Nick Comstock
Nick Comstock MegaDork
10/9/24 3:18 p.m.

My son just got his first car. A one owner low mileage (around 110K according to the previous owner as the Odo is stuck at 90K) 1991 Audi 80. 

 

We are going to be working our way through the car to make it a solid reliable driver for him.

What are some good resources for information about these things?

On the list of things to address are the aforementioned speedo/odo being non op, A/C non op, heater core bypassed, passenger window switch on the drivers door non op, faded paint, brakes all around, full tune up, new tires, new struts, and whatever else we may find while we are working on it. 

 

Thanks 

Mr_Asa
Mr_Asa MegaDork
10/9/24 3:27 p.m.

Fairly sure the 91 and 95 are different generations, but I'd ask Jehannum and see if he has suggestions 

https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/my-rs2-tribute/273303/page1/

Nick Comstock
Nick Comstock MegaDork
10/9/24 3:34 p.m.

In reply to Mr_Asa :

I've only opened the hood once but I definitely saw a fuel distributor, no fancy futuristic electronic fuel injectors here...I wonder how similar these are compared to the old K-jetronic systems I used to play with in my E21s

iansane
iansane SuperDork
10/9/24 3:41 p.m.

Heck yeah!

I had a '90 90 for awhile and definitely enjoyed it.

For tech stuff check out Motorgeek. It's not too active but there is a lot of info there.

Is it manual or digital HVAC controls? You can get still get a lot of OEM parts from Audi Tradition if you can get your local dealer to order from them.

Turbine
Turbine HalfDork
10/9/24 3:43 p.m.

Oooh nice. I've also got a 5 cylinder build thread here (shameless plug) 10V or 20V? Quattro?

As far as resources go, the old forums are still around and have a bunch of good info, although they're not anywhere near as active as they once were. I still use motorgeek, theprojectpad, and quattroworld somewhat often. The facebook groups are pretty good as well. I'd recommend 'Small Chassis Audi', 'Audi Yacht Club', and The S-Car Preservation Society'. The community around these cars is one of the best I've encountered.

For basic parts, FCPEuro's your friend, although they might not have much beyond consumables. ECSTuning and 034Motorsport have some old 5 cylinder stuff too, although quality and service are pretty hit or miss with those. EFI Motorsport, Ultra Performance Engineering, and iAbed Industries are great for the more specialized stuff. Otherwise, scour ebay, facebook groups, and forum classifieds for part outs.

Audi Tradition doesn't support the US for whatever reason, so unless you've got a connection out of the country, you're out of luck. Issam (iAbed) occasionally does community bulk orders from them since he's in Canada.

Nick Comstock
Nick Comstock MegaDork
10/9/24 4:03 p.m.

In reply to iansane It has manual HVAC controls

 

In reply to Turbine : Appreciate the forum and Facebook suggestions. It's a FWD auto car. As far as 10V or 20V I'm not sure. I'm not at all familiar with the various nomenclature and whatnot in the Audi world. In the limited research I've done so far (YouTube videos) it seems that they sold both B3 and B4 variants in 91, I'm not sure what the differences are. Alot of what I saw was targeted to the Euro audience and I'm not sure if that is accurate for what we got in the states. 

 

I gotta say I kinda fell in love with how it drives on the two and a half hour ride back to my house. 

 

Berck
Berck HalfDork
10/9/24 4:06 p.m.

"We are going to be working our way through the car to make it a solid reliable driver for him." -- I'm not sure this is a realistic goal, or even an attainable feat.   But I'm excited to watch you try!

I don't know a bunch about the 80, but I own and regularly do battle with a '87 5000 Quattro.  The 5 cylinder engine is reasonably reliable, but nothing else is.  It's possible the 80 isn't as bad as the 5000, but there's a short summary of my ownership (copied from a totally different post):

When I bought it and drove it home, it smelled like burning hydraulic fluid because the steering rack was dumping hydraulic fluid on the exhaust.  The warning display was alternating between coolant overtemp (it wasn't), low hydraulic fluid (it was), and brakes (eh, who knows?).

That was a few years ago, and the Audi and I have had some great battles.  My weapons have been perseverance, an inscrutable Bentley manual and eBay parts from Estonia.

I managed to fix the cold start issues by installing the missing fuse for the CIS computer. Point mine.

The odometer stopped at 184,199.  I took it apart, unwedged it and it restuck at 185,299. Point Audi.

The after-run relay for the electric cooling fan melted.  I replaced it, and the replacement melted and drained my battery.  Point Audi.

I fixed the coolant temperature warning by replacing the multi-malfunction sensor in the thermostat housing. Point mine.

Oh man, the GM-sourced Cadillac climate control.  It mostly worked, but did what it wanted to do, with occasional random responses to button-pushes.  But then the heater core started dripping on my feet, and I replaced it.  I fixed the leak, but the servos and levers and springs and magic for the ducting have never worked correctly since.  Tie?

I fixed the acceleration hesitation by replacing one of the electric valves for the CIS.  When I removed the electrical connector, fuel came out.  Of the electrical connector.  Point mine, but it gets a nod for creativity.

And then the clutch failed in a weird way.  I couldn't get it in gear reliably.  I replaced the clutch master and slave cylinders.  That did not fix the problem.  Against my better judgment, I replaced the clutch.  The pressure plate was just plain worn out.  Plenty of life left in the disc.  While I had the transmission out, I replaced the steering rack.  This was less than $200 in parts from rock auto, but geeze was that a lot of work.  Many points to me.

A relay of uncertain function started clicking while driving and after driving.  I removed it.  After doing so, the driver side door chime stopped working, which is a huge relief.  Unfortunately, the power windows stay powered until you open and close one of the non-driver doors, which means every time I get out, I have to open and close another door to keep the battery from dying.  I think the Audi won that one.

