Boggy/sluggish TPI motor when warm..........
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Boggy/sluggish TPI motor when warm..........
Hey guys, newbie here.........have a 406SB in my Blazer with a Frankensteined '90 TPI unit on top........24 lb/hr injectors, 52mm throttle body, custom chip. All this on top of a one year old rebuilt 400 with lots of goodies. OK, the motor has run great up until recently, so its not a compatibility issue, this combo ran flawlessly for months with no problems. What it does now is this - first, it does not have a good cold start personality - it runs like a poorly adjusted carb would until it goes into closed loop (2 minutes after startup apx.). Then it runs fine.......for a while. Then, after about 20 minutes of driving around town, you will notice it act like it doesn't want to accelerate........like the timing all of a sudden got retarded big time. Kicking the loud pedal makes it get moving again, but it returns by the next slowdown/takeoff again. No codes/no light coming on. Have replaced the EGR (had a history of EGR issues in the computer) and a new knock sensor. No change at all. My engine builder was 'sure' it was the EGR but if so, maybe its a bad one.
By the way, this motor and TPI was set up by a local guy here in Portland that has done literally over a hundred of these conversions..........mostly in Jags, but plenty of trucks. He is currently unavailable for this issue.
Anyone have any ideas on this? Fuel filter/EGR/voodoo? Help!!!
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'79K5 Blazer with 406TPI
By the way, this motor and TPI was set up by a local guy here in Portland that has done literally over a hundred of these conversions..........mostly in Jags, but plenty of trucks. He is currently unavailable for this issue.
Anyone have any ideas on this? Fuel filter/EGR/voodoo? Help!!!
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'79K5 Blazer with 406TPI
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Check your fuel injector resistance when cold and when warm, my bet is that the problem is with those when they warm up. They should all be 12-16 Ohms and if you find a couple that are like 8 Ohms hot then that's more than likely your problem.
Is the computer giving any trouble codes?
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1990 IROC 350
Mods: Too busy trying to make it run right to mod it.
Airfoil, Dynomax cat-back, MSD coil, 180 t-stat, Bald Eagle tires,
Hypertech fan switch, Accel 23# injectors, Holley module, ported plenum,
Ported Daytona Yellow stock base, Moroso valve covers, other stuff,
Streetdampr, Ruger P95DC, hot wife, new oil filter, !cats, !TBC, !AIR.
18.0 @ 85MPH since I'm one big-a$$ MF
"It's better to have and not need than to need and not have."
Is the computer giving any trouble codes?
------------------
1990 IROC 350
Mods: Too busy trying to make it run right to mod it.
Airfoil, Dynomax cat-back, MSD coil, 180 t-stat, Bald Eagle tires,
Hypertech fan switch, Accel 23# injectors, Holley module, ported plenum,
Ported Daytona Yellow stock base, Moroso valve covers, other stuff,
Streetdampr, Ruger P95DC, hot wife, new oil filter, !cats, !TBC, !AIR.
18.0 @ 85MPH since I'm one big-a$$ MF
"It's better to have and not need than to need and not have."
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mdtoren
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08-16-2015 05:45 PM