RE_TurboFB

All right..... This S4 rx7 has a fresh rebuild on it used to start up great... It has 100 PSI on the front rotor 110 PSI on the rear rotor! Good even sweeps of compression!!!



Anyways it was running like a champ exept I cant seem to get the TPS set right. Its real hurky jerky when I try to cruise with it more so around 2000RPMs and it searches for idle..( most of the time )



Then bam out of the blue it starts running like it fouled the plugs!! So i took them out and cleaned them.. ran good for a few minutes, then started the fouled plug sound again (like a helicopter) Cleaned the plugs again it still sounds like ****!!!! when I look at the plugs the ones from the front rotor look fouled but the rear ones look Ok..



The front ones still spark when they look fouled but barely!!



Any advise would be helpfull!!



Thanks guys!!!!



P.S. I can get pics of the plugs if it would help....

RE_TurboFB

hummm......... I put new plugs in it, And still it runs like ****... I did a nother compression test and both rotors have perfect sweeps of compression...



So the engine has good compression, good spark and I know air is not a problem ... so could this be a fuel problem..??????

fc3sboy1

whats the fuel presure set at. what ecu. what other mods. kinda sounds like you have some tuning issues. also do you have the engine grounds on it?

RE_TurboFB

I have a ground to the tranny, one to the block and one from the ecu to the block...



It sounds like it is running on one rotor.. I'll pull the plugs and the front ones look burnt and the rear ones look clean.. like the rear rotor is not firing, But I have good spark on all plugs..



I know when you over rev one of these engines or over boost one it will cut fuel from the rear rotor.. Right...??? Could the ECU be fried..????



The engine is basically Stock. The emissions have been removed (EGR, BACV, ACV, ECT..) And it has a throttle body mod done to it.. it has a Stock ECU, Stock Fuel pump and fuel pressure regulator...



I guess I need to check the fuel pressure..???



I installed a air/fuel ratio gauge and it reads lean like all the time... Unless I rev on it, then after I let off the throttle It moves up to optimal for sec then back down to lean....



It was running great.. holding it at 2000 RPMs then all at once it just started running on one rotor.....



Is there any way it could have a stuck seal and I'm just not seeing it on the compression tester..???



Thanks for the help guys!!!

RE_TurboFB

So I installed a fuel pressure gauge, And The car only has 26PSI of fuel pressure... The car needs 35PSI right..???



But could this be this engines problem..??



I guess I will find out.....

FIREFLYS4

when was the fuel filter replaced last? a blocked fuel filter will cause a drop in fuel preasure.



Keith

RE_TurboFB

Just did a fuel pressure test with a new filter and it read 30 psi .... That should be plenty of fuel pressure to run the engine right..????



WOW I'm really stumped on this one...

hillbilly

timing?

RotaryRocket219

Everything you describe makes it sound blown...but as you stated the compression is good. hmm. never heard rotary with a clogged cat but maybe something to consider. are the injectors plugged in good? hmmm good luck

RE_TurboFB

Bingo!!! I decided to tear the intake manifold apart to see if the injectors were spraying and the rear primary injector was not....

It turned out that there was a bad injector clip!!



It's kinda funny how it all of the sudden just went out....



Any way the car is running strong now!!!



Thanks for the help guys...!