Thread: VVl crazy idle issue

I am having the same exact issue with a stock 2001 g20t. Idles between 2500-3000 with maf plugged in, unplug maf, idle drops down but still fluctuates a little. When I first unplugged the maf the car was in a heated garage and it idled normal but now out in the cold it still bounces around with the maf unplugged. I have gone through 4 cans on brake clean looking for a vacuum leak and for the life of me I can not find one. Looks like someone tried to fix the issue before as it has a new IACV, new aftermarket maf(don't like that too much but it looks pretty new). It really acts like a vacuum leak but I can't find one. I am wondering if the ecu or the dizzy is the issue. I don't have either one to try and don't want to buy something that I am not sure of as this car is getting sold as soon as I fix it. If anyone in the Vernon ct area has an ecu I could borrow I would be grateful to either eliminate that as a cause or confirm. Sorry to thread jack but it sounds like we have the same issue going on besides I have a RR and you have a ve. I started a thread in the p11 section but haven't gotten any replies. If a mod could move it to the general sr20 section that may help get some more responses. Thing is unless someone else has had this same problem and fixed it, not sure there will be much help. I have been dealing with these cars since 2002 but this is the first time I have run into this. This is also my trade and it has me stumped. First time with a RR engine and anything newer than a 96 model year. I am getting to the point of borrowing a smoke machine and checking for vacuum leaks that way but I would rather it be an ecu or sensor issue than having to pull the intake manifold off. Wondering if it could be leaking from the bottom of the intake manifold gasket and that is why the brake clean is not causing the car to die out. Just kind brain storming while responding so maybe we should both try and spray some brake clean from the bottom of the intake. That seems like my next task.
Drew

I just tried it, and it stalled within 4 or 5 seconds. Got real lopey and shut off and wouldn't start. I don't know if it shouldnt idle with the MAF disconnected, but my car won't even start up that way

You check the throttle plate to make sure both the screws are in place?

I know what you mean, I have had the same thing happen to me on a few cars but then again I have had a few that did still run but ran like shit. I have a very strong feeling it is a vacuum leak from the underside of the intake manifold but I hope not since I don't feel like taking the manifold off and replacing the gasket but once I stop working on other people's shit I will get it up on the ramps and spray the underside of the intake manifold with brake to check. If not I am leaning towards a computer issue, loose connection, bad ground or idle control circuit in the ecu itself.
Drew

Yeah checked throttle plate, everything is a ok. Not sure about the op.... I have never had one of these cars give me this much trouble but I have really only spent three hours troubleshooting since I have been working on too many customers cars and haven't figured out yet if I need to title this car or can q1 title reassign to sell it so it has been on the back burner as I know I will figure it out when I have some real time to spend on it. I posted in the p11 section and got not one response. I guess it isn't a common issue. I am still leaning toward the intake gasket leaking on the bottom side.
Drew

Have you tried disconnecting the IACV with the engine running? If it drops or dies, it means you need to reset your idle speed. This usually happens when you adjust the TPS with the engine running (Loose TPS screws). BTW disconnecting the battery won't do the trick.

To reset the idle speed memory:
While on timing mode, stop engine (with disconnected TPS)

1.- Turn the key to "On" position (Just before the starter cranks and with all warning lamps on), just for a second.
2.- Then turn the key to the off position (ECCS relay must click off) and count 5 or 6 seconds after the relay's off.
3.- Repeat 1.- & 2.- for 20 more times.

That's how you reset idle speed memory. It takes practice to do it right.

That is worth a shot for sure. I just got the car and I'm not sure what the previous owner did to it. It has a new battery, IACV, MAF, O2 sensor. I know that most newer cars have to relearn the idle but every sr20 I have owned has been older so I never had to do that. The thought did cross my mind but I figured you would need a consult cable which someone borrowed and never returned. I do have a data logging and obd2 code scanner for my tablet which I am still learining to use called Torque. Thanks for the idea.
Drew

Yikes. Starting it 20 times in a row? Thats like, 2 weeks of starting it up crammed into a few minutes

Auto quoted myself. Do not start the car... just the warning lamps

key on engine off