Is this idle surge, and if it isn't then what is it called?

[4gfun]

I have read alot on how to get rid of the idle surge. Basically, I received my car with the lower honeycomb and silencer removed on the MAS.

The car idles normally when I start it, but after about 3 minutes of warming up, the idle goes back and forth between 800 rpm and 2500 rpm.

I just want to make sure that this is clearly the "idle surge" that others complain about before I try to troubleshoot.

Thanks!

 

[mach4g63t]

Ya, that sounds like Idle surge. Generally, your car will run about 1500 RPM's for the first few minutes that you start it cold until it warms up. It's generally a good idea to let it warm up. However, once it's up to temp, it should sit at about 800 rpm's, give or take a few, and not surge. If it is, you might want to check your car for vacuum leaks/boost leaks, etc. Just do a search on Idle Surge and you'll find lots of good info.

 

[VETTE_50_TH]

Usually the good thing to do is block the EGR, block the FIAV, replace the ISC, and make sure the biss is all the way down, sometimes they become rotten and you must replace them. Read up on those things, and that should help significantly.

James

 

[pdc]

Many cases are the Idle Speed Controller.

 

[fubar_mdw]

I read on vfaq.com that he tried that drove it for awhile and said not to do it because it causes bad side affects, but thats just what i read on there.

 

[VETTE_50_TH]

I read on vfaq.com that he tried that drove it for awhile and said not to do it because it causes bad side affects, but thats just what i read on there.

If that was the case, we wouldnt have websites like this

James

 

[fubar_mdw]

If that was the case, we wouldnt have websites like this

James

sorry should have been more clear,
i was talking about the removal of the lower honeycomb in the maf

 

[4gfun]

Thanks all....

I read the same thing about the lower honeycomb to.

Interestingly enough, the previous owner provided me with an extra maf that seemingly looks brand new.

Has it's lower honeycomb intact etc.

It seems that removing the lower honeycomb causes scenarios from no problem at all, to plenty of problems.

Funny thing is that I can't do a damn thing with my SAFC to stop the idle from bouncing. Makes me lean towards a bad ISC.

 

[fubar_mdw]

you could go to a junk yard and get one just to see if its that or not.
have you put the other maf in yet?

 

[4gfun]

you could go to a junk yard and get one just to see if its that or not.
have you put the other maf in yet?

Not yet....

 

[VETTE_50_TH]

Im not sure, but i drove mine around for quite some time with the lower honeycomb gone, and it ran fine. No improvement in gas mileage. When i went to the maf-t, my idle surge went away. Then, i had to get a new ecu, and it came back. WTF

James

 

[Ryn1727]

I had really bad idle surge with my car until I took apart the throttle body and cleaned it up and replaced the seals, probably not your problem but I just thought id give some input in case you hit a dead end.

 

[AWD_Boosted4g63]

I also removed my lower honeycomb, but it didn't idle surge, the only thing i noticed different, was that if i was at 4 to 7 grand on the tach, and shift into neutral, or clutch it, it would sometimes die or get to extremely low RPM 200 to 400, but i got a 2g mas now so it's all good now

 

[4gfun]

Thanks for all of these responses.

This car also "supposedly" has aftermarket cams. Vacuum on my autometer is only between 15-17 at idle and it seems like alot of the dsm's get 20 at idle.

I wonder if cams could be causing this....