I've checked many things to find my hunting idle and I've come to the conclusion that perhaps it is just that my engine needs a higher idle.

Could this be the case?

I run a 350, ZZ3 cam, 1.6 rockers on the intake, edelbrock heads, ported this that, bla bla bla.

For those of you with a ZZ3 cam/motor (or any larger than stock cam), did you find that you need to raise the base idle?

Mark.
PS not directly prom related, but the audience here would be the ones to know if an idle change was required.

 

I've tuned cars with both ZZ3 and ZZ9 cars with and without 1.6 rockers in speed density LT1's.

I've always been able to leave the Idle alone on both of these cams. even with a automatic/stock stall I can get them to do quite fine at a 550-600 idle in a LT1.

ZZ3's have really tame idles

I've noticed that improperly tuned VE tables will cause a wavy idle. Also sometimes with a high stall convertor say anything above 2600 the car sometimes will get a little wavy while driving but not surgy.

Also sometimes a car with a split BLM problem will do this.

 

I did not think the ZZ3 was wild by any stretch. My problem has to be in the fuel. I've eliminate the IAC, MAF, Spark, etc.

What do you mean by split BLM?

Mark.

 

What type of car are you tuning? Speed density or MAF.

by split BLM's i mean that the left bank differs from the right bank.

When they start to seperate by alot you can run into some problems.

 

My setup is a MAF. So your saying a split left and right bank of injectors? Or split block and int learn. Sorry if I don't follow.

Mark.

 

exactly when block learns differ injector pulse will too.

to bad your not on a speed density setup. I'd send you a ve table or two from some ZZ3 cammed cars.

I have a small idea about tuning MAF cars

 

You know, tonight I tried something else. I disconnect my O2 for the heck of it. The darn thing hunted worse than with the O2 connected.

Without the O2 input, does it still vary the pulse widths to make it go rich/lean a bunch of times. But since there is no O2, it varies it ALOT?

Does this sound like the symptoms of a lazy O2? Or is it fuel delivery?

Scanner shows the O2 doing it's thing. Cross counts vary from 3-11 or so.

Even tried a seperate ground on the O2 just in case. IT's only two years old.

I sound so scatter brained on this.

Mark.

 

just try to get the BLM's to 128 at idle and see what happens

I think it just needs to be tuned better

 

BLMS are usuall 130-131 for me. I can try to get it down to 128 and see if the helps. They have always been at 130-131 and never had an issue with the idle. I may have just been on the edge of a bad idle. Who knows.


Thanks,
Mark.