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View Full Version : need help in diagnosing a problem!!!!!!



b00st
11-26-2006, 07:56 PM
well i went to drive my car. drove it over to my parents house just fine. no issues. i'm driving home and about 2 minutes later...idle issues. i'm sitting at the light and the car just dies. no CEL's have come on. car didn't want to start. took about 5 minutes...it fired back up. but he idle was real bad. it was bouncing up and down badly and holding below idle. then the after driving the car a few blocks it died again. i let it chill out and about 5 minutes later i was able to start it again. the idle is garbage. this almost seem like my bad ecu but then again not really cuz i can get the car started up. i think it has to do with the idle.

my plugs are 6E's with about 2k on them.
my MAF is new and it is plugged in.
i don't think the ECU went bad.
I have no CEL.

i just have a bad bouncing idle....and half the time it likes to hold underneath normal idle. this is about all i got to go on? could it be a bad coil pack? MAF is just a couple months old....not that i can't go bad. i had to leave the car at my p's and take theirs.

any ideas for things to look at?????

pipe7284
11-26-2006, 08:01 PM
it happened to me too, it started right, but after a few min it turned off, after ooking around (thanks to AZ) it was a boost leak, the hose that goes to DV was unhooked, clamped it back on and it runs great. check for any boost leaks, probably a hose cracked or something.

94jedi
11-26-2006, 08:01 PM
ICM or a coil pack maybe? I dunno, I'm guessing here. bad idle is usually plugs or maf related. I'd say check your plugs and maf anyway to be sure.

fred2ka4
11-26-2006, 08:03 PM
Have you tried to vag it yet?

A bad maf would show up when you vagged it, but I don't know if it would throw a cell.

b00st
11-26-2006, 08:18 PM
plugs look normal for pc16.

no vag at parents house. car is there. no vag period anymore though. it is gone like my old laptop.

MAF is new....i suppose it can fail. took 7yrs for first one to go.

boost leak is possible. though nothings been touched. when i had a bad ECU it did give a ECU that blink for about 3 seconds and then shutdown. i can fire up the car. so maybe it is a boost leak. i will check hoses tomorrow.

maybe it has something to do with the day i left my car on for 2hrs in the sealed garage. thought it was the turbo timer on. i left the key in the ignition. that sucked. found oil on the floor after that. cleaned up all the leaks. and they never returned. maybe something happened to the some of the hoses.

so i guess maybe a boost leak. if i get it vagged at renn-art...then they can check the MAF signal. or maybe a coilpack has finally gone bad. i thought CEL showed up when they go bad. not so much as they are going out but when they are dead...i thought a CEL happens.

b00st
11-27-2006, 11:39 AM
ok so i'm at my p's house with the car looking it over.

no cracked hoses that i can find....for the simple ones i can look at. but i noticed something.

at idle. i'm seeing the proper vac. about 17Inhg. when i rev the car. normally that doesn't change. in this case. when i rev it...its like the car is under load or in gear. cuz when i rev it....it goes to 21-22InHg. then goes to 17InHg. normally when you rev in neutral...it stays at 17InHg. It only drops to 21-22InHg when i'm driving and i left off the gas. at a stoplight/sign it always reads 17InHg. So i tried to back it out. and the car just died. didn't make it 2ft. i let it run for 2min....what i think was good. cuz the car didn't have bouncy idle. when....it did just as i started to pull away. any ideas....why it would incase vaccum...on a rev. i'm in neutral the whole time. fuel pump or fuel filter starving the car? vacc leak that i can't find?

mike-2ptzero
11-27-2006, 11:56 AM
Originally posted by fred2ka4
Have you tried to vag it yet?

A bad maf would show up when you vagged it, but I don't know if it would throw a cell.

Damn can your SIG picture get any bigger? [;)]


BTW should it say
"Just a squirrel trying to get a CF nut"

a4sleepa
11-27-2006, 12:41 PM
seriously

Quattrocket
11-27-2006, 02:42 PM
You should be around 20-21 in vac at idle. I think you have a big leak somewhere. check around the intake mani and DV/turbo area. squeeze the hoses and see if the feel funny. My leaks were around the throttle body off the intake mani. I think it was for the brake booster or something to that effect. good luck

b00st
11-27-2006, 05:34 PM
what.
i've been 17InHg since the start. when i drive and then get off the gas. its about 20-21InHg or so.

i check the rubber intake pipe...its good there. i didn't really disconnect the TIP to see if there were any tears.

I'm starting to get the feeling that my ECU is bad. I could be wrong. what is everyone else at, at idle? what i do know is that even at idle and you rev....you don't see more vac. and i do...maybe those vac discs went bad.

mike-2ptzero
11-28-2006, 07:03 AM
Originally posted by b00st
what.
i've been 17InHg since the start. when i drive and then get off the gas. its about 20-21InHg or so.

i check the rubber intake pipe...its good there. i didn't really disconnect the TIP to see if there were any tears.

I'm starting to get the feeling that my ECU is bad. I could be wrong. what is everyone else at, at idle? what i do know is that even at idle and you rev....you don't see more vac. and i do...maybe those vac discs went bad.


