Well, I just got done porting and polishing my intake manifolds on my s5. I got everything back together and started her up. She started, dropped to 1000 rpm's and died. So I took all of the manifolds back off to check for anything left disconnected, etc. I put everything back together as it should go and tried again. Same thing, she will start up with a loud *** backfire then die. WTF is going on?
Oh yea, I can keep it running if I keep revving it, but just barely.

 

sounds like a vacuum leak, go buy a can of starting fluid and get a helper to start the car and keep it at a steady rpm and spray the fluid were you think the leak is, when the rpms change thats were the leak is


good luck

 

Sounds like a vaccum leak, did you reuse your gaskets or did you buy new ones? If you didn't buy new ones I suggest that you do or go get some RTV to use.

 

I bought brand new gaskets and used RTV so I dont think any of the manifolds could be leaking.

 

mine acted similar to that after i ported and such, and then i reved it a few times and it coughed, etc then idled smoothly. I dont know what it was but its fine now

 

Well, Ive tried turning it on and keeping it going like 10 times now and it didnt do anything different. Wouldnt a vaccuum leak have to be a lot more than just a little vaccuum hose to keep the car from even running?

 

I think you knocked your TPS out of spec.
Readjust the TPS to recommended...


-Ted

 

HMMM, the tps. That could be it. Would it be messed up if I took the throttle cable off? How can I check it if I cant keep the car running?

 

ive took my cable of numberous timed, tightened it, loosened it etc etc and ive never readjusted it and it works 100% still and is accurate, so i dont know..

 

Ironically from Ted's sig I found...

http://fc3spro.com/TECH/HOWTO/TPS/tps.html

 

it could also be the pressure sensor.. mine did the same thing when i forgot to hook mine up.. or the idle hose from TB to the inlet pipe??

you checked these too?