Papasmurf

Was out putting some run time on my new 540 EFI Stroker motor that M E R Performance just built for me (see Building a Sleeper thread in general discussion) and my baby just laid down and died!
Cruising along around 3500 RPM and then nothing.

Motor turns over, but not a cough

Get Mark from MER on the phone, has me check all the plug in connections (all good) and then ask me to spin the engine over and watch oil pressure and tach.

Oil pressure was dancing, tach was not..........................17 year old tach shorted out, canceling the signal from the coil to the fuel pump and ECM, telling those two, HEY I'm trying to start,
Removed gray signal wire from back of tach..........................................and she lite right off!

Now how long would I have hunted for that?

Hope this saves someone some coin

ROB FREEMAN

Awesome. You're the one that kept him from getting my ignitions done all summer. :-)))

Papasmurf

Yep! That was me

ROB FREEMAN

well im glas youre on the water , although if mark would have go to me . id known all summer my piece of chit msd s were garbage . lol he told he was working on a efi 540 that he had to finish before me . so just jaking around here .. glad something easy .

TxHawk

Can someone explain how this would have to be wired for this to happen? I am under the impression that a tach gets power, ground and a signal. Why are fuel pumps etc. relying on the Tach?

Papasmurf

Please understand this is a COMPLETE custom built engine from the ground up. Nothing Mercruiser about it. Runs a Holley 2000CFM Direct Injection Fuel system with its on ECM and fuel manager.
The coil in my case has two output signals. One going to the tac and the other going to the ECM. Its the same signal. When the tac shorted or grounded out the ECM could no longer read the signal. So the ECM doesnt know the engine is turning over trying to lite.
ECM is controlling fuel pump, injectors and ign system.

Hope that clears things up abit

Papasmurf

I had two 650 HP engines for a Cig in front of my engine. The cam profiles where an issue with those. Mark spent a lot of time and effort getting those perfect before starting on mine. Thats just the way the man works.

He has tried to teach Jacob how to turn a wrench, but I think his tail keeps getting in the way!

ROB FREEMAN

Bro. I'm patient man. He's flying in to hook me up. Me and mark knew what he was doing and when I was getting some love. I was just playing. And enjoying the Internet. No worries here. I'm just glad you're stuff is up n running.