engine won't rev over 2000 RPM (thanks)

Zsolt zed123 at telusplanet.net
Wed Feb 6 23:33:14 EST 2002 

Hi Blu,

Thanks for the tip. Martin has already suggested the cat and we were
thinking about the same thing here at home as well, I just haven't had
the time to check it out yet. I will definitely give it a try.

Thanks again,
   Zsolt

bludodger at att.net wrote:

> Had a similar problem (except my rev limit was 2500).
> With the help of the list, I was able to attribute it to
> a clogged cat. See if banging the cat makes a noise
> or "resets" the problem. That was how I was able to make
> sure it was the cat that was giving me problems.
> Basically, I drove around the block...when it acted up I
> took my hammer out climbed underneath and hit the cat.
> When the car was brought back up to speed the problem
> wasn't there (until a hard acceleration forced the
> broken cat. piece back to clogging the pipe).
>
> Good Luck
> --
> Blu
> '88 80q--178,000mi.
>
>>Hi Bob,
>>
>>We have already been there. The car has a new idle switch. I also forgot
>>  the possibility of the
>>
>>- cat itself could be plugged.
>>
>>Bob wrote:
>>
>>
>>>Try disconnecting your idle switch, if its shorted, this is what you would
>>>
>>see.
>>
>>>Bob
>>>
>>>Zsolt wrote:
>>>
>>>
>>>
>>>>*This message was transferred with a trial version of CommuniGate(tm) Pro*
>>>>Hi Martin,
>>>>
>>>>It is no coincidence. It makes it up to 2000 load or no load, but
>>>>sometimes even before it gets there it starts bucking. I can set the
>>>>cruise at 2000 though and sail quite smoothly with only occasional
>>>>jerking. If I step on the gas however, it looses all power, it does not
>>>>stall, but it kills all power. Weird!
>>>>
>>>>So far I was told it could be
>>>>
>>>>- oxygen sensor
>>>>- mass air flow sensor (MAF)
>>>>- fuel filter/plugged fuel line
>>>>- fuel pump
>>>>- wiring connections
>>>>- speed sending unit/missing teeth on flywheel
>>>>
>>>>Zsolt
>>>>
>>>>Martin Pajak wrote:
>>>>
>>>>
>>>>
>>>>>Don't know, coincidence?
>>>>>If the speed sensor was faulty most likely the engine would not even start.
>>>>>If it fails at high rpm possibly wiring or mounting.  However does it
>>>>>consistently fail at 2000 rpm?
>>>>>Does not make much sense, than again it's an Audi ;o)
>>>>>
>>>>>Hope this helps.
>>>>>
>>>>>Cheers
>>>>>Martin
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>-----Original Message-----
>>>>>>From: Zsolt [mailto:zed123 at telusplanet.net]
>>>>>>Sent: February 5, 2002 10:47 PM
>>>>>>To: Martin Pajak
>>>>>>Subject: Re: engine won't rev over 2000 RPM (thanks)
>>>>>>
>>>>>>
>>>>>>Thanks Martin. That's an interesting one. But why would it cause to give
>>>>>>me a speed sensor error?
>>>>>>
>>>>>>Zsolt
>>>>>>
>>>>>>Martin Pajak wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>Try your catalytic.
>>>>>>>If it's pluged it would prevent the engine from reving up.
>>>>>>>I used to work at a place that had a Ford Ranger in.
>>>>>>>The thing would not rev past 2500rpm.
>>>>>>>Any attempt would see it rev-limited.
>>>>>>>After half an hour of floorin' someone smeled burning.
>>>>>>>It was the exhaust before the cat, cherry red hot.
>>>>>>>Very impressive.
>>>>>>>
>>>>>>>Onece a cat goes, it cloggs pretty quickly.
>>>>>>>
>>>>>>>Cheers
>>>>>>>Martin Pajak
>>>>>>>
>>>>>>>http://www.quattro.ca
>>>>>>>
>>>>>>>1983 Audi Ur-quattro (265,000 km) Winter car
>>>>>>>1985 Audi Ur-quattro (141,000 km) Euro spec. import ;o)
>>>>>>>1986 Audi 4000 S Quattro (442,000 km) with 5 bolt pattern RIP
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>-----Original Message-----
>>>>>>>>From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com]On
>>>>>>>>Behalf Of Zsolt
>>>>>>>>Sent: February 5, 2002 9:47 PM
>>>>>>>>To: quattro at audifans.com
>>>>>>>>Cc: V8
>>>>>>>>Subject: engine won't rev over 2000 RPM (thanks)
>>>>>>>>
>>>>>>>>
>>>>>>>>Thanks for all your responses.
>>>>>>>>
>>>>>>>>We haven't done anything yet, I wanted to see the responses first in
>>>>>>>>case somebody had to deal with a similar problem. I hope we can sort it
>>>>>>>>out soon.
>>>>>>>>
>>>>>>>>Zsolt
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>dsaad at icehouse.net wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>This is a problem no matter what kind of car you have. I
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>scrounge up connectors
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>of all sizes at the junk yard. For the 2 and 3 wire varieties
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>you have some
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>choices. For the bigger stuff like the MAF I would suggest
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>making individual
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>jumper wires using the contacts from old connectors. You end up
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>with a sort of
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>universal breakout box. Fortunately most of the Audi/VW
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>contacts are the same.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>Only the number and housing shape change.
>>>>>>>>>If you can access the back of the connector (on the MAF this is
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>possible) you
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>can just pull back the boot and probe the backside of the
