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.

Yes i saw it reaching 1,3. One time the limiter hit and cut the boost.

Ok, yes the O2 sensor is connected. First I had forgot one of the ref/speed sensor connectors so the engine didn't start and hen I found that out I saw the connected O2.
Don't know it's function though.

Anyone know how to test the MBC? This is the universal black knob type.

Here is a guide for checking the O2 sensor:

http://www.clarks-garage.com/shop-manual/fuel-18.htm

Not sure how to test that MBC, but I'm sure someone else will.

Nice thanks!

I also could try Another one from the shelf to see but the symptoms look familiar...

What boost controller are you running? I just installed my tial on Tuesday and tried to hook it up as rennlist said and was having problems with uncontrollable boost as my controller is not able to be used for dual port. I went back and connected to single port (side port) and all is well.

Ahhhh, yep side-port on the wastegate is what I meant (edited my earlier post)...

+1

Why not contact the vendor when you have a product from a vendor. Non one but him(Josh) knows exactly how his product works.

I have contact with Joshua, that was the first thing I did.

But as mentioned earlier I wasn't sure and am still not sure this is where the problem lies. There seem to obviously be more problems with the engine and I never said M-Tune was causing them.

And I appreciate all inputs from those responding with useful solutions!

So if you have a problem with your 951, you contact a Porsche dealer and don't ask things here...? :confused:

/Peter

Peedster, the problem lies with your original post. It makes it seem like the problem was caused by installing an M-Tune.
If you were to read this post, what would be your 1st impression?

Engine started after M-Tune install - Slow drop RPM

Hopefully, you see what people are trying to tell you.

I understand, but these issues can come up due to many things and 30% of all listers certainly know what's involved in a MAF conversion so things around the install could have been messed with.

Therefore I contacted Joshua and all the other knowledgeable people who might had this issue after installing a MAF!

Anyway if someone is willing to help out I think I discovered the overboost issue...

I think I'm on to something here involving a stuck WG! I changed the MBC lines to the WG using Lindsey's last picture of the vacuum diagram so that the banjo to MBC line goes to the top of the WG and the outgoing line fom MBC to the side port and the overboost was still there.
Last summer when my engine was spitting water out of the exhaust the WG must have rusted in closed position.

Does this sound likely? And can I wake this thing up? It's actually brand new except 5 years and a few miles driving.

Thanks!

Have you tried running it in single port mode as I and other have suggested? You should run the line from the mbc to the side port and have the top port vented. Having just had this exact problem two days ago this was my issue try this and report back.

Ok thanks.

Will try it out as soon possible.

What will be negative doing this opposed to dual port?

The LR diagram for how to hook up a wastegate is the reverse of how to hook up a Tial unit. This is because the valve operation is a different between the two.

Hook it up in single-port for the moment, until the overboost situation is figured out. Here is the correct diagram for the Tial:

The diagram you posted looks correct to me for a Tial (with the middle example being the one to follow if he wants to set up his Tial in single port mode, with the hose going to the wastegate coming directly from the banjo bolt in the intercooler pipe). Or is that what you are saying?

Peter, was the wastegate and boost controller working fine before you installed the MAF? With a manual controller and no cycling valve, it's pretty much a different system, so curious how one could affect the other unless you made other changes when you installed the MAF and/or disconnected things and reassembled them wrong. Were you careful about keeping track of which hose when where? A few detailed pictures of your engine and plumbing might help folks spot something obvious...

Yep, I see how my post wasn't quite clear enough - so I edited it. Yes, that diagram I put up is the correct one for use with a Tial.

Rogue and everyone else, correct me if I am wrong but with a regular manual boost controller you CAN NOT Run it in Dual port mode unless your controller is specifically made for Dual port. Is this not correct?


I found this out when researching my problem with my tial.

I believe you can run Dual Port, hook up as shown below (Tial 38):

Note: I have the WG supply line coming from the output of the IC but it can be in the stock location at the input to the IC.

http://www.refresh951.com/Config031612.jpg

Also, here is Tial's diagram:

http://www.refresh951.com/Tial%20Install.jpg

So Shawn, my manual controller (reliaboost) should work in Dual port? I attempted to hook it up as shown and it was uncontrollable boost. I also have 46 mm if that makes a difference.

