Wisconsin Joe

Well, that doesn't look as bad as I would have expected.

First off, the plugs are identified by letter. Each plug has a letter on it. In the wiring diagram, the wires are identified by plug and wire position. I forget exactly how the numbers work.

Second, just because there isn't a wire hooked to the specific spot on a fuse does not mean it's not hooked up and powered. One of the peculiarities of this car and the CE panel is that the fuse blocks have 'crossover busses' in them. The plugs are connected internally to each other. In specific and different ways. Each fuse block is different, and it also varies from year to year. DO NOT, under any circumstances, replace a fuse block with anything but the exact same one from the exact same year. Doing differently has a pretty good chance of releasing some very expensive smoke.

It's your car and your choice, but if it were me, I'd take a really good look at the belt. Turn the engine over a number of times, inspecting the entire length of the belt on both sides. If it looks ok, Then maybe try to fire it up. Don't run it for any length of time, and understand that you are taking a chance.

captainOCD

I did some more digging last night and found out about the letters. Still having a bit of trouble deciphering some of the shorthand on the wiring diagram though. I did start a new thread for the wiring stuff so I don't just keep spamming stuff here and having a mess. https://rennlist.com/forums/928-foru...ring-help.html I'll poke around with a multi-meter and figure out what the deal is with some of this wiring. The EE in me doesn't want any blue smoke.

I have all of the parts to do the timing belt (hopefully), so I'm still planning on doing that before I try to start this thing.

One thing I was curious of, when I having the timing belt off, can I turn the oil pump over and prime the engine to a degree (since it's been sitting so long)? I've done that before on chevy and chrysler v8s to get oil to the top of the engine before starting, not sure if that applies with an OHC motor let alone a Porsche motor.

soontobered84

Yes you can. It turns clockwise.

captainOCD

I've mainly been working on the blue 86 since I bought it, but here's an update for this (tan) one.

Put a new fuel pump on it and tried starting it for the first time. It would crank and crank but didn't want tire fire. After lots of messing around I found that if I jump the fuel pump relay I'd get fuel pressure at the rail. Also got a clicking from under the intake (injector?) with the key on and the relay jumped. Car wouldn't try to fire with the relay jumped.

If I put a know good relay in place of the jumper jumper the car will run for a couple seconds until the pressure drops down. That clicking also goes away with the jumper removed. So I only have fuel pressure with the relay jumped, but the car won't start with it jumped.

drscottsmith

captainOCD

So some research suggests that the fuel pump relay won't get energized unless the lh (I think) gets a tach signal from the ezk. The car ran some I'm guessing the ezk is getting a crank position signal or something to fire the plugs. And I'd think if it was running until it lost fuel pressure it must have been operating the injectors at the right time, so I'm not too sure what's going on with it.

drscottsmith

captainOCD

So it seems like the LH I bought for this car is the problem. Hooked up both the EZF and LH from this car to my blue car and it cranks but wouldn't start (tach did move though). Left the EZF alone, but plugged the blue car's LH back in and it started right up. Seeing that it's been so long since I bought that LH on ebay I'm probably stuck with it at this point.

captainOCD

Took a while to get back to this LH computer for this car (had some family issues and then hurricanes going on), but I did manage to repair the LH computer. Poking around in the computer testing for bad components I found these two transistors, one of which someone on a volvo forum (apparently 240s had a similar LH 2.2) mentioned one of these controls power to the injectors. It's been a while since I tested the transistors (one NPN and one PNP), but I think they were leaking current from the emitter to the base. Anyway, I replaced the transistors with as close to equivalent parts as I could find and now this LH works in the blue car which it wouldn't before.

Old transistors.


New transistors.



So then I tried the LH in the tan car. Unfortunately it still won't start, but the behavior it's exhibiting is a bit different than before. When the LH wasn't working before I had no tach activity. Now when cranking the tach will bounce around a bit (like it does in my blue car when cranking), but that only lasts a second or so then stops. So I'm wondering if that's indicating a problem with the crank sensor or something. Seems that if the LH doesn't think the engine is turning it won't send fuel, no?



After trying this LH in the tan car, I put it in the blue car again to make sure it was still working, and it is. So I'm fairly sure that it was bad when I got it. So does the crank position sensor seem like it could be the issue now?

captainOCD

So it's been several months, but I haven't forgotten about the tan car. When I last tried to start the car it seemed like the tach wasn't consistently moving while cranking. So I figured a new crank sensor was cheap enough and bought one. Of course the old one is stuck in there good and I couldn't get it out without destroying it. Before I ended up destroying it I noticed the connector for it had disintegrated (big shocker) and it looked like one of the terminals was awful close to if not touching the bracket that it sits in. So I pulled the pins out, cleaned them, put them back in, and made sure nothing was touching. Not ideal, but good enough for the moment.





After fighting with the new fuel pump that didn't want to run (it was stuck) I tried to crank the car and it started up. I only let it run for a couple seconds two times, but it didn't try and die and was running smoothly (no exhaust right after the manifolds, thanks platinum pirates).




If you ask me this is a big step with this car. Now that it'll run I can get the trans filled the rest of the way up, get the brakes working, and the car should drive.

Christopher Zach

Nice job!

captainOCD

Today I decided I'd top the trans off and see if the car would move around a bit in the yard (still only the parking brake works). I started the car so I could pump the rest of the trans fluid in, but while I was doing that the idle just jumped up to 2000rpm all of the sudden on it's own (was around 1000-1200 before). I checked to make sure the throttle body was returning all of the way, looked for vacuum leaks, plugged the booster line, etc and couldn't find anything obvious or anything that would make it change. By this time it's idling at 2500rpm on it's own now. Blipping the throttle doesn't make it come back down any.

I jumpered the C and B pins on the diagnostic connector at the front of the engine to disable the LH idle control. That makes it come back from 2500 to 2000 rpm. When it is jumpered blipping the throttle off the idle switch will briefly make it drop back down to 1000rpm or so, then speed back up to 2000. Doing this several times in a row I was able to make it only come back up to 1500 or so, but after leaving it for a few seconds it goes right back up to 2000.

To me this behavior sort of makes it seem like an electronic issue. ISV maybe? But maybe this behavior makes something else jump out at someone?

captainOCD

That drop in rpm right after starting is the same thing it does if you blip the throttle real quick (basically open then close the idle switch). Giving it more gas and holding it increases the idle speed like you'd expect.

captainOCD

I haven't done a ton of work on this car still. Again it's a project to work on with my parents, but for various reasons I haven't got them to invest much time. Over the winter the carport over the car blew over (didn't damage the car) so it spent the rest of winter under a tarp. Finally got around to getting a new carport so it come out from under the tarp.

I wanted to put it further back so the house was shielding from the wind. After realizing that the fuel pump was full of crap from the tank and cleaning it (pump) out, the car started right up and (while still idling at 1800rpm) I backed it up the 10 feet or so under it's own power. This was the first time it's moved on it's own, so that's something.






Maybe this summer I'll have some better luck getting work done on the car. Changing coolant is at the top of the list since it's been 2 years.