Idle surge,I changed everything!

[Pro3racer]

Okay, i had idle surge when i bought the car, it got worse as usual. I changed every vacuum line, the spark plug wires, the ENTIRE throttle body, with a new ISC! I put a new gasket on the throttle body>intake mani. What could my problem be, seriously, any help????

 

[tim_korn_99]

im not 100% sure about the n/t's, but if you have a FIAV (fast idle air valve) block that bastard off. From what i've experienced, and have read about, most all idle problems are because of this...
-Tim

 

[Pro3racer]

is that in a FAQ anywhere? The method and procedure to block it off. Also, could it be the PCV valve, or the egr valve, or would the FIAV be the easiest and most common reason.

 

[tim_korn_99]

is that in a FAQ anywhere? The method and procedure to block it off. Also, could it be the PCV valve, or the egr valve, or would the FIAV be the easiest and most common reason.

VFAQ is your friend, buddy.
http://www.vallotton.com/fiavblockoff.asp

My guess is still on your FIAV if you've replaced the ISC.
Good luck
-Tim

 

[Thunderskull]

He said he replaced the entire throttle body. The FIAV is part of the throttle body I do believe. Adjust your biss as per the service manual. You might also have a leak in your intake piping somewhere. The problem could also be egr related or even ECU related. I'd put money on ECU.

 

[Pro3racer]

what the hell, the ECU, man. I'll give you all the info i can remember. When i bought the car, it only did it for about 5 seconds after i started the car, then it stopped. When i start the car, it does a quick rev to about 3500(yeah, i'm not driving it anymore till i get that fixed!). then it drops to its normal 1200-1500. I'm performing a leak test(pressure), tomorrow night, then i might find aleak. There might be a leak in the accordian, its pretty old, and the ends aren't exactly new. A fricken ECU is so hard to replace, and you have to find the exact same one right?! When i do the leak test, is it okay to open the butterfly valve and hose air in the there too? Just making sure there aren't any leaks anywhere....anywhere. I talked to a friend today(haven't seen in a while...college), he said on his TSI, his idle surge was actually an oil pressure related problem, and it was fixed! Stupid cars are too complicated, i want a carbrated car!

 

[Mike1992]

Seems like you've gone over everything. Whats your idle set to when the cars warmed up? I remember back in the day when I turned the idle up via biss screw i would get idle surge, then I set my idle back to 750 and everything is good.

 

[Pro3racer]

I've never had my idle below 1000rpm, alright, if i could get idle surge, but be that low in rpm, i'd be happy, not too much, bu a little. I was doing more research last night, and i tested my TPS, and it was off a little bit, so that would cause my problem. I'm putting my car back together tonite, and we'll see, everything is very clean now, so at least i know my motor will run a little better. My EGR valve is not spotless, my throttle body is like new, my FIAV is looks like new, everything checks out okay on the OHM meter, it has to work, it has too.

 

[92DSMErdrick]

I had idle surge with my car. First started it and it went to 2000 something RPM's. ONce it warmed up it would rev between 1500-2000. I checked the ISC motor and one of the terminals was bad on it. IF you replaced that allready then it is most likely the Biss screw like mike said. Even after i replaced the ISC it still idled like shit until i turned it down.. you have to play with the adjusting alittle bit and eventually the motor will start to idle correctly.

 

[Pro3racer]

The thing is though, that when i ground the stuff, it doesn't seem to make any difference in the way stuff works. I dunno, maybe it does and i can't comprehend it, cuz i'm to busy doing other stuff. My BISS right now is 1 turn out, just because i don't like having it bottomed out, trust me, that isn't the problem. I will test the isc tomorrow again, when i remove it to see if the plunger works, can i also test the points(without running the car)?

 

[92DSMErdrick]

you can just read the terminals with a ohm meter. A haynes/chilton manual will tell you what it should read between the different leads on the ISC. (Chilton im not sure even has it. Haynes is the better of the two honestly) IF you get no readings on one of the pairs then the ISC is shot and even if you did the test to seeif it probes in and out it will prolly click and vibrate.(thats if its bad)

 

[Pro3racer]

I've done the ohmeter test many times over, i have not done the plunger test yet, because of lack of time. I should probably say, that i have done all the simple stuff, so no need to keep telling me it, if theres any really advanced stuff that may be the culprit, bring it on, i'm not afraid of touching this car.