How Lomg To pump?

[bison]

bison, it seems to be both. The chip locks the blm at 128 at wot.
TurboDave, I would love to send you the files but I'm on this stupid Webtv and it can't happen. But it will cough and pop before the maf ever reaches 255 sometimes. Right now I have the boost turned back to 15 psi, running 48psi of fuel pressure and my 02's are at 790 wot! I don't believe I could get the 02's over 800 running 55psi of fuel pressure! R.B.

What if you unplug the MAFS and try it. It should ignore other readings if the BLM is locked at 128. Its reading directly off the fuel map at this point. What ever duty cycle is programmed is what you get assuming it stays at 128.

 

[rb68rr]

You mean unplug the maf and drive it? That won't work will it? R.B.

 

[TurboDave]

You mean unplug the maf and drive it? That won't work will it? R.B.

NO, you DO NOT want to try that, especially any WOT stuff.

 

[rb68rr]

One thing that I've noticed is when I first start the car in the morning while it's cool I can go wot in 2nd gear 2 or 3 times before getting the cough, pop. It runs perfect and all of a sudden there it is! Driving me crazy!!! R.B.

 

[rb68rr]

OK, here we go. Unhooked the ribbon cable from directscan. Took the chip out and cleaned the pins. Took the car out for several wot passes and never had a pop or cough! However on the last pass the check engine light came on for a few seconds and then went out. Checked scanmaster and had a code 41 (cam sensor). Got home and reset the computer with the orange wire. Wouldn't start. Finally after resetting three times it started. Haven't driven it again. What do you think? Thanks, R.B.

 

[rb68rr]

This is getting crazier by the hour but I think I've almost got it fiqured out. Took the car out for a few wot blasts with the ecm laying in the floorboard. Not one pop or cough! Put the ecm back in the kick panel and went again. Pop, cough, pop, cough! Took it out again and left it in the floorboard again, ran perfect! Everytime I put it back in the kick panel it goes crazy. After unsnapping and snapping the conectors a few times and wiggling around the wires I finally got it back in the kick panel and running without any coughing and popping!!! Man, these cars can drive you NUTS!!! Hope this fixes it for a while. Thanks for all the help. R.B.

 

[TurboDave]

This is getting crazier by the hour but I think I've almost got it fiqured out. Took the car out for a few wot blasts with the ecm laying in the floorboard. Not one pop or cough! Put the ecm back in the kick panel and went again. Pop, cough, pop, cough! Took it out again and left it in the floorboard again, ran perfect! Everytime I put it back in the kick panel it goes crazy. After unsnapping and snapping the conectors a few times and wiggling around the wires I finally got it back in the kick panel and running without any coughing and popping!!! Man, these cars can drive you NUTS!!! Hope this fixes it for a while. Thanks for all the help. R.B.

Sounds like you got it. Dirty connections.

 

[Blown&Injected]

Well, without any direct scan data to look at it would be impossible to tell. Besides that, keep in mind that any fuel pressure adjustments you make are just going to be erased by the BLM in the chip. That's what it does, sees an A/F ratio change because of the fuel pressure adjustment and then changes the BLM to compensate and nullify the adjustment.

I know the issue seems to be dealt with, but I wanted to understand more about something TurboDave said.

But the pop is at WOT. I thought that fuel pressure adjustments would make an AFR change at WOT and that fuel pressure adjustments at part throttle do not make a difference due to the computer readjusting based on O2 measurements.

Also never heard about MAF resets before. Is that a reason some chips lock the MAF at 254?

Thanks

 

[TurboDave]

I know the issue seems to be dealt with, but I wanted to understand more about something TurboDave said.

But the pop is at WOT. I thought that fuel pressure adjustments would make an AFR change at WOT and that fuel pressure adjustments at part throttle do not make a difference due to the computer readjusting based on O2 measurements.

Also never heard about MAF resets before. Is that a reason some chips lock the MAF at 254?

Thanks

Fuel pressure adjustments will only have much affect at all if you had a chip that locked BLM at 128 as some predetermined WOT setting. If you made a fuel pressure adjustment and just went for a short cruise around the pits you'd see your BLM adjusting for that fp change.
There are several schemes for locking the MAF at WOT but only one or two that actually do it well enough to help the MAF "drop out" problem.
That's why the Extender chip is such an eloquent solution. The maf never hits 255 to cause those problems, and fueling at WOT keeps doing it's thing properly.

 

[Blown&Injected]

Fuel pressure adjustments will only have much affect at all if you had a chip that locked BLM at 128 as some predetermined WOT setting. If you made a fuel pressure adjustment and just went for a short cruise around the pits you'd see your BLM adjusting for that fp change.
There are several schemes for locking the MAF at WOT but only one or two that actually do it well enough to help the MAF "drop out" problem.
That's why the Extender chip is such an eloquent solution. The maf never hits 255 to cause those problems, and fueling at WOT keeps doing it's thing properly.

Hummmm, now another thing to think about - BLM's! Thanks for the help in understanding this stuff. I spend so much time going after more basic stuff I do not spend much time learning about the finer aspects.

I think my chip does this BLM lock as well, as the 254 MAF lock because I notice my scan tool displaying 128/128, the Block Learn and the Integrator, whenever I go to WOT and it seems to do it when the car is coasting on the highway too.

So in such a case, the fuel pressure changes will make a difference, and will not be "learned in", at WOT, if I am correct about the BLM's locking on 128 at WOT - right?