GPM

That sucks, Dick, you're still welcome to my spare Fast ecu and harness.

Vinny P

Dick,
We have talked about this countless times over the phone and via e-mails. I wish I could have been more helpful. My thoughts still stand.. I would love to see you use the simplest form of ignition, no electronics, no nothing.. just to see the damn thing hold steady timing. That way it would eliminate any sort of mechanical engine problem that we havent thought of. As you said, this system worked on your last engine. Nothing has changed electronically.
Does anyone have a Magneto to lend him just to try it out?

fbc25el

Have you tried running a ground wire off your cyl. heads to the neg. side of your battery?

Boat1

If I understand you correctly when you say your use an HEI distributor does that mean you are using none off the MSD components, just the HEI. If so, that rules out all MSD components for causing the problem. The solid square wave shows the crank trigger and the box are doing their job. Try a known good set off wires and change the plugs, I would also gap the plugs small so you get a strong spark.

mike tkach

iTrader: (3)

dick,i have a msd 20 promag you can borrow if you want.it is locked out,meaning it has no advance curve.my thinkikg is if you try a hei dist with coil in cap,and disconnect all the msd components,with plugwires non msd,and the problem is still there,then the efi is causing the problem.o i forgot,replace the plugs and tighten up the gap just for the test.i am about 40 miles sw of chicago,i wish i was closer to you,as i love a challange,and as every other problem,IT CAN BE SOLVED.

Mr Gadgets

Thanks Guys..

the heads are grounded to the Battery Neg..
I did run the HEI alone, no MSD, accept the plug wires..
Plug gap on both sets I tried are at .028".

Mike, I may take you up on it.. but I would think the HEI would tell the tale.
I may hook up a seond sensor to run the EFI on a seperate battery.. and the MSD on another.. see if that tells me anything..

All good ideas.. keep them coming. I need to take a trip to the speed shop.. Just an hour from home.. and I am an hour from home, while at work..

Thanks
Dick

ezstriper

when the timing jumps, does the engine change ? should be a big change if timing jumps that much...I like the idea of trying a HEI or a mallory unilite stand alone dist and see what happens..if it stops would say some sort of RF interferance effecting the MSD stuff. try calling nelson specialties 800-494-7532, he works with tons of ignitions mostly in nascar..but knows his stuff, Rob

Mr Gadgets

Rob, I did run it with an HEI dist without the MSD components and it still did it. I do hear the motor change at times.. Sometimes it does so much, it is hard to tell. But when it runs sort of ok.. I can hear it miss when it jumps the 90*.
Thanks for the contact, I will keep his number...

I did think of a way to run the EFI and MSD on different batteries using the MSD dist pick up for the EFI tach pulse.. and then use the crank trigger for the MSD.. on a seperate battery. That should simulate the Magneto, I would think..
I picked up new wires tonight.. Did not install them, I want to do some testing before I switch them.
Next session I am going to do some RFI sniffing with the scope. I got advice on what I should see from a very experienced guy.. Then I am going to try the seperate batteries again, with different sources for a tach signal. Boat1 gave me the idea when he mentioned cam position sensor.. That should allow me to completely seperate both systems, electrically..
Then I will try the new plug wires.. and another set of plugs, different brand this time, just in case.
Just wish I didnt need to sleep or work.. I would have solved this by now.

Thanks guys!! When I do find it I will let everyone know..

Dick

BenPerfected

If you don't find the issue soon, we have a NIB Crane marine distributor & set matched coil that you are welcome to try....but you can't have it

Mr Gadgets

Thanks Ben, I will keep that in mind..

Dick