Engine started after M-Tune install - Slow drop RPM
 

Hi,

I just installed all components of the M-Tune and converted my DME myself, added the jumper and cut the resistor leg.
MAF is getting 12V from CV red cable.

Also installed Rogue injectors, Larts SS fuel lines and a 3.0fpr.

What happens is that the idle sits at around 1200 and if I flip the throttle it's staying at around 3000 on its way down and after a few seconds it's slowly going down to 1200 again.

My boost gauge shows -0,6 bar at idle.

Any tips what it could be?

Thanks
/Peter

Reset your Idle/TPS.

http://www.lindseyracing.com/LR/Parts/IDLE944T.html

If you haven't already, I'd recommend contacting Joshua (Rogue Ant) directly, I'm sure he can help you sort it out.

funny my car occasionally does this as well on stock AFM, stock injectors, 24pin DME

Joshua has been mailed, but patience is not my friend since I really need this thing running now so I'll let some more smart people in on this one.

The TPS was tuned in recently and I checked it tonight and it was clicking at first movement. Do I need to check this further you think?

I've got pump gas in the tank now but the plug is not "plugged" so the map is pump-map.

Could vacuum or air leaks have something to do with this? I know I've got a leaking crossover but I had that earlier too and no issues with idle.

The idle stabilizer?

/Peter

First of all, make sure your tb is closing immediately all the way. You may have an obstruction or the spring is off.

Next you may want to look for vacuum leaks.

Next, try to block off the isv hose somehow to remove it from the idle loop. It may want to die rather than stay at fast idle.

Next, start looking at what voltage is coming from the maf and what your afrs are doing. I don't think you'll get into this but that would be my next step

Peter, check for leaks as others have suggested. Also, reset your idle:

http://www.clarks-garage.com/shop-manual/fuel-08.htm

The RPMs should hang slightly at 2000 on decel (this is right where the DME turns back on the injectors), then come down slowly from there. If it is still an issue, let me know, and I'll lower the RPM point where the DME turns back on the injectors.

Patience is your friend. Take your time and double check everything step by step. Is your idle really 1200? Are you getting that from the stock tachometer? My stock tach reads 1200 but the ZT-2 says about 950 at idle.

Also, Peter, is this on a cold-start? If so, the idle should be 1200rpm or so, until the engine starts to warm up.

I had this happen when I made my first attempt to convert to a 28 pin DME. Maybe check your solder job? I didn't actually fix the problem, I just used a different DME, sorry I can't help more

Other than intermittent glithes for bad connections, I would think car just wouldn't run if the socket were not soldered in correctly.

Ok took the car out for a spin and yes the idle settles at around or just under 1000 rpms when getting temp so this is fine.

But the slow dropping continues and I'm also noticing a hesitation when blipping throttle before rising. I bet this is caused by the same issue.

The TPS is still in the same position like yesterday but it really clicks at first minimal movement. So does this really need to be reset? I mean if I touch it I'll only set it where it is now.

Other issues is that I don't really know the function on my black nob MBC? I've turned it maximum counter clockwise and it still boosted almost 1,3 bar and when turning it CW it gets little "harder" to turn and boost do the same thing.
How do I test that this thing really works? I've "wired" like LR says with a Tial 38. I think I've got a 0,9 bar spring in it.

The crossover leak is really annoying and probably ruin much performance but overall I'm actually really depressed about this car.
It just doesn't run well, feels insecure and sloppy and doesn't wake that feeling in me that my previous 951 did.

And after all I've got:
Leda suspension, 968 caster blocks, a few poly bushings, Edge controll camberplates, GT3 brakes, Recaro/GT3 seats, LSD tranny.
Engine is lightly overhauled with fresh head, bearings, gaskets etc etc, K26/8, Tial 38.
The car definately looks like a GT3 killer with all the 968 bits and wheels with new alcantara interior so it's got some really good potential to kick ass..

The car just doesn't feel any good... :-(

Nothing above has guaranteed Nothing to do with M-Tune I just wish I could get that "Holy crap" feeling that everybody else gets!

/Peter

Peter,
Do you have a WBO2? If so, can you send me some logs/data?
When you say you are boosting 1.3bar, is that on the stock gauge? What port are you using on the Tial?
A crossover leak will definitely impact both spool-up and general performance.
What is the status of your factory O2 sensor?
We will get it figured out!

Hi,
No WBO2 yet I'm sorry! Will get in a month.
Just put in a new VDO boost gauge. So read on this one.
Don't remember exactly which ports but followed instructions on RL and LR. One is on top of WG I'm sure. Which should there be if you recall? Tomorrow I'll look which.

I really want to sort that crossover leak and will try to fix it next month.
No idea on stock O2 sensor...? How cn I check? And what would it cause?

Thanks Joshua, your service is outstanding! To bad there's thousands x1000 miles between!

/P

So, you are seeing 1.3bar positive pressure? I.E. ~19psi of boost?

The wastegate line should go to the side of the WG.

The stock O2 sensor should be in the crossover pipe, after it turns up to go to the turbo. There is a 3pin plug that connects it to the harness, which should be right near the speed & reference sensor wiring plugs. If it is disconnected, it will cause the DME to assume the engine is lean, and it will add fuel. This can cause the car to be a bit too rich, and sluggish w/ poor tip-in response.