I purchased an engine wiring harness in May of last year from Jeff Bowlsby for my '75 1.8L. It was beautiful and performed great until recently. The car has developed significant run problems. Won't idle, runs erratically, dies at intersections… that sort of thing. I think the problem is in the harness itself because you can move it while the car is idling and it will die. The harness was laid over the engine and I think may have been damaged from the heat (no fault of the harness construction itself). What is the proper way to route a harness? Should it be routed away from the engine to minimize exposure to heat? Thanks for your thoughts/input.

The harness usually routes pretty close to the engine tin and under and around components. It's going to get hot in an air cooled engine compartment, not much you can do about that. I'm sure Jeff would test the harness out for you to see if there's a problem with it...he's a good cat!

I am sure you checked, but do you have any loose connections? Wires pulling out of connectors ? It is possible to have a high joint( wire going open under the sheath) in the wiring. Did you check the relay board? Pulled the cover and looked at the AFC board ?

What connection are you close to when your wiggling the harness?

Thanks. This harness was installed by the mechanic who had worked on the engine rebuild. It was "draped" over the engine. I've written Jeff a few emails and haven't heard from him. A phone number contact on his website would be helpful.

Yes. All the connections are solid and have looked at the AFC board. I think there is an open connection possibly at the point the splays off to the temp head sensor. The running problems have been progressive. First, the car bucked when it was cold. When it got to 180 operating temp, it was fine. I replaced the temp head sensor and that seemed to cure the cold running problems. Then it would buck at 60 mph when at full operating temp. Now, it won't idle at all, and cuts out whenever the engine is loaded even slightly. Will run in third but bucks in 4th.

It seems that the area around the splay off to the temp head sensor is where the problem occurs every time. The engine has to be running for a few minutes and then wiggle at that point. It will die every time. Jeff is a frequent contributor on this site, so I'm sure he'll show up at some point and comment.

Hi Harve, I was out all yesterday and just responded to your email. Happy to inspect the harness if you will send it to me and see where we go from there. They can always be repaired or replaced. It could be the harness or it could be any number of other things on the engine.

You know that I stand behind my work, and at the very least I can eliminate the harness as being the problem.

it started doing this AFTER the car was worked on? the onset of the crappy idle leads me to suspect a vacuum leak.

The only problem that I know of that anyone has had with a Bowlsby wiring harness was me. One of the female connectors in the four-pin plug from the injection harness to the relay board kept coming out of the plug rather than getting plugged in.

I was all ready to email Jeff and yank his chain about the problem, when I remembered: Right after I got the harness, I popped the pins out of the plug bodies and tightened them up by (gently) squeezing with some pliers. On this one connector, I was not quite gentle enough and I didn't get the connector all the way back into the plug body. So it was my own darned fault!

Yes, I told Jeff about that later. Yes, he did chuckle at me.

--DD

I had a harness rebuilt by Jeff. I don't think I would install another engine without sending in the harness to Jeff first. If there's an issue with the harness he will sort it out.