cambria

I would check the flywheel sensor.

backnblack

Hello all, I am still try to get this started, I am going to review all of your suggestion and make sure that there isn't anything that I've missed.

questions.
at the relays I am not getting ground on the 85 connection on the lh relay or the fuel pump relay these connection go from the relay to the lh unit pins 17 & 21 , I bought and lh unit from a rennlister
and he told me that the unit works but it didn't start the car, by looking at the wiring diagram the LH unit is the only reason I can see that I am not getting a signal to my fuel injectors.
Big Dave told me I could try my LH in his car to see if that is the problem but we just need to schedule the time to do it.

I think EuroSark and Timco may have the same problem.


Thanks again for al the help I receive

tv

Yeah check your LH and if it works then i would second what cambria says. Mine went on me last summer. I had to pull the engine when it snapped off. If your LH does work and you need to replace the flywheel sensor, remove everything above it, all fuel lines and hoses, then get some liquid wrench around it and slowly and carefully try to get some movement out of it. DR has some experience with those. good luck.

heinrich

if it fires with fuel squirted the problem is not KH or sensor, rather it's fuel delivery

Big Dave

Matt tried the LH in my car, and it would not start. However, I'm not sure if the LH unit has to be bolted into the car (as opposed to just unplugging the connector from my LH and plugging in Matt's LH) for it to operate properly.

With his plugged in, my car cranked but would not start. I plugged my own LH back in and after about 30 seconds of cranking and pumping the gas, it started again.

Unfortunately, we don't know for sure if Matt's problem is his LH unit. He purchased a used unit from another Rennlister for $300 (including Matt's own LH in trade) and Matt has no idea if the used on he purchased itself works. So now we have the used LH unit that won't work in my car, and the seller won't return Matt's original LH (which Matt has no idea if it worked anyway).

The big question in my mind is whether the LH has to bolted down to the footwell for it to operate properly. I imagine it might need to be bolted do to be grounded, but I'm not sure.

Wally...are you out there?

SharkSkin

Dave, I'd say you ought to at least put a ground jumper on it.

Shane

Change out your crank position sensor. I had the same problem with my 86. It would crank all day long but not fire. I too had to jumper the relay to get the pump working. There wasn't any signal to the brains that the engine was turning over so the pump wasn't building pressure and no ignition. What I believe happened is this: Pulled the stock intake and fuel system. When I did that some of the gas from the regulator got down on the crank position sensor, and fouled it. Once I mounted the supercharger and all the other stuff and went to fire it up it was a no go. I tried numerous other things, to get it to fire, brain swap with my other car, MAF swap, spark plugs, you name it. Put in a new crank position sensor and was good to go!

Chances are when you washed your engine you fouled the same sensor.

Mrmerlin

OK I was wondering if you ever investigated the wire harness on the passenger side near the front of the cross barce? I think you might some corrosion here also i think that you may have gotten water into your fuse panel from washing the engine to see if you have a leak open up the pass footwell and spray some water around the heater blower motor under the hood you may to remove the wiper motor cover to do this, then get in the car and look under the pass dash you will be looking at the bottom of the blower box just above the fuse panel see if is leaking where it seals against the body, after this pull every relay, and any relay that has any corrosion on the edge where the cover seals against the circut board will have to be opened, I am betting youwill find some fouled up relays also remove every fuse and cleam and reinstall, and the wire harness under the hood will also have some issues, Stan

backnblack

Thanks again Dave for letting me put that in your car.

Can anyone tell me how I might get in touch with Wally and the guy in the UK that works with the LH units ?

I didn't want dave to put the unit back into his car with a ground on it after we had a little scare getting it stared when we hooked his back up, I don't want to pass my problem on to his car if I can send the unit out to be tested.

Thank for any help you can give me.

backnblack

How much is a crank sensor? Can I get it from my corner parts store? this is located at the top of the bell housing under the air cleaner, is that corect?

WallyP

The ECUs do not have to be bolted in to work - they have their own ground wires in the harness.

The Timing Impulse Sender - P/N 944.606.115.00 costs $117.23 plus shipping from us - I don't know whether you would find that at the corner parts store or not. The crank sensor is on the top back of the engine, on top of the bell housing. There should be a connector near the unit.

Throwing parts at a 928 to try to solve a problem gets really expensive really quickly...

I would suggest that you check the wiring first. The sequence of events sounds as if you got water in a connection somewhere in the engine compartment. DeoxIT-5 is a good contact cleaner, and is available at Radio Shack. Cheap contact cleaners are a waste of time and money.

Cleaning and checking the connections near the jump start terminal would be a good idea.

Jeff928S4

Have you tried putting a known working LH into your car? That could confirm things.

If the LH you swapped into Dave's car caused it not to run (when it ran fine before), then that LH is bad.

I recently had my LH rebuilt and I went through the exact same series of events that you did......checked all the relays/checked all the wires/pump would only run when jumped off of the battery, but car would still not run correctly...etc, etc.

Jim bailey - 928 International

If that used LH brain you bought would not run Dave's car it is NOT going to run yours ! And no the do not need to be grounded to test. And the comment ..." and the seller won't return Matt's original LH .." is unfortunate since that one might be good !

Big Dave

Jim:

I only tried cranking the car for about 5 seconds at a time. It definitely didn't sound like it was going to start. When I put my own LH back in, it sounded the same but eventually started after I let it keep cranking for about 15 seconds, pumping the gas.

Does this sound like Matt's LH was dead, or is it normal for a car that typically starts immediately to struggle with a swapped LH? I guess I'm wondering if the car needs to "re-learn" anything each time the LH is unplugged and re-plugged, accounting for the slow start.

I'd hate to think that his LH is dead, since as I mentioned before, he purchased it from someone who took Matt's original LH in trade, and is refusing to return it or his money. We don't have any idea if the LH he traded still worked. It would really suck if he traded a working LH for $$$ and a bad LH.

AO

Doh!