[urq] Intake Air Sensor '83 UrQ - substitute?

[Ben Swann]

Steve/all,

The specific problem the engine is having and has had since I got the car running:

1. Engine starts usually at the turn of the key when cold, but then immediately sputters and dies - this hapens regardsless of outside temp.  After 2-3 times engine starts and runs at slow RPM first then gradually increases speed.  Attempts to give throttle during this approx. 1 min initial running result in stalling often accompanied by backfire like pop.  Once engine is running and can rev engine fine and drive - engine runs fairly well except...

2.  mid/part throttle lag during acceleration - not extremly pronounced, but evident then engine goes quite nicely and develops 1.8 bar or so.  At full throttle, a bit of lag present - suspect lean condition.   Had a full throttle cutout problem, until fuel pump relayed and jumpered on with ignition.  The cutout resembled overboost cutout, but no leaks in the system - this I am quite sure of.  I had readi somewhere ( in the aforementioned service guide/elsewhere?) that the sensor could be contributing to cause of this set of symptoms, particularly the cutout.

I have not done much troubleshooting except to find and fix obvious.  No fuel pressure testing has been done.  Injector seals may need replacement, as I don't recall replacing them or injectors.  New fuel pump was installed and system completely flushed when I got the car - initial problems basically old bad gas and blocked return line.  CIS airflow plate is adjusted fine and free moving and throttlebody clean and vacuum lines replaced throughout.  Ignintion stuff is good too.  I have been avoiding getting it thoroughly sorted, as am presently building another engine with EFI for the car and just not worth getting this motor completely sorted because it runs fairly well for now - I have put significant mileage on the car with no major problems, but it can be better.  Engine idles beautifully after a minute or so and despite my complaints is a fairly fast car.

I do suspect the WUR/CPR to be out of spec. but suspicious of the intake sensor  and was checking on availability of this part  - not dumping in a lot of money when I suspect there is an inexpensive replacement even if it is not and OEM part.   I can certainly test the resistance of this.     If the fix is over $40 then I live with it, cause the engine is coming out sooner or later which will be sooner if I don't start dealving into getting this engine perfect, as that would be best done out of the car and on a stand even, if I weren't planning on replacing it. 

Ben

p.s. Is the WUR/CPR from the '83/'84 GT Coupe CIS engines the same?

[Date: Thu, 3 Mar 2005 10:40:11 -0800
From: "Buchholz, Steven" <Steven.Buchholz at kla-tencor.com>
Subject: RE: [urq] Intake Air Sensor '83 UrQ - substitute?
To: <urq at audifans.com>
Message-ID:
<BD316B4584174147B080289F69FC76160166E98C at CA1EXCLV03.adcorp.kla-tencor.com>

Content-Type: text/plain; charset="us-ascii"

No, the parts from the newer cars have a different resistance curve ...
Audi learned the problems with having such a low valued resistor and
raised the value in the MC.  

The thing is that all of the resistance in the connectors can add up to
impact what the ECU reads ... there should only be the one unsoldered
connection at the ECU ... all other wiring should be hard wired to
eliminate the contact resistance issue.  

I don't know what the problem you are experiencing is, and what other
troubleshooting has been done (there are other things that can create
the situation you describe) ... but if you do have an intermittent
problem and you've done everything else, it might be worthwhile to
simply try replacing the resistor ... they can develop cracks and such
from the heating and cooling over time which can lead to difficult to
find problems ...

.... after writing all of this I realized that there are lots of folks
who have swapped out the WX engine in their cars ... it seems to me that
there may well be folks on the list who have resistors they could
provide to you ...

Steve B
San Jose, CA (USA)
> 
> I'd like to replace the intake air temp sensor on my '83 UrQ 
> to see if a cold starting/warmup problem is resolved along 
> with a full throttle hesitation problem.    Dealer cost make 
> this prohibatively expensive.  Is there a substitute for 
> this, eg. can solder in the component - what is it?   Can one 
> from an '86-88 5000 turbo quattro be made to work?
> 
> Perhaps someone has one they don't need.]