Oxygen Sensor

Huw Powell audi at humanspeakers.com
Fri May 29 12:15:28 PDT 2015


Regarding the pump, I believe the SQ used EFI - it had a completely 
different fueling system than your car does.  It is my understanding 
that the CIS fuel pumps operate at about 90 PSI, perhaps more.  Your 
pump appears to operate more in the 30-60 PSI range typical of EFI 
systems, and also recommends an in-tank pre-pump.

It's the wrong pump for your car.

Your temperatures are fine.  The fan comes on, lowers the coolant 
temperature, then turns off.  It's working.  Yes, the engine etc. get 
very hot when they are running.    These are "hot running" little 
engines that routinely burn all the OEM paint off the cam cover. Have 
you measured the actual temps?  IR thermometers are really cheap these 
days (I got one at HF for about $20).

When the engine is running, the IM is usually moderately cool, due to 
fresh air running through it.  When you then turn the engine off (and 
sometimes just sitting at idle), the cool air ceases and the IM rapidly 
absorbs a lot of heat from the head, making it too hot to lean your hand on.

You are making too many incorrect guesses in terms of how your car works 
and what may be wrong and how to fix it.  You need to slow down and fix 
things one at a time and properly (this means your power windows simply 
do not matter yet).

Is the fuel pump now powered correctly by the fuel pump relay and 
associated circuitry?

Oh, and don't let that mechanic who ran your fuel pump off another 
circuit instead of a dedicated fused, switched wire (a common affordable 
fix on old EFI/CIS cars) touch your car's wiring again.

