non-fluxuating DPR current (was: CIS-E brain damaged?)

[amalventano1@comcast.net (Allyn)]

Toby,
    Good testing, but did you check the compression...
Im serious on this, i had the exact same symptoms (not all the electrical tests, but the end effect)
on a car due to bad/going rings. Did it do it all of the sudden or has it worked its way up to this
level of non-revness???
Al

----- Original Message -----
From: "T. Reed" <treed2@u.washington.edu>
To: <scirocco-l@scirocco.org>
Sent: Sunday, March 24, 2002 8:11 PM
Subject: non-fluxuating DPR current (was: CIS-E brain damaged?)


> Well, I did all the Bentley electrical tests yesterday and here were my
> results:
>
> 87 16v Scirocco:
>
> After-start enrichment OK
> DPR current - measured: started at 158 mA then slowly decreased
>       spec: more than 120 mA for 30 to 60 seconds
> Cold-running enrichment OK
> DPR current - measured: 90 mA
>       spec: 80 to 100 mA
> Coolant temperature sensor OK
> Resistance - measured: 2060 ohms
>      spec: 1500-3000 ohms (68 F - 86 F)
> Cold acceleration enrichment OK
> DPR current - measured: brief 150 mA spike
>       spec: briefly exceed 80 - 100 mA
> Air flow sensor plate potentiometer OK
> Resistance - measured: between 2 and 3 at rest: 4640 ohms
>        between 1 and 2 at rest: 863 ohms
>        between 1 and 2 while lifting:
>         * I skipped this test because I had
>   already put the intake boot back on and
>   I did this test about 6 months ago and
>   it tested out fine
>      spec: between 2 and 3 at rest: greater than 4000 ohms
>    between 1 and 2 at rest: less than 1000 ohms
>    between 1 and 2 while lifting: should steadily
>   increase to approx. 4000 ohms
> Full-throttle enrichment --
> DPR current - measured: * I skipped this test because with the
>   coolant temperature sensor disconnected
>   I was unable to raise the engine speed
>   above idle to the necessary 2500 rpm
>       spec: approx. 16 mA
> Deceleration fuel shutoff --
> DPR current - measured: * I skipped this test because with the
>   coolant temperature sensor bridged I
>   was unable to raise the engine speed
>   above idle to the necessary 3000 rpm
>       spec: briefly change to approx. -45 mA then return
>           to a positive value
>
> CIS-E electrical tests:
> Terminals Spec Measured
> ========= ==== ========
> 1 and 2 (ignition on) 12V 12V OK
> 1 and 2 (starter on) > 8V 10.3V OK
> 2 and 24 (starter on) > 8V 10.2V OK
> 10 and 12 17-22 ohms 18.7 ohms OK
> 17 and 18 (afp at rest) > 4000 ohms 4636 ohms OK
> 14 and 17 (afp at rest) < 1000 ohms 860 ohms OK
> 14 and 17 (afp lifted) > 4000 ohms (skipped, see above) --
> 2 and 21 1500-3000 ohms 1600 ohms ** OK
> 2 and 8 (o2 wire @ gnd) continuity continuity OK
> 2 and 8 (o2 wire @ blk) no continuity (skipped, see note 1) --
> 2 and 15 continuity continuity OK
> 2 and 7 continuity continuity OK
> 2 and 9 continuity (skipped, see note 2) --
> 2 and 3 (ignition on) 12V 12V OK
> 2 and 4 (ignition on) 12V 12V OK
> 2 and 5 (ign on, WOT) 12V 12V OK
> 2 and 13 (ignition on) 12V 12V OK
> 2 and 25 (starter on) LED flickers LED flickers OK
> 2 and 6 (ignition on) 12V 0V FAIL
> 2 and 16 (ignition on) 12V 12V OK
> 2 and 19 (ign + a/c on) 12V 12V OK
> 2 and 20 continuity continuity OK
>
> ** = the engine had warmed up a bit since the coolant temp
>      sensor was last measured so the resistance dropped
>
> Note 1: the test between terminals 2 and 8 was skipped because the test
>         conditions reading "green oxygen sensor wire connected to black
>         wire" are pretty vague about which black wire to connect to and I
>         wasn't sure what they meant.
>
> Note 2: this test was skipped because on trying to test between terminals
> 2 and 9 I discovered that there was no terminal 9 (or at least no
> metal crimp inserted in the spot for terminal 9). It looks like
> its been missing from the factory - its function is listed as
> "Ground connection to intake manifold (manual transmission only)"
