Quick question
 

Installing a used EFI system on a previously carbed 502. Everything is working correctly as far as fuel pressure, spark, etc. with the exception of injector pulse. We have checked to make sure the computer is good on another boat, we can probe the harness at the dizzy and get the injectors to fire, but can't seem to get them to hit while we turn the motor over. We have the pictures connector left with no where to plug in, does some thing on it need to be jumped or connected? [ATTACH=CONFIG]561500[/ATTACH]

What are you doing for Crank position sensor

No Cps on this unit

Is the power to the injector stay on when cranking?

Zero power to injectors, fuel pump is good, relay isn't sending power down small pink wire from relay. But if back proved through the purple/white from back of dizzy injectors fire, but won't stop firing until you try to crank it, then they stop and won't start up again

Any other ideas?

There is no quick question with boats, lol. Don't you need an efi cam if this is a stock merc system?

2003 system....don't think it's got cam position sensor

I would think it would need something to tell it when to send a signal to the injectors. Cam or crank sensor.

You haven't mentioned if OE Mercury fuel injection or not, but if Mercruiser, have you looked at wiring diagrams ?

http://www.boatfix.com/merc/Techbk/96/96HGD4.PDF

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?

did you use the EFI dist ?

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.

Really ? Both ?

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

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??

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.

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]

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

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

Update- we now have power to EVERYTHING when the key is switched on. The pink wire in the starting/charging harness requires 12v + while the white wire comes from the coil and heads to tach. But, we still have yet to figure out why we don't get signal from distr through ICM to injectors to pulse.

Is the distributor assy for these motors the same as the automotive, with the exception of stainless hardware?

get an efi engine harness and your problems will be fixed :lolhit::funnypost:

Edit: I have an efi dist. if you need one

Lol, I've got the harness figured, I may take you up on that distributor....how much you want for it

pm me an offer

OK the harness, distrubtor, and mefi 3 all came off of a running motor. Intake and everything. The only thing that wasnt purchased was the starter charging system harness but I dont think that has anything to do with the injectors getting pulse. JMO. Any other Ideas?? I am bringing my boat over and maybe we can use mine to get some answers. I dont know. Thank you guys for all your replies so far. Please keep the advice coming.

the dist is a GM EST, but the module is marine specific and the dist is what tell the ECM to fire the injectors