OB1 Question...w/background
11-22-2004, 11:06 PM
#1
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OB1 Question...w/background It is my brothers truck… I am posting this for him. The '92 SWB truck originally had a 4.3 v6 5 speed. Right now he has a built 355ci SB w/TB injection and a 700R4 w/mailorder chip (Specs Below). He has been running this setup for about 2 years/81,000. Upon initial startup the headers got hot enough to see through w/in the first few seconds. They retarded the timing and it's been running ever since.
I think that the rings were hurt on initial startup…...after it as been idling for a 30-45 seconds (warm engine, temps stabilized)...it starts to surge at idle and smokes. Every 500-800 miles it uses close to 2qts of oil.
He had to change the plugs every 2 weeks due to buildup on the plugs. When he went to a hotter plug that problem has seemed to go away.
I also think that it us under-fueled. It pulls hard down low, but near the top end under a load, even in the lower gears, there is no difference between just under 3/4 throttle and full throttle. Maybe the injectors are going static?? (not sure if the same would be true in the higher gears because anything more than 3/4 throttle causes the tranny to downshift). 2 Days ago during some “Spirited Driving” 2nd gear started slipping. So that’s got to get fixed. Is it possible to dyno-tune a OB1 Chip style computer? Is there anyone in the Houston area that would do something like that? Any Suggestions on what the surging idle might be??
Engine
Block: Stock 92 Vortech .030 Over
Crank: Stock (Turned)
Rods: Scat 6”
Pistons: Signature Series Keith Black Hypereutectic 10.2:1
Heads: World S/R Torquer 2.02/1.06 Intake runner 170cc, 76cc Chamber
EDITED CAM SPECS: 212/212 @.050 444/444 on 112 LSA
Comp Cams P/N: 12-314-4.....Grind Number: 260AH-12
Intake: Eldelbrock Performer TPI w/Throttlebody spacer
Throttlebody: Stock w/Stock Injectors Mail Order Chip
Tranny:700R4
Shiftkit: Fairbanks Street/Strip (valve body kit….not manual valve body )
Converter: Stock lock-up
The Cam Specs did read:
Cam: 256/268 @.050 449/456 on 112 LSA
After an arguement over the cam not sounding as big as I was being told, we looked it up. They were quoting me the aprox. advertised Duration.
I think that the rings were hurt on initial startup…...after it as been idling for a 30-45 seconds (warm engine, temps stabilized)...it starts to surge at idle and smokes. Every 500-800 miles it uses close to 2qts of oil.
He had to change the plugs every 2 weeks due to buildup on the plugs. When he went to a hotter plug that problem has seemed to go away.
I also think that it us under-fueled. It pulls hard down low, but near the top end under a load, even in the lower gears, there is no difference between just under 3/4 throttle and full throttle. Maybe the injectors are going static?? (not sure if the same would be true in the higher gears because anything more than 3/4 throttle causes the tranny to downshift). 2 Days ago during some “Spirited Driving” 2nd gear started slipping. So that’s got to get fixed. Is it possible to dyno-tune a OB1 Chip style computer? Is there anyone in the Houston area that would do something like that? Any Suggestions on what the surging idle might be??
Engine
Block: Stock 92 Vortech .030 Over
Crank: Stock (Turned)
Rods: Scat 6”
Pistons: Signature Series Keith Black Hypereutectic 10.2:1
Heads: World S/R Torquer 2.02/1.06 Intake runner 170cc, 76cc Chamber
EDITED CAM SPECS: 212/212 @.050 444/444 on 112 LSA
Comp Cams P/N: 12-314-4.....Grind Number: 260AH-12
Intake: Eldelbrock Performer TPI w/Throttlebody spacer
Throttlebody: Stock w/Stock Injectors Mail Order Chip
Tranny:700R4
Shiftkit: Fairbanks Street/Strip (valve body kit….not manual valve body )
Converter: Stock lock-up
The Cam Specs did read:
Cam: 256/268 @.050 449/456 on 112 LSA
After an arguement over the cam not sounding as big as I was being told, we looked it up. They were quoting me the aprox. advertised Duration.
Last edited by A_W_O_L; 11-30-2004 at 07:36 PM.
11-23-2004, 09:55 PM
#2
Who burnt the chip for him. Something is not right with the tune from what it sounds like. It should never heat the headers that much. With the exeception of the cam it sounds like a fairly normal powertrain upgrade for trucks in those years. I have a built 454 in my 90' model and just ran a stage 2 hypertech in it. But I changed out the pcm to a 94 model and added a 4l80-E as opposed to the stock pcm. Is the stock serv
# on your computer 1227747. If so that is a terribly slow computer and has problems dealing with much in the way of speed equipment. That is also another reason why I swapped PCM's. When I did mine I cut the plugs off a 94 3/4 PCM and snagged the trans. I got the pin outs for my 90' and 94' off of alldata at the shop and started soldering. The difference with the faster PCM the hypertech chip and the 4l80 was amazing. It had driveability issues prior to this along with a idle that constantly hunted due to the cam along with being lean in the top end. The swap solved all of my problems. If you are interested in upgrading to a faster PCM PM me and I will get you the schematics. good luck
# on your computer 1227747. If so that is a terribly slow computer and has problems dealing with much in the way of speed equipment. That is also another reason why I swapped PCM's. When I did mine I cut the plugs off a 94 3/4 PCM and snagged the trans. I got the pin outs for my 90' and 94' off of alldata at the shop and started soldering. The difference with the faster PCM the hypertech chip and the 4l80 was amazing. It had driveability issues prior to this along with a idle that constantly hunted due to the cam along with being lean in the top end. The swap solved all of my problems. If you are interested in upgrading to a faster PCM PM me and I will get you the schematics. good luck
