SAFC tune gone wrong

[awdtalon4451]

I didn't want to have to resort to posting a new thread but I'm out of options. Ive searched tuners, source and VFAQ with no luck. Well a long story short. I just got back into DSM's here in the past month. I bought a 1990 gsx with the following mods (for those who don't check profile specs) Big16G, MAF-T, SAFCII, Walbro 190 W/ new oem FPR, Front mount, Intake, full 3" exhaust, stock 450's, Boost is set to stock.

When I bought the car it ran great but kept hitting fuel cut. I fooled around with the SAFC and got it running much better. Well I picked up my friend for work and he was messing with the AFC and reset EVERYTHING on accident!! Needless to say my car runs like absolute shit now. It starts bogging down and breaking up at 4K bad. I figured since I'm only running stock boost with 450's just zero everything out and I'll be ok till I get my WB02 and datalogger in next week. Wrong!!! Still runs like crap. So I disconnected the SAFC from the harness and now when I drive it bogs down at 3K terribly and then opens back up at 5k. Also my IAC started searching when I disconnected the AFC. Does any of this sound normal? Im running stock boost on 450's why would I need to add or subtract fuel? Do I need to add fuel due to my upgrades? Tuning has never been my strong point but this makes no sense to me. I don't think I have any boost leaks but I'm fixing to check for sure after i post this. Please help this is my DD!! Any input or advice is GREATLY appreciated.

 

[sciondan]

Your not running a stock turbo so ya you need to tune for it. A big 16g is pumping out a lot more air than the stock 14b the car is currently tuned for. I would upgrade the injectors to 550's and retune with a wideband. With your current setup and the safc at zero you would be running lean while boosting. Need to add fuel to compensate for the additional air that 16g is kicking out.

 

[awdtalon4451]

Yea I don't know what I was thinking, I thought even though its a 16g stock boost it shouldn't need any additional fuel.

 

[WES_393]

Need to add fuel to compensate for the additional air that 16g is kicking out.

That's incorrect. You can run any size 16g at stock boost with the stock 450cc injectors, I've done it multiple times. On my 1990 TSi, I ran a Evo3 16g at 13psi with a bone stock fuel system and had no issues. The injectors were well over 90% IDC, but I never ran into these issues. On my current small 16g I could creep to 15psi with a Walbro 255 and 450cc injectors yet still maintain a 10.9:1 A/F ratio. Granted I had an AFPR, but that wouldn't make a whole lot of difference since I ran it at stock fuel pressure.

To me it sounds like you have a boost leak or some fuel flow problems. I'm not sure how well GM MAF's deal with boost leaks, but that's where I would start first. If you find none or very little, I would start looking at the fuel system for problems. Also, is the car an auto? If so, your ECU is still programmed for the stock 390cc injectors which could also be the reason you need to tune the fuel settings.

 

[Eclipse2630]

If you just disconnected the SAFC from the harness and not the ECU its going to run like crap cause now the pink wire and orange wire are not connected back to there appropriate source from factory. If your not gonna use the safc make sure you reconnect the wires you cut on the ecu back to factory. i got curious one time i was having issues with mine and i just unplugged it from harness not ecu and it does make a big difference!

ok forgot you have a 1g, on a 2g its the pink and orange wires that get cut, not sure which ones u cut on a 1g but im sure u cut something to make the safc work correctly. but like i said if your not gonna use it put it back to stock.

 

[Chaosweaver]

You set up the Karman sensor on the SAFC? As well as set it to 4 cylinders, ect? Now if you disconnected the SAFC from the harness make 100% sure you re-connected it correctly, make sure that the MAF cable in and MAF out cables are fully connected and connected properly.

NEVER let anyone mess around with your tuning equipment, its asking for trouble. If you where rolling down the highway and he decided to lean it out completely as you hit boost you could have kissed your engine goodbye.

 

[RamenPride]

At the very least, I hope you punched your friend in the face for doing that...

 

[Eclipse2630]

the safc2 also has the option to put a password in so only the password holder can tune the car.

