Matt Sheppard

OK, I am tracking down an oscilloscope for the weekend to test the signal from the reference sensors per Clark's Garage instructions - I'm getting no tach bounce but the sensors ohm out correctly and the gap adjustment is spot on. When I bridge the DME circuit the fuel pump runs fine.



I have these connections in the footwell (circled). The one on the right says Knock Sensor Diagnostic Port in the manuals and it shows it unterminated so I think this is ok not connected to anything. Correct?Possibly related, possibly not

The one on the left has current on 2 pins with key on. Where does it go to usually? Could this be part of the problem? This one is not part of the DME harness, it comes from under the dash.

Rogue_Ant

Ok, just went through this last weekend with a fellow 'Lister... Exact same symptoms as you, the car wouldn't fire (no spark and no fuel injector pulse), and the tach would not bounce...
I even tested the Speed & Reference sensors with my oscilloscope. Everything, and I mean EVERYTHING tested completely fine.

After a wasted day of testing, we replaced the Speed & Reference sensor wiring harness, and then the car started right up.

Frankly, I'm at the point now that if anyone is still on stock 25year old wiring, then at least replace speed & reference sensor harness immediately, and really should also replace the fuel injector one as well.

Luis de Prat

Won't wiggling the S&R sensor harness side connectors get it to start? Works for me every time.

Matt Sheppard

Interesting. Thanks Rogue. I've fought injector harness shorts before so I get it.

The DME harness on this car is so pliable and clean, the best out of the 10 cars I've ever pulled apart, but I hear you load and clear. Lindsey sells a new harness, correct? Is that where you sourced yours?

Rogue_Ant

Yep, Lindsey is where I got mine.
And I hear you on have a decent harness, mine is too - as was the Listers that I mentioned earlier.
IIRC, the speed & reference harness was ~$100.

Matt Sheppard

And you splice it in right before the DME connector in the footwell?

Rogue_Ant

No, it completely replaces the entire wiring and pins inside the harness connector.

Matt Sheppard

I think I will go this route first:

https://rennlist.com/forums/showthre...eferrerid=9117

great write-up

New hope! thanks again, I will get back to you on this.

minho78

Matt I just replaced mine two weeks ago. It was pretty easy.

RC713

Replaced mine too, they have pretty good instructions with pics on their website and include printed ones as well with a useful diagram. The hardest part is getting the "barb" to release on the wire ends to remove them from the harness. I used an awl type of tool I got in a cheap set of dentist implement looking tools I had originally gotten to extract seals from the body of a brake caliper body. $100 and then you can cross it off the list as a possible cause and know you have new wiring, worst case scenario. I got mine from Paragon (it's the Lindsey Harness).

http://www.paragon-products.com/Harn...44-har-ref.htm

http://www.lindseyracing.com/mm5/mer...ode=REFINSTALL