Gum in your ISV valve or TB will do that definitely

 

I just installed my m-tune and took it out for its first drive. I was delighted when it started up on the first try.
I let the car warm up for 10 minutes while I made sure everything was ok, I noticed the idle was high and had a severe idle hang, like you said 30+ seconds at 2k. After it warmed up I set the idle per Clark's garage and it was a lot better, but I still have some idle hang. I'll redo the idle later this week after taking it for a drive.

I haven't pushed the car yet. I still want to take it easy until I check everything over again.

Install was very very easy. I also put new wires in (grounds, alternator and starter) and put the nissan alternator in. I put a CEP fuel rail, adjustable FPR and new fuel lines. I added a PLX dm-100 gauge with wideband and boost module.

First impression when driving is that the car responds better when I get on the gas. The bypass valve is now audible, whereas I couldn't hear it at all before.

The car idles pretty rough, but hopefully this'll be fixed when I redo the idle.

More to come this weekend.

 

Here's the log file. Not exactly 30 seconds on this one but you get the point.

Still haven't hooked up the wideband yet, sorry.

Cold 2K RPM.xdl.zip

Cold RPM Drop


Hot RPM Drop

 

Yep, what did you set the idle to? The reason I'm asking is that if the idle is set too high, it will bypass more air then expected, which results in the RPM hang you are seeing.

 

Between 840 and 920.

 

According to the tach, or the logger? Set it according to the logger.

The RPM shouldn't hang like that. Your TPS is triggering idle. So, your throttle doesn't look to be sticking.
The ISV could be sticking though.

Once that is done, if the idle still hangs, let me know - I can lessen the drop-throttle response in the software.

 

I set it according to the logger. I rather not try to compensate for a failing part.

I am planning a turbo swap in the coming weeks and can test the ISV then.

 

Switched to E85 tonight. Runs great.

I need to get one of those code plugs from Joshua though as I had to rig something up.

 

Changed to BPR7ES spark plugs gaped at .027 tonight and then took it for a drive.

The idle when hot doesn't seem to be consistent. It sometimes idles right where it should but noticed tonight it was at 1200 RPM. Decided to reset the idle again and noticed that after I re-enabled the ISV it goes up to around 1000 RPM and if I rev the engine it settles at 1200 RPM.

Does this confirm that the ISV is sticking?

This weekend I will do a pressure test to see if there is any vacuum/boost leaks as alxdgr8 mentioned.

Edit: The idle is not surging.

 

It could be that your ISV is sticking... Also, the TPS not triggering idle will do something similar.

 

Got done this weekend with a huge amount of work. New turbo, wastegate, alternator, A/C compressor, ISV, AOS seals, and some other stuff I am forgetting.

Car again runs great when cruising and boosting but I still have the slow RPM drop when cold and high idle(1200 RPM).

Clark's Garage procedure for resetting the idle says to "Turn off the fan motor". What exactly does that mean, the HVAC blower or the coolant fans?

 

Any other thoughts Joshua? The brand new ISV didn't change anything and I replaced my TPS and rebuilt the throttle body in March. The logger shows the idle switch being activated as well. Can you verify everything is correct in the software? Like I said before, it idled perfect with the AFM and the A-Tune.

Here are the pictures I promised.

 

When setting the idle, you don't want any of the fans on...
Can you set the idle to the proper 850 RPM?

 

So if I am letting the car warm up and the radiator fans come on is the car too hot at that point to set the idle?

 

No - that is fine. But best to wait for the fans to kick off.