android606

I've been a BMW guy for a long time, but thought I would give this poor old Porsche a try.


I bought it at a Copart auction. I wish I could say I got an "awesome" deal, but now that I know everything that's wrong with it, I'm not so sure. It's been sitting neglected in Vermont for, as far as I can tell, about five years. It needs pretty much everything any car needs after sitting neglected in Vermont for five years.

I had it transported to a semi-local shop to get the once-over and had planned to drive it home. Once they had a look at it, it turned out to need a lot more than an oil change and a spit shine.
Many thanks to Andy at South Shore Autoworks in Kingston MA for helping out with:

• Intake refresh
• Vacuum hoses
• Fuel Hoses
• Knock sensors (One was rotted completely OFF.)
• Resealed injectors
• Air filter housing, intake, engine valley general clean up (There was a literal rat's nest in the air filter housing!)
• Oil and oil filter
• Chassis lube
• Excellent advice

After I got it back from them, I did some more work:

• Timing belt, and tensioner reseal (Thanks to Roger for getting parts out to me fast!)
• Water pump
• Bottle of "fuel restorer and dryer" and a fresh full tank of 93 octane gas.
• Plugs (All but two (#1 and #5) were sooty dark black. All had electrodes that were completely worn down and rounded off)
• Wires (lit up like a christmas tree when I fired it up in the dark and did the "mist" trick.)
• Unfroze, cleaned and lubed window motors and gears
• Replaced cracked vacuum modulator hose to transmission. (What a PITA! Why did they route it that way?!?)
• The tires (Continental ContiSports) are old but in amazingly fantastic condition. Almost full tread, no sign of cracking at all, no sun damage. Holding air perfectly. I'm taking my chances and using them for now- I just won't be attempting any 100+ MPH runs on them. ;-)
• The brake discs looked really good, just barely grooved at all, so I just cleaned them up with a little steel wool and made them pretty.
• The brake pads appeared to have nearly 100% of their thickness left, but the backing plates were rusty to the point of being swollen and flaky, and they squeaked like a mother. So, I just cleaned up the calipers and slapped on some new Hawk HPS 5.0 pads. It seems to stop extremely well now. No squeaks, no vibration, very even and well-controlled grab. 60-0 distance feels only a bit longer than my 10-year-newer BMW M3. I'm very pleased!
• Thoroughly cleaned & detailed in and out!

That was enough to get it very driveable. I drove it from Massachusetts to California and made it home in one piece. It stalled on me once coming down a grade under light throttle for what feels to me like an electrical problem. After pulling over for a minute to check everything out, it started right back up. Not quite sure what happened there. I feel like it's done it a couple more times since then under the same conditions, just not badly enough to die. Any ideas?

I purposely timed my driving to avoid driving in large metro areas during high traffic times because I know the electric fans weren't working. Otherwise, a pretty uneventful trip, and she stayed nice and cool on the freeway.

Problems that still need resolution:

• Sunroof switch doesn't work
• Sunroof leaks (probably a plugged up drain)
• Tons of corrosion on fuse panel and other connections inside, thanks to the leaky sunroof
• Heater won't turn off all the way (Small vacuum leak in hvac controls, or faulty heater valve, maybe?)
• Parking brake works really well when facing uphill, absolutely not at all when facing downhill
• Radiator is missing passenger-side upper mounting bracket, which causes the driver side cooling fan to hit the radiator hose. I've got the radiator tied forward with a giant 4 foot long zip tie for now. :-P
• Radiator fans won't come on
  • This seems like an epic saga for being such a simple thing...
  • Both channels on final amplifier are toast.
    • Driver side channel probably burned out from excessive current because the fan was hitting the radiator hose
    • Passenger side probably burned out because it was running all the time trying to compensate for the busted driver side fan
    • I'm pretty good with a soldering iron, so I'm going to replace the capacitors and MOSFETs ($10) and see what happens. The amp looks pretty simple inside. Easy to diagnose if a MOSFET refresh doesn't do the trick.
  • Resistance reading on the temp sensor in the radiator is consistently 10000 ohms higher than the WSM says it should be
  • It seems like one channel is also bad on the fan controller module, but it's hard to really tell with the other failed components in place
• Cooling air flaps continuously open and close so I unplugged them. Should I fix them or just delete them?
• Engine still misfires badly at 1500-2000 RPM. Maybe Temp 2 sensor? Maybe because MAF looks like it was recovered from the Titanic? Not sure yet.
• Coolant pressure sensor has blown apart, and seems to have no electrical connection inside. I bypassed it with a bit of hose. Can I just hook the two wires to each other to eliminate it? Or, can I install an aluminum or stainless steel tee and a more generally available and less fragile screw-in type pressure switch?
• Coolant level sensor seems to have an open connection inside. Maybe a dead magnetic reed switch? Is this repairable?
• Coolant reservoir cap looks ancient but not technically "bad".
• Windshield fluid filler neck is crumbly and has snapped off
• Windshield sprayer nozzles are snapped off
• Probably needs fuel injectors
• Probably needs a fuel filter
• Fuel pump will probably die soon after sitting in that half tank of crap fuel for so long
• Anyone know how to fix dashboard cracks?
• One headlight is missing the lens (a truck kicked up a rock and broke it on the way back to CA! Grrrrrr!)
• New floor mats / floor carpet?
• Miscellaneous weeping seals and gaskets are leaving spots on my driveway. Not enough to worry, but enough to be annoying.
• One of the instrument cluster illumination bulbs is out.
• Cluster illumination brightness potentiometer loses connection beyond about 20% brightness.
• "Antilock" light comes on intermittently.
• "!" light is a permanent fixture.
• Air conditioner clutch wire insulation has fallen apart, rubs on everything around it, and blows fuses. I have no idea about A/C system condition otherwise.
• Rear speakers are buzzy and terrible and I'd like to add a small subwoofer.

