84 RoW Coupe - Winter Project Help

[aherngang]

Hi,

Thank you in advance for looking and for your help. About a year ago, I bought an Slate Blue/Blue 84 RoW Coupe with 95k and have been enjoying it as I slowly fix the numerous quirks and kludges that came with it.

While it has been a mild Winter in the Northeast, I'd like to do a couple of the more major (to me) projects/problems. Any help or advice would be much appreciated!

My car has an aftermarket A/C (please see pix below) - I would like to remove it as it doesn't work and the PO's all said that it never worked going back 20 years. Plus all the plumbing and brackets are just in the way. Can I just start disconnecting stuff and assume that all the freon is already gone or do I need to take it to a shop and have the system purged? Once Would anyone like the parts?

Cat bypass pipe - I have a cat bypass that I'd like to install in place of the Euro cat or whatever is in there (to me it looks like someone welded a GM cat in there instead of the Euro pre-muffler). The nuts/fasteners all look frozen solid with rust. Would heat and judicious amounts of penetrant be enough for a shade-tree mechanic like me or should I take it to a pro?

There is a weird box (FAC-2 Fuel Control Unit made by DC Johnson) under the driver's seat (see pix) that has a broken white wire coming out of it. The wire appears to be coax or shielded. Is that the wire to the O2 sensor? Can I just reconnect/solder/mend the central wire or does it need to be mended so that the outside coax stuff is fixed too?

Even after complete tune up and new plug wires, the engine has a hesitation/stumble between 2200-2400 RPM (Tachometer indicated - not sure how accurate it is) that is most noticeable under light throttle or maintaining speed. Otherwise car runs great and pulls strong above that. Could this be related to the disconnected wire in the above problem? This stumble problem at 2200-2400 RPM also occured in my 84 US Carrera, but the problem went away with a good tuneup.

This is more than enough to keep me busy for a while. Thank you in advance for your time and thoughts around these problems!

Regards,
Tom

[Joe Bob]

Non barrier hoses leak....very likely there is little or no freon left. I just removed the big stuff and left the rest.

[DanielDudley]

If it is stumble at a cruising RPM that is held for long distances, it could be the potentiometer in the AFM. Some people bend the swing arm contact to hit a different area on the arc of the resistance strip.

[aherngang]

Thank you both for the help. I'll look forward to removing as much of the A/C system as I can this weekend.....

As for the stumble, I will research how to do the AFM/potentiometer tweak to see if that cures it. The stumble happens as soon as you settle into a steady speed at that RPM no matter what gear I am in.

Thanks again,
Tom

[r_towle]

Welcome to the porsche fun.
The potentiometer fix is simple, its fast, and from the sounds of it, it may be your issue.
Mine did the same thing (84 cab) and that fixed it.....took about 30 minutes.

For the AC, just pull it all and safely cap all the wiring.

Rich

[aherngang]

I'm a bit behind in posting the progress on this car, so here is a bit of news from last weekend for anyone who is interested.

Started removing the A/C from the car. Found an aftermarket heat exchanger hidden in the left rear quarter panel. Behind it was the last (hopefully) of the rodent living quarters in the car. Yes, that is a pork chop bone on the left amongst the leaves and trash bags! And a broken bulb from my stupid droplight - gotta find a better light that doesn't roll/fall all the time. I am at best 1/3 of the way thru this project with lots of challenges to come.

Then I sprayed some penetrant on the exhaust header / catalytic converter bolts so that it would hopefully work its magic and that I can put on my cat-bypass pipe next weekend. The fasteners are all rusted solid, so I'll probably snap or ruin most of them. This could get ugly.....but it has to be done!

Geez I worked about 4 hours on the car (yes, I'm a novice and slow) and it didn't seem like I got very far. So I needed something to cheer me up, like an easy task with a high return rate of satisfaction. The Euro taillights went on with nary a hitch and, yes, it felt great and repaired my bruised ego a little bit!

[aherngang]

Made some more progress on the 911 this past weekend. Got the majority of the A/C system out without cutting or botching up anything else (see pic 1 & 2 for before/after perspective). It may not look like it, but it makes a HUGE difference in getting access to all the stuff deeper in the engine bay. Plus, I found a disconnected vacuum hose and reconnected it to the potential target (fuel pressure regulator). Perhaps that is the source of the rough acceleration at 2200-2400 RPM?

Here are all the pieces removed thus far from the A/C system (picture 3). There was some R12 gas in the system when I unbolted the lines (I feel badly about leaking that into the environment), so it did still hold some sort of a charge. I will ask on the Porsche bulletin boards if anyone wants this stuff. There is still a wicked fugly homemade bracket from the compressor that looks like it can only be removed if the engine is dropped. The motor mounts are pretty sloppy, so it will be a great time to replace those as well.

Bonus discovery from the A/C removal was the original wires that used to run to the Euro rear foglite. I'll find a replacement and eventually this car will be back to its former glory.

Other notes of interest? Well in picture 3 you will see a broken light bulb, which is yet another one which breaks in my stupid droplight. There was another one pictured in last week's debris.

The fasteners for the A/C components are all std (not metric) sizes. So it feels really good to be removing these alien pieces off of the car.

Same thing for the cat convertor - it is all std fasteners and the cat was obviously a cheap weldup from a Chevy Chevette or something that the original US owner had to create so that the car could pass emissions in 1984. I cannot wait to get that POC off of the car. But due to the absolutely awful rusted solid condition of the bolts/nuts, I will likely go to a muffler shop to have them cut it off.

Ideas and suggestions welcomed. Thanks for the support/advice so far!

[rattlsnak]

getting there! Keep going!

take the compressor bracket off while youre at it..

[Winter]

Nice work! Keep hitting the rusted bolts with liquid wrench or whatever you are using.

Good luck!

[aherngang]

Good news! The bucking/surging problem between 2200-2400 RPM was 95% cured after reconnecting that errant vacuum hose that was lying near the spark plugs under that fugly A/C bracket. I gotta go tell the folks on the "Hurky Jurky" thread in case it might help them.

I say it was 95% cured because I think I feel a oh-so-slight buck every once in a while. Maybe it is my imagination, or maybe there is another vacuum leak in there somewhere, or maybe the AFM does have that "tracking" problem. But the car is so much better than it was.

Oh and I'm going to cheat on the Cat Converter bolts and bring it to a shop. I was having awful gory nightmares about breaking studs in the heads and in the manifolds. Sorry to disappoint....guess I ain't as tough as I think I am....