Fw: No start condition - 1988 90Q - SECOND UPDATE

[Huw Powell]

Did you ever get it running again?  Cars can _always_ be fixed, it's 
just a matter of diagnosis, which can be difficult.

On 8/2/2011 11:44 PM, Vincent Gelinas wrote:
> This sounds exactly what I went through with my beloved 89 90q. Which
> incidentally was built exactly 10 years before my jetta. This is good info!
>
> -V
>
> On Aug 2, 2011 11:41 PM, "Huw Powell" <audi at humanspeakers.com
> <mailto:audi at humanspeakers.com>> wrote:
>  > I'd check what the timing actually is. The second butterfly does open
>  > rather "suddenly" at WOT, but should close fairly smoothly if you
>  > gradually pull off the throttle.
>  >
>  > Luckily, you can get to the ECU connector by "assuming the position",
>  > and it unclips fairly easily. Don't forget the ignition ECU behind the
>  > passenger right foot kick panel as a possibility.
>  >
>  > Check the idle switch is still good.
>  >
>  > Unplug knock sensor, OXS (separately).
>  >
>  > Unplug control pressure actuator.
>  >
>  > Pull spark plugs and examine.
>  >
>  > Check IM ground wires (I guess you did when you pulled the IM top...)
>  >
>  > Check engine fuses in fusebox under the big red clip.
>  >
>  > On 8/2/2011 10:47 PM, Radek wrote:
>  >> Played with fuel pressure regulator (attached a vacuum pump to it) -
> no difference.
>  >> Changed idle stabilization valve - no difference.
>  >> Advancing ignition timing seems to help - instead of a single fire
> we get two or three, but still does no start.
>  >> An observation - does not fire at all with fully depressed throttle,
> but will fire with throttle off.
>  >> When firing, sometimes loud knocking can be heard, seems to come
> from the intake manifold - backfire?
>  >>
>  >> Also, throttle body butterflies seem to be weird. The small one
> opens and closes smoothly, but the large one only opens fully in one
> shot at WOT then, when slowly released, snaps back with a loud ping. Is
> it supposed to work like this? All levers and springs seem to be in place.
>  >>
>  >> Planning to switch ECU tomorrow, hate to think about contortions
> necessary to get deep into the passenger well.
>  >> Cheers;
>  >>
>  >> Radek.
>  >>
>  >>
>  >> ----- Original Message -----
>  >> From: Radek
>  >> To: quattro at audifans.com <mailto:quattro at audifans.com>
>  >> Sent: Tuesday, August 02, 2011 12:21 PM
>  >> Subject: Re: No start condition - 1988 90Q - UPDATE
>  >>
>  >>
>  >> Fully charged battery overnight. Blinked out codes - nothing.
>  >> Replaced ignition cap, rotor and wires with good looking old set -
> got car to sputter a bit. It seems to catch a bit initially and then no
> more. It is actually catching when cranked with foot off the gas - with
> throttle open, nothing at all.
>