Steverino

I am running an 86 RX7(non turbo) in ITS SCCA class road racing. I am having a real problem isolating a problem that has plagued me at the last three races and prevented me from running. The car is running perfectly at cold, warm and hot conditions. After a few laps on the track it just flattens out. It will sit and idle fine but acts like it is starving for fuel or has an electrical breakdown. Fuel pressure is fine, but when you try to rev it just bogs. When it is running fine it revs incredibly well. I took it to a local dyno shop, ran it for an hour and it was fine producing 172hp at the rear wheels.
I have replaced everything that makes sense,the ecu, the tps, the throttle body, fuel pump, filter, alternator, injectors, wires, etc.

The problem is that I can't duplicate the problem to get it fixed until I get it out on track and that only happens every few months. (not street legal).

If anyone has an idea or has had a similar experience, please respond. I would appreciate hearing about it as I am running out of ideas.

Thanks

JamesBong

At what RPM does it start to bog. Have you checked for any grounding issues? Idealy, the resistance between the NEG battery terminal, body, and engine should be 0ohms . Have you checked your plugs? I have heard that for racing, you should be running different plugs. But that's not something I'm experienced with. Also, there's a small screen filter in the tank. Did you change that?

NOPR

it might be a dirty fuel sock or bad baffling in the fuel tank. this is a somewhat common problem and it causes fuel depravation during hard turns because the gas is swishing away or getting clogged and not getting pumped into the engine.

read this thread: https://www.rx7club.com/showthread.p...ight=fuel+sock

i think theres something in the FAQ too.

-=1OneShotNO2=-

is there gas in the car?

Steverino

I have gone that route as well with the fuel pump and screen. That was actually the first thing I changed. It runs fantastic and always idles fine. When it starts it's problem it is on acceleration, when you give it throttle it just flattens. If it were carburated I would say it was acting like a bad pump in the carb. I really thinkit is alergic to asphault The grounding was another area that I considered but it only acts up after a few laps on track, bring it back to the pits and after a while it sounds fine, take it back out and once again it does it.

JamesBong

It sounds like the problem is heat related. Do you have a cone filter? Is it isolated from engine heat? I'd still investigate the grounding.

Steverino

Heat was one thought but it does it inconsistently. I have had it on the dyno and fan off with the heat to extreme and no problem. Possibly the other components of the car contribute to the heat. The grounding is one area I have not gone through terribly well and I will definitley rethink that one and add additional grounding straps.