Rescuing an '81 Caddy 16v

[arne2]

Copying this thread here, from Vortex. Will be a little bit of catch up to get current.

Hi all, after many years and many other cars (both VW and other), I've gone back to a Mk1. In particular, an '81 Caddy.

I am a serial car rescuer. I have a history of buying derelict vehicles and working to refresh or restore them. I also have a lot of history in German cars, and water cooled VWs in particular.

I bought my first VW in 1979, a '78 Scirocco. My wife and I liked it so much that in June of '81 we traded it in to get a new one before the 2nd gen Scirocco arrived for '82. That was my first new car ever, a Cirrus Gray Scirocco S. We kept that car for 10 years.

It was replaced by a new '91 Jetta GLI 16v, as we needed a car with better back seat access for our growing son. We kept that one for 18 years, then gave it to our son after he graduated college. He still drives it today.

Other VWs over the years were an '86 GTI 8v, '90 Corrado G60, and a '10 Golf TDI. When the TDI buyback came, we bought an Audi A3 etron plugin hybrid to be the new daily driver.

My rescue projects over the years have been more varied. A '67 MGB basket case, gray market '81 BMW 323i, '71 240Z, '84 944, '73 914 2.0, '64 Toyota FJ40 soft top, and most recently a '72 911T. Only the 911 is still in my possession. The rest moved on to new owners when the projects were completed.

Anyway, on to the Caddy. I came across it recently. Born as a silver LX gas truck, it now has a 2.0 16v and 5 speed from a '92 Passat. Was parked a little over a year ago with an apparent fuel delivery issue. It sports a rather amateur Mars red paint job, but has a full round headlight conversion.

Not sure how far I'll take this yet, maybe just a quick repair to make it run, drive and do so safely. Or maybe I'll go full boat with a GTI-look refresh.

[arne2]

The Land Cruiser was a major, frame-off project. Sold on BaT in late 2018 - https://bringatrailer.com/listing/19...ruiser-fj40-4/

This could be almost as major, if I let it.

I could simply de-bug the functioning parts, make it run and drive safely and reasonably reliably. Then sell it to let the next owner do the cosmetics to suit themselves.

Or I could do some mild clean up of the basics, maybe a few improvements, and sell it as an improved but not super-great rat-rod type vehicle.

Or I could strip it down and and make it fairly nice...

Not sure where I'll go yet.

I've got the battery charger hooked up now, and started some cleaning under the hood. Wasn't ready to really start digging into the fuel delivery issue, so I took apart the tailgate latch because the tailgate was stuck. Some progress on that, tailgate is open now, and I'll probably get it back together tomorrow.

Some history - PO had owned the rig since 2008 at least, and the Passat 9A was already in it and running at that time. He used it as a daily driver for years, until it started having fuel-related problems. He mostly parked it in 2015 or so, occasionally tinkering with it to make it run right again. Mostly, he failed.

Last fall, he had it towed to a local shop to see if they could find and fix the problem. Of course, after sitting mostly unused for 4 years, things had deteriorated badly. He ended up spending over $3k at the shop, with some of the notable items including a rebuilt fuel distributor, and new ignition distributor, and O2 sensor.

After all that, the shop said it would run, but not especially well. They felt that the ECU may be faulty, due to how it was crudely mounted in a location unprotected from rain. The owner decided he'd spent as much as he could afford and brought it back home, where it has sat pretty much ever since.

That's where I'm at with it. I'm going to need to start stepping through the troubleshooting from the very beginning. For example, I don't hear the fuel pump priming the system when I turn on the key. So that's where I'll start.

This could be a not-to-difficult thing to get a handle on. Or it could be a long slog. Wish me luck.

[arne2]

First order of business was to get it running. Found the fuel pump relay was bad, so I ordered a new one.

While awaiting the new fuel pump relay, I did more cleaning and exploring.

• Found idle control valve wires disconnected. Reconnected same.
• Tested both throttle switches. WOT working correctly, but throttle-closed switch was improperly adjusted and not closing when throttle was closed. Corrected.
• Connected speedo cable.
• Found broken wire for tach. Corrected.
• Discovered the horn is missing, as is the flasher relay.
• Front brake pads look new, and hoses look fine, but there's no telling how old they are. Rotors are rusty and pitted from sitting. I'll probably do vented rotors, pads and hoses up front at a minimum, might rebuild or replace the calipers too.
• Front suspension is toast. Bad inserts, bump stops missing, typical collapsed Mk1 strut bearings. Left side bounces undamped, right side sticks down when pushed, then slowly jerks up as it rebounds. Will probably do ball joints also, maybe control arms.
• Has power steering, rack boots destroyed, and it all looks a bit wet from leaks. Not sure if I want to try to repair it all, or convert to manual.

Over all, somewhat encouraged so far. I think I can get it up and running reasonably easily.

[arne2]

After installing the new relay, it started instantly, and ran, although not great. Good enough for a short assessment drive through the neighborhood.

