Electrical prob's - how bad are they really?

[tadink]

HI guys -

I'm investigating the 928s ownership experience, and am struck with the notion that there are lots of niggling little electrical issues - but can't really get a handle on how bad they are? So - my question:

1. are the elec issues generally stupid annoying stuff, like headlamps not going down, that are bothersome but won't strand you on the side of the road?

or -

2. are the elec issues generally the sort of thing that one day you just can't get started? Stops on the freeway? Lights won't go on at all and you are stranded at night?

I can live with #1 and plan on doing all the PM to the elec system as recommended here and elsewhere - #2 seems stressful!

Can anyone shed some light on this? I appreciate the vagueness of the question - and everyone's experience is different - but some general guidance would be helpful....

thanks -

td

[JhwShark]

Electronic complexity on the 928 varies by model year (MY). Early editions much less complicated since CIS.

The main issue besides Electronic Fuel Injection that I have seen as a general issue is the wire harness which comes from below the engine servicing the Starter, Alternator, and oil pressure & level and goes up across the front of the engine to a 14 pin connector degrades over time due to heating and moisture. The moisture usually enters the harness when someone does not replace a $12 cover to the Hot post, 14 pin and transistor ignition unit (TIU).

The other main issue is typical corrosion at all ground points and at the Central Electronics Panel (CEP) connections and relays.

I would expect that Alan, our electronics wizard, will provide more granularity.

For me, not a problem to explore and diagnose, though some can be very frustrated in this domain. The car is the best balanced high speeed ride...the 3.0csi is right there too; IMHO!

Best wishes to your pursuit.

[tadink]

Thanks for the note - I'm looking at a 1983 928s 5spd on the weekend.

It sounds like the 14pin connector could be a show stopper at random times, so my #2 scenario above. But it is a well known and well documented fix. Ditto grounding points....just gotta make them clean and with good contacts, no other choice.

With those two out of the way - I'm in for years of trouble free enjoyment? Suspect not - but sounds like maybe things are not as bad as the overall reputation paints the 928?

I'm a former owner of most of your stable!! LOL - MGB, 3.0cs, various Porsche's....

thanks for your comments...

td

[syoo8]

TD,

Most 928 owners will have one of the following or more inoperative: A/C, power locks, rear hatch release. For me, all three when I bought my first 928. It took a little patience and some new parts to restore them.

My radio would cut out whenever the music got loud because of low voltage in the system. After changing the circuit board in the instrument cluster, changing the ground strap, completely disassembling and cleaning the CE panel and cleaning all the grounds, I got about one volt more out of the system.

Stuff like that.

[Alan in AZ]

Well my car is relatively young - IF 21 years (last month) is young?

Yes there are some annoying details - mainly with accesories - however my car has 125K miles on it (93K of them mine) and has never let me down immobilized - ever.

I have always been able to drive home - worst inconveniences have been twice due to dead batteries - fortunately close to an auto store each time. I now have an easier solution to that issue.

Older cars that live in more humid environments seem to have more issues from corrosion - but really nothing that good preventative maintenance can't keep in check - just need to be disciplined about that.

The engine electronics are pretty reliable IMO - yes we see some failures but on 20-35 year old vehicles I think you have to expect some wearout mechanisms, good support for fixing these - sometimes even on the road!

Abused or neglected cars have many issues of course - and we hear of them on the forums because folks are trying to bring them back... (and stumbling across all these 'challenges'). However there are also a lot of very reliable 'drivers' out there that are well maintained and have few issues... I've met these guys/gals after we've driven many many hundreds of miles to events all over the west.

Best thing you can do for these cars is drive them regularly, get attuned to everything and attend to things as soon as you detect something going south.

When its all fully up to snuff you'd have no qualms about jumping in the car and driving thousands of miles - and that's the kind of car it was always supposed to be.


Alan

[tadink]

Guys -

perfect - that is what I was hoping to hear!!

I'm somewhat used to funky electrics since I'm doing a 1971 914 now - pretty simple by comparison but has its share of old weirdness along the way! It HAS stranded me on the road due to electrical gremlins....so I've no where to go but UP!!

seeing the car this weekend, will report what I find. Hopefully will be joining you all here soon!

cheers - and thanks!

td

[aluminum]

If you plan to Pay someone to repair any Electrical Issues make sure your well off $$$$
on a 1 to 10 scale I would rate the 928 / the 911 as a 10 for problems .
Extremely problematic .

