thanks for reading this post. I've been trying to diagnose and eliminate a problem with my GN for a LOOONG time now. I have a very irratic popping and misfire under boost. Sometimes I can go WOT and it runs flawlessly but most of the time, it starts popping and misfiring as the boost starts to build (usually starts between 5-10 psi). I also register a lot of KR - usually 10 degrees or more when this happens. Over the course of about 3 years I've replaced all the fuel system compnents *except* the injectors and all of the ignition components *except* the alternator (if you consider that part if the ignition system). I've also gone through and checked, replaced, added grounds, swapped MAF's, swapped numerous chips, swapped ECM's, and of course the coilpack, coil module etc. Nothing has eliminated the problem. I also have removed the Translator and put the stock MAF back on and it didn't make any difference.
I finally bought a Power Logger and logged some data when the problem was occuring. Can someone take a look at the attached Power Logger dat file and see if you see anything that might indicate whats going on? I'm no tuning guru, but one thing I've noticed in the attached data file is that when the "event" occurs, the MAF reading pegs out at 512 and the injector pulse width maxes out also. Am I going lean???? The O2 mV don't look particularly low to me, (could be wrong) and I've got plenty of fuel pressure (data logged that with a Snap-On data logger). The only thing I can think of is maybe I have a bad injector??? I've checked plugs and they look fine and all of them appear very close to the same color. One import note, the car runs absolutely *perfectly* under normal driving conditions. This is the third turbo Buick I've owned since '96 and this one runs the best under normal conditions.
The attached data file has three seperate occurances of the popping misfire event. The first occurance begins at about 25 seconds into the file. There are two more occurances, but I don't remmeber what time they begin at.
Any input is greatly appreciated.
Info:
- '87 GN
- stock long block
- TE-44
- MSD 50 lb inj.
- Walbro 340 pump
- Accufab fp reg.
- Power plate
- Big Mouth CAI
- Trans. + w/extender chip and 3" MAF
- 10" non-l/u stalling at about 3k
TIA!!
I finally bought a Power Logger and logged some data when the problem was occuring. Can someone take a look at the attached Power Logger dat file and see if you see anything that might indicate whats going on? I'm no tuning guru, but one thing I've noticed in the attached data file is that when the "event" occurs, the MAF reading pegs out at 512 and the injector pulse width maxes out also. Am I going lean???? The O2 mV don't look particularly low to me, (could be wrong) and I've got plenty of fuel pressure (data logged that with a Snap-On data logger). The only thing I can think of is maybe I have a bad injector??? I've checked plugs and they look fine and all of them appear very close to the same color. One import note, the car runs absolutely *perfectly* under normal driving conditions. This is the third turbo Buick I've owned since '96 and this one runs the best under normal conditions.
The attached data file has three seperate occurances of the popping misfire event. The first occurance begins at about 25 seconds into the file. There are two more occurances, but I don't remmeber what time they begin at.
Any input is greatly appreciated.
Info:
- '87 GN
- stock long block
- TE-44
- MSD 50 lb inj.
- Walbro 340 pump
- Accufab fp reg.
- Power plate
- Big Mouth CAI
- Trans. + w/extender chip and 3" MAF
- 10" non-l/u stalling at about 3k
TIA!!
I've been chasing this problem WAAAY to long.