All the best,

Huw

On 5/29/2015 2:46 PM, David Vanden wrote:
> I hope this new pump will work.  It is a performance pump.  It is the
> Bosch Motorsport 044.  I really wanted to try it.  I think ECS tuning
> had it listed as compatible with the Quattro Sport of the same year,
> which is what made me think it was viable and want to try it.
>
> While the temperature gauge is within acceptable limits, like somewhere
> around the middle, the cooling fan comes on too frequently. Also If you
> feel the top of the radiator, engine, and intake manifold they are all
> really hot.  Then today after I reset the throttle position set screw
> (the one you aren't supposed to adjust) back to its original setting out
> of fear that might be the problem, for the short time the engine was on
> only the top of the radiator got hot.  The engine and the intake
> manifold were not at all hot.  Yet, when I came back some minutes
> later all three were very hot.  I am wondering if the hot water from the
> radiator is sending water back into the engine after the car is shut
> off, and then that in turn  is creating heated air in the intake
> manifold.  This may sound like a ridiculous hypothesis but it is the
> only one I could come up with.
>
> Anyway, seems like the radiator isn't cooling properly. I hope it is in
> o.k. shape, but it is very old. It has been in there since I had the car
> which was 2000 and who knows how long before that. But I am probably
> going to try liquid moly radiator flush or just straight citric acid.to
> <http://acid.to/> clean things out.  I will read your web page.
>
> Also, the old fuel pump just broke.  First it was staying on all the
> time and then it stopped pumping fuel.  I think it broke because the
> mechanic had jumped the rear window defogger circuit to the fuel system
> circuit when the latter circuit stopped working.  So when my power
> windows started having problems I guess they were on a related circuit
> to the rear window defroster and perhaps that is what made the original
> pump fail.  That is all I can conclude.  Anyway, I have restored power
> to the original fuel system circuit, so that should not be a problem.
>
> David
>
> On Fri, May 29, 2015 at 1:47 PM, Huw Powell <audi at humanspeakers.com
> <mailto:audi at humanspeakers.com>> wrote:
>
>     David,
>
>     1. Why do you think the engine is running hot?  What tests did you
>     perform and what were the results?
>
>     2. When at idle the ISV rapidly opens and closes, with the duty
>     cycle of this process determining the amount of air it lets into the
>     engine.
>
>     Read my web site.
>
>     3. Now you finally tell us you put the wrong fuel pump in your car.
>
>     EFI and CIS have very different fuel pressure/flow rate requirements.
>
>     What was the original problem that led you to replace the pump?
>
>     - Huw
>
>     On 5/28/2015 9:23 AM, David Vanden wrote:
>
>         How much do you want for the O2 sensors?  Are they Bosch?  What
>         type of
>         connections do they have?  Mine is three wire with the two
>         connections.
>
>         I have it idling down to about 950 rpm's which isn't bad.  While the
>         temperature sensor reads within acceptable limits it seems like the
>         engine is running a little hot.  I did some tests and I think the
>         thermostat is stuck, so that is the next thing to fix.
>
>         I think the idle stabilization valve is working.  It is
>         definitely doing
>         something.  When I hook it up  and look at it with it getting
>         juice it
>         buzzes and stays in one position then opens for a second and
>         immediately
>         closes again.  I think it must function differently when hooked
>         up to
>         the air intake.  Does anyone know otherwise?
>
>         I have a confession. Part of the reason it has started running a
>         little
>         differently is because I installed the Bosch Motorsport 044 fuel
>         pump.
>         However, that is causing other problems to be revealed so
>         perhaps it is
>         just as well.  Once those ideosyncrasies are  fixed  I hope I
>         can keep
>         running it on that fuel pump after all the effort I put into
>         installing
>         it.  My God is it noisy though. For about 55 dollars I can try
>         to guiet
>         it down some by installing Silicone Silencer Cradle Kit for
>         Bosch 044
>         Racing Fuel Pump.  Has anyone ever tried using one of these?  If so,
>         what did you think?
>
>         Thanks for all the help*.*
>
>         David
>
>         On Thu, May 28, 2015 at 12:22 AM, <dgraber460 at aol.com
>         <mailto:dgraber460 at aol.com>
>         <mailto:dgraber460 at aol.com <mailto:dgraber460 at aol.com>>> wrote:
>
>              I haven't been following every post or detail, to this
>         point, but
>              from the scanning I have done, I am flashing back to my days of
>              fighting the idiosynkracies of my stock CIS URQ. I was helped
>              incredibly by a few experienced listers, who had tread
>         these paths
>              before me. There are too many to name them all, but the
>         late Phil
>              Payne, and Huw Powell, talked me off many a ledge.
>              What I remember quite clearly is Phil's sage advice that when
>              it comes to getting a CIS car to a decent base point there
>         are 3
>              main issues to get sorted. They are in order of importance;
>              1. fuel pressure
>              2. fuel pressure
>              3. fuel pressure
>              If that isn't sorted, all other specs are chased in vain.
>              If you want to swap O2 sensors, I can send you a couple.
>              Dennis
>              Denver
>              -----Original Message-----
>              From: David Vanden <dvanden46 at gmail.com
>         <mailto:dvanden46 at gmail.com> <mailto:dvanden46 at gmail.com
>         <mailto:dvanden46 at gmail.com>>>
>              To: audi <audi at humanspeakers.com
>         <mailto:audi at humanspeakers.com> <mailto:audi at humanspeakers.com
>         <mailto:audi at humanspeakers.com>>>
>              Cc: quattro <quattro at audifans.com
>         <mailto:quattro at audifans.com> <mailto:quattro at audifans.com
>         <mailto:quattro at audifans.com>>>
>              Sent: Wed, May 27, 2015 11:07 am
>              Subject: Re: Oxygen Sensor
>
>              Yes, now I feel stupid I was measuring milliohms and not
>         ohms. When
>              I measure it in ohms it reads infinity. Another question.
>         How can
>              you tell if the Idle stabilization valve is working? On
>         Wed, May 27,
>              2015 at 11:19 AM, Huw Powell <audi at humanspeakers.com
