backfire and smoking motor

[porsche gt3]

Hi,

I have a 73 2.8 mfi, twinplug motor that backfired very loudly today when I was driving the car. The motor was very unresponsive to throttle inputs until prior to it backfiring. It was more responsive after backfiring although it still was not running great When I parked the car i noticed the motor was smoking and apparently very hot. The paint on my rear fiberglass bumper discolored from the heat off the muffler.

Please let me know what is causing this and what can be done to correct this problem.

Thanks

[Steve@Rennsport]

Your symptoms tell me the engine is running too hot and perhaps due to late ignition timing or insufficient fuel.

You didn't mention anything about the details nor specifications about your engine so its not possible to offer more specific suggestions.

I'd also check:

1) Fuel pressure at the pump in case the filter is obstructed or the electric pump is failing.

2) Fuel pump timing.

[porsche gt3]

Hi Steve,
Thanks for your reply. What other information would be helpful for you to diagnose the problem. Most of the engine components are new or rebuilt.
Thanks

[stlrj]

Something like that happened to me on my 86 3.2 engine after I crossed a couple of ignition cables after a tuneup. Not only did it run like crap, but after shutting off the engine, it smelled like smoke and when I peaked under, the cat was glowing orange.


Cheers,

Joe