Rennlist - Porsche Discussion Forums

Rennlist - Porsche Discussion Forums (https://rennlist.com/forums/)
-   944 Turbo and Turbo-S Forum (https://rennlist.com/forums/944-turbo-and-turbo-s-forum-72/)
-   -   # 2 cylinder detonation (https://rennlist.com/forums/944-turbo-and-turbo-s-forum/598148-2-cylinder-detonation.html)

renvagn 10-24-2010 09:01 PM

# 2 cylinder detonation
 
# 2 cylinder in the track car was found to have a missing electrode and 1/2 it's insulator. Symptoms were an uncommon flatness on acceleration then an occasional miss with no real audible change until the car had cooled. At that point I suspect it went terminal.

Compression is good, and I didn't see anything upon scoping it. Pulling the ejector wire with the engine running is positive for decreased function then returns to normal once reinstalled.

Temps were in the 60's, 14 pounds of boost, 94 octane. So what do you think caused this??????

I am thinking I need to have the injectors flow tested or do you think visual inspection of the spray pattern if uniform with the other injectors would be sufficient. Thanks.

hp18racer 10-24-2010 11:29 PM

I'd get the injectors flow tested, very cheap. http://www.lindertech.com/reconinj.htm

Also take a look at the wire harness for the fuel injectors. A problem with the wires to the injector could generate the same symptoms as a bad injector.

Chris White 10-25-2010 09:29 AM

That’s pretty bad detonation, I am surprised that the rings held up to that amount of abuse. Is the compression that same as all the other cylinders?

Could be the injector or the injector wiring. Also could be excessive oil in the intake – that will lower the effective octane of the fuel and increase combustion temperatures.

renvagn 10-25-2010 11:02 AM

Chris,
Compression is from 1-4: 130+, 125, 130+, 110. In fact the # 4 looked to be the most carboned. I have had excessive oil use this year despite limited car use. I figured the engine is getting tired despite 57K of which 12-15 are track.


All times are GMT -3. The time now is 03:54 AM.


© 2024 MH Sub I, LLC dba Internet Brands