• Engine - Not bad. Still not at 100%, power falls off and stumbles a bit above 3500 at WFO. Plus the fast idle. Still some work to do there.
• Transmission and clutch - Pretty good. Linkage might be a touch sloppy, but not bad. New bushings will take care of that. Otherwise transmission and clutch both worked fine.
• Brakes - Functional, but noisy up front, grabby and really quick to lock in back. Good pedal feel. Parking brake non-op. Will pull the drums in back tomorrow to lay plans on this. May throw a pair of vented rotors and pads on the front rather than try to clean up the rusty rotors on it now.
• Suspension - Rear is fine, has a pair of recent Sachs shocks, springs and bushings look OK. Front is totally toast. Needs inserts, upper mounts, bump stops. Will probably do ball joints just because. Power steering actually seems to be working OK, but will need new inner boots.
• Exhaust - Header feeds 2" pipe, one glass pack resonator under the seats, then into a Walker/Dynomax turbo muffler and the 2" all the way out the back. Sounds pretty good, actually. Looks a bit cobbled just downstream of the header. I may clean that up with some new pipe, or perhaps even a universal catalyst just to de-odorize the exhaust some.
• Other - Will need to service or replace at least one half shaft, probably both. Boots shredded and full of grit.

I think that's it for now. Can already tell, this thing is going to be a riot to drive once it's all debugged. Quick, loud and responsive. Fun has begun.

[arne2]

A whole bunch of parts were ordered.

Brakes - Pulled the rear drums to see why the RR was locking up on almost any brake application. Found it. PO's shop replaced leaking wheel cylinders last year. That's well and good. Might have been nice if they had paid any attention to any of the rest of the rear brakes. The friction material is saturated from the prior leaking cylinders, and the RR drum is more than ¼" over spec. LR is at max. RR adjuster wedge is dropped as far as it will go, brakes are still way loose and bind up on application, causing that wheel to lock. Ordered shoes, spring kit, 2 drums, bearings and seals. Up front things are better, but the rotors are badly rust pitted from sitting in the weather, and already almost at minimum thickness. So I ordered a pair of vented rotors and matching pads for the front. That should fix up the brakes.

Suspension - New strut inserts, upper mounts and bump stops ordered. Also new ball joints because they are cheap, and why not?

Engine - New timing belt kit coming, since I doubt this one has been replaced since the engine was swapped in over 12 years ago.

Other - Turn signal relay.

[arne2]

Finished brake and front suspension work. New brakes front and rear—rear including drums and bearings, front upgraded to vented rotors. Front suspension got strut inserts, top bearings and bump stops. Will take it out for a short test spin tomorrow, before beginning the next steps. Timing belt next, then knock sensors, and finally starting the electrical tracing, repairing, tidying and simplifying.

Then spent some time today working through wiring. Tagging things that I know what they are, testing them to make certain they work, and trying to identify things that don't work or are simply loose unconnected wires (of which there are plenty).

It appears as if the harness splice work was done by Cro-Magnon man. There is some sign of intelligence behind what was done, but very little actual understanding.

For example - the radiator and cooling fan appear to be from the donor Mk2 GTI, which looks to have been an A/C car, based on the number of unused connectors in the fan harness. Nice, 2 speed fan with a hi/lo temp switch in the radiator. The person who set it up did not bring over the after-run controller, but simply connected the harness to an always-hot and ground.

Here's where things get scary. The Mk1 fan circuit has a 15 amp fuse. On a Mk2 with the much beefier fan motor they use a 30 amp fuse. On this Caddy, they did neither. Simply hot-wired the harness to the battery, unfused. Apparently didn't want to try to find the wire to the fusebox.

Worse, the wires (both hot and ground) for the cooling fan on these little trucks was 14 gauge wire, and the Mk2 used a metric wire between 14 and 12 gauge. Nice heavy stuff for a 15-30 amp load. But in my truck, the caveman used scrawny 18 gauge wire for both hot and ground. It was a fire waiting to happen!

I simplified the harness to eliminate all the pigtails for A/C interlocks, etc. Next I'll either add an inline fuse holder (with 30 amp fuse) to power the fan, or maybe run a nice fat wire to the fuse box and use the factory fuse location (again with a 30 amp).

Fun times.

[gereonb]

Working on a similar project myself, MK1 GTI 1984 Westmoreland, but with a 16V PL engine in it, badly wired, like yours.

I redid the whole harness for the car, firewall back it is all OEM GTI now, and the 16V Harness is powered by battery, ignition and tach signals in the engine bay and of course all the sensors directly, so if I want to go back to original JH I don't need to do anything inside the car.

The problem I am finding is the 16V uses extensive knock sensing and right now my engine is knocking from the water pump or oil pump and of course the engine mounts are shoddy too so I have the same result as you wont rev above 3500, I assume its sensing knock and going to limp mode. Going to try repositioning the knock sensor and see if that makes a difference.