When you rev the car the vac should go to zero, then drop back down to normal after the rpm has peaked and drops back down. If your vacuum increases when you rev the car then you most likely have a huge leak between your turbo and throttle body or something is blocking the air from getting into your intake manifold.

b00st
11-28-2006, 09:33 AM
Originally posted by mike-2ptzero
When you rev the car the vac should go to zero, then drop back down to normal after the rpm has peaked and drops back down. If your vacuum increases when you rev the car then you most likely have a huge leak between your turbo and throttle body or something is blocking the air from getting into your intake manifold.

aight...I'ma take the TIP off and inspect it. take off the

yes before this randomness happened. when i would rev...it went to 0InHg...then would drop down to my norm. i think after i drive around a bit...it becomes 19InHg.

at any rate. now vac increases when i rev it...and basically just cuts the motor. i will inspect the TIP and intake mani side and report back.

b00st
11-29-2006, 06:19 PM
well car was towed into the shop.

all that was retreived from the ECU was an intermitent ICM code.
dunno maybe the ECU is going bad again?!

car is not dying out on the shop.......figures. he said he ran it in the shop and the car never died once. he cleared the code. and is going to drive it. dunno what the deal is...thats the only code he got. stuck between a rock and a hard place. the second i get back into it...it will die on me.

b00st
11-29-2006, 10:55 PM
no ideas huh?

badassbaldie
11-29-2006, 11:36 PM
Kev, you might want to check the the vac hose that connects into the bottom of your DV. I believe that it is 3/4" and it kind of has a "S" bend in it near one of the pulleys (A/C I think). Mine managed to rub on the pulley causing a 1" slice and a HUGE boost leak, which would support what others have said. The only thing was that I was able to hear my leak, which is something you have not mentioned.

iin10ded
11-30-2006, 12:21 AM
have you checked the obvious stuff? battery, alternator, etc?

b00st
11-30-2006, 10:00 AM
the car was towed to Chicago Performance & Tuning. i don't have possession of it. according to them the car runs fine.
has something to do with this intermitent ICM or something like that...he told me over the phone while i was driving in traffic. bad thing is i know it doesn't run fine. before CPT picked it up, the towing company was there....they started my car and tried to back it out...it died. CPT let the car run...they can't get it to do it again. but now...i gotta drive it knowing it will eventually stall me out somewhere. its feeling more and more like a bad ECU....well on the way going out. nothing they can do for that.

www.gocpt.com its a great place...they build so seriously fast s4s.

TQMB5
11-30-2006, 10:07 AM
that happend to me when my dv line popped off, try unhooking your MAF and then see if that fixes the problem, if so you probably have a big boost leak somewhere

b00st
11-30-2006, 12:34 PM
they did do that. car seemed to stay running. but they called me and said they found nothing as far as boost leaks.

b00st
12-01-2006, 09:50 PM
update. no boost leaks.

i'm getting code 16988 - internal control module
i'm assuming that means my ECU is going bad....but i'm
assuming that here.

also the new list of junk.
OIL LEAKS:
cam seals
cam shaft adjusters

water pump leaking
hose by water pump leaking - this explains the mysterious disappearance of the coolant level.
coolant leak on turbo - just needs to be tightened or something.

rear diff leaking

suspension: front right side lower curved arm. or basically control arm.

so basically i need a new TB Kit done including waterpump. oil has messed everything in the front end.

TB KIT $269
Labor for that plus something with the adjusters is screwed up $600-700
fix seals on rear diff. $500
control arm + labor $280-300
and if the ECU is dead. i'm looking at $2000+ in repairs. this sucks. just as i get close to buying my BT kit. i get slammed. its a nice xmas present...maybe santa will pick up the bill. santa are you reading this. i want this bill picked up for XMAS!!!!!!

i coulda just put this money into buying a new daily driver. but no...i drive an audi a4.

Poopie
12-01-2006, 09:53 PM
damn sucks bro. You can find used ecus for about 200 buck though. I'm sure a local GIAC dealer won't have a problem socketing it for your pc-16 chip. If you were local I would swap ecus with you.

BzeB5A4
12-01-2006, 10:09 PM
sh*t man, just read all thats going on with your car.

If you wanted, we could switch ecu's if you wanted.

let me know if you wanna do that.

badassbaldie
12-01-2006, 10:33 PM
TB KIT $269
Labor for that plus something with the adjusters is screwed up $600-700
fix seals on rear diff. $500
control arm + labor $280-300
and if the ECU is dead. i'm looking at $2000+ in repairs. this sucks. just as i get close to buying my BT kit. i get slammed. its a nice xmas present...maybe santa will pick up the bill. santa are you reading this. i want this bill picked up for XMAS!!!!!!


Kev, you realize that all the above repairs are not THAT difficult to do? I've done the water pump, control arm (I did all mine), and that rear diff. seal is about a $3 o-ring. You might want to reconsider paying someone all that $$$ and do it yourself...

b00st
12-02-2006, 12:22 AM
john,
yeah control arms aren't that big of a deal.
rear diff....i know the parts are cheap...the labor is killing me on all this. its not the parts part. i'm sure i can look it up and figure out how to do the diffs seals......but i don't really have time to play. its time that is the problem.

sure i can do the TB kit if i really wanted to....but i don't. i don't have time anymore to screw with the car. CPT is a class "A" operation....i just can't spend my weekends tooling with the car anymore.