Reviving Dead Cobra

[eschaider]

Unless your engine failure was caused by an overheating problem, it was a tune problem. You will need to get your EFI retuned for your new engine, or it will suffer a similar but more extreme version of the failure you are currently repairing because of the increased power levels.

[C5GTO]

Originally Posted by eschaider

Unless your engine failure was caused by an overheating problem, it was a tune problem. You will need to get your EFI retuned for your new engine, or it will suffer a similar but more extreme version of the failure you are currently repairing because of the increased power levels.

It wasn't a coolant system overheat problem as the coolant temps at the gauge sensor didn't exceed 195 degrees prior to the failure. It might have been a localized overheat issue around that cylinder but I have no way of knowing that.

It could be a tune issue as the EFI system is a 30 year old EEC IV setup. The EFI was dyno tuned about 10 years ago but that was done much closer to sea level. The engine failure occurred at about 7,000 ft elevation. Yes, the ECU should have adjusted for the elevation change but you never know.

I am looking into a new EFI for this engine at this point. Another reason is driving this but I'm also concerned that the existing 30 year old EFI tech is a shaky foundation to build on and my trust level with it is low.

[twobjshelbys]

Originally Posted by C5GTO

It wasn't a coolant system overheat problem as the coolant temps at the gauge sensor didn't exceed 195 degrees prior to the failure. It might have been a localized overheat issue around that cylinder but I have no way of knowing that.

It could be a tune issue as the EFI system is a 30 year old EEC IV setup. The EFI was dyno tuned about 10 years ago but that was done much closer to sea level. The engine failure occurred at about 7,000 ft elevation. Yes, the ECU should have adjusted for the elevation change but you never know.

I am looking into a new EFI for this engine at this point. Another reason is driving this but I'm also concerned that the existing 30 year old EFI tech is a shaky foundation to build on and my trust level with it is low.

The old EFI system probably doesn't do altitude compensation, but going up in altitude causes a rich condition. Did it backfire? Engine overheating from fueling is usually caused by a lean condition.

You should get a new EFI system, but at the cost these days, and if you don't need the benefits - ie, automatic altitude compensation - and unless you use a MAF based system which does compensate for altitude and other conditions, then you're just as well off with a well tuned carb(s). There are many topics on this subject here so I won't repeat any more other than to say that in most cases an EFI system operates as a very expensive carb.