it was my mas.

 

[spaugh]

Also just because your ecu looks good doesn't mean much.

 

[cgmtboarder]

well none of the caps r leaking or anything so im assuming its fine. i also did change the mas and it did nothing. so i will do the vacuum leak test tomorrow.

 

[Rotten]

are you getting a check engine light? if so, find a way to read the code, data loggers are mighty handy. but if you are i would check the CAS had the same problem with my new gsx that i just got, second day i had it, and it already wouldnt start , typical. it would start but die in a few seconds if i didnt have the gas down and the idle was really high when it would stay running for a little bit. but i ran to my friends got a datalogger from him (he sells the kits) got code 23 checked it BAM ran out got the part and problem sovled.

 

[PIMking]

Just because the caps are not leaking doesn't mean squat.

My car did that and it happend to be a intake gasket. Changed that and volia!

 

[cgmtboarder]

i have a good feeling its the intake gasket. but ya the car wouldnt start at all originally and i changed the cas and now it starts just wont stay running. so i think maybe i just need to adjust the cas to the right setting. i never used anything to check the timing. just put it on where it looked like it was before

 

[cgmtboarder]

ok so i took the plugs out today and the number 4 plug sparks quite abit brighter than the other plugs. the number one doesnt spark very bright. so would this be the coil pack or the power transistor?

 

[Mr PopUps]

1 and 4 and 2 and 3 are together, sounds more like plug wires, but it would point to the CP not the PT since its batch fire not sequential.

 

[PIMking]

Get some good wires and plugs gapped to .28 NGK BPR6es is what you need.

Try that.

also it took me a total of maybe 45mins to do the intake gasket.

 

[cgmtboarder]

i got brand new plugs for it and no real difference and plugs are gapped right. so it would have to be the pt right? cause its not giving out the same power to each plug right? im sure i still have a vacuum leak i need to find. that comes next.

 

[jdodds]

check your base timing, do a proper boost leak test, check the coolant temp sensor, and make sure everything is plugged in. sometimes the connectors break or come loose.

 

[v-mac]

hey brother im not a pro on this stuff but your starting symptom sounds like what i had not long ago,my Coolant Temp Sensor had went bad ad i had to give it gas to start and then it would idle real low when i finally got it started until i gave it gas for a few seconds and it started working, if its that it sounds like urs is very far gone, but luckily its a cheap 30 dollar fix man

 

[cgmtboarder]

thanks v-mac! i will try that! no ones come up with that idea yet and i have a feeling that might fix it. the wires on that plug were rotted away so i had to build new connectors for it. so ill swap that and check results!

 

[chanley talon]

I to have had the coolant sensor do this. I think thats where you need to start!

 

[Alex Bland]

Did you happen to take apart your TB latly? and could it be ISC?