No start/No injector pulse
 

I know this may not be the ideal forum to be asking ski boat questions, but other sites have been little help. Perhaps some experienced minds will chime in.

I am working on a 94 mastercraft with a throttle body injected 350. It will not start due to no injector pulse. I have power at the injectors, and if I ground the injector circuit at the ecm connector they will pulse. I am also getting ignition spark. I have tried 2 different ignition modules thinking that the output side of the module may be bad. Still no start. I have ohm tested all wires from the ignition module to the ecm. No open circuits. I have checked TPS voltage and it is at .5 volts, thinking possibly in clear flood mode. Coolant temp is at 65 deg, and shift interrupt is working properly. I have tried a new ecm, and still no start. Is there anything else that would tell the ecm not to pulse the injectors? Any help would be GREATLY appreciated..


Thanks
Charlie

Crank trigger ?

pick up coil inside the distributer

When you crank the engine over is the tach on the dash moving? Meaning, are you getting an ignition signal? I know you have spark, but you could still not get an ignition signal to the ecm to tell it to fire the injectors.
Eddie

There is no per say "crankshaft position sensor" the sensor is the pickup coil/ignition module. I have replaced the ignition module, but didnt think the pickup coil would be the problem seeing how I have spark. I dont see any RPM in the data stream while cranking. Not sure if you would see any during cranking. No the tach does not move during cranking either.

Cranking spark is generated by the ignition module in the distributor. Only when the engine passes 425 rpm does the module switch over to ECM based timing. You need to verify that the distributor output signal reaches the ECM. If it does, you prolly have a toasted ECM output driver. GM TBI used one Quad driver to run both injectors. If it fries, no injector drive.

I tried a new ECM, but Im not confident that is was the proper application. I am sure all 4 wires from module to ECM for the high/low IC reference signal are good.

You should absolutely see rpm data at cranking speed. That is what tells the ecm that the engine is turning over and the injectors need to be fired. The tach should also move when the engine is being cranked. You are not getting a signal to the ecm to tell it to fire the injectors. Your problem is either in the distrubutor or the wiring from the dist. to the ecm.
Eddie

Ok. Got a new GM distributor from parts, installed it and same thing. The tach on the dash does move while cranking. I did ohm test all 4 wires from dist to ecm again. Also drag tested all terminals. Everything is good.

Im running out of hair to pull out. :mad:

there is a pink wire that has a dieoed in line that plugs into the distributor module that dieoed is the weak link to theas engines and always over looked and if i remember right you cant find it in a ohm test that easy or something like that it been a while.that dieoed is hard to find becouse it is wraped up in tape or conduint.you will ned to order a new wire it just plugs in.that should get you running again.hope this helps.let us know.

Well I got it figured out. When I replaced the ECM, the original was a
MEFI I, Well they are no longer made. So when I ordered a new one I was told I had to get a MEFI II that was "retrofitted" with the MEFI I software. Well apparently it did have the proper software, but the ECM connector pin outs are different. After installing the ignition high reference wire in the proper position in the J2 connector I got the injector pulse. It still runs poorly, but Im sure there are more wires that need to be moved. I asked them 3 times if there where any wires that needed to be moved and they told me NO. UUUURRRGGG..... well at least Know what it is.

Thanks for all the input
Charlie

Considering it took out the quad driver for the injectors on the original ecm, you better make sure that the injectors are not shorting when hot and the wiring to the injectors from the ecm are clear of any possible shorts to power. You don't want to fry the new puter.

Good point. I will do an amperage test when I get everything together. I know the wires are good and not shorted to ground or to each other.

Thanks for the help
charlie