> but I have a 5 speed and it's a 16v so it has to be a stock 5
> speed (no 16v autos)! Weird, eh?
>
> The test between terminals 2 and 6 that failed was for "Voltage signal
> from air conditioning system". While it seems highly unlikely, could this
> have anything to do with my problem (ie. compensating for extra load of
> a/c compressor when its not there)? My A/C doesn't work (it has lost its
> R-12 charge) and when I turn on a/c or defrost with the blower running
> when the car is warmed up my idle will rise to 1800 or 2000.
>
>
> So that's that. My dpr current sits at 9.95 mA and the car refuses to come
> off idle when cold. I've replaced my plastic fuel injector inserts and
> all 3 o-rings on each injector. I've tested the cold start valve and it
> sprays a nice mist of fuel. I replaced the thermo-time switch. Pulling any
> one of the four spark plug wires when the engine is running (and cold)
> causes the engine to stumble until it is re-installed (ie. all cylinders
> are getting spark). The plug wires, distributor, cap, rotor and plugs are
> all relatively new. I've pulled apart my coil and cleaned off all the
> corrosion I could get to on it. I have a ground wire run from my battery
> directly to the coil mounting bracket and from there to the stud at the
> back of the intake manifold. My battery terminals are shiny as a mirror.
> I've cleaned out the idle stabilizer with carb cleaner and it buzzes
> smoothly when the ignition is on (about 3 seconds on, 1 second off, 3
> seconds on.. etc). Its resistance checked out last time I measured it. I
> have a relatively new fuel filter, air filter and I've replaced all my
> vacuum hose with new german cloth-braided rubber hoses.
>
> Which brings me to another question - my air flow sensor plate.
>
> When I checked it 2 days ago, it was smooth as butter. Pinching the center
> bolt between my thumb and forefinger I could lift it up and down without
> the need for a death grip on the bolt.
>
> Yesterday when I did these electrical tests I tried lifting it just for
> kicks. I couldn't get a strong enough hold on the center bolt - it just
> slipped out of my fingers without budging. My magnetic tool wouldn't lift
> it either.
>
> So I'm thinking something is different between these two circumstances.
> I've already cleaned and lubricated the pivot point once (last summer)
> because it was excessively 'resistive'. Does the plunger in the fuel
> distributor become more difficult to push when the fuel pressure is
> different? Maybe that has something to do with it - although I thought
> that a constant pressure was maintained there.
>
> It seems to me that given the symptoms (unable to raise engine above
> idle.. it seems to stumble a bit if I open the throttle completely) might
> point to the air flow plate or something connecting to it binding and
> preventing additional fuel from being thrown in to the mix because of the
> acceleration. More air might sneak past the edge of the plate at its rest
> position because of the wide open throttle butterfly valves but no
> additional fuel with it to keep the engine at stoich, thus causing the
> slight rpm drop upon stepping on the throttle.
>
> What doesn't make sense is why the problem would usually go away (the
> intensity of this symptom goes away at least by 50%) when the car warms
> up. There is still a noticable sluggishness off idle - and it seems like
> above a certain rpm there is a sudden woosh of power - not an on and off
> difference but definately not a smooth curve either.
>
> Also could there be any link between the constant dpr current and a
> constant air flow plate? I wouldn't think so.. unless the dpr current was
> constant because it was sitting at the relative maximum allowed by the
> computer for compensating for the air flow plate.
>
> Thanks for any insight or ideas..
>
> -Toby
>
> --
> '87 16v
>
>
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