LGT Stalling/Won't hold idle

[Robb]

Hi all,

 

I have a 2006 LGT (stock) that I'm having a stalling issue with. The bottom end was replaced ~7,400 miles ago, turbo was done ~2,500.

 

Over the weekend, I noticed that the idle was getting a bit funny, kind of low - but I didn't think anything of it. Temperature was changing, I hadn't driven it in a while (my wife drives the car ~30 miles per week), etc.

 

Tonight, the car started to stall - this occurred whenever I pushed the clutch in at a stop light, so I limped it the rest of the way home by continually giving it gas, otherwise it would stall out. I pulled into the driveway and attempted to idle the car, however it wouldn't hold idle unless I was on the pedal a bit.

 

- No CEL or pending codes (previously, I had an intermittent cylinder 1 misfire - that's gone)

- No improvement when MAF is disconnected

- Checked intake, TMIC, and BPV to ensure nothing was disconnected

- Reset battery at an attempt to relearn the idle

 

I did noticed that when I let it sit for a minute or so or brought the car to ~3,000 RPM there was the slight sound of piston slap. The noise didn't change with pushing the clutch in or out, so I don't think that there's any drivetrain issues present.

 

Any ideas?

[V8lolsubie]

Bottom end as in a complete short block er....

 

And are you running a front mount intercooler?

[Robb]

Yup, complete short block. And no, TMIC - car is stock.

[Robb]

Update: I cleaned both OCV's (no noticeable sticking, but I did it anyway) and replaced the spark plugs. It runs and drives without stalling, but it falls pretty low in RPMs when I push the clutch in.

 

Also, it's got pretty bad slap/knock at this point. This happens in neutral and when there is load. Any thoughts for that?

 

Here is a video with terrible volume that shows the slap/knock throughout the low to mid power band:

- is it possible that this is the tensioner? It sounds like some sort of internal noise to me.

[AF_3C2]

Any way to log?

 

Injector, coil, or intake leak are the usual suspects for low/rough idle. That almost sounds like a heat shield loose- using any oil?

[apexi]

I was almost going to say maybe a loose heat shield, because that sounds similar to a noise I had when my heat shields were loose. In my specific case, a tack weld up near the oil filter was broken. Since you have a LGT I don't know where the heat shields are, but it wouldn't hurt to check for loose nuts/bolts, or broken rusted nuts/bolts. I don't remember how I eventually narrowed down the cause of the noise in my car, but I you can also try putting pressure on the heat shields when the car is running to see if the sound goes away.

[Max Capacity]

If its a heat shield you can just remove it. I only have the drivers side one left. the others have some DEI heat wrap as best I could. they are really not that important.

 

Do you have the new larger orange o-rings between the intake manifold and TGV's ?

 

Oh, get the car off the factory tune.

[Robb]

Ah, back to this morning and it's just cranking again. Eventually it caught and started, but stalled out a few times.

 

 

Any way to log?

 

Injector, coil, or intake leak are the usual suspects for low/rough idle. That almost sounds like a heat shield loose- using any oil?

 

Intake looks okay, I disassembled and reassembled to ensure every. I'm assuming I can compare a value with logging to check for the injector or coil functionality?

 

I have access to a VCDS cable that I use with my VW, I'm assuming that I can just use that with some software to log. Do you have a recommendation on a particular piece of software? I see some people use ECUExplorer... what specifically should I be looking for when logging?

 

I know the downpipe is from an AT car (mine is 5MT), so it rattles occasionally. It's never sounded like this before though. Is there a specific heat shield that commonly causes a rattle like this? I'm not going through oil, have been pretty steady overall.

 

 

I was almost going to say maybe a loose heat shield, because that sounds similar to a noise I had when my heat shields were loose. In my specific case, a tack weld up near the oil filter was broken. Since you have a LGT I don't know where the heat shields are, but it wouldn't hurt to check for loose nuts/bolts, or broken rusted nuts/bolts. I don't remember how I eventually narrowed down the cause of the noise in my car, but I you can also try putting pressure on the heat shields when the car is running to see if the sound goes away.

 

That is kind of reassuring that multiple people are thinking heat shield (I can hope, right? ) I'll have to crawl around under the car to see what I can find. I don't mind pulling the heat shields at all.

 

If its a heat shield you can just remove it. I only have the drivers side one left. the others have some DEI heat wrap as best I could. they are really not that important.

 

Do you have the new larger orange o-rings between the intake manifold and TGV's ?

 

Oh, get the car off the factory tune.

 

TGV = Tumble Generator Valve, correct? I hate being new to a platform and not recognizing acronyms lol. Seems like these are beneath the intake manifold, is there a way I would know this without pulling everything?

 

Speaking of which, if I were to pull the intake manifold, what gaskets are not reusable or should I consider replacing during that process? My next thought is a sticking throttle body, so might be time to check and clean.