sebastian944

Ok, so here is the situation. I bought the Lindsay Racing Speed/Reference Sensor harness. It was installed yesterday. Started the car and drove around all day then it died again and i had to be towed. Wiggling the sensors did not resolve the issue this time (it shouldn't i have two new sensors and a harness) however, the same problem i had before still exists. Which means it may never have been the sensors or the original harness at all. We take it back to the shop, this time we can't confirm spark at the spark plugs or the coil itself. Also using a noid light, there is no signal at the reference sensor plugs while cranking. We found there was intermittent signal on the sensor mount plug. pulling that out we noticed the sensor was being rubbed against the flywheel. The replaced sensors and the brand new sensor has the rubbing marks. According to the troubleshooting guide, there is a required gap (i don't remember how much) but it seems a washer is supposed to be there so that the gap exists. The part number is: 944.101.335.00 It is number "32" on the diagram. The following are some pictures of the plug and harness/engine. I'd love to just pay for a $1.00 washer. I just paid $1000 on buying two reference sensors, LR harness + labour.

Duke

Wait, you paid $1000 for two reference sensors, LR harness + labour and they did not check the sensor gap?
If the replaced sensor have marks the gap is incorrect, and the new sensors will of course get the same marks. Have the gap adjusted to spec (0.8 mm).

BUT I will say that gap problems usually don't generate intermittent problems so the problem might be elsewhere.

quinnfiske

It looks like you are 90% there. There is supposed to be a gap between the flywheel and the tip of the sensor. It is .8 mm. Clark's Garage has a good write-up on how to do this. If you rub off the tip of the sensor it is trashed. These sensors are Hall Effect proximity sensors. They have a tiny magnet inside. When the flywheel teeth sweeps past, the magnet induces tiny pulses which is what the DME reads and calculates speed or crank position.

The new harness looks good, how easy was it to install it? This might be the answer to this annoying problem.

http://www.clarks-garage.com/

kdjones2000

If you don't have/lost that washer, then your speed sensor will touch the teeth on the flywheel. Get one, make sure the gap is correct, and see if that helps out or not.

Good luck...

sebastian944

Yeah they didn't check the gap It has been narrowed down to this mount plug though. There is an intermittent signal, while cranking and using a noid light. Also this happens when ever i put the clutch in and start in first gear. Then it quits and doesn't start after that.

Bri Bro

The way these sensor works make the gap very important. They have a LOT of small wire in them that picks up the change in the magnetic field as the steel tooth passes. The magnet is also inside the sensor. The problem is that the signal from the sensor is related to engine speed. The slower the engine RPMs, the lower the signal. If the gap is incorrect, your signal will be too small to start the car. Too close, you damage the wire inside the sensor. There is a tool to set the gap (sharky47 made them) and you can also use the glue and washer trick.

MichelleJD

You MUST have that washer (#32 in the PET). The gap is critical as it can only be off + .3mm IIRC. GL!

sebastian944

well as expected my problem continues. The washer has been put in place, and the sensors have been properly gaped and they have good signal. Have spark and fuel pressure, but it won't start. Going back to the original thread (Injectors are not opening) I'm back at square one. Replacing the sensors and harness from LR was just the wrong diagnosis on my part. Again the blame is being put on the DME or KLR. After replacing the belts, waterpump, resealing the turbo, vacuum lines, coolant hoses and reference sensors and tonnes of diagnosing my funds are exhausted for probably the rest of the summer. Maybe in a few months i can afford to spend another $1000 on a used DME/KLR.

MichelleJD

What year is your car? I have a used DME and KLR. I'm moving to Toronto and would be happy to bring them to you. If they work, we could work something out. Lemme know.

quinnfiske

I had a similar problem and tore my hair out until I had the DME fixed.

My problem sounded like yours. It started as an intermittant issue and got worse until it would not run at all.

Cracked solder joints are not uncommon. There is a transistor that fires a signal to the coil which is subject to this failure. My spark went away so that is what happened to me.

I had it fixed by Systems Consulting who is a sponsor here. Did it quicky and for a good price. I think they are/were a sponsor here.

http://www.systemsc.com/

sebastian944

I may take you up on that offer. When are you Toronto bound?

MichelleJD

It'll be a couple of months before I move up, but we'll probably be up on house hunting trips before that. Once we come across, all of our property comes in duty free. If it looks like it'll be awhile, I can just ship it to you. Is this your primary mode of transport?

Luis de Prat

So, back to the original issue. Why would wiggling the speed/reference sensor wires solve the non starting problem in the first place if the harness was not at fault?

OntarioTurbo

How are you ascertaining that the injectors are not opening? Checking for electrical signal or just no fuel? A friend of mine with a 944NA had a similar problem. He started with wiggling the sensor wires as well and oddly enough it would work once in a while (coincidence). Ended up being bad copper conections in the fuse box below the DME relay, thus no fuel. He got a used fuse box from Whaletail out of Waterloo. $50.00 I believe. Not saying this is your problem, just that it could still be other things.

Totally unrelated: Did you sell your rad?

sebastian944

Yeah i sold the rad. Wiggling the sensors doesn't fix anything anymore since the new sensors and LR harness was installed. However, after getting the new sensors/harness installed it ran for a few hours (went for a drive) then it stalled and never worked again. I havn't ruled out the fuse box yet, i will ask about it.