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I have a freshly rebuilt ZE with pistons, headers, porting driven by a kl31 with je-50. We use the vehicule for ice racing. the engine runs fine when in idle or normally driven. Nightmare starts when we load the car under racing situation, after few laps the engine starts to lose power and makes fuuny noise (not funny at all) we tough engine was too lean so we installed an inline fuel pump but no improvment, tried different fuel pressure, not better.

If you have any suggestions, please advise, we need that thing back on track asap

Describe the "funny" noise?

It is like if you would have a misfire or wrong firing order

I'm going to suggest a weak alternator. Mine would work fine untill it had been running for a bit then it would heat up and my engine would start to die, no power. Feel your alt and see if it's running hot. If you can't touch it you probably have a problem.

Ya, alternator could definitely do it, you're straining the car somewhat more. Are you using the standard disty? The disty's wear out from heat and could cause misfiring...but I think you would notice that in normal driving too. If it only happens after awhile of being under heavy load, something is getting HOT and preventing other things from working right. Are you getting any codes?

To check alternator, you don't need to necessarily feel it - check the current coming from it.

onlytrueromeo wrote:Are you using the standard disty? The disty's wear out from heat and could cause misfiring...but I think you would notice that in normal driving too. If it only happens after awhile of being under heavy load, something is getting HOT and preventing other things from working right.

Hmm, I'm wondering if it's a problem with the coil or the ignitor...

Stupid question. Why not remove the hood at the track, takes like 2 minutes?

Daninski wrote:Stupid question. Why not remove the hood at the track, takes like 2 minutes?

Why would you want to do that?

^Engine bay cooling? Will keep car running MUCH happier if you're pounding on it. You drive in winter though, so I don't know if that's really an issue...Also, weight reduction!

Overheating is not an issue here, most of our race are done around -15 C and our colling fan is always on. We need the hood to prevent snow to get into air intake.

Update, we just bought a fuel cell that we are going to install tonight. We think that oem fuel pump might be tired and not supplting enough fuel. We tried to put another pump inline but we do not trust the fact that if rear pump is not supplying enough, front pump won't cover for it

Our last race, last year, ended with an accident in a snow bank. It turned out it damaged the fuel tank under the car and squeeze the fuel strainer. enough fuel was supply for normal operation but when under heavy load, fuel was not sufficiant.

W"e installed a fuel cell and a new pump and...Bingo like a new car

I LOVE when people write the conclusions!
Thanks!

yeah thanks for posting the conclusion...

I had similar problems and it ended up being injector failure...