TruxtonFox

Ive got the service manual, and think I am reading it all correctly. My thinking is that I am not getting any signal from my ignition module. I replaced the entire distributor assembly with no luck. If I unplug the distributor harness and take my test light (clamped onto positive), turn the key to the ON position, let the fuel pump run its startup cycle, then touch my test light to the Pur/Wht signal wire going to the computer, the injectors begin to fire. But if they are not manually told to do so they wont, nor will they continue to fire once you try to start the engine.

Could the distributor assy be bad?

ezstriper

did you use the EFI dist ?

swan2

Yes the factory EFI dist. is being used. It a 2000 MPI. We have Spark and when we spray fuel into it with a spray bottle it will run until you stop spraying it in there. If we hook up a noid light to the injector harness there is no injector pulse. But with the key on engine off there is 12 volts to both wires at the injector. And when you start cranking the engine over theres still 12 volts to both wires going to the injector. They bought this MPI as a take off so we are trying to get it to work. Its A MEFI 3 computer and I did put the computer on my boat and mine runs fine with it. So its not the computer. Check out the pics he posted that the connector that I believe goes to the Starter Charging system. Would the Starting Charging system have anything to do with it not pulsing the injectors?? Thank you guys in advance for all the help and replys. We have been working like crazy for several days to get this thing going and we are running out of Ideas. Im trying to give as much info as possible to help with what you guys think might be the problem. The engine is a 502 that was carb. and we are switching iit over to the MPI. So we are still using the carb harness that was on the motor for the Starting and Charging system. Not sure is that might be the issue. There Again not sure if the Starting Charging System has anything to do with the Injectors firing.

SB

iTrader: (1)

Really ? Both ?

F-2 Speedy

iTrader: (6)

part of the efi engine harness plugs into the coil, its a split connector and the other to the distributor, if I remember right, and the injector harness plugs into the engine harness.

I think it would be difficult to use a carb engine harness on an efi upper wiring, JMO

swan2

Yes both wires going to the injectors are hot. KOEO Both wires are Hot. Both wires are Hot when cranking the motor over also.

The wiring harness connected from the harness to the split connector to the coil is hooked up. And the wires from the coil to the distributor is also hooked up.

The engine runs as long as you keep spraying fuel in it!

Does the Starting, Charging System have anything to do with making the injectors pulse??

airjunky

iTrader: (2)

Going to be a high and low reference signal from 2 of the 4 wires from dist to ecm . Compare avg volts and or freq signal from your runner test mule.
If the ecm isnt grounding your injectors to spray fuel you will see 12v on both sides .
Hopefully you have a distributor that will deliver mefi 1-4 reference signals.

TruxtonFox

We have swapped over everything from the test boat to the new engine and still cannot get the injectors to fire, ICM, Distributor, Computer, everything. I am assuming the injectors work off of ground interruption? The ECM housing is grounded, both black wires in the harness are grounded. Still no pulse.

Side Note - The main relay that takes 12V feed from the batteries does NOT pass 12V through. If you jumper wire across that relay to the line going to the fuse block, the fuel pump turns on and cycles, but the injectors still do not pulse. The black wire in the relay is grounded. We swapped the two relays with the same results (we are assuming we don't have two bad relays).

There is a rectangular plug on the backside of the harness by the distributor that plugs into the starting/charging harness. Unless it is picking up some sort of signal to send to the distributor I don't think it has any effect on the main harness.

One thing we did find was the white wire going into the distributor on the 4 pin connector is supposed to be grounded when cranking, it is not grounding. But again the ICM is tested good.

Thoughts?

[ATTACH=CONFIG]561671[/ATTACH]

F-2 Speedy

iTrader: (6)

did you check the fuses on the efi harness, should be 3 under a gray or black cap, I know one is for the fuel pump

TruxtonFox

yes, all three have power in/out...fuel pump is working correctly with jumper wire on relay, remove jumper and nothing