tom3

I can not seem to find a way to get a good idle... this is starting to get on my nerves...

I tried more fuel, less fuel, more advance, more retard and yet... I have a crappy idle.
Anything below 750 and the car dies, I have the idle at 900 rpm
(I have the mods below + home ported heads)

in a way it sounds nice (like an old muscle ca with no cat and long tube header), but at the same time it sometimes just die, and when I leave off a red light, sometimes I hit a spot where it's happy and revs right away, sometimes it stumbles and then goes.

I tried to disconnect the injectors one by one to see if I have a misfire and here's the funny thing: when my car was stock, removing one injector wire would drop the idle; this time, it doesn't matter which one I remove, the idle and the sound stay identical !

what should I look for?

badass383

You aint burning on all cylinders bud. You have to do the basics and then it will stare you in the face. Check spark to all cylinders and compression and leak down to all cylinders. remember you need fuel spark and compression.

If compression is bad you have to tend to the valves. If spark is bad look at the opti. Depends on how many cylinders is bad

n2ceptor

you could alway drill a small holes' in the thottle body blades..just for thought...

tom3

I tried to remove injector wires all over the place (one at a time of course) and it never changes the idle to be on 7 cylinders vs 8, no matter what cylinder I disconnect. I tried to run on 6 cyls and then, yes it shows but not 7.

All the header primaries are hot, so I think they all fire, but it seems like they're missing randomly at low rpm (could be the same but less visible at high rpm actually)

I heard about drilling the throttle blades to even out BLMs in case they're split, but they're pretty even here.

grygst76

If you converted to standard (m-6) your idle is supposed to be 900rpms, anything les it will die it is part of the ecu and the fact that auto's run at lower rpms

tom3

I flashed the CPU with a M6 copy of the eprom.

grygst76

check your wires, plugs, and especially the msd connectors set everything back to normal since you said you advanced-retarded-more fuel-less fuel---go back to the beginning

Mizz96Z28

I noticed you messed with your MAF, this could account for some of the problem. And M6's do idle around 900 RPM's so that sounds about right.

grygst76

One of the things I noticed right away is not all but most people I know who cammed their LT1's with a descreened stock MAF started to have idle problems because I did too so I put another MAF on and my idle was back to normal. The problem I had was a small stumble and erratic idle--in other words it would vary from 900 to 850 then back up and down it was miserable! Borrow a friends MAF and see if it goes to normal. You might have to buy a ZO6 MAF or a slightly larger diameter one like I am going to do.

snake_skinner93

how's your Fuel Pump? My 93 M6 does the exact same thing... sometimes it'll stay around 900 or 1000 and sometimes when i start it, it'll die as soon as it turns over. Other times it'll idle around 500 - 700. My fuel pump is whining BAD, so i figure thats what the problem is for me... just a thought if you havent replaced it already? Good luck!

tom3

I have to check my fuel pressure, I don't have a gauge yet, but I'll make sure to check it out. I hope the pump's fine though, it looks like a mess to replace. I never changed it.

The maf seems like an excellent bet, I'll check it out !