Pig rich and strange blm's
Thread Starter
Joined: Feb 2002
Posts: 3,462
Likes: 4
From: N. Illinois
Car: 92 GTA/ 00 TA
Engine: 383/350
Transmission: 700R4/T-56
Pig rich and strange blm's
I'm hoping one of you masters can point me in the right direction.
My car used to get 22 mpg. Suddenly it dropped to 13. I found a vacuum leak at the HVAC/CC/Plenum check valve and replaced it. I no longer have a vacuum leak and my MPG only went back up to 16.
I've made no changes in my flash prom during the mileage change. For 2 weeks now I've been trying to get my BLM's even somewhat close to 128 to no avail. I had a couple of slightly modified chips in there mostly injector size and a few other minor changes. My BLM's were bottomed out at 108, INT's were as low as 98, and FFC was hanging out around 110. During this time I saw no improvement over a week of cycling the engine. No learning. My car also was spending quite a bit of time in Cell 4.
As of yesterday I put in S_AUJP from Traxion that I found on Moates site (I believe) with CCP off. The only current change that I made to this bin was changing the injector size to 2.98 g/sec (I have 24#). These are the new interesting BLM's.
The cells move much better but now my BLM's are hanging out around 100 with INT's and FFC spending a decent amount of time AT 128. This is at 60 mph cruise. Also my non-WB O2 is saying 57mv. Most of the time the O2 does cycle relatively well. Maybe you guys could point me in the right direction?
92 GTA auto
7730 ECM
AUJP prom
$8D
My car used to get 22 mpg. Suddenly it dropped to 13. I found a vacuum leak at the HVAC/CC/Plenum check valve and replaced it. I no longer have a vacuum leak and my MPG only went back up to 16.
I've made no changes in my flash prom during the mileage change. For 2 weeks now I've been trying to get my BLM's even somewhat close to 128 to no avail. I had a couple of slightly modified chips in there mostly injector size and a few other minor changes. My BLM's were bottomed out at 108, INT's were as low as 98, and FFC was hanging out around 110. During this time I saw no improvement over a week of cycling the engine. No learning. My car also was spending quite a bit of time in Cell 4.
As of yesterday I put in S_AUJP from Traxion that I found on Moates site (I believe) with CCP off. The only current change that I made to this bin was changing the injector size to 2.98 g/sec (I have 24#). These are the new interesting BLM's.
The cells move much better but now my BLM's are hanging out around 100 with INT's and FFC spending a decent amount of time AT 128. This is at 60 mph cruise. Also my non-WB O2 is saying 57mv. Most of the time the O2 does cycle relatively well. Maybe you guys could point me in the right direction?
92 GTA auto
7730 ECM
AUJP prom
$8D
Joined: Apr 2004
Posts: 3,180
Likes: 3
From: Browns Town
Car: 86 Monte SS (730,$8D,G3,AP,4K,S_V4)
Engine: 406 Hyd Roller 236/242
Transmission: 700R4 HomeBrew, 2.4K stall
Axle/Gears: 3:73 Posi, 7.5 Soon to break
Just from the sounds of it, I'm thinking you lost some timing.
Check some old logs against the new ones to see if it seems correct.
If they indicate reletivly the same then check the base timing at the distributor. Loss of timing will get you looking rich and loose milage like that.
Hyway fuel/spark may be coming on in the S_ bin causing the lean reading at high speed/ light load conditions making things seem better there than they are. You can disable it by setting the coolant temp threshold to max and see if the readings change.
Check some old logs against the new ones to see if it seems correct.
If they indicate reletivly the same then check the base timing at the distributor. Loss of timing will get you looking rich and loose milage like that.
Hyway fuel/spark may be coming on in the S_ bin causing the lean reading at high speed/ light load conditions making things seem better there than they are. You can disable it by setting the coolant temp threshold to max and see if the readings change.
Joined: Mar 2000
Posts: 1,692
Likes: 1
From: Corona
Car: 92 Form, 91 Z28, 89 GTA, 86 Z28
Engine: BP383 vortech, BP383, 5.7 TPI, LG4
Transmission: 4L60e, 700R4, 700R4..
Axle/Gears: 3.27, 2.73
Is the fuel pressure regulator OK? Did the vacuum line come off it?
Thread Starter
Joined: Feb 2002
Posts: 3,462
Likes: 4
From: N. Illinois
Car: 92 GTA/ 00 TA
Engine: 383/350
Transmission: 700R4/T-56
Timing appears to be fine between the logs. This new S bin supposedly requires 93 octane. That's all I run but I'm getting lots of knock counts and retard. I'm going to have to massage the tables a bit to be more friendly.
My base timing is correct.
I have not found any vacuum leaks.
I think maybe my regulator might be having issues since I'm now running 39psi at cruise instead of what was normally 36.
Why would my BLM's get stuck ~100 with the INT's and FFC both at 128? During this time my O2 sensor reads ~50mv with no oscilation. Shouldn't my BLM's be changing?
My base timing is correct.
I have not found any vacuum leaks.
I think maybe my regulator might be having issues since I'm now running 39psi at cruise instead of what was normally 36.
Why would my BLM's get stuck ~100 with the INT's and FFC both at 128? During this time my O2 sensor reads ~50mv with no oscilation. Shouldn't my BLM's be changing?
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