engine won't rev over 2000 RPM (thanks)

[Zsolt]

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.
>>>
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