1990 Audi 80 running problems
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Audiworld Junior Member
Joined: Jan 2010
Posts: 15
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From: Burnsville
1990 Audi 80 running problems
I have a 1990 Audi 80 FWD, and the problem is that it just doesnt run right.
When you start it up, it chugs and runs rough, UNLESS you feather the throttle JUST right then it will smooth out.
When its driving, its incredibly nonresponsive. If you put the gas to the floor it hardly crawls, and slowly builds rpms then stalls out at about like 4000ish? It acts similar to being starved of fuel buuut the plugs dont look leaned out.
My thoughts,
Vacuum leak
Control pressure too high
Clogged injectors
I dont know much about the K-Jetronic system at all, nor how these audis are really set up, ive been a mitsubishi guy for a long time.
Any and all help will be GREATLY appreciated.
Also, does anyone know where to get a repair manual for this that isnt like 120 bucks?
When you start it up, it chugs and runs rough, UNLESS you feather the throttle JUST right then it will smooth out.
When its driving, its incredibly nonresponsive. If you put the gas to the floor it hardly crawls, and slowly builds rpms then stalls out at about like 4000ish? It acts similar to being starved of fuel buuut the plugs dont look leaned out.
My thoughts,
Vacuum leak
Control pressure too high
Clogged injectors
I dont know much about the K-Jetronic system at all, nor how these audis are really set up, ive been a mitsubishi guy for a long time.
Any and all help will be GREATLY appreciated.
Also, does anyone know where to get a repair manual for this that isnt like 120 bucks?
AudiWorld Member
Joined: Nov 2006
Posts: 153
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From: Lakewood, Co.
Three things, first as was already suggested pull your codes, second try runnin some seafoam through it, third is the fuel pump loud at all, if so it's prolly crapping out, you might also check your fuel lines and replace fuel filter, oh also you could try starting it and spraying ether on vac lines while it's at op temp the engine will rev a bit if ya hit a leak, typically. You could also use an unlit propane torch for this(shrug) whatevers handy at the time. Guess that was more then 3 lmao
Thread Starter
Audiworld Junior Member
Joined: Jan 2010
Posts: 15
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From: Burnsville
Hmmm, no I havent tried pulling any codes yet. I think I have the schematic for a code reader too. I guess I just didnt think it would throw a code. But Ill be sure to do that here in the next few days.
And, the fuel pump doesnt seem any louder than any other car Ive ever owned so I will assume its ok. But Ill try the seafoam thing, and then also replace the fuel filter when I get some money to throw at it. I know they arent that much, im just tight budgeted right now.
Also, after posting this I did find a couple vac hoses that were old and showing sings of cracking, soooo new question, just how detremental is a vacuum leak on the k-jetronic. In my mind it would be pretty bad considering the way these meter the air, and how the air meter runs the fuel delivery.
So I was thinking of unhooking the vac hoses from the intake plenum and capping them and trying to run it. See if it gets any more responsive. Any thoughts on that?
And, the fuel pump doesnt seem any louder than any other car Ive ever owned so I will assume its ok. But Ill try the seafoam thing, and then also replace the fuel filter when I get some money to throw at it. I know they arent that much, im just tight budgeted right now.
Also, after posting this I did find a couple vac hoses that were old and showing sings of cracking, soooo new question, just how detremental is a vacuum leak on the k-jetronic. In my mind it would be pretty bad considering the way these meter the air, and how the air meter runs the fuel delivery.
So I was thinking of unhooking the vac hoses from the intake plenum and capping them and trying to run it. See if it gets any more responsive. Any thoughts on that?
AudiWorld Member
Joined: Nov 2006
Posts: 153
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From: Lakewood, Co.
Wouldn't recommend it, you'd be better off wrappin em with electrical tape for the time being, and vac leaks cause mass problems, few other things you might check are the o-rings on you'd oil dipstick, and the gasket on the oil fill cap, also, check your crankcase breather connections, down on drivers side of engine near the transmission(this of course assumes your model is similar to mine) there should be a rubber coupler, a steel tube with a capped nipple coming off the side, and another rubber coupler connecting another metal pipe that will run over to the air intake boot on the bottom, if any of those are loose, or If that nipple isn't capped it will cause that, oh, if you do tape those vac lines you might spread some caulking or some orange rtv on them as well, not a permanent fix but it'll hold ya till ya can get new lines(when you do i'd recommend the mr.gasket Overkill kits, nice stout vac line should last a long while and ya can pick a color if ya want ) (shrug)
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Joined: Jan 2010
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Bring to mechanic, have them check the O2 sensor, my 80 Quattro, 1990, had an intermittent problem with the O2 sensor, it would work sometimes and then not work others. I could feather it through but it kept getting worse and worse. I tried everything, plugs, wires, cap, rotor, fuel filter, air filter, vacuum leaks fixed. Also, check under the stabilizer valve , that black hose sometimes wears out as it touches the intake manifold. Check the bottom of the hose for holes and check the other hose too. They come off easy and put on easy, although I used a little oil , very little on a tissue to make putting on easier in the back under the intake manifold. Good Luck, Orange County, CA
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AudiWorld Member
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From: Lakewood, Co.
Aye no problem man n yes it could also be the o2 sensor as veerve said but if ya have a voltage meter and the patience to find the proper readings for a working o2 on these ya can check it for free on your own, if ya give me a few days I'll see if I can't track those readings down
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From: Lakewood, Co.
OK this assumes you have the cisIII injection system(or i think its labeled as KE III jetronic injection system in these?) to test your o2 sensor, from the sensor itself read pages 32, to 36of this pdf http://www.dmcnews.com/Techsection/B...chtech-12d.pdf
if i understand correctly, the voltage it puts out at op temp should be 0.8-1 volt, but the pdf also explains what everthing else does and how it does it, so might be some good reading material if your interested, or thinking about it, its prolly 0.8-1 ohms of resistance (shrug)
if i understand correctly, the voltage it puts out at op temp should be 0.8-1 volt, but the pdf also explains what everthing else does and how it does it, so might be some good reading material if your interested, or thinking about it, its prolly 0.8-1 ohms of resistance (shrug)
Thread Starter
Audiworld Junior Member
Joined: Jan 2010
Posts: 15
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From: Burnsville
Ok, well, while waiting for money (saturday) I decided to insepct the vacuum lines. And well... there were quite a few that seemed to be loose at their connections. And then of course the one that was absolutely cracked to hell. It was pretty bad. Waiting to replace that one. the rest I either electrical taped, or silconed to help them seal better, then tightened up the connections.
Next step will be to replace that one vacuum line, its like a 1/2" line, pretty big leak there.
After that try to run it again, maybe with a can of seafoam in it, and see if it gets any better. If not. Then on to the engine codes and scoping out that O2 sensor.
Btw, I really appreciate the responses Ive been getting thanks guys.
Next step will be to replace that one vacuum line, its like a 1/2" line, pretty big leak there.
After that try to run it again, maybe with a can of seafoam in it, and see if it gets any better. If not. Then on to the engine codes and scoping out that O2 sensor.
Btw, I really appreciate the responses Ive been getting thanks guys.