[928 Bro]

I have come to the conclusion that most European car makers have electrical problems and it's need just the 928. It's volvo, bmw, porsche, alfo romeo etc. I believe and I might be talking out of my a... but There wiring might work good and true in there climate and weather but chemicals or conditions in this part of the world effects the wires different and cause issue with time. Like salt to melt snow in the winter, I'm in FL and I know there is ozone in the air especially if you live around any action parks, High humidity and to low humidity is not good for wiring. That's my 2 cent

[syoo8]

TD,

If you find Wally Plumley's 'bible' on 928 Annual Electrical Maintenance, and follow it, you will be in good shape. Finding electrical gremlins is sometimes frustrating but never difficult, and once you get into it you will find it to be challenging and fun.

I would strongly, strongly recommend that you get a long piece of heavy gauge wire- long enough to attach to the ground strap of the battery and reach anywhere in the car. That, and a good-quality digital voltmeter.

You will need the wiring diagrams. They look intimidating, but with the help of Alan Moore's electrical primer (you can search for that as well) you should be off and running.

[harborman]

A lot has to do with how the car was kept and in what climate. I have seen some real beaters on here and some very well kept cars. On electrical issues, it's mostly the CE Panel, fuses, relays, grounds, battery and engine bay connections. Some pretty easy to fix with time, money and patience.

[Landseer]

We have a very well-preserved red 86.
It has been reliable.
This weekend it failed to restart at the grocery store.
Now its running, but with a real oddball miss at 50 mph.
Am diagnosing. And there is a long list. On a car that was dead-reliable til now.
Fortunately I have a complete 86 parts car and a complete DD 85 from which to draw copious amounts of swap parts.
And the symptoms included no control voltage on fuel pump relay during start attempt.
And no tach movement whatsoever.
I think its intermittent failure of the 6 year old CPS (which has perfect plug connections on both harness and sensor)
Gounds are so clean they sparkle.


Bad timing.
Plan was to leave from Chicago area Wednesday in the 86 to drive to VA Beach.
There, I would diagnose fix the electrical problems causing no-start on my daughter's 84 USA car, then drive the 84 home. The reliable 84. Meanwhile, my wife would tour the east coast in the 86.

So reliable 86 is down, reliable 84 is down.

(And tomorrow, to appease the gods, I will own a new Hyundai in addition to these relics. It had better prove reliable).

The answer is that the electrical problems emerge from nowhere and grip you by the throat. Expect it regardless.

BTW, Alan, I remember that both your and Dr Bob's cars suffered the ground strap kiss of death. Out of nowhere.

[Alan in AZ]

Originally Posted by Landseer

...BTW, Alan, I remember that both your and Dr Bob's cars suffered the ground strap kiss of death. Out of nowhere.

I think for both of is this was a gradual issue that was not an immobilization problem. Since mine is a true daily driver (twice a day in fact) - it was quite apparent that something wasn't quite right. Sluggish starts etc...

Jiggling the strap in the garage proved to be telling - so I replaced it proactively. You will recall that it looked very ugly! (but of course that was under the plastic sheath)

I think Dr Bob replaced his primary battery to starter cable chasing a voltage droop issue before realizing that it was really the ground strap that most needed replacing - But IIRC that also was not an immobilization event.

Like I said - preventative maintenance is key - and if you have a good handle on what normal feels/sounds like (it being a DD helps) you can more quickly pinpoint the things going south.

Of course most of these are very old cars and things still go wrong & just wear out. Coastal living is probably the worst environment for corrosion, but high humidity and/or lots of rain aren't so far behind. Especially for cars that live life outside. With that you need to pick up the annual cleaning & protecting rituals - but this is hardly unique to a Porsche.

Alan

[curtisr]

I never cease to be amazed at the condition and strength of the materials used in manufacture of these cars. I have yet, for example, to strip the head of a screw. Sadly, I cannot say the same for my 1970 Datsun 1000--even when it was new. No, especially when it was new.

My '82 has never had a 'hardware' failure. Sure, sure moving parts have a finite life span; however, routine maintenance means few surprises. What has kept me from enjoying the car each and every day have been electrical issues--almost always traceable to a faulty relay. Perhaps these items should be a part of said routine maintenance. I would also echo Alan's comment--with all the deference I can muster as I am by no means a mechanic--that the electrical issues seem to be insidious. The solution? Routine cleaning and replacement seems to be the order of the day.

[harborman]

Yes, that ground strap can look good but inside the plastic covering the connection can be all corroded. I was lucky, mine failed in my garage! A cheap easy fix everyone should do immediately when getting the car. Just another issue with these older cars.