Idle issue 85 Coupe GT

LBCoupeGT · 06-09-10, 03:00 AM

So I recently purchased the car and it has a problem holding idle. The previous owner said it had to do with the fuel injection system.

Today I changed the oil and also replaced the battery in my Coupe GT. I also added in some fuel injection cleaner crap to the gas tank for the hell of it

After that I disconnected the throttle cable and started the car. To my amazement it started right up and idles at 1k rpm no problem. The car was close to empty though (halfway on E), so I stopped it and went to the gas station (in my truck

). Got back, put in a gallon of gas, connected the throttle cable back up and started the car. It went right back to its issue of not holding idle. It would die after almost nothing and on top of that now the fuel gauge wasnt working.

Any ideas? Im at a loss here.

quattrostyle · 06-09-10, 07:15 AM

checked the ISV and cleaned it?

4v6 · 06-09-10, 07:21 AM

What engine do you have?

Cornholio · 06-09-10, 07:36 AM

Clean out and / or replace the small bore airhoses

Like so......

http://kvquattro.com/techdocs/breather.html

msh · 06-09-10, 04:58 PM

ISV control unit can be defective as well

saint001 · 06-09-10, 05:29 PM

it does sound like the isv same thing happened to me with my 80 after checking/borrowing the part with a friends car i ended up getting a second hand isv (quite expensive).cured the prob,if you no someone with the same engine as you just "borrow" their isv and see.obviously give it back to them though

LBCoupeGT · 06-09-10, 07:35 PM

Ok thanks guys. I will look into the ISV and see whats up with it. Today I am changing the fuel filter out so I'll look at the ISV next.

LBCoupeGT · 07-09-10, 07:14 PM

Changed the fuel filter yesterday and yes it's on correctly =P

Issues afterwards:

- a lot of fuel came out of the old filter.

- gas gauge still not working after.

- car won't start now. Just sits there turning. I can hear the whirrr of the fuel pump.

Sigh...looks like it's best to just take it into a shop.

mikes2 · 07-09-10, 08:12 PM

If the gauge isn't working, is it possibly out of fuel

LBCoupeGT · 07-09-10, 08:23 PM

I'd say a soda can worth of fuel came out of the filter, and I had started it 4 times. That occurred with 1-2 gallons in the tank. Seems like there should still be a reasonable amount in there but yeah I guess it wouldn't hurt throwing another 5 in there to see what happens.

07-09-10, 07:14 PM	#8
LBCoupeGT Grown up member Join Date: Aug 2010 Location: Long Beach, CA Posts: 35	Idle issue 85 Coupe GT Changed the fuel filter yesterday and yes it's on correctly =P Issues afterwards: - a lot of fuel came out of the old filter. - gas gauge still not working after. - car won't start now. Just sits there turning. I can hear the whirrr of the fuel pump. Sigh...looks like it's best to just take it into a shop.

07-09-10, 08:12 PM	#9
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	If the gauge isn't working, is it possibly out of fuel __________________ 1991 90 quattro 20v sport 1991 90 quattro

07-09-10, 08:23 PM	#10
LBCoupeGT Grown up member Join Date: Aug 2010 Location: Long Beach, CA Posts: 35	Idle issue 85 Coupe GT I'd say a soda can worth of fuel came out of the filter, and I had started it 4 times. That occurred with 1-2 gallons in the tank. Seems like there should still be a reasonable amount in there but yeah I guess it wouldn't hurt throwing another 5 in there to see what happens.

06-09-10, 07:15 AM	#2
quattrostyle 4 ring whore! Classic Audi Club Member Join Date: Feb 2010 Posts: 2,188	checked the ISV and cleaned it?

06-09-10, 07:21 AM	#3
4v6 Ex Member Classic Audi Club Member Join Date: Dec 2007 Posts: 5,565	What engine do you have?

06-09-10, 07:36 AM	#4
Cornholio Grown up member Join Date: Jul 2007 Posts: 555	Clean out and / or replace the small bore airhoses Like so...... http://kvquattro.com/techdocs/breather.html

06-09-10, 04:58 PM	#5
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	ISV control unit can be defective as well

06-09-10, 05:29 PM	#6
saint001 Grown up member Join Date: Aug 2009 Location: devon Posts: 237	it does sound like the isv same thing happened to me with my 80 after checking/borrowing the part with a friends car i ended up getting a second hand isv (quite expensive).cured the prob,if you no someone with the same engine as you just "borrow" their isv and see.obviously give it back to them though

06-09-10, 07:35 PM	#7
LBCoupeGT Grown up member Join Date: Aug 2010 Location: Long Beach, CA Posts: 35	Ok thanks guys. I will look into the ISV and see whats up with it. Today I am changing the fuel filter out so I'll look at the ISV next.