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>contacts directly.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>You really have to be careful whenever playing with connectors
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>to not damage
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>the contacts with your meter probe or whatever. This is a well
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>known and common
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>cause of future problems.
>>>>>>>>>For hard to reach connectors I often can just use a length of
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>wire stuffed into
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>the interesting contact cavity and taped onto the wire harness.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>It aint pretty
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>or fast  but it is effective and cheap.
>>>>>>>>>btw, the manual gives a fair amount of detail for checking the MAF. I
>>>>>>>>>discovered that it is also electrically quite similar to other
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>Bosch MAF
>>>>>>
>>>>>>
>>>>>>
>>>>>>>>>sensors so any testing methods for them would probably apply.
>>>>>>>>>There are pinout differences though.
>>>>>>>>>When I wanted to check mine out, I made a test harness from a
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>junk connector,
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>and had another Bosch MAF (actually from a Mazda!) and just
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>compared readings
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>while blasting them with my shop-vac. They both responded the
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>same way so I
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>concluded mine was OK.
>>>>>>>>>
>>>>>>>>>The timing senders are just inductors (coil of wire) so off the
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>car a good test
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>would be to measure resistance while heating it up with a hot
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>air gun. If it
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>opens up it is bad. On the car try an AC measurement across the
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>terminals. The
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>voltage should vary with speed. If you have an o-scope you
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>should see a sort of
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>sine wave that changes frequency and amplitude with speed.
>>>>>>>>>btw, the anti-lock senders work the same way.
>>>>>>>>>
>>>>>>>>>Dave
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>Quoting "Buchholz, Steven" <Steven.Buchholz at kla-tencor.com>:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>>... seems to me this is easier said than done!  It so happens I was
>>>>>>>>>>looking
>>>>>>>>>>at the same signals on my urq yesterday ... I want to build a
>>>>>>>>>>"stimulator"
>>>>>>>>>>so I can test the MAC-xx boxes off line.  What I ended up doing was to
>>>>>>>>>>open
>>>>>>>>>>up the ECU and probe the signals inside it to see what they
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>looked like.
>>>>>>
>>>>>>
>>>>>>
>>>>>>>>>>This is not the sort of thing I'd recommend that the normal
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>"shade tree"
>>>>>>
>>>>>>
>>>>>>
>>>>>>>>>>V8
>>>>>>>>>>mechanic try ...
>>>>>>>>>>
>>>>>>>>>>BTW, I do plan to test the sensors I pulled from my V8 *somehow* ...
>>>>>>>>>>actually I'm contemplating comparing the sensor iteslf to the part on
>>>>>>>>>>the
>>>>>>>>>>ury, and may well simply install one of the sensors from my
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>V8 onto the
>>>>>>
>>>>>>
>>>>>>
>>>>>>>>>>urq
>>>>>>>>>>and scope the signal out to see what characteristic failed.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>Given these
>>>>>>
>>>>>>
>>>>>>
>>>>>>>>>>things are not cheap I may see if there is some way that I
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>might be able
>>>>>>
>>>>>>
>>>>>>
>>>>>>>>>>to
>>>>>>>>>>make something that would allow an otherwise "bad" sensor to
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>be made to
>>>>>>
>>>>>>
>>>>>>
>>>>>>>>>>work
>>>>>>>>>>again ...
>>>>>>>>>>
>>>>>>>>>>Steve Buchholz
>>>>>>>>>>San Jose, CA (USA)
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>>Look at the timing and reference sender signals with an
>>>>>>>>>>>oscilloscope. If there is a problem you should see it this way.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>_______________________________________________
>>>>>>>>>>Audifans v8 mailing list
>>>>>>>>>>Send posts to: mailto:v8 at audifans.com
>>>>>>>>>>Manage your list options: http://www.audifans.com/mailman/listinfo/v8
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>_______________________________________________
>>>>>>>>>Audifans v8 mailing list
>>>>>>>>>Send posts to: mailto:v8 at audifans.com
>>>>>>>>>Manage your list options: http://www.audifans.com/mailman/listinfo/v8
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>
>>
>

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