Things I've never even tried to fix: the hydraulic accumulator for the brake assist (really, it has one of these!) was busted from the beginning and I've never even tried.  The brake assist works fine as long as there's hydraulic pressure.  It won't work if you use the brakes a lot or if the engine isn't running.

The right-rear brake caliper sticks.  I ordered a replacement, and the part number was actually the left rear.  So I installed that one and tried to order a left, hoping it would fit on the right.  No left exists.  I disassembled the caliper, cleaned the piston, honed the bore and it stopped sticking for awhile.  Just last week I did it again. 


In the time I was winter-commuting in it, I have never actually gotten stuck anywhere but my own house, which is really decent of it.  I have discovered plenty of pools of fluid underneath it when leaving work, but it always got me home.  There were lots of days, however, that for one reason or another it did not actually manage to leave my driveway.  Or the time it left my driveway, but the clutch stopped working on my street, and I limped it back.  If I were relying on it exclusively to get me to work, I'd be unemployed.
 

Nick Comstock
Nick Comstock MegaDork
10/9/24 9:37 p.m.

In reply to Berck :

LOL, sounds like you have had some fun! I'm hoping maybe the kid will develop a bond with this thing after putting some sweat equity into it. 

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
10/9/24 10:08 p.m.

The odometer is probably just a gear in the unit that came unstuck from a shaft.  I fixed my Quantum with a dab of superglue.  Then broke the speedometer needle and glued a toothpick to the stump.

 

The fuel injection system is going to be K-Jetronic based, and it's either Motronic (with ignition timing control) or just KE-Jetronic (no ignition timing control).  When it works it works very well, and it usually shades towards working well. 

 

z31maniac
z31maniac MegaDork
10/9/24 11:20 p.m.
iansane said:

Heck yeah!

I had a '90 90 for awhile and definitely enjoyed it.

For tech stuff check out Motorgeek. It's not too active but there is a lot of info there.

Is it manual or digital HVAC controls? You can get still get a lot of OEM parts from Audi Tradition if you can get your local dealer to order from them.

I just wanted to point out this is a super sexy car. 

ddavidv
ddavidv UltimaDork
10/10/24 7:11 a.m.

The 5000/100/200 chassis had a lot more problems than the 4000/80/90.

The five cylinder is pretty much unkillable. I haven't been involved with Audis for decades now, so have forgotten a lot of what I learned. I never had trouble with the CIS injection on mine. Most of the problems on the older models revovled around what you've already found:  HVAC, heater core, power functions like windows and sunroofs, and yes the speedo/odos were a regular complaint. It probably is one of the gears has shifted on a shaft in it. The radiators weren't the most robust. The heater core is bypassed because replacing them sucks. The automatics weren't exciting. I'd say it is a car that will require a good amount of little fixes to bring back, but after that you'll probably find it is pretty reliable. 

porschenut
porschenut Dork
10/10/24 8:03 a.m.

If it is auto the motor is probably 4 cylinder, not 5.  And autos are just not worth working on, IMHO.  The quattro is always 5 speed, sometimes 20 valve and always fun to drive.  You will find yours to have wiring issues, Audi used too thin a wire and by now just looking at them sideways will cause electrical issues.  Parking brake mechanism usually doesn't work and getting it to work will cost a lot of new parts.  Fuel injection is CIS, cold start can be an issue.  I just wired the cold start injector to a momentary switch in the car to prime it.  Again wiring issues and bleed down of fuel pressure are typical, weeping injectors are also common but not a big deal.  Run serious amounts of fuel system cleaner and fix vacuum leaks, both cheap and will do the biggest benefit.

As someone who owned a dozen of the 5 cylinder cars in almost every configuration I would not consider one now.  Especially a 4 cylinder auto.

pinchvalve (Forum Supporter)
pinchvalve (Forum Supporter) MegaDork
10/10/24 8:50 a.m.

If it doesn't look like this in a year, I will be dissapointed. 

iansane
iansane SuperDork
10/10/24 10:17 a.m.

In reply to Nick Comstock :

Hopefully your kid gets the same enjoyment you already have out of it. Any desire to manual swap it?

In reply to pinchvalve (Forum Supporter) :

Literally the first thing I did when I bought my 90 was price out that kit. Something like 10k!

In reply to z31maniac :

Thanks! I'm realizing now even though I say I don't like pearl white and gold I must be lying because the pearl white b5 s4 avant I traded that 90 for just got gold wheels put on it...

Nick Comstock
Nick Comstock MegaDork
10/10/24 2:13 p.m.

In reply to porschenut :

It's a 2.3L 5 cylinder and a 4 speed auto.

Nick Comstock
Nick Comstock MegaDork
10/10/24 2:14 p.m.

In reply to iansane :

If it was mine I would but he is intimidated just trying to drive let alone try to learn a manual. Maybe one day.

ddavidv
ddavidv UltimaDork
10/10/24 6:00 p.m.

That photo:  the grille is held in with bolts. The 4000s had little clips that held them in place. Was really nice to just pop them off to gain access. Bolts = meh. 

Nick Comstock
Nick Comstock MegaDork
10/10/24 6:26 p.m.

In reply to ddavidv :

I can see where the clips are broken and someone has ran those in there to hold it on.

ddavidv
ddavidv UltimaDork
10/11/24 6:14 a.m.

No, not the same. You mean they had round clips. The old ones had sleeve clips. The grille would turn up and be vertical at the back and you'd slide the clips down from the top. I always scarfed a few from the junkyard because inevitably one would go flying. "Never gonna see that again" -- Derek Bieri.

Edit: found a pic.

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