1990 Audi CQ Running Rich
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AudiWorld Newcomer
Joined: Aug 2011
Posts: 9
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From: Central valley, California
1990 Audi CQ Running Rich
Hi, I'm new to this forum. I have a 1990 CQ and I have been experiencing problems. I have a code 2341.
The car was running great, then one day it went into limp-mode. Found out the fuel pressure supply line was leaking, so I fixed it. The car started running awful, so I did a tuneup, replaced the cap and rotor, all new spark plugs, and a new bosch fuel filter. Still had an issue, so I traced it to a bad fuel injector. Next I replaced all the injectors with the 034 motorsports fuel injector upgrade. Following that I still had a CEL.
So now, I am stuck. I still get a 2341 code (translated to 02 sensor control limit exceeded). I experience slightly longer starting time, somewhat fuel odor, and limp-home mode. The fuel pressure gauge I installed recently shows a residual 40psi which eventually drops to zero. At idle the pressure is 43-44 with vacuum, and without vacuum the pressure goes at most 54-55psi.
Does anyone have any ideas? I am automotive graduate, but brand new to Audi, let alone the rare 90' CQ.
The car was running great, then one day it went into limp-mode. Found out the fuel pressure supply line was leaking, so I fixed it. The car started running awful, so I did a tuneup, replaced the cap and rotor, all new spark plugs, and a new bosch fuel filter. Still had an issue, so I traced it to a bad fuel injector. Next I replaced all the injectors with the 034 motorsports fuel injector upgrade. Following that I still had a CEL.
So now, I am stuck. I still get a 2341 code (translated to 02 sensor control limit exceeded). I experience slightly longer starting time, somewhat fuel odor, and limp-home mode. The fuel pressure gauge I installed recently shows a residual 40psi which eventually drops to zero. At idle the pressure is 43-44 with vacuum, and without vacuum the pressure goes at most 54-55psi.
Does anyone have any ideas? I am automotive graduate, but brand new to Audi, let alone the rare 90' CQ.
AudiWorld Member
Joined: May 2011
Posts: 218
Likes: 0
1990 audi CQ code 2341
Hi, I'm new to this forum. I have a 1990 CQ and I have been experiencing problems. I have a code 2341.
The car was running great, then one day it went into limp-mode. Found out the fuel pressure supply line was leaking, so I fixed it. The car started running awful, so I did a tuneup, replaced the cap and rotor, all new spark plugs, and a new bosch fuel filter. Still had an issue, so I traced it to a bad fuel injector. Next I replaced all the injectors with the 034 motorsports fuel injector upgrade. Following that I still had a CEL.
So now, I am stuck. I still get a 2341 code (translated to 02 sensor control limit exceeded). I experience slightly longer starting time, somewhat fuel odor, and limp-home mode. The fuel pressure gauge I installed recently shows a residual 40psi which eventually drops to zero. At idle the pressure is 43-44 with vacuum, and without vacuum the pressure goes at most 54-55psi.
Does anyone have any ideas? I am automotive graduate, but brand new to Audi, let alone the rare 90' CQ.
The car was running great, then one day it went into limp-mode. Found out the fuel pressure supply line was leaking, so I fixed it. The car started running awful, so I did a tuneup, replaced the cap and rotor, all new spark plugs, and a new bosch fuel filter. Still had an issue, so I traced it to a bad fuel injector. Next I replaced all the injectors with the 034 motorsports fuel injector upgrade. Following that I still had a CEL.
So now, I am stuck. I still get a 2341 code (translated to 02 sensor control limit exceeded). I experience slightly longer starting time, somewhat fuel odor, and limp-home mode. The fuel pressure gauge I installed recently shows a residual 40psi which eventually drops to zero. At idle the pressure is 43-44 with vacuum, and without vacuum the pressure goes at most 54-55psi.
Does anyone have any ideas? I am automotive graduate, but brand new to Audi, let alone the rare 90' CQ.
Thread Starter
AudiWorld Newcomer
Joined: Aug 2011
Posts: 9
Likes: 0
From: Central valley, California
I haven't narrowed the problem further, although I am burning rich, oil smells like rich mixture. I did replace the rear coolant sensor on the firewall side of the motor, and that helped much, but the problem persists.
AudiWorld Member
Joined: Feb 2012
Posts: 125
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From: Ashland Oregon
When I first got my 90quattro 20v I had very long crank times and power issues. The Audi tech diagnosed it as a bad fuel pressure regulator, which was causing a mixture so rich it destroyed the O2 sensor. I had to source the part from a 200. I can provide the PN if it sounds like something you'll need.
AudiWorld Member
Joined: May 2011
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Probably, you have to look the operation of 02 sensor when you could start engine, Here is how to probe the 02 and hook up either teat wire of DVM to 02 wiring to( insert wire between or connection on 02 wiring = Green and black wire) and other test wire of DVM goes to chassis ground with setting DC Volt scale. You will see the voltage and should see 0.2 ~ 0,8V fluctuated with idling even engine raised high RPM. if you see the voltage that I listed, furl mixture is OK. Out of CO adjustment makes hard to start too. x19
AudiWorld Junior Member
Joined: Nov 2016
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Sorry for bring back a dead post but how did it work? I am have the same issue as you had and need to do the same I believe. The stock regulator is ridiculously hard to find for a reasonable price and not 700 to 800 dollars. I can get a 200 reg for 75 to 80 bucks so if it will do I will try it or use one from an NG I have here and the smaller fitting not needed for the 7A
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