rx7ahh

alright so the stock exhaust rusted out on my car so i bought the turbo back racing beat exhaust.. car has 93000 miles on it ran fine before and a day after then i was driving down the road and took off from a stop and the engine made a loud bang (detanation) im thinking and then the engine seemed like it had alot of vibration and then stalled out... i checked oil level, spark they were ok coolant level was ok..next day tried turning over car and it started up but i had to hold the gas to the floor and it started slowly once running sounded like a lawn mower and was running really shitty..sounds like its only running on one rotor...i have not done a real compression test just put my thumb over one of the rear spark plug holes...felt air pushing out sometimes but other times felt like no air was pushing....im thinking an apex seal let go but i dont really know much about these engines...i did not upgrade the fuel pump after putting the exhaust on...ive herd that i was supposed to...im wondering if anyone has run into this problem and i was wondering if there are other tests i could do on the car to figure out the problem... thanks

mike

rx7ahh

does anyone know anything that could help me out?

jenkin

i'm thinking that you are correct in your assumption that you lost an apex seal...

get a compression tester, pull the stem (so it doesnt hold pressure)

and have somebody spin your motor (disable ignition!).

i suspect that you will see a pulse followed by 0 compression x2 and then another pulse.

what you want to see is 3 pulses of 80 to 90 lbs on a rotor with good seals.



the better exhaust let the motor lean out, probably, but at 93K, who knows?

good luck



(if you are gungho, get a rebuild video and have at it! think oif it as a learning opportunity)

rx7ahh

yeah with my thumb over the spark plug hole it felt like every three turns i only had pressure once...if that makes any sense at all haha... thanks for the feedback

1Revvin7

Stock fuel system with the stock ecu, even with a bigger fuel pump cannot support a full exhaust system upgrade.

j9fd3s

and who knows what kind of shape everything was in? (poor battery cables + headlights = low fuel pressure) + (high load + open exhaust) = blown engine....

BDC

I agree.



The "bang" you heard/felt was probably fuel cut.



B

zRotary

yea, i guess it was fuel cut too. With a full-exhaust, you have to use a FCD.

also, a full racingbeat may lean out at higher rpms.. i guess it was the reason how i got my engine to death i was driving for about 20-30 minutes around 5000rpm on the autobahn (highway)

BDC

I'm gonna yell at you for the FCD recommendation, zRotary. I hope you don't hold that against me.



I wouldn't recommend that as I would instead recommend the use of a standalone at best or atleast one of those RTek re-chipped doowhippers, provided that the stock turbocharger still remains. The FCD "cures" an initial symptom, but it doesn't avert the overall problem and can, in fact, give a false sense of security about how the engine is running when the proper stuff isn't being metered and monitored. I say ditch the FCD idea.



B