 

[awdtalon4451]

Ill start off by saying I bought this car from an older man who knew nothing of the car or its upgrades. I tried to find out about it as much as I could from visually looking at it but the more I dig the more I seem to find. Which isn't a bad thing cause it looks to be done the right way. But trying to diagnose when you don't see the whole pictures sucks sometimes. its set up for ecmlink ( ecu chip and cable to ecu) and I believe he had a different motor or at least a different turbo setup and fuel rail (signs of recent install). I'm starting to think the maf setup may be set incorrectly. I printed out fullthrottletechs maft settings, gonna check them when I get home. As for friend I really wanted to chin check his ass for messing with it but I see a pass lock on it next go around. My wide band and datalogger will be here thursday also

You set up the Karman sensor on the SAFC? As well as set it to 4 cylinders, ect? Now if you disconnected the SAFC from the harness make 100% sure you re-connected it correctly, make sure that the MAF cable in and MAF out cables are fully connected and connected properly.

NEVER let anyone mess around with your tuning equipment, its asking for trouble. If you where rolling down the highway and he decided to lean it out completely as you hit boost you could have kissed your engine goodbye.

Oh yea I forgot to mention. All the initial settings were restored except the fuel trims. Set to karmen, had to set it to 2 cylinders with the arrow northeast if it were a compass. cause my rpm were off by half.

 

[Eclipse2630]

Ill start off by saying I bought this car from an older man who knew nothing of the car or its upgrades. I tried to find out about it as much as I could from visually looking at it but the more I dig the more I seem to find. Which isn't a bad thing cause it looks to be done the right way. But trying to diagnose when you don't see the whole pictures sucks sometimes. its set up for ecmlink ( ecu chip and cable to ecu) and I believe he had a different motor or at least a different turbo setup and fuel rail (signs of recent install). I'm starting to think the maf setup may be set incorrectly. I printed out fullthrottletechs maft settings, gonna check them when I get home. As for friend I really wanted to chin check his ass for messing with it but I see a pass lock on it next go around. My wide band and datalogger will be here thursday also



Oh yea I forgot to mention. All the initial settings were restored except the fuel trims. Set to karmen, had to set it to 2 cylinders with the arrow northeast if it were a compass. cause my rpm were off by half.

why 2 cylinders? ive heard of people doing this, but why?

 

[awdtalon4451]

I can't remember off the top of my head but I think it has something to do with it being hooked up a certain way. So I fixed the issues with the safc. I winded up just waiting for my Wideband O2. Got the Innovate mtx series and its sweet . Installed it this afternoon. My high and low settings were fubar. Changed the plugs an hit 3 pulls and I got it to 14.3-14.8 cruising and 10.7-11.2 wot. I'll spend the next day or two dialing it in more. Really surprised me how much it came to life after the fix. It was like night and day. So if your reading this for info and you don't have a WB02, take it from me get one! It makes things so much easier.

 

[jason91dsm]

the reason it is set up on 2 cyl is because the way the ignition fires on the dsm's.

 

[red1993gsallmt]

the reason it is set up on 2 cyl is because the way the ignition fires on the dsm's.

You can correct that by hooking it up correctly. My old car was like that when I bought it but I looked around and found the correct way to wire it and was able to set it to 4cly. I dont think running it the way you do hurts the tune tho. Im just pickey

 

[jason91dsm]

You can correct that by hooking it up correctly. My old car was like that when I bought it but I looked around and found the correct way to wire it and was able to set it to 4cly. I dont think running it the way you do hurts the tune tho. Im just pickey

correct me if im wrong but from the manufacture the ignition was setup on like a wasted spark setup there for if you hook the safc up you would do it as a 2cyl. if im wrong let me know

 

[steve]

If you hook up the SAFC to the ECU so that it picks up the RPM signal from one of the outputs to the poer transistor it only see's half of the ignition signals forcing you to set the SAFC to 2 cyl mode to display the correct RPM. If you use the output from the power transistor or the tach gate on a 90 coil pack then you'll see all the ignition pulses.