Motor only revs to 3000 RPM before cutting out...Running DFI v6.32...

[Markolc]

I put a '95 LT1 motor into my IROC, and hooked it up using DFI. To fire up the motor, I used a program off the internet from someone who had a somewhat similar engine combo on ther DFI v6.32. So I uploaded his file, and the engine idles and low revs (to 2500 RPM) very well and smooth. Not lean or anything. I put on a free flowing exhaust, new air filter, new ignition coil, new spark plugs, new opti-spark, new fuel pump (Walbro 255LPH), 24# injectors used injectors. My motor ONLY revs to 3000 rpm, then it stumbles like it hits a rev limiter. The tach jumps all over the place at that RPM as well. What do you think it can be? Can the DFI program I'm running be too advanced in timing? I'm looking for any help I can get as I'm stumped. Could this problem stem from fouled spark plugs, or maybe a bad ignition module? I'm looking for any help I can get...please respond. Thanks.

 

[Markolc]

Something I was just thinking while reading over the Calmap manual. The built in rev limiter function of the DFI lowers the RPM by 1000 when it hits the rev limiter, and that's kinda what the tach reflects when it hits that 3000 RPM mark. The tach bounces, but it bounces from 3000, down to about 1500-2000, then tries to climb, then bounces. I have the rev limiter on the DFI set to 6300, but would there be a bad circuit or something inside the DFI that would invoke the rev limiter at 3000 RPM?

 

[Butch]

Markolc, I am running the Accell DFI (Bank to Bank) with a 94' LT1 (No crank position sensor) and I have not had a problem like that. Maybe you are running out of fuel at 3000 rpms? What does your timing look like? What are you using for timing reference angle? Where did you get your wiring harness?

Butch

 

[TurboJim]

Does the DFI have P/N switch input? Could it be a protection? Shuts down at 3K in P/N to keep from over reving it?

 

[Markolc]

Thanks guys for your suggestions, But I figured out the problem. The problem was with the DFI ECM itself, and nothing mechanically. I sent it back for repairs and it works perfect now. For some reason, whatever I set the RPM limit to, it would only rev limit at 3000. I tried 2200 all the way to 25000, and it would still limit my revs to only 3000. But it's all set now, It must've been an internal circuit failure or something, but it works now .