motor wont rev past 4500rpm any suggestions?
03-08-2015, 10:28 AM
#1
motor wont rev past 4500rpm any suggestions? UPDATE: THANKS TO CAL HARTLINE WE FIGURED OUT IT WAS THE FAST CRANK TRIGGER SENSOR SO I PURCHASED A HONEYWELL HALL EFFECT SENSOR FROM BRIAN MACY AND GOOD TO GO NOW CAN REV TO 8K NO ISSUES!
ok here is the issue and specs
car starts and runs great rev in neutral all sound and feels great till it hits 4500 it hits a wall like a rev limiter and if i peg the throttle it will just stay there.
now driving it will do the same thing even under boost.
here are the specs and things i have done and changed
397 stroker lt1
afr 210 #1101 heads
custom comp solid roller turbo cam and lifters
88mm turbo
th400 jw converter (too tight)
fast xfi 2.0
fast xim
ls7 coils
tr7 plugs gap .29
ok first when i built the car it had a billet optispark and msd dig 6 and coil with the fast xfi and this was an issue from day 1 so i sent everything electrical back to each company to have them check to make sure all was up to working spec and everything was so fast tech support suggested it was a interference issue between fast and msd ect.
so with there suggestion i went and upgraded to the xim box and ls7 coils and the fast crank pickup setup and i purchased a cam sensor kit from efi connections.
well after alot of work it still had the same exact issue! so brian macy aka turbonova built me an opti for just cam signal and i replaced and same issue so that is off the list also below is all the other things i did
checked valve springs and measured height and shimmed where was needed to all match.
changed wires and spark plugs and gaps.changed coils.
changed valve train to t&d shaft rockers.
checked tune and asked a tuner to look over my working tune.
plenty of fuel actually runs very rich!
checked and re checked my lash.
there's probably more i just can think of everything right now but any suggestions i would be grateful cause im at a loss and spent so much time and money also would the torque converter possible be too tight to create this issue? on a good note the car runs great and pulls great till it hits 4500 lol
thanks everyone
ok here is the issue and specs
car starts and runs great rev in neutral all sound and feels great till it hits 4500 it hits a wall like a rev limiter and if i peg the throttle it will just stay there.
now driving it will do the same thing even under boost.
here are the specs and things i have done and changed
397 stroker lt1
afr 210 #1101 heads
custom comp solid roller turbo cam and lifters
88mm turbo
th400 jw converter (too tight)
fast xfi 2.0
fast xim
ls7 coils
tr7 plugs gap .29
ok first when i built the car it had a billet optispark and msd dig 6 and coil with the fast xfi and this was an issue from day 1 so i sent everything electrical back to each company to have them check to make sure all was up to working spec and everything was so fast tech support suggested it was a interference issue between fast and msd ect.
so with there suggestion i went and upgraded to the xim box and ls7 coils and the fast crank pickup setup and i purchased a cam sensor kit from efi connections.
well after alot of work it still had the same exact issue! so brian macy aka turbonova built me an opti for just cam signal and i replaced and same issue so that is off the list also below is all the other things i did
checked valve springs and measured height and shimmed where was needed to all match.
changed wires and spark plugs and gaps.changed coils.
changed valve train to t&d shaft rockers.
checked tune and asked a tuner to look over my working tune.
plenty of fuel actually runs very rich!
checked and re checked my lash.
there's probably more i just can think of everything right now but any suggestions i would be grateful cause im at a loss and spent so much time and money also would the torque converter possible be too tight to create this issue? on a good note the car runs great and pulls great till it hits 4500 lol
thanks everyone
Last edited by lordrazo; 06-17-2015 at 05:34 PM.
03-08-2015, 02:31 PM
#2
TECH Addict
Injector Duty cycle? Usually the only thing that would stop your engine from revving past a point is fuel or air restrictions. I honestly don't think the injectors would max and cause a sudden rev limiter (it'd be more gradual). But reaching max air volumes for a given part can absolutely do that (like a clogged cat converter).