Just like to post that following the install of my series 2 PTU into the Godfather, I no longer have any erratic idle. Car is a manual - not sure if that has any relevance. It's almost disconcerting that when I pull up at the lights etc that the idle goes straight back to 700 app RPM. It used to rev to 1500 RPM then over about 5 secs reduce to 700 RPM. I almost feel like revving a little because I'm not used to it and think it might stall. LOL: My NA with a series 1 PTU still revs to 1500 and drops slowly. Has anyone had a similar experience with installing a series 2 PTU? Cheers, Peter
Hmm sounds weird Have you looked at your aac valve with a computer. It not only controls the idle but it opens up with throttle operation i guess to smooth the falling revs when you get off the gas. If the idle adjust screw is adjusted to give an aac % of about 20 - 25% at idle thats good. 15% is minimum try to get above that else its not able to work well. maybe the valve is sticky so could do with a cleanup? some carby cleaner down the auxiliary air pipe while its idling and revving might just free it up.
Pete is saying that the series 2 PTU fixed it. Got nothing to do with the AAC valve or idle adjusting screws...
I installed a S2 and it didn't make a difference. Maybe you just had dirty connections on your S1 PTU?
2nded. If he had dirty/poor connections on the S1 PTU and by replacing with a S2, the connections were fixed. The ECU is smart enough to know when a cylinder(s) is not firing 100% and tries to compensate through the others. You can test this doing the load balance test on datascan/consult. You'll see the RPM drop briefly as each injector signal is interrupted and then the revs rise again. This is the ECU doing the compensation thing. This might explain the weird behaviour.
OK, The N/A as you know is my DD. I maintain it well, but generally don't spend improvement money on it. Therefore it stilll has a Seres 1 PTU and goes really well (and now I have a spare). It has no fluids consumption, and no other problems other than some slop in the drivetrain (previously posted) that I am still chasing and will fix. Re rpm, my NA does take some time to get to 700 rpm at idle. Generally about 4-5 seconds after stopping at a set of lights. Same as the TT before the Series 2 PTU install. I therefore, wiithout scientific proof, expect that if I replaced the Series I in the NA to a Series II, this would be fixed also, and the car would go to idle almost immediately. So, I will re-clean the male and female plugs on the S1 PTU, but I think the PTU circuitry is to blame, not the connectors (but I could easily be wrong). Cheers, Peter
When I replaced the CTS many of my idle issues were resolved. Similar to yours, starts high then after a few seconds it takes a while to drop down. What I've noticed now is the idle sits around 750 and you can hear the engine kind of compensating because it's about to stall. Don
