88 427 Camaro

The setup is a Holley 750 Vac sec on a performer rpm. External Holley blue pump with KN filter. Last year it started dieing sometimes after the burnout. Still happenes now, but seems to be getting worse. Runs great during the run though, so it doesn't seem like the fuel pump since it uses a lot more fuel during the run than during the burnout. It's ran great for 2 years prior, then this started happening. Any ideas?

Thanks
Miles

cr125r

i think it means u have a vacuum leak. it does that to me too, but cant find a leak. i dont know if thats it cause im pulling 16 inches at 700 rpm

five7kid

iTrader: (14)

If you wouldn't mind, describe your burn-out routine and what happens before, during & after, in a little more detail. Also what fuel pump you're using.

Damon

This is going to be a rater odd response to your question but hear me out.....

It COULD be your ignition. I JUST went through something similar with my friend's car/engine. After 2 YEARS of gradually getting worse we FINALLY nailed it. The ignition coil got flaky. It would pull like a mule running through the gears. As soon as you let off the throttle and let it coast down it would DIE. It used to just kinda stumble around for a while and then clear up. But if got worse over time, eventually leaving us stranded by the side of the road for several minutes before it would restart after every WOT run. It occasionally seemed a little weak in the upper RPMs but no popping of hesitating like you would normally associate with a "dead" coil.

Something in the coil went wacky any time the coil would heat up. Let it cool down and it would run fine.

I am NOT saying that this is definitely your problem. But we chased carb issues out the wazoo before we started looking at the ignition. And that car uses basically the same HEI distributor/coil that your car uses. Coils die sometimes. And sometimes in very odd ways.

A vacuum leak is another definite possibility, as CR125 says. In fact, I'd check that first. Just wanted to let you know of this "odd" ignition behavior in case some of the symptoms line up with yours.

Remember- 90% of all carburetor problems can be found in the ignition!

icebird_1981

Damon
thanks u just said everything my car does>and its getting worse for me fast. so did u only need to replace the coil?

Damon

Yes. I did a new cap at the same time. That made it an easy swap. Assemble the new coil into the new cap and then swap the whole assembly with your old coil/cap as a unit. Saves for from the possibility of dropping/losing any small parts trying to do it leaning over the fender of the car one piece at a time. Still gotta swap the coil cover over separately but that's easy.

The only other part that I'd consider swapping that could cause similar problems would be the ignition module. Usually, though, they either work perfectly or not at all.

sqzbox

R-U running an atomatic trans with stock converter? Sudden off throttle with tires that are hooking up will pull the rpm's down to 0 and kill the motor not to mention wear and tear on the conv. might try easing off the throttle instead of jumping off it suddenly. Just a thought! If your running a man. trans, don't pay any att. to this!

88 427 Camaro

Thanks for the input everyone. I'm going to try and dig in to this week.

Miles