928 Mechanical restoration - Reliability? (1981model)

[wayner]

I'm new to 928 ownership although not new to Pelican having saved a 73 911.

I didn't buy this car because I wanted a cheap sportscar, but because I wanted a 928 that I could drive reliably.

While I don't want to wast money, I don't want to be cheap and shoot myself in the foot, so preventative maintenance is what I am planning. I see the sticky thread on common issues, but I'd like to baseline the car and create a brief paint by numbers list for myself of what to take care of before it causes problem, so if you want to contribute please jump in.

(I see lots of relay problems for instance, and wonder if I shouldn't just try to replace them all and keep the old ones as spares? ... or at least the ones that would make it non drivable (things that would stop the fuel pump and injectors from working for instance)

Here is my list of accomplishments so far, working from back to front with the fuel system. What else in order of while I am in there, or in order of importance?

1. Replace leaking gas tank
2. replace fuel pump
3. replace filter
4. replace all rear hoses by the tank
5. fix connectors and brittle wire near the fuel pump
6. ???

[wayner]

1981

[spooledx2]

Nice car, I've always wanted a gaurds red 928. I would start at the grounds, clean them all very well along with the 14 pin connector. Those two areas seem to cause a huge amount of issues in these cars. The fuel hoses in the engine compartment are also prone to failure if they are original. Roger @ 928's R Us has the fuel hoses and tons of other parts you will need. If you need used parts Garage 928 on FB has a huge selection of good used parts along with 928 International of course.

Ramon

[Danglerb]

A thorough professional inspection by someone expert in the 928 is the best initial investment. Anyone with a helper can take about an hour off the normal time by doing all the basics like checking switches, lights, and fluids.

Fuel injection hoses under the hood are item one.

Replacing all the relays should stimulate the economy, not a "bad" idea, just expensive when the primary need is to clean all the contacts. Many here like the Caig products like deoxit.

Replace the ground strap on the battery, do the ground service and make sure it has a good battery, then drive it a lot and fix anything you notice.

[stepson]

Originally Posted by Danglerb

A thorough professional inspection by someone expert in the 928 is the best initial investment. Anyone with a helper can take about an hour off the normal time by doing all the basics like checking switches, lights, and fluids.

Fuel injection hoses under the hood are item one.

Replacing all the relays should stimulate the economy, not a "bad" idea, just expensive when the primary need is to clean all the contacts. Many here like the Caig products like deoxit.

Replace the ground strap on the battery, do the ground service and make sure it has a good battery, then drive it a lot and fix anything you notice.

+928 Very good advice posted here!!

[wayner]

Thanks everyone

In anticipation I already ordered and received upgraded brakes from a newer model ( to replace seized calipers. They’ll get put in a box and reconditioned one day if keeping it original makes sense in the future

I’ve also got ALL belts and hoses and lines for replacement

I think that’s just prudent on any car this age

Are relays even much if an issue or do problems stem from corrosion of grounds and connectors leading up to the relays?

( I’m already skilled at cleaning up grounds as I had a late model Honda motorcycle where the frame was painted by the factory covering all ground points that never had the paint removed before screwing down lugs

As far as a 928 expert, the car got a cursory once over, but I’m mainly looking for a more comprehensive list of preventive tasks rather than waiting for failures

The car is old, clean and seems reliable and well cared for but deserves some TLC to keep it that way, but it seems that aside from replacing old rubber, cleaning up the electrical is where it’s at?


Thanks for the product and vendor recommendations

[stepson]

Originally Posted by wayner

Are relays even much if an issue or do problems stem from corrosion of grounds and connectors leading up to the relays

Short answer is: Yes, relays can be a problem. Replace the relays that concern the vehicle running:

Fuel Pump (XVII) next to large relay at bottom right (928.615.113.01
Fuel Injection (XVI) 4th from the right on top row (928.615.119.00)
Ignition/Starter (XIV) 5th from the right on top row (928.615.117.00)

If it ran before you replaced these relays, you can keep the old relays as back up spares only.

Replace any other relays as necessary.
Spin your fuses around in the fuse holder to get a good connection initially, but plan to clean and polish the fuse holders at some point.

The more you drive your car, the better it will run generally.

These cars like to be driven!

[Opelotus]

Nice car! Is it a 5-speed, or automatic?

As others have already stated, a good all-around electrical system/contact cleaning and inspection goes a long way on these cars.

Also a good idea to check the condition of the "green wire" which runs from the ignition distributor to the ignition control module on the passenger side of the engine bay. If this wire fails, your engine won't run!

If it's a 5-speed car, plan on replacing the clutch master and slave cylinders, unless they were already replaced recently.

Post up some engine pictures!

[wayner]

Thanks!

I know what you mean

I’ve already experienced how they like to run when a few dropped cylinders finally started firing while idling waiting for the trailer after the tank and fuel pump were replaced

Thanks for the relay advice

P.S.
Yes 5 speed
Engine needs a good cleaning from storage
I’ll grab some pics this weekend
Good thinking on the clutch components, master and slave should be easy

Tranny is weeping so I’ll likely pull it and refurbish it next season

[honerboys]

clutch slave is easy to get to...clutch master..not so much

[Opelotus]

So since you have a 5-speed, I would highly recommend removing/inspecting the clutch assembly when you have a chance. A little bit of fresh lubricant on the clutch shaft and release fork pivot points goes a long way for longevity and smooth operation. With the high prices of clutch components for these cars, you don't want to wear anything out unnecessarily. I would recommend replacing the release bearing and pilot bearing while you are in there, especially if they are old. Also renew the plastic pivot bushing for the clutch fork. If the clutch fork is worn where it contacts the release bearing, it can be welded up and filed down to it's original profile pretty easily. I've found on several cars that it makes a difference in clutch operation and driveability.

