I'll try to keep this as short and informative as I can...
The car:
Stock LC2 engine
TA-49
57-lb high-impedance injectors
Other usual bolt-on's (fuel pump, THDP, FMIC, etc.)
-if you need to know more information, please ask.
I am running a T+ with a 3-inch LT1 MAF. The chip is an Extender Extreme Rev. F with some custom tweaks by me (mostly WOT fueling, boost control, and things like that). Other than playing with idle speed in an attempt to fix this, I've done nothing with idle control.
Last year, I was running a re-stalled D5 converter (i.e. a heavy one). Over the winter, I upgraded to a 9-inch converter (Mike Ridings) that is much lighter. Prior to this past winter, if I would stab the throttle and then let-off, the engine would almost stall as the car came back down to idle. Now, with the lighter converter, the engine will stall when it comes back down to idle. The stalling is very repeatable - I can make it stall at will by simply stabbing the throttle and then letting off. It will also sometimes stall when I'm just coming to a stop at a traffic light or something.
Here's the rub: I recently had to pass emissions here in Indiana, so I disconnected the T+ and put a stock MAF and catalytic converter back into the car. I also took a 1986 stock chip, changed to injector parameters to match my 57's, and ran it in the car (the goal was to run the EGR valve in a stock way). With these changes, the car did not stall at all (and it passed emissions with flying colors). After passing emissions, I changed everything back (3-inch MAF, T+, Extender Rev. F, and removed the cat). Sure enough, the stalling problem came back.
Since that time, I've changed the MAF sensor to a different 3-inch MAF - no change. Along the way I also changed out the coil pack and module - no change. I tried playing with idle speed - raising it a bit did help but did not solve the problem. I also re-adjusted my IAC and checked all of the usual standard stuff - don't see anything amiss. When I look at DS results of a stall, I can see the MAF reading fluttering up and down as the turbo spools down. During that time, the O2 sensor reads very lean (less than .1 volts), and stays there all the way down until just before the stall. As the engine RPM's drop, the IAC does try to open, but by then it's usually too late to save it.
Any ideas on how to get around this? For the life of me, I can't figure out why a stock chip would handle this better than a good Extender chip... Has anyone heard of a T+ causing this problem?
All ideas appreciated,
The car:
Stock LC2 engine
TA-49
57-lb high-impedance injectors
Other usual bolt-on's (fuel pump, THDP, FMIC, etc.)
-if you need to know more information, please ask.
I am running a T+ with a 3-inch LT1 MAF. The chip is an Extender Extreme Rev. F with some custom tweaks by me (mostly WOT fueling, boost control, and things like that). Other than playing with idle speed in an attempt to fix this, I've done nothing with idle control.
Last year, I was running a re-stalled D5 converter (i.e. a heavy one). Over the winter, I upgraded to a 9-inch converter (Mike Ridings) that is much lighter. Prior to this past winter, if I would stab the throttle and then let-off, the engine would almost stall as the car came back down to idle. Now, with the lighter converter, the engine will stall when it comes back down to idle. The stalling is very repeatable - I can make it stall at will by simply stabbing the throttle and then letting off. It will also sometimes stall when I'm just coming to a stop at a traffic light or something.
Here's the rub: I recently had to pass emissions here in Indiana, so I disconnected the T+ and put a stock MAF and catalytic converter back into the car. I also took a 1986 stock chip, changed to injector parameters to match my 57's, and ran it in the car (the goal was to run the EGR valve in a stock way). With these changes, the car did not stall at all (and it passed emissions with flying colors). After passing emissions, I changed everything back (3-inch MAF, T+, Extender Rev. F, and removed the cat). Sure enough, the stalling problem came back.
Since that time, I've changed the MAF sensor to a different 3-inch MAF - no change. Along the way I also changed out the coil pack and module - no change. I tried playing with idle speed - raising it a bit did help but did not solve the problem. I also re-adjusted my IAC and checked all of the usual standard stuff - don't see anything amiss. When I look at DS results of a stall, I can see the MAF reading fluttering up and down as the turbo spools down. During that time, the O2 sensor reads very lean (less than .1 volts), and stays there all the way down until just before the stall. As the engine RPM's drop, the IAC does try to open, but by then it's usually too late to save it.
Any ideas on how to get around this? For the life of me, I can't figure out why a stock chip would handle this better than a good Extender chip... Has anyone heard of a T+ causing this problem?
All ideas appreciated,
