I've just finished my first plenum pull and from what I can tell the injectors are fixed but now onto the next problem, the car wont idle , will just slowly drop rpms till it dies, ECUTalk is telling me that the AAC% is stuck on 90% at all times . everything else seems normal and it doesnt sound like there any air leaks ? what could cause the aac to run at 90% all of a sudden
Did you touch the base idle? Checked and double checked the connectors? Checked and double checked the vacuum lines?
all the connecions are plugged in, ive tried adjusting the idle by unplugging the yellow connector and playing with the screw, it was all the way in before and now its all the way out and no difference . double checked everything and as far as i can see it should be all good
The idle speed should be very high with the screw turned out and the plug disconnected. What did you do while the plenum was off?
changed the injectors, there isnt any unburnt fuel coming out the exhaust any more and the engine sounds better at higher rpm, but now it just doesn't idle its got to be something to do with the constant 90% aac reading don't you think ? or if there was a leak does the ecu set it higher to try to compensate ?
Have you checked Throttle position sensor? It could have been damaged or the connections are corroded with green residue or the adjustment has been moved. MichaelZ
TPS was fine on ecu talk But now I'm thinking it might of been the fuel rail to lower plenum seals . They were really perished and I knew I should of replaced them but needed to get the car running so I just reused them . Could air be getting into the engine though those seals ? The top set in this picture http://www.z1motorsports.com/popup_image.php?pID=47&osCsid=v3jag9ukmnpbt1jc8jkodkpac7&imageNum=2
Yes - Air is getting in somewhere Could be the lower rail insulator/ air seals, but regardless, this is typical of air getting in - a fair bit IMO Time to do a Air pressure test - it will be harder to hear it if its the lower fuel rail seals - you will need a funnel to help with a tube you can slot down in there
OK well I wasn't sure if air could get in though there since the injectors are all sealed but if it can it is definitely those seals because they were bad. Will get some new ones and do plenum pull number 2 this weekend ! (Gasket should be fine to reuse shouldn't it , has only been used for like 15 mins of engine running?)
