mrgoodwrench

i was wondering if my 91 trans am with a 305 has a rev limiter at or around 5000 rpm... fairly recently i had put in a new motor built built with forged pistons, rods, crank and ported heads bigger cam and all the goodies... its got 22 lb injectors, tpis manifold, headers, and a jet chip... but it has no power above 4500 rpm and wont go past 5100 at all(in gear or park), doesnt feel like a rev limiter to me but i was told that it does have one... anybody got any ideas?

Guest

If it does, the car didnt originally come with it. The chip does have a provision for a fuel cutoff IIRC, but its set to 10k RPM or something stupid like that. I doubt that is wrong.

Sounds more like a problem, not a limiter. Likely suspect #1 is the cat. You might also want to verify that the engine is getting enough fuel at that point.

brutalform

ho big is the camshaft? sounds like it could be a secondary ignition problem. check the simple things, like burned plug wires, cap, rotor etc. maybe the pickup is on its way out. also put another prom in that you know is a good one, to rule that out too....tom

brutalform

also, put a vacuum guage on it. you should have a steady 15 to 17 inches at idle. no bouncing, or you may have a bad valve. then while the engine is idleing, smoothly increase the throttle, to about 2000 rpm. the needle should rise to about 24 inches or so. if it goes down while you increase the rpms, you have a restriction in the exhaust, probably the cat, or too small of a system.

89 Iroc Z

Is it TPI because that's about where it should die.

z28monster

iTrader: (1)

my car is tpi and it will free rev to 7000 rpm if i want to so even if it is TPI it should still rev higher then what he is getting out of his...

maybe you need a better chip burnt for your engine set up.. the 305 chip may not be able to handle it... just guessing though

JMatlock88

A slightly unplugged MAP will cause this also. Check that the MAP plug is secured properly and the pins are not bent.

mrgoodwrench

well its got all new plugs wires cap rotor, bran new distributer and module, and msd blast coil, an msd box, the map is fine, and i have no cat... the only thing i think it could be is my chip, or not enough fuel volume... thats the only thing left

mrgoodwrench

thx for all your guys idea's, but im stumped

DuronClocker

iTrader: (1)

Put your stock chip back in.

As for TPI, my entirely stock LB9 can pull to 5500 no problem (though not very strong after 4700ish).