Gonzotiki_666

Hey folks

I have an issue. I replaced the original heater valve to stop the constant rush of hot hot air. That part went smoothly & took all of like 30 minutes. A perfect job for someone of my automotive skill set :-)

When I was plugging in the wire harness back into the funnel off the bottom of the air box I noticed that the "wrap" around the wires was quite broken and brittle. I started the car & looked underneath to make sure there was no leakage from my job-none...all good. Car fired up right away & idled fine. Shut it down & cleaned up my mess.

Started the car again not five minutes later pulled like 5 feet out and saw that the volt meter was reading <10--pegged at the bottom. "Damn gauges" I thought and then the idle SLOWED and the car stalled. Restarted it and managed to get it back in the garage where it died again. It will rev up under throttle, but as soon as it comes back down to idle speed it sputters & dies. The air was filled with uncombusted gas smell.

Took off the airbox again & unplugged that brittle harness. There is some copper showing from those wires near the plug where the insulation has obviously flaked off.

Has this caused a "ground-out" & made the no-run situation here? If that's the case-where does this harness terminate? Am I on the right path here? Or has my alternator died? I've has this thing like 6 months and have learned a lot about it, especially from this board-but I'm no expert by any means. Now I'm going to be paranoid about fixing anything with all this brittle 30 year old wiring!

Thanks in advance for your expertise!

Landseer

If the wires cross beneath the boot on the AFM under the air cleaner, it won't run.

Similarly, if wires fray and cross beneath any of the eight injectors, none will fire.

If barely / sometimes touching, intermittent.

The O2 sensor, AFM air flow meter under air cleaner, Ljet brain ( mounted inside cockpit) and the harness for the ground-switching of the injectors are all grounded in the engine compartment.

Specifically, they are mixed between two ground bolts on the engine passenger cam cover.

One is hidden, one is more visible.
The hidden one grounds beneath the valve that is mounted at the top of the "O" in PORSCHE on that cover.

The other one is located above the first leg of the "H".


The newbie / FAQ section doesn't properly show this for early cars, so don't bother with it.

Here's a link for a Euro that is similar to your setup --- a little wordy, skim for pictures.
http://forums.pelicanparts.com/porsc...-16v-euro.html

My vote is bared wires at AFM connector that meters the air.
*the link I posted doesn't show that specifically, as it uses a later MAF instead, similar connector though)

Hope this helps. Generally on a no start I concentrate on what my hands touched last.

Gonzotiki_666

Chris

Thanks for your reply-I've seen your awesome Pelican posts and you're pretty much exactly who I was hoping would chime in

If one of the wires is toast in that particular harness, what would be your recommended next step-attempt to repair the break by snipping the wire just beyond the break and reconnecting to the AMF connector, replace just the broken wire, or the harness in its entirety on the assumption that if one wire is gone there are more to follow? The other issue being I'm not sure if that AFM connector comes apart that it'll be "easy" to reassemble. Has anyone out there taken this connector apart & reassembled with success? I'll post a pic later on of where the break appears to be--it's actually just a cm or 2 from the connector.
Thanks again!

Landseer

The AFM connector, like most of them, can be disassembled.

Takes patience and some technique.

If you look into the female connector there is a channel adjacent to each electrode.
Thats where a tool is inserted to depress the hook part of each little metal terminal end.
Once pressed, the terminal theoretically can be pulled out by the wire.

Some I have a hard time with.

Best then to replace the terminal ends with new ones (hard if not impossible to reuse).

You want to crimp around each wire insulation and solder the wire, tricky, especially around fuel lines and throttle body. But doable. Better way is new terminals with wires attached, then splice wires into harness. Roger has the parts. Can be cobbled up various ways, too. Just be careful

Gonzotiki_666

Turns out the AFM wire had continuity. Upon closer inspection from the opposite side that I'd been working on saw that I'd knocked a vacuum line off it's connection. Seems to be fine now, except for the voltmeter not moving. Guess I'll buzz down to Auto Zone or sumpthin and have the charging system checked out.

awdmoke

Give the throttle a good "blip" and see if the voltmeter magically works.
My '80 needs about 3,000 rpm to bring the alternator to life, after that it works perfectly.

Gonzotiki_666

I'm getting used to generally bizarre behavior now. Voltmeter was still sub 10V when I moved it out of the garage to get to lawnmower et al, when I came back to it, of course it wouldn't start! Whirr whirr clikk clikkclikkkk. Damn. Then I accidentally whacked a good chunk of my finger tip off hurling open the big sliding gates I have that lead to the garage. When I got back from the ER and jumped it from my Element ( I had to--it was blocking my neighbor's driveway too) it fired right up AND the meter took its rightful place at just about 13 & stayed there. Oh, and now the hatch that would never latch has decided to be the hatch that will never open. Maybe I just need an exorcist...

Landseer

Hope your hand heals fast.


Have you cleaned grounds?

The ground points and a few of the hot connections are notorious sources for this type of intermittent behavior.

For instance, the negative battery strap itself is known to fail. The woven copper gets a band of grey corrosion, sometimes under the plastic shroud. We've seen a bunch of them in the last few years.

The 14 pin connector has the exciter wire for the alternator. That can cause poor charging if the connector is dirty or the wires damaged (the insulation tends to fail).

Methodical cleaning of the electrical contacts solves so many problems. And, it helps identify where the wire insulation is breaking down. Sounds like some rewiring is in your future.


Side note, have you replaced the fuel lines on your 81?
If not, the car may be saying "don't drive me until"

Gonzotiki_666

Thanks for the kind thoughts-I have an awesome large wrap on my index finger now!

I haven't gotten around to the grounds yet-its been so damn rainy here & the garage is small--but its very much on the radar as a weekend project, and I bought a Dremel tool just for that purpose. I plan on having my netbook out and your grounds cleaning writeup on deck when I do it.

I can tell at least one of the fuel lines is pretty new, the rubber looks nice & has clean white lettering on it. But I shall definitely heed yours and other warnings about those lines and inspect the others-I have no desire to resemble the Hindenburg while driving around town.