I'll try to post updates here as I knock things off this list.

If anyone has any helpful advice or parts, or especially any local resources, please let me know!
Cheers!
Andrew

Bigfoot928

not sure they could provide "excellent advice" after charging you for "chassis lube" as there is no such thing on the 928.

android606

Haha, good point. I'm brand new to the 928 and didn't know that it doesn't need chassis greasin'.

My list above is based on what I asked them to do, not what they charged me for.

To be honest:

• Their shop rate was pretty steep and the guy at the desk didn't communicate as much as I would have liked.
• The actual notes from the technician seem pretty spot-on to me, though.
• The work he did looks very nice and clean.
• I dropped in and checked it out while he had the intake manifold off. It was really rough in there. Absolutely everything plastic or rubber was cracked, rotted, and falling apart. There was just a corroded nub where one of the knock sensors was supposed to be. The items included in the intake refresh definitely needed to be done.

I am not the kind of person that takes their car to the shop, ever. I used to own a six-bay transmission and muffler shop, and have no problem twisting a wrench. It kills me to pay people to do things I can do just fine myself. I only brought the car to this shop because the car was 3000 miles away from my driveway.

However, I can't say they were not competent, and that means a lot when you're talking about auto repair shops. Or, really, any kind of service.

If some 'normal person' were to ask me if they should pay this shop to fix their car, I'd say "sure". It won't be cheap, but it will leave fixed.

928 GT R

Congratulations! That is pretty interesting that the car took you rom Mass to CA after sitting for so long and having that amount of service... A small bit of testament as to how good this car might be after you refresh more of it.

Enjoy and post more photos...

The Forgotten On

Welcome to the group!

Anyways, the first thing you should do is refresh the CE panel and clean all the corrosion off of it. Same goes for all the other grounds on the car and both ground straps. They're probably toast.

As for the gauge potentiometer, get some Deoxit and coat the coils on the potentiometer with it. It'll clean them up nice enough in situ.

Or you could pull it and soak it in CLR for an hour. It worked for me when I did it.

The HVAC system is sensitive to leaks, and most likely most if not all of the diaphragms have failed by now. You should pull the dash out to deal with them. This also gives you room to fix other things to WYIT.

And definitely post more pics! We all like to see what people are working with in threads like this.

Petza914

Wow, that's quite a list, but just from your analysis of everything, you're certainly competent and can handle what's needed to bring this car back.

I had a coolant level sensor where the float developed a leak and sank to the bottom of the tank, throwing a false low coolant error. Maybe yours has done the same.

For the fans, at the bottom corner of the radiator is the temperature switch that turns on the fans. If you disconnect the two female spade terminals and jumper them together, that would make the fans run all the time. That will tell you if it's just the temp switch sensor that's bad or something with the fans themselves.

Good luck with it. We'll be following along.

mb911

I am impressed with your drive home. That is really a testament to the car. Mine has traveled 10 miles in the 2 years I have owned it and constantly am nervous about fuel lines and electrical items. Maybe I need to chill on that.

Zirconocene

Awesome work bringing this thing back, and kudos on somehow fitting your massive stones into the car for that drive.

You're way more on top of things than I am but one of the things that jumped out at me with your stalling is that it sounds a lot like what was happening on my S4. I was really worried it was the LH, or some other electrical gremlin, but it seems to have been the fuel pressure regulator (or the dampers, I replaced them all).

I didn't see that on your list, so it may be worth looking into.

Good luck, and welcome!

mskar

Congrats on the purchase, she's good lookin'

From my perspective, barring serious compression/leak or thrust bearing issues (I'd check those asap), once you catch up on this car it will be reliable and wonderful to drive. I've "brought back" two 928s, an 88 S4 Auto and a 91 GT (which is on bring a trailer right now). The S4 needed TB/WP and "little" things like door handle mechanisms, sunroof and window switches, all the HVAC actuators, and eventually an LH computer rebuild. Your LH will fail at some point, I waited for both of mine to rather than being proactive. This summer I purchased a coolant pressure tester and also an exhaust gas leak kit for the coolant so I can monitor it for potential issues with the head gaskets until I can do a top-end refresh.

