Issue with dsm link and meth helping a friend

[Pirrofab]

I just wanna start by saying this is not my car so im going to give as much info as possible. he just purchased a 92 tsi awd with meth, link, 16g running 26psi, 750cc injectors, walbro 255 rewired, afpr, thermal exhaust, gm 3bar sensor.Hallman in car manual boost controller. meth is hooked up to 6lbs pressure switch. We don't have a computer capable of running dsm link at the moment.
took it out for a test drive in the morning and it ran good but not 100 percent, you could hear it break up and miss a little bit. we did a check over on the vehicle and boost leak tested it without any leaks except for a VERY VERY small leak at the throttle body shaft. We haven't been able to get into dsm link yet but as he was driving the check engine light would randomly come on and go out and under ful boost it breaks up and misses carries on very bad with black smoke and back firing and while cruising at highway speeds light throttle it burps black smoke occasionally like a diesel. Also coming to a stop the car will shut off, like the iac doesn't want to pick it up.
The other problem i noticed is that the gauge cluster boost gauge does not zero out with key on engine off and it just stays at -7. Could that be an indecation of a bad ecu or can that boost gauge actually be unplugged? (I'm thinking worse case scnerio)
Could we also try disabling the meth and driving it thinking that the way its set up right now might be to rich?

I know this is long but I didn't want to make several new threads. My friend was going to pull plugs today and see how they looked just in case. He does belong to the forums but im just trying to get him a jump start on fixing it.

 

[propeine]

The CEL coming on under boost is most likely from DSMLink. It is probably set to flash the CEL after a certain amount of knock counts. If you're seeing this thats bad. The boost gauge is also likely to show something different than boost as thats an option in DSMLink as well. It could be showing battery voltage, timing, coolant temp etc. Either way the stock gauge shows boost based on ECU calculations not what the actual pressure is so don't worry about that. You really need to get a laptop or a logger in there to see what is going on. Until you can get some logs turn down the boost before you frag his motor.

As for the car shutting off. If the BISS is set wrong the ISC can't pick up enough airflow to keep the car running. If the TPS is set up wrong in link then its not even going to try unless it sees .63Volt with your foot off the gas peddle.

You could have all kinds of CEL's turned off in link and the misfires would never even show up on the dash. Those would cause your backfires and black smoke. Find a friend with a laptop or hell come to erie and I'll help you out but do not keep driving it with it set up the way it is currently.

 

[Pirrofab]

thank you for your help and the offer to come out to erie unfortuneatley its over 4.5 hours away. I spoke to my friend today after i posted this and he told me the plugs that were in the car look almost brand new and the electrodes looked clean without anything abnormal, my guess is thats the meth essentially clean burning everything. I do remember his dsmlink being set to flash the check engine light for knock however this would randomly come on and stay on for a few minutes or so then go out. If it means anything or not the dsm link was set to hold idle at 1000rpm if that sounds correct? unfortuneatly the wideband a/f guage was not given with the car but the wideband is wired to the dsmlink along with the gm 3 bar sensor from what we were told. How would we correctly set the biss screw? I'm asuming set the correct timing and make sure tps reads .6 and then adjust biss screw so it idles at 750? Also when I spoke to him today he mentioned that the car feels like it has no bottom end or top end only midrange. Now my gears are turning, maybe its a tps adjustment along with some minor kinks. Thank you

 

[propeine]

TPS adjustment is here...dsmlinktpsadjustment [ECMTuning - wiki]
BISS you want to be datalogging your ISC position and have someone else adjusting the BISS. You want ISC position to be around 32 if I remember correctly. This will give the ISC the best control over the idle. The unfortunate thing is you really need link up and running to do this stuff.

If you guys can't come up with a laptop a cheaper alternative is a one of the palm devices. You can probably get a Dell x50 for 50-100 bucks and a serial adapter for another $50. I have that exact setup and it works great. I use my laptop for tuning and the Axim for datalogging and maybe tweaking if I'm feeling lazy.

Axim on Ebay
Axim x50
Serial Adapter

The check engine light going in and out could be too many things to guess at if its not just flashing for knock. Is he running straight meth or 50/50 mix? Man even if you could get a log somehow it would help a ton.

It sounds like his car has got a great base to work off of at least. DSMLink is a damn valuable tool. The wideband is nice to have even without a gauge. MAP sensor will be good for getting your MAF dialed in. I'll be happy to help as I can. I'm pretty new to DSMLink but not tuning.

 

[Pirrofab]

Problem solved! Our laptops with vista and a radioshack usb serial converter just wouldn't connect, we found an old desktop and plugged in the serial port without an adapter and we can get into dsmlink anytime we want however we can't figure out how to save our adjustments to the ecu through the "save to ecu" option. Thank you for your help so far. We found that tps was reading .41 and we compensated to bring up to .63 we still have the idle set to 1000 but can't seem to get the isc position down past 90 if im lucky.

 

[doggo]

Your knock count and associated CEL indication might not be a problem. If you are getting CELs even when not boosting then it may just be phantom knock. Check your knock sensor and see if it's bleeding goo, if so it needs to be replaced.

I just ordered one from JNZ they are like $75.

Regarding your ISC and idle issue. Have you FIRST set BASE idle by grounding out the ISC action, then adjusting the BISS for 750 RPM? This needs to be done first. With DSM link you can tell it to ground the ISC activation pin without having to do it under the hood.

Let me know how it goes...

 

[Pirrofab]

Thanks again for the help. Were slowly getting into it around our work schedules. we did not get to set the isc yet but it is running better with the adjustments made. Now are battle has moved to locating an old latop with a db9 port so we can capture some data instead of just being hooked up to a desktop. Now when I ground out this isc should i also have dsm link set to make the car idle a 750 or just keep the idle set at 1000 while I adjust the biss?. I'm assuming 750?