Starting problem with 200T A -88

[isham-research.freeserve.co.uk at pop.pol.net.uk]

> I have starting problems with Audi 200 Turbo Automatic 1988.
> It has a MC engine with Hitachi MAC-12D box.

> Sometimes when starting it doesn't give a spark at all. The diagnostics says
> 2111 and 2113, HALL and RPM senders. Also when RPMs are above 3000 the
> check-engine light is on which could be a knocking sensor problem but there
> is no diagnostics faults about knock sensor. I have changed the RPM sender
> and checked the HALL sender with LED and it seems to work ok. Also the
> wirings to ECU are ok I quess that the coil and ignition power stage are ok
> because when the engine doesn't start there is no signal to ignition power
> stage. The distributor shaft seems to have quite a big cap when turning it
> by hand, I wonder if it might be the problem...the engine also "hits back"
> sometimes when starting which could mean the ignition timing being too
> "early" but I have done the basic timing adjustment for the distributor and
> it should be ok.

You will often see 2111 on a failure to start.  It may be spurious.

I would re-check the ECU grounds - all wires off the ECU connector with
a base colour of brown, irrespective of the stripe colour.

> What is the relationship between TDC sensor in flywheel and HALL sender?
> Should they give the signals at the same time?

2:1.  The Hall sender signal matches #1 cylinder TDC for the
compression/firing stroke only - the flywheel sender signal matches #1
cylinder TDC then and at the exhaust/induction stroke as well.

> Is the hall sensor a inductive or capacitive unit, I mean if I measure the
> Hall sensor, is there continuty between pins or not?

Neither - it's a semiconductor.

--
 Phil Payne
 http://www.isham-research.freeserve.co.uk/quattro
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