[wayner]

Ok, here is my list so far:

COMPLETED:

• Replace leaking gas tank
• replace fuel pump
• replace filter
• replace all rear hoses by the tank
• fix connectors and brittle wire near the fuel pump

TO DO:

• All engine compartment hoses and belts
• Water pump (while I am in there)
• Brakes and lines

Electrical

• Clean grounds
• Clean fuses and holder
• Fuel Pump relay (XVII) next to large relay at bottom right (928.615.113.01
• Fuel Injection relay (XVI) 4th from the right on top row (928.615.119.00)
• Ignition/Starter relay (XIV) 5th from the right on top row (928.615.117.00)

Future:

• Clutch (see prev posts for parts to refurbish)
• Inspect rad, replace with aluminum?

Harebrained idea that may never happen or maybe should never happen:

• Recover seats in Pasha and install phone dials in place of black leather and manhole covers

This should keep my busy for a while

[928JimL]

timing belt is important to change if it hasnt been done recently. axle boots in rear need to be inspected. replace if cracked or split before moisture gets in there

[Danglerb]

What the expert inspection does is give you an accurate baseline on the car, pointing out things that need fixing before you drive it or even run the engine much, and things that are more a waste of money (most brake upgrades). In rare cases it may point out serious unknown issues that may not be practical to fix.

OTOH the learning potential is much greater if you wing it.

[wayner]

Thanks!
I'm in with both feet now
Compared to my 911 project this will be easy!
(Search thread in 911 forum " Saving a 73 from the crusher")

The car is too clean to not save.
Paint and body are fantastic.
Engine is strong
Slight leak from the transmission. Will save that until I do the clutch, but clutch seems fine right now


Current update:



COMPLETED:

• Replaced leaking gas tank
• replaced fuel pump
• replaced filter
• replaced all rear hoses by the tank
• fix connectors and brittle wire near the fuel pump
• Aquired phone dials
• Replace rear hatch struts

Immediate next steps:

• Fix fuel pump electrical circuit - no power (runs great when jumpered with a test lead from another circuit )
• Remove and reinstall rear wiper properly (it appears to have been installed incorrectly. its parked to the passenger side and only moves 1/4 of its travel)

Longer term TO DO (baseline):

• Parts acquired for this phase
• All engine compartment hoses and belts
• Water pump (while I am in there)
• Brakes and lines (brake calipers seized so using trickle down economics, I bought bigger take-off brakes off a newer model that was getting a brake upgrade

Electrical

• Clean grounds
• Clean fuses and holder
• Fuel Pump relay (XVII) next to large relay at bottom right (928.615.113.01
• Fuel Injection relay (XVI) 4th from the right on top row (928.615.119.00)
• Ignition/Starter relay (XIV) 5th from the right on top row (928.615.117.00)

Future (when the time eventually comes):

• Clutch (see prev posts for parts to refurbish)
• Inspect rad, replace with aluminum?

Harebrained idea that may never happen or maybe should never happen:

• Recover seats in Pasha and install phone dials in place of black leather and manhole covers (leather seats are ok but drivers seat is torn)

This should keep my busy for a while.
The car is a clean enough early car that I want to make it a 9 out of 10 car, and I got it for next to nothing, and would rather have it than a new civic, so that leaves lots of room to take care of its needs, and with the market moving a bit on these cars, my parts budget may not depreciate as quickly a civic, in fact with luck it will go the other way or at least close to break even.

[stepson]

Waymer,

Have you driven the car yet? For some reason, I get the impression that you have not.

If you have not driven the car yet, get it driveable. It is much more fun to drive a car that you have worked on. In addition, you will find additional things that may need attention. Take them one thing at a time so that you can keep driving it.

If you have driven it, tell us what you think!!

[wayner]

I have driven one like it that a friend owned back in the day.
As a young adult I was asked to help shuffle some cars to the detailers, and at that age and my then financial status ( or any lack of) that was a big day (944, 928, 300zx turbo HKS, and a fresh off the showroom floor first yearNSX)

Now many years later this car completes my collection of rear, mid and front engined early Porsche’s

I would love to say that I have driven it, but no, aside from moving it around, unfortunately not but I can’t wait!

The fuel pump problem was at the top of the list, now it finally runs but only by steeling power from somewhere else

My list is prioritized around getting it running and then passing a safety check
Since I’m still bogged down by snow I won’t be driving it for a while, but meanwhile I can methodically tinker and plan

[wayner]

A bit of trivia

I had no idea that the 928 was conceived as a prototype way back in 1973
While it was advanced for its time, it was even more advanced by 1973 standards!

(I gleaned this from an old book I bought written as an insiders view of its development
The picture on the left taken in 1973 is a 1:1 scale model, and the one on the right taken a few years later is a production version)

Since I have a 73 911 I’ll be able to recreate this picture when the snow clears

[stepson]

Originally Posted by wayner

The fuel pump problem was at the top of the list, now it finally runs but only by steeling power from somewhere else

Did you actually wire it to another circuit or did you remove the relay and make a jumper wire? (term 30 to term 87) (diagram on the relay usually)

I always make a switched jumper wire so that I can remove the relay from the list of things that could be wrong and still be able to turn the fuel pump on and off.

[wayner]

I came jumped with a switch when I got it

Power is coming directly from the batter
(Obviously that will not be my long term solution but it did point to an intermittent fuel pump that needed to be replaced )

Good tip on bypassing the relay for a test since the original circuit is not supplying power