Yep, should work.

Does the reliaboost look like the LR MBC? Basic flow regulator?

http://www.lindseyracing.com/LR/Parts/951BOOST1.html

No, mine is a ball and spring type.

Is there any advantage to running dual vs. single?

Yes, I think you need to run single port with a ball and spring.

Tom: Im pretty sure the system wasn't working correctly before either. Last summer I only drove it for a few miles and I didn't have a boost gauge then but if remember correctly it boosted quite crazy then too. It's not until now that I understand this though.

But since installing the MBC I've had the lines hooked up exactly like Rogues diagram and got confused when I saw LRs diagram so I changed it to their setup with lines goin opposite.
Will change it to single mode and see what happens now.

Any comments on stuck wastegate? Could this be it?

Refresh951: How many turns does it take your MBC to go from closed to fully open? Mine takes about 3 complete turns and then I can continue turning for a couple of turns without function.
Also my MBC ( looks identical to the LR) closes when turning to "minus" and open when turning "plus". Is this correct?

Thanks

If the lines were backwards, the wastegate could stay open and seem like it's stuck. Try correcting that first.

The lindsey diagrams are for their dual port wg. The Tial needs to be run opposite.

Hi guys,

I took off the WG and put compressed air through the side port and the valve opens fully at 0,9 bar and closes fast when the air is shut off.

Also tried to have the MBC setup in single port mode but still overboosts.

I have one last thing to test....switching the WG upside down...
My is pointing upwards to the passenger side of bellhousing.
This means that crossover comes to the side and discharge is in the bottom.

Is this really correct? Anyone have pictures of the correct position?

I also saw that the three pipes that's connected with a metallic 3-leg connector between ISV and MAF were really loose with their original clamps. Maybe it's good to replace those clamps with screw type ones.

/Peter

Wastegate sounds backwards -- see the Tial illustration in this thread. Here's a picture of my Tial 46mm pipes for reference.

Yes I have it installed the opposite to you.

The funny thing is that when I mounted it the first time I had like that but someone said it was wrong....

I guess that the exhaust gasses work against the spring in my install causing it to overboost?

Hoping to change any day.

Thanks

You do have a tial, correct? If it is a lindsey dp it will go opposite.

Yes I've got a Tial 38.

So I should install as Tom with crossover connected in the bottom port?

Hoping this will solve boost issue!

I have seen and read in here more times than not of problems trying to run in Dp mode.

Also, I have yet to hear any feedback of anyone noticing any difference in Dp over single port. Maybe with EBC but never with MBC.

So I installed the Tial the correct way with crossover pipe going to the bottom port and the dump pipe to side port.

This was so tight that the WG scratches the torque-tube and I had to take away the top port banjo and run it in single mode from the side.

So now the boost line goes from banjo on ic-pipes to the MBC and then to the side port on WG.

But it still overboosts.....??

Cant the exhaust pressure push the WG valve open? The spring is only 0,9 bar. I was not able however twitch my fingers push down the valve.

What is still not correct? :-(

This may sound obvious. Have you tried to adjust the mbc since reversing?

Yes, and when I turn it completely shut the boost should be minimal and the WG spring sets the boost (0,9bar) when the exhaust gases pushes it open?

If I open the MBC so air goes through it should set the boost pressure higher right?

Could someone explain this simple process to me please?

Try bypassing the mbc and run your vacume line straight from the ic pipe to the wastegate. If this does not work check the wastegate with compressed air and make sure it opens.

Have made sure your vacume line is not torn?

I've got controlled boost!

I did some thinking and bypassing the MBC means that boost signal goes uninterrupted to the WG and this will make the WG open at spring pressure.

My MBC is constructed that if I turn knob clockwise to + it will open fully and let air through. If I turn minus it will close airflow.
I thought turning it to plus it would mean more boost but it's the opposite which is strange to me.

Anyway it's working but in single port mode until I fix a 2-piece crossover.
It's really sensitive though because the MBC has about 8 turns totally but the adjustable boost range is only a quarter turn.

Now it's only the strange startup idle left!

/Peter

My MBC was perfect for the stock afr...once I added the M-Tune I needed a more finite boost controller so I bit the bullet and went with the eBoost2...pricey but cheaper than grenading an engine !!!!