Weird Idle Surge, Please Help.

[jb0821]

I have a 2G GSX with a 6-bolt swap. The car experience idle surge only some times.

I've replaced the IAC, BISS and O-ring, cleaned the throttle body, checked the vacume lines

Here's the weird part. I experience I.S. constantly until I was on the highway and the BISS backed itself out. As soon as I put in the new screw the idle was perfect. Its been about one month now and the idle suge is back but it only happens on certain days. I always notice it happens when I go to start the car and it does not fire up right away. It will crank about four or five times and then fire up. After that it will I high and then start surging. (95% the car will start on the first crank and idle perfect)

If anyone can help please let me know.

Thanks a lot,
Jon

 

[mark95turbo]

Did you check the ECU before you put it in? The 1st gen ECU's have a tendancy to have leaky capacitors which can cause irratic behavior. I've gone through 3 ECU's on my current DSM. How much is it surging? Does it surge up and then back to normal RPM's, does it surge from idle to almost stalling? Does it jump way up then almost stall? If it just almost stalls, I would try and replace the fuel filter. Good luck!

 

[91dsmeclipse]

my rpms go iratic they go beetween 3000-2500 rpms and when i stop sometimes the car dies on me and the car will not start for about 10-15 mins then starts back up fine until it does it again may it be leaking caps.But i do know my tcu is burnt in my car so im waiting to get it off of ebay. may it be the tcu cuasing this. i dont want to end up buying 2 computers.

 

[jb0821]

I replaced the ECU. It still has a 2g ECU. I also replaced the MAS sensor.

The car idles between 1500 and 2000 RPM when I come to a stop.

 

[91dsmeclipse]

i have a feeling at least with my problem its my aic opening at the wrong time

 

[21stEagle]

Originally posted by jb0821
I replaced the ECU. It still has a 2g ECU. I also replaced the MAS sensor.

The car idles between 1500 and 2000 RPM when I come to a stop.

MAAAAAAN, I have the same problem, and if you changed the computer and it didnt help I dont know what to do, because I want to replace it too and now I'm not sure if it's gona help

 

[21stEagle]

I'm going to check my PCV( Positive Crankcase Ventilation) and EGR(Exhaust Gas Recirculation) , EGR sumptoms are rough idle and driveability problems. PCV and EGR deal with vacuum. Problem with vacuum > problem with ideling.

 

[crankbender]

If you are surging you are getting extra air. This really can only come from a few places.

Fiav
TB gasket
ISC
Vacume hoses
EGR
PCV

find the leak and plug it

 

[mitsugsx95]

Dont go too crazy with buyin things just yet. Have you tried adjusting the throttle cable yet? It may be off (cable too tight) and still read 0% throt. I would check that out, also, try using your 2g FAIV... the 1g ones have a tendancy to keep the revs up, even after the cars warmed up. GL on that.

 

[jb0821]

My throttle is sometimes reads 0% and some times it will read up to 8% (according to the SAFC) when at idles but even if the throttle is reading open it idle fine.