>         <mailto:audi at humanspeakers.com>
>              <mailto:audi at humanspeakers.com
>         <mailto:audi at humanspeakers.com>>> wrote: > Ah, I see, you have an
>
>              auto-ranging meter, silly me. I still use the > Micronta I
>         got in
>              the 80s, which I set to 300 ohms when testing continuity, >
>         so of
>              course it goes off-range when "open". > > Yours selects an
>              appropriate range. What you are getting is "close enough > to
>              infinite" I am sure. You're measuring the resistance of the
>         path >
>              through any dirt, insulation, and the air and nothing else.
>          > > And
>              good catch, you need that idle switch to actuate before >
>              troubleshooting the idle! Remember I said what a pain it is to
>              install > correctly "on the car". > > You might want to
>         read a lot
>              of this site and digest/bookmark whatever > seems useful,
>         especially
>              the middle drop-down on the left (1980-87 4000, > Coupe,
>         UrQ) since
>              there is a lot about your car there: > >
>         http://audi.humanspeakers.com/index.html > > I hope you also have
>              the Bentley repair manual by now. > > - Huw > > On
>         5/26/2015 10:33
>              PM, David Vanden wrote: > >> Well apparently the button on the
>              bottom wasn't getting pressed because >> the location of
>         the switch
>              must have slipped, so adjusting the location >> of the
>         bottom switch
>              tomorrow will be a good place to start. >> >> What was
>         weird was
>              after I pressed the bottom switch manually the >> readings
>         for both
>              sensors began reading infinity when not pressed. Just >>
>         before that
>              the top one was reading 20.82 mohms of resistance when not >>
>              pressed and the bottom one was reading approx. 3.82 mohms
>         when not
>               >> pressed. I will have to see what they read tomorrow. At
>         least I
>              know >> what I have to do with the bottom switch. Thanks
>         all. Good
>              Night. >> >> On Tue, May 26, 2015 at 9:39 PM, Huw Powell
>              <audi at humanspeakers.com <mailto:audi at humanspeakers.com>
>         <mailto:audi at humanspeakers.com <mailto:audi at humanspeakers.com>> >>
>              <mailto:audi at humanspeakers.com
>         <mailto:audi at humanspeakers.com> <mailto:audi at humanspeakers.com
>         <mailto:audi at humanspeakers.com>?>>>
>              wrote: >> >> What DO they read? >> >> Please give us
>         numbers when
>              you take measurements... >> >> You don't have to buy a smoke
>              machine! EVERY repair shop worth its >> salt will have one,
>         and they
>              are simple to set up. >> >> All they do is take very low air
>              pressure from a compressor line and >> heat up some special
>         oil to
>              make the smoke, IIRC. Pull a vacuum line >> and pump the
>         smoke into
>              it. >> >> On 5/26/2015 9:11 PM, David Vanden wrote: >> >>
>         Well I am
>              pretty sure I got them wired correctly. The only >>
>         problem, as >> I
>              mentioned is that they are not reading infinite when open.
>          >> >>
>              There has got to be a way to locate vacume leaks that does
>          >> not
>              require >> buying a smoke machine. However, if I did is there a
>              model that >> you >> recommend. They come in all shapes and
>         sizes
>              and prices on EBAY. >> Anyway, I will debate it more in the
>         morning.
>               >> >> David >> >> On Tue, May 26, 2015 at 8:17 PM, Huw
>         Powell >>
>              <audi at humanspeakers.com <mailto:audi at humanspeakers.com>
>         <mailto:audi at humanspeakers.com <mailto:audi at humanspeakers.com>>
>              <mailto:audi at humanspeakers.com
>         <mailto:audi at humanspeakers.com> <mailto:audi at humanspeakers.com
>         <mailto:audi at humanspeakers.com>?>> >>
>              <mailto:audi at humanspeakers.com
>         <mailto:audi at humanspeakers.com> <mailto:audi at humanspeakers.com
>         <mailto:audi at humanspeakers.com>?>
>              <mailto:audi at humanspeakers.com
>         <mailto:audi at humanspeakers.com> <mailto:audi at humanspeakers.com
>         <mailto:audi at humanspeakers.com>?>
>
>              >>>
>              >>
>              >>         wrote:
>              >>
>              >>              Well,
>              they are just switches.
>              >>
>              >>              When closed they should read zero or
>              as close as possible
>              >>              (definitely less than one ohm).  When open
>              your meter
>              >>         should just
>              >>              read off scale/infinite.
>              >>
>              >>
>              They won't "vary" anything, the idle switch tells the ECU
>              >>         to use
>              the
>              >>              ISV to maintain about 800 rpm (and kills
>         fuel if it is
>              >>
>              above ~1400
>              >>              rpm). The WOT switch tells the ECU to go
>         into open
>              loop with
>              >> a
>              >>              richer mixture for enhanced acceleration.
>              >>
>              >>
>              - Huw
>              >>
>              >>              I hope you got them wired correctly.
>              >>
>              >>
>              >>
>              I soldered a set of the throttle body switches I got.
>              >>
>              Unfortuneately,
>              >>                  they read they had some resistance as
>              opposed to being
>              >>         infinite
>              >>                  when the
>              >>
>              switches were not activated.  I don't know what
>              >>         happened to them
>              >>
>              in the
>              >>                  process of pairing and soldering them.
>         However,
>              they
>              >>         were both at a
>              >>                  perfect 0 when activated so I
>              used them.  I don't think
>              >>         they would
>              >>                  increase the
>              idle?
>              >>
>              >>                  This is a 1987 Audi 4000
>              Quattro.
>              >>
>              >>
>              >>
>              >>
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