Hi guys I haven't posted in a long time and im not sure of the proper etiquette but im hoping someone can shead some light on a issue im having. I have a 1993 Enfini Rx7 with a street ported 13b with a single turbo set up running a Apexi power FC ECU. I am having an issue with my car. She is freshly rebuilt and still in the break in phase. I noticed recently that it’s starting to so some 3.5k hesitation and stuttering. It runs fine for 10-15 min then shuts off. checked the TPS and it’s working properly. I think the issue might be a failed fuel filter, a bad ground on my ecu. The thermostat switch is bad or maybe there is an issue with the relay banks for the fans on the rad. I am not 100% sure what is causing the issue but it seems something is sending a kill engine signal of sorts. It was suggested also that it could be a bad coil that's causing the spark to break up under load. This seems most likely. Anyway Just thought where better to ask my questions then on this site?

 

Are you running an ignition amplifier like an HKS Twin Power?

 

Yes I am

 

If you've never changed the fuel filter it is probably a really good idea to start there, do you notice a change in your AFRs when it hesitates at 3.5k?

Do you have any other aftermarket gauges for temp or anything? I'm not sure what would cause it to run fine for 15 min and then randomly shut off. Is the idle sputtering before it shuts down or does it just cut out as though someone has turned off the key?

 

My thoughts where the filter as well. i have a am air fuel gauge and boost guage the problem definitely seems to be electrical i did a bit of research and i think it might be the thermostat switch that is causing the issue but i'm not sure yet. and yes it just dies like the car was tuned off. unless i hit the throttle then it sutters and dies...some times it will be fine other times i cant get it go go down the drive way it's quite frustrating

 

Since your running a pfc I'm not sure if you can pull engine codes from the Rex, but if possible might be an idea to try and see if you get anything?

 

What is the pressure on your fuel pressure regulator when it's idling/ about to die?