Join Date: May 2002
Location: Vicroads inspection bay
My car seems to be running on 4 cylinders....done a few tests that seems to confirm this but I can't seem to fix it....any help appreciated!!!
This is what I've tested so far. Removed the plugs from the injectors one by one, idle should drop. Idle dropped for cylinders 1-4 but removing the plugs from injectors 5 and 6 made no difference to idle.
This can indicate bad injectors so I removed the fuel rail while it was still connected and cranked over the engine. Fuel sprayed from all injectors and none of them had irregular spray patterns. So it was getting fuel ok.
Also tested the fuel pressure and it was spot on 250kpa. So the pump and reg are ok.
Next I tested for spark. Got a spark plug, opened the gap to 6mm earthed it with a jump lead and hooked it to cyl 5 and 6 spark plug lead one by one. Spark was there and was ok.
Next I started the engine and removed the no.1 spark plug lead. The idle got worse. Put it back and removed no.5 lead....no change in idle. Removed no.6 lead, also no change in idle. Seems as if no.5 and 6 cyl aren't doing anything.
Also you may or may not know that each turbo is running a separate manifold (3 cyls each). The second turbo is running off cyl 4, 5 and 6. If I remove the injector plug from no.4 cyl the engine starts backfiring and stuttering as if there is no exhaust gas to spin the second turbo and its just creating a massive restriction. Also, the front turbo gets a lot hotter than the second one....initially I thought this was a problem, but now I'm thinking that maybe thats normal the second turbo is cooler cause it only has the exhaust gas from one cylinder spinning it.
So if cylinders 5 and 6 both have spark and fuel, why then are they making no power??? They were fine before the turbos went on and the turbos haven't been plummed in yet so the engine is not under any extra pressure.
I also ran a ECU fault test and it showed up nothing. The car is running very rich though...I got 30ks out of 15bux.