I just installed a new engine harness from M&H Electrical (spectacular product) and upon hooking up the battery I got a big spark and heard the starter motor turning. I immediately unhooked the positive lead, removed the starter, and tested the voltage to the leads. My purple wire was connected to the "S" lead, yellow to the "R" on the starter. With my voltmeter I hooked up the yellow wire and the battery cable connector for the starter and found 12.44 volts with the ignition off, same in the "run" position, and ZERO in the "start" position. The purple wire and starter cable read ZERO in all positions! What am I missing??

 

OK, you should not have any voltage on the purple or the yellow wire with the key off! There must be 12v to the big lug at all times! Basically when you turn the key to start the purple wire will get voltage, therefore engaging the starter. When the starter engages and moves forward, you will then get 12v to your coil through the yellow wire!

When you release the key from the start position the purple wire is at 0v, the starter pulls back and the yellow wire drops to 0v.

My only guess is that you changed something else at the same time, like installing an HEI. Or you plugged the purple wire into the wrong socket on the harness!

 

Well, connecting the wires to the voltmeter properly would help, I hadn't done that... After doing it properly I found power going to everything properly, the problem was a shorted solenoid! Thanks!!!

 

Ahhhhh the old shorted solenoid routine!!! Glad you found it!

 

I'm looking to do this same job on my 71 Cutlass and have a few questions:

Was this installed on an A body Cutlass, and do you splice into the existing harness, or connect to the back of the fuse block?

What circuts are included with the engine harness? (alternator, starter, coil, distributor etc...)

How was the quality of the kit from M&H, and were the connectors original style?

Would you leave this job to a pro or do it yourself-er?

Appreciate your replies, thanks!

 

It was installed on a '72 A-Body Cutlass and it replaces the entire engine connector harness. It connects to the fuse block under the master cylinder (it's half of the entire connector, the other half from the fuse block is for the lights). The quality was outstanding, all of the wire colors were spot on, the connectors were identical to the originals, and factory correct down to the harness tape. If you are good with a wrench I don't see why you couldn't install it. I've got a lot of restos under my belt and it took me about an hour to install.

 

I also installed a new engine AND light harness from M&H on my 72. Everything just plugs in at the fuse block as said. Very high quality. It helps to have an assembly manual for the proper routing of the wires. If your drivers fender is removed as mine was, this is a very simple install.

 

Simply removing the left plastic inner fenderwell will give you all the space you need to reach the fuse block connector!

 

Thanks for the replies, that helps a lot! I called M&H and it sounds like the harness is plug and play operation, but I was curious if I had to pull the master cylinder and booster to access the fuse block. I will try Rob's idea, and pull the inner wheel well. I also ordered the factory style heat shield for the starter, but can't picture how it attaches. Any suggestions here?

 

No, dont need to pull any brake stuff - just whatever attaches to the plastic well, then pull the well. After the well comes out, a lot of mightaswells might pop up!
https://classicoldsmobile.com/forums...tml#post292889

See if this might help you for the heat shield...
https://classicoldsmobile.com/forums...tml#post322110