gkrcr882
SyTyless......for now!
I've had this problem for some time, and learned to live around it, but knowing things aren't right is getting to me. Scenario:
Flat-foot it from a light, engine revs up, truck takes off, boost is normal, but around 4700-5000 the truck will suddenly slow down.(no shift yet) I thought it was overboost, but doing a rolling 3rd gear WOT reveals on my aftermarket gauge a solid 14.7.
I know the factory shift point is around 4700 at WOT, when all this chaos begins...Rev limiter maybe?
So far I havent done much, just the basic ignition tuneup in the spring, and recently cleaned the TB/upper plenum. The truck runs and has power at all other times, even at WOT except for when it gets to the upper range.
I'm thinking that something is sketchy with the governor weights or the trans itself, since the shifts are at the right time, (speed vs throttle pos), and they're quick, but not necessarily "firm"?
Other thought is that there may be knock retard, but I don't have DM or access to one, so determining that would be hard.
I might try another cap/rotor and a set of good NGK's and try a .030 gap, see if its the spark getting blown out or something along those lines.
The only other issue is erratic boost. Getting on a freeway onramp, constant throttle, the boost will go up and down, almost surging, but not overboosting. Truck has a Waller 57mm turbo and no cat- I thought about installing one to try to bring it back to stock as far as backpressure is concerned to see if that is the source of problem.
Other info- I checked (or tried) the timing, it appears as though the mark on the balancer is 180 out, although the truck runs fine. Slipped balancer? (yes I unhooked the wire)
IC system is fully functional, EGR vac line is unhooked and plugged, decided to try it as an experiment. Fuel pressure is 50lb @ idle w/ the line hooked up. (truck had an Ultimate before I bought it), stock injectors, silicone vac lines installed by the previous owner(s) stock chip/ecm. Still havent figured out the TC lockup issue either, but I'm leaning towards the solenoid (new brake switch, tried to manually lock through ALDL with no luck)
Long list of little (irritating) things, but I'd like to get to the point where I can confidently drive it a few hundred miles at a shot without worry. Thanks for any and all input!
Flat-foot it from a light, engine revs up, truck takes off, boost is normal, but around 4700-5000 the truck will suddenly slow down.(no shift yet) I thought it was overboost, but doing a rolling 3rd gear WOT reveals on my aftermarket gauge a solid 14.7.
I know the factory shift point is around 4700 at WOT, when all this chaos begins...Rev limiter maybe?
So far I havent done much, just the basic ignition tuneup in the spring, and recently cleaned the TB/upper plenum. The truck runs and has power at all other times, even at WOT except for when it gets to the upper range.
I'm thinking that something is sketchy with the governor weights or the trans itself, since the shifts are at the right time, (speed vs throttle pos), and they're quick, but not necessarily "firm"?
Other thought is that there may be knock retard, but I don't have DM or access to one, so determining that would be hard.
I might try another cap/rotor and a set of good NGK's and try a .030 gap, see if its the spark getting blown out or something along those lines.
The only other issue is erratic boost. Getting on a freeway onramp, constant throttle, the boost will go up and down, almost surging, but not overboosting. Truck has a Waller 57mm turbo and no cat- I thought about installing one to try to bring it back to stock as far as backpressure is concerned to see if that is the source of problem.
Other info- I checked (or tried) the timing, it appears as though the mark on the balancer is 180 out, although the truck runs fine. Slipped balancer? (yes I unhooked the wire)
IC system is fully functional, EGR vac line is unhooked and plugged, decided to try it as an experiment. Fuel pressure is 50lb @ idle w/ the line hooked up. (truck had an Ultimate before I bought it), stock injectors, silicone vac lines installed by the previous owner(s) stock chip/ecm. Still havent figured out the TC lockup issue either, but I'm leaning towards the solenoid (new brake switch, tried to manually lock through ALDL with no luck)
Long list of little (irritating) things, but I'd like to get to the point where I can confidently drive it a few hundred miles at a shot without worry. Thanks for any and all input!
