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Audi 90 2,3 20v engine problem

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 Post subject: Audi 90 2,3 20v engine problem
PostPosted: Thu Jun 11, 2020 11:42 am 
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I have an audi 90 2.3 20v quattro with an engine problem, i use the car for autocross so it has an external fuel tank and pump on it. the car idles poorly and fluctuates at 200 rpm. the idle speed controller is working and have replaced the labda sensor. the boegies are also New. but it doesn’t help. It is with cold and warm engine. The temp sensor is broken I think it is for the fan? Is this the problem?


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Fri Jun 12, 2020 8:30 am 
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The coolant temp sensor is one of the most important for fueling. If the sensor is for the temperature signal to the ecu then it could be your issue. If it is just the fan sensor for turning the fan on and off, then not the issue.

Does the fan cycle on and off normally if you let it get up to temperature?


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Fri Jun 12, 2020 9:36 am 
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"Idle Adjustment
Unofficial Idle Adjustment (may only work on pre-March '90 cars)
(Bernie Benz) This procedure sets the idle speed to minimize the effects of sudden engine braking when the throttle is slammed shut.

With engine at operating temperature, disconnect the ISV electrical connector.
Adjust the idle speed with the throttle valve air bypass adjustment screw to 700 to 750 RPM. (This is just below the speed at which the ECU computer will control idle.) This sets a minimum idle speed well above zero.
Reconnect the ISV elec. connector, and check the idle speed. The computer should control idle at 800 to 900 RPM. If it's faster, the ISV is not accurately following computer control, the sign of a sticky valve."

http://20v.org/engprob.htm#idleadj


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Fri Jun 12, 2020 9:38 am 
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There are 3 temp sensors.

One on back of head is the ECT for the ECU and fueling. (2 pins white)
One on the lower radiator is for the fan (3 pins)
One under the intake manifold is for your cluster gauge (3 or 4 pins brown)

You must tell us why and which sensor you think is broken.


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Fri Jun 12, 2020 9:38 am 
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https://www.audiworld.com/forums/attach ... rottl2.gif


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Sat Jun 13, 2020 7:46 am 
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20v90q wrote:
There are 3 temp sensors.

One on back of head is the ECT for the ECU and fueling. (2 pins white)
One on the lower radiator is for the fan (3 pins)
One under the intake manifold is for your cluster gauge (3 or 4 pins brown)

You must tell us why and which sensor you think is broken.


Image
Here you can see the broken sensor. I dont know which one it is. He has 2 pins
The sensor is broken down with replacing the engine. It is under the intake manifold. At the Cooland inlet.


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Sat Jun 13, 2020 8:49 am 
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What country are you in?


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Sat Jun 13, 2020 9:18 am 
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20v90q wrote:
What country are you in?


Netherlands why?

Is this sensor the fan sensor or the temp sensor for the ecu?


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Mon Jun 15, 2020 8:40 am 
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I have check the idle motor I have remove the connector when the engine was running idle and There was no hearable differents. Does it mean the motor is broken ? I have check or it get electriciti and He have.


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Wed Jun 17, 2020 9:36 am 
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Did you remove it with the engine warm or cold? You try adjusting the idle screw on the throttle body? What year is the car? It's either a Hitachi idle valve or Bosch. Very possible it's dead.


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Fri Jun 19, 2020 12:46 am 
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20v90q wrote:
Did you remove it with the engine warm or cold? You try adjusting the idle screw on the throttle body? What year is the car? It's either a Hitachi idle valve or Bosch. Very possible it's dead.


I have check with warm and cold engine. When I set the idle adjusting There is no problem with the rpm fluctuating. The car is from 1988. The idle valve is a bosch.


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Fri Jun 19, 2020 10:57 am 
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In the U.S. and Canada we only got the 20v from 1990-1991. Didn't know there was a 20v offered that early in the rest of the World. In the U.S. and Canada the early 1990 cars had a "bag of snails" header and Hitachi idle Valve. The 1991's got a Bosch idle valve. I heard if someone installed the Bosch idle valve it would blow out the idle controller in the ECU.

Can you please post a pic of your engine bay (1), A shot of the B pillar build date sticker (2) and the ECU part number (3)?

Thanks!


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Sat Jun 20, 2020 3:39 am 
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20v90q wrote:
In the U.S. and Canada we only got the 20v from 1990-1991. Didn't know there was a 20v offered that early in the rest of the World. In the U.S. and Canada the early 1990 cars had a "bag of snails" header and Hitachi idle Valve. The 1991's got a Bosch idle valve. I heard if someone installed the Bosch idle valve it would blow out the idle controller in the ECU.

Can you please post a pic of your engine bay (1), A shot of the B pillar build date sticker (2) and the ECU part number (3)?

Thanks!


Here the pictures, i Made a fault, its a hitachi valve Image
Image
Image
Image


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Mon Jun 22, 2020 12:35 pm 
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Thanks for the pics. Looks like a Hitachi idle valve then. What do you mean it has no problem idling cold or warm? What is the idle RPM now? Can you explain more what it's doing?

You check for large vacuum leaks? These things are real picky about those.


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Tue Jun 23, 2020 1:02 pm 
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20v90q wrote:
Thanks for the pics. Looks like a Hitachi idle valve then. What do you mean it has no problem idling cold or warm? What is the idle RPM now? Can you explain more what it's doing?

You check for large vacuum leaks? These things are real picky about those.


I mean it’s only with idle rpm not with driving. It runs about 700 rpm. I have remove the electric motor from the hitachi valve and test if it pushing when I start the engine but electric motor doesn’t push or do something. There are no leaks in the vacuum system. The adapter to the gastank is capped. Only the carter breather is not connected but the hole inside the intake pipe is closed. Can this give problems if the cartersmoke come not back in the intake?


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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Tue Jun 23, 2020 9:47 pm 
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Mikemul wrote:
20v90q wrote:
Thanks for the pics. Looks like a Hitachi idle valve then. What do you mean it has no problem idling cold or warm? What is the idle RPM now? Can you explain more what it's doing?

You check for large vacuum leaks? These things are real picky about those.


I mean it’s only with idle rpm not with driving. It runs about 700 rpm. I have remove the electric motor from the hitachi valve and test if it pushing when I start the engine but electric motor doesn’t push or do something. There are no leaks in the vacuum system. The adapter to the gastank is capped. Only the carter breather is not connected but the hole inside the intake pipe is closed. Can this give problems if the cartersmoke come not back in the intake?


Obviously, you cant just plug it.
Its called positive crankcase ventilation for a reason, the fumes/pressure has to go somewhere

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 Post subject: Re: Audi 90 2,3 20v engine problem
PostPosted: Fri Jun 26, 2020 10:19 am 
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varia wrote:
Mikemul wrote:
20v90q wrote:
Thanks for the pics. Looks like a Hitachi idle valve then. What do you mean it has no problem idling cold or warm? What is the idle RPM now? Can you explain more what it's doing?

You check for large vacuum leaks? These things are real picky about those.


I mean it’s only with idle rpm not with driving. It runs about 700 rpm. I have remove the electric motor from the hitachi valve and test if it pushing when I start the engine but electric motor doesn’t push or do something. There are no leaks in the vacuum system. The adapter to the gastank is capped. Only the carter breather is not connected but the hole inside the intake pipe is closed. Can this give problems if the cartersmoke come not back in the intake?


Obviously, you cant just plug it.
Its called positive crankcase ventilation for a reason, the fumes/pressure has to go somewhere


The crankcase ventilation is not closed only it is not connected to the air intake. The smoke going to the hood


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