So after a little diagnoses of my ACD problem, I discovered I needed my pump replaced. I bought one from a low mileage Florida car and recently installed it. After bleeding the system I started up the car and all was fine. Only the Tarmac light was lit up and I was happy. Then out of nowhere the car almost dies and then starts idling really rough, loping really bad. So i decided to take it out for a drive to see if warming the engine would solve things. I figure along with the crappy idle the drive ability would suffer. It seems to be largely unchanged. Low speed drive ability is the same, and there is no missing up top when boosting. But when it comes back to idle, it just sounds rough, sometimes sounding like it's missing a cylinder completely. Some of my other thoughts are that this pump is putting an enormous amp load on the car, maybe something is wrong with it, but wouldn't it throw the ACD lights on if that were the case? When I cycle the pump when the car is off, it runs for a second and then shuts off after reaching pressure. It doesn't sounds bad. Sounds like it turns freely and does what it's supposed to. I just find it odd that the car is now idling strange immediately after installing this thing. One thing to note, I was very low on gas and the car was jacked up in the front. Maybe I sucked something up, I don't know. Could be a coincidence I guess. My next step is to unplug the pump and see if that changes things. In the meantime, does anyone have any ideas?? Mods are in sig.

 

So last night I disconnected the newly installed used pump to see if this would correct the idle issue, it did not. So something must have happened somewhere else coincidentally. Not sure really where to even start.

 

Go back through and look at all the areas you worked in for anything left disconnected. Almost sounds like you didn't connect the MAF to me.

 

If that were the case he would not be able to boost...

 

No MAF, I'm SD on an AEM. I never disconnected anything other than the three plugs on the ACD unit itself. It's REALLY strange. The car was idling absolutely fine for about 30 seconds,then almost died, corrected, then went to a straight crap idle that doesn't seem to want to correct itself. I drove the car for about 20 minutes last night, it drives fine, just idles on 3 cylinders. My AFR's are much richer at idle too so the AEM is compensating for something.

 

Air temp and manifold sensor still connected? Can you log them and see their values are correct?

 

Yes, they are connected. I have not logged anything but will tonight. I wasn't able to investigate much further than simply ruling out the pump. I'll try to figure it tonight.

 

Any luck on this?

 

No, honestly I haven't had time. I did drive the car for some distance a couple days ago, and it drives fine, just idles like crap. I'm waiting for some parts to fix a couple other small issues. I'll be sure to update when I figure this out. I've got a two week old newborn at home though so time is definitely hard to come by.