89 Chevy Pickup 350 Probs
torquefiend
07-17-2003, 07:39 PM
Hey all nice site here..
K shes not mine, but a friend of mine..
K heres the deal
Its an 89 350 with a 700R4 behind it. Whenever you drive it up a grade @ 70MPH it will downshift unless the air filter lid is turned upside down. The Rotor, cap, plugs, fuel filter, air filter have been replaced and the injectors are good to go. The truck doesnt have a CAT, and there is a slight exhaust leak on the passenger side by the exhaust manifold. I think it may either be the exhaust manifold gasket or where the manifold dumps to the Y pipe, but its not bad enough to be causing this much power loss.
I suspect that the CAT may be the problem, but i really dont know much about the way the PCM operates on this truck. Could the absence of the CAT be causing a rich/lean condition? It feels like its not getting enough advance when required. Theres no SES light on or anything.
Also we may just decide to get a crate motor for it, anyone know whats available that would be hotter than stock and still be a plug and play type of a deal? any input is appreciated thanks guys.
K shes not mine, but a friend of mine..
K heres the deal
Its an 89 350 with a 700R4 behind it. Whenever you drive it up a grade @ 70MPH it will downshift unless the air filter lid is turned upside down. The Rotor, cap, plugs, fuel filter, air filter have been replaced and the injectors are good to go. The truck doesnt have a CAT, and there is a slight exhaust leak on the passenger side by the exhaust manifold. I think it may either be the exhaust manifold gasket or where the manifold dumps to the Y pipe, but its not bad enough to be causing this much power loss.
I suspect that the CAT may be the problem, but i really dont know much about the way the PCM operates on this truck. Could the absence of the CAT be causing a rich/lean condition? It feels like its not getting enough advance when required. Theres no SES light on or anything.
Also we may just decide to get a crate motor for it, anyone know whats available that would be hotter than stock and still be a plug and play type of a deal? any input is appreciated thanks guys.
4onFloor
07-17-2003, 09:45 PM
the exhaust would have nothing to do with the power loss. Same for the cat, cat or no cat it's gonna run the same, just a little louder. Engine wise, you could by a 383 or you could stroke out the 350 to a 383. I'm not sure, but I think a big block would probly starve for gas if you used the set-up you've got now.
MunsterGarage
10-06-2003, 03:53 PM
Does it have the original air cleaner assembly? if so...the temp controled flap inside the snorkle might not be opening all the way causing less air flow.
BOOZER
10-10-2003, 01:58 PM
Not a lot of vehicle info to work with{GEAR RATIO,
TIRE SIZE, ECT} but it sounds normal. These trucks
usually have a 3.42 or 3.73 & with a tall tire & in 4th
gear with tcc engaged & 70mph your not spinning a
lot of rpm. Also a lot of people feel the tcc disengague & think its a shift. You might try to readjust the T/V cable, but do it correct. The T/V
cable controls more than just the old detent cable,
it affects line pressure, shifts & shift feel, & can cost you a trans if not adjusted correctly.I think the
A/C trick is letting you keep just enough throttle angle out of it to prevent the shift.
TIRE SIZE, ECT} but it sounds normal. These trucks
usually have a 3.42 or 3.73 & with a tall tire & in 4th
gear with tcc engaged & 70mph your not spinning a
lot of rpm. Also a lot of people feel the tcc disengague & think its a shift. You might try to readjust the T/V cable, but do it correct. The T/V
cable controls more than just the old detent cable,
it affects line pressure, shifts & shift feel, & can cost you a trans if not adjusted correctly.I think the
A/C trick is letting you keep just enough throttle angle out of it to prevent the shift.
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