LS1FC3S

Situation:

1991 Camaro RS
New 383 stroker motor.
MSD Box and MSD Coil.
Mels Ignition HALL Effect Distributor w/two wires (unused)
Magnetic Crank Trigger wired to MSD box.

Problems:

1. Engine will turn over fine and will fire on starter fluid, But Fuel Pump will not come on. Have voltage to the pump, also have installed a brand new pump. I can hotwire the pump and it works just fine, but will not come on when the ignition key is turned on.

I've heard that the ECM needs a separate Oil pressure sender, and that would cause the ECM to NOT start the fuel pump, but where is that located? I have a new Oil pressure sending unit on the drivers side over the oil filter.


2. Fuel injectors will not fire.

I've heard A Bad Igniter Module in the distributor might be causing the Ecu to NOT fire the fuel injectors. Does anyone know what the ECU needs to see from the MSD box or HALL effect distributor in order for the injectors to fire? The MSD has an output for a "Points" style set up, should I connect that to the Distributor and then connect that to something on the harness?

Dave89IROC

you won't get fuel injector pulse without a reference signal from the ICM, I am not sure if the ref. signal is a standard tach signal though

I would get a GM dist. and wire it up enough to get a ref signal

ringo234

Sometimes the VATS won't let the fuel pump work. And if you bypass that the the ECM may not enable the injectors. May not be the problem but it was for me once.

LS1FC3S

Well basicly I was just trying to swap long blocks with this new engine. The only thing different was the distributor. I figured this would have been something that alot of people have already encountered, but maybe not.

Thanks for the tips though.

red94chicken

if it were your vats the engine wouldn't turn over... does the fuel pump prime when you turn the key? have you tried to swap your relays? you do need a reference from the oil pump showing at least 15psi to the ecm to keep it sending power to the fuel pump relay....

raul.garcia

The ECM needs 4 signals from the Dizzy - EST, Reference, By-Pass, and Ground.
As Dave89IROC suggested get a GM dizzy, or aftermarket replacement with the correct MSD box.

RednGold86Z

I've done something like that. If you're using some other device to control all the spark timing, and have no connection to the distributor, you can run the TACH output of the MSD box to the REF input of the ECU. It will have a check engine light though. You might be able to ground the EST Bypass through a high resistance resistor (like 1k or so), to get rid of the check engine light.

You also have that hall effect output of the distributor - if it's 8 pulses per 2 revolutions, then you could connect one side to the REF and the other to the EST Bypass, I THINK. The hall switch should take that 5v EST bypass and switch it on and off to the REF input of the ECU, thus giving it an accurate RPM signal.

You will also probably have to disable the knock check in the chip as well, to avoid another check engine light.

VATS shouldn't be your problem (older '165 ECUs only disabled the fuel injectors, some then had a starter disable, and I think most of the 89-92 had starter disable as well), but it's probably a good thing to disable when you do your new chip.

ALSO, to dispel the myths about this = the oil pressure switch for the fuel pump is a BACKUP to the fuel pressure relay, not a kill switch. Sure, it can fail in a bad way and cause a no start, but it's purpose is to ALLOW fuel pump power IF there is oil pressure, as a backup for a failed fuel pump relay.

YOU DO NEED TO BURN YOUR CHIP FOR YOUR ENGINE, don't even bother with mail order.