The 91 GT needed "everything" like what you are describing. It had been parked for 10 years in an car port, covered in dust and mildew but cleaned up beautifully. I planned on the TB/WP for this car, but a leaking bridge forced me to do the complete top-end refresh too. The GTs (later models in general?) have absolutely no clearance to get at one of the bridge bolts with the manifold on. Turned out to be a good move, mine wasn't as degraded as it sounds like yours was, but having all new rubbers, rebuilt MAF, TPS, knock sensors and such was definitely the right move. I highly recommend getting your injectors tested, cleaned and refurbed. Many here use WitchHunter, he did an excellent job on mine. I've also dealt with injector-rehab.com for my Vanagon (he does all models and retrofit kits for some cars). That guy could not have been nicer or more responsive. Glad to see you did your fuel lines. Check your P/S hoses too.

It sounds like you are "in for a pound" at this point, unless you stole it, you'll be upside down in no time, like many of us! However, you'll have an absolutely killer classic GT when you are done. I will say w/o reservation that these cars are super reliable, as long as they are 1) maintained and 2) driven. BTW, I was able to do my CE w/o removing it (the first harness I pulled broke a tab so I started looking for alternatives). If you are real careful-like, the fuse sockets remove from the CE carrier, I was able to use deoxit to clean everything up, and carefully bend my fuse contacts back to "tight" (PO had forced blade jumpers into several sockets to put in ghetto aftermarket amps and other garbage I had to pull out and perform harness repairs).

You are in the right place, this forum contains information on everything you could possibly want to know about 928s of all eras, and is full of not only technical experts, but vendors like Roger and Mark that can find you just about anything. The technical knowledge of the senior members of this forum is deep and wide. Even relative noobs like me have more 928 knowledge than many thousand-post experts on a VW or Toyota forum! Congrats!

android606

Thanks, everyone! This is all awesome information and advice!

1) I'm definitely in it neck deep now. After buying the car, doing all that maintenance catch-up, and a not-exactly-planned two week vacation on the Eastern Seaboard, the car has sucked up far more money than my wife would prefer. Fortunately, she's into synthesizers. She can only give me so much crap about buying expensive toys. :-)

2) I tend to lean towards trusting the engineers when I'm bringing a vehicle back from the dead, but sometimes I just see something and think "wow, that's lame."
Case in point: The pressure sensor on the little hose coming off the coolant reservoir.

First, why? I feel like the "warning system" engineers had some leftover budget to spend when they decided to add this coolant pressure switch.
Second, they designed a part that contains a hot pressurized fluid, and sandwiched it together with glue?!? Mine made it all the way home from Massachusetts and then blew apart in my driveway. It could have just as easily happened in the middle of the Nevada desert.

What do you guys think about me putting a stainless steel adapter in its place, with a screw-in pressure switch? Like these:


Will that be some kind of blasphemy if I install a generic part on a Porsche? Does anyone know what pressure rating the original switch has? The one above switches on at 2 psi.

I could just install an OEM replacement switch, but I really don't like the design.

android606

Thanks!
I had just replaced all of the rubber fuel lines and injector o-rings, and gave the electrical system a good once-over, so I was pretty confident nothing would catch on fire.

Besides that, I had a pretty complete set of hand tools, a multimeter, and four gallons of distilled water riding with me. That's my insurance policy!

It really does look like a well-designed engine to me. The only real problem is how difficult it is to get parts! It's faster and easier to get parts for my 1968 Dodge van!

Michael Benno

Those pressure switches are a common source of failure and many of us have replaced them with a double ended hose barb and left the switch harness disconnected. Curiously the factory lists an alternative to the switch as well so if you really wanted to go OEM you could for about $5.

karl ruiter

Congratulations. Whey the radiator vent slats on my '88 went nuts, I deleted the system. Earlier and later cars don't have them so I figure its OK. Plus, if they do anything at all, its must be at 150+mph, and in Hawaii 80 is reckless driving. On my car the ABS wiring generally, and the connectors specifically, totally turned to dust. Would have been very expensive to replace, and I don't think I need ABS anyhow. As for parts, you know Roger, and there is also Mark, Greg, and Sunset. Can still be trouble as parts go NLA, and for sure not like getting parts for an Explorer or something, but not bad really.
Fuel filter is the one thing you CAN get at your local Autozone.
Most folks send injectors to Witchcraft of similar to be tested and refitted with orings, covers and filter baskets. Much more cost effective than new, although there is also a cost effective option to replace with Ford injectors, which I have used in the past. Roger sells special O rings for this.

Zirconocene

@android606 : If you do go the route of what you proposed, with that self made adapter, please share the parts list and sources, if you would be so kind. I like Mike's solution, as well, but there's something appealing about maintaining that connectivity and alert. (At least to me, there are enough connectors already sort of hanging out in my engine bay. Everyone has their different OCD things, I guess).

Cheers

checkmate1996

This is how the 928s got a bad wrap. They sit for an extended period of time. People pick them up "cheap". Sticker shock on labor and parts. They sit for an extended period of time. However, I applaud your tenacity to getting her up and running. I hope you see it through because once they run, they run.