Vurtrue

I have a 1990 Audi 80 2.0 4cly AT sedan. I have had the MAF sensor replace along with the fuel distrib and a few injectors (with used parts) This fixed the problem I was having with the car not running at all. Also replaced fuel pump and filter (new parts). But now I am having the problem of really rough starts, takes me a few times to get it started (it did this b4 the fuel pump and filter was replaced.) When I do get it started it idles rough. It goes from 900-1k rpm to 2k, down to 500rpm or lower almost cutting off making the engine shutters badly. It does this for about a min. till it mellows out at a stable 900-1k rpm. If I cut the car off it will usally start up again np. But if the car sits for a while, its the same thing all over again.
I tried cleaning the Idle Stabilization valve a while back b4 the MAF sensor was replaced and that didn't do anything. What can this be? I'm really starting to hate this car. I paid $2k US for the car and I already put like $3k into it
Please help, I don't have much hair left!

Thanx
Vurt

repeater

Your 8v IS idleing badly enough to need attention, but understand that all 4yls really suffer from idle problems regardless. I just replaced my 02 sensor for the first time and it did make a slight difference, but not much. Pull you ISV and shake it, you should hear something inside rattling back and forth, slightly, if you dont, try standing it up on end and leave it overnight with some WD40 in it. Check for vacuum leaks too as they are prone to that as well. Other than that, I can't think of much else. You could try to advance the timing just a smidge and see if the higher idle helps clean it up a bit - but my guess is something's going on with the ISV or a vacuum problem. LATERS!

Audithority

we have plugs to replace, plug wires, clean the air filter, maybe run some fuel injec cleaner in it, ummm... im not really sure none of this will probably help that much though my car idels a tad rough im trying to fix it as well

repeater

MAF sensor? On a CIS 8v?

88audi90_Q

maybe cold start valve?

Vurtrue

Don't want to sound dumb, but what is a 8v?
But if your talking about the type of car I have, it is a 1990 Audi 80 4door sedan with a 4cyl 2.0 engine. The engine only takes up about half the space a normal car would take up and sits more on the left side (passenger side).
I got it at an auction, who knows what freaky stuff someone did to this car b4 I got it. The engine could have been from a diff car, who knows. I got as lot of things fixed. Belive it or not, when I first started this car at the auctions, it started without any troubles. Wasn't till I had this replaced and fixed that it got worse. But this things were old and going bad or were bad. I will try and get a picture of it some time.
As for the cold start valve. Can that still cause problems even when it is like 80 degrees outside? I thought that was really onle for winter when it is really cold.
Thanx for the post!

Vurt

88audi90_Q

and bcuz ur car is 4 cyl, 4 x 2 = 8 , well done u just passed todays math lesson :-P

repeater

Yeah, Vurtrue I generally refer to all VAG 4cyls. is either 8v, 16, 20. Depending on what. Cold start valve is probably not the issue if you are still having problems in heat. If you let it run for about five minutes and then shut it off and re-start, do you go through the same issues? Might want to check residual fuel pressure and make sure you're not loosing pressure when it sits. This would happen via a fuel line leak near the rear of the car before the filter / pump area (sometimes small leak), leaking back through the pumps check valve, or possibly injectors/CSV. If you can get your hands on a nice MAC fuel pressure tester, you can hook it up to the banjo bolt going into the the potentiameter, start the car and run, then shut off and monitor the pressure over the next few hours. See how much it drops. ALso, next time you go to start the car, turn the key on and off a few times and then try to start - see if it's any easier.

I asked about the MAF because you said you changed it. Unless somethings amiss, you shouldn't have a MAF sensor on that car!

Vurtrue

The thing that I call a MAF sensor is a all in one unit. it sits on top of my air box and has the fuel distributor bolted on top of it. If you took off that hard black thing that connects the MAF sensor to the stabilization vavle you would see this thing that looks like a bowl which has a plate in the middle that move up and down I think this is the potentiomter(sp) The sensor is what is at the end of the arm that holds the plate.
Am I right? Is that the Mass Air Flow sensor?

Vurt

repeater

It's different in the sense of a MAF sensor, the potentiameter is electrical, but also mechanical in the sense of the airflow metering plate moving up and down, determining the amount of fuel going into the engine. A MAF sensor takes the place of the whole unit - minus the fuel distribution. Bosch FI is really amazing, considering it withstood the test of time in various forms (including CIS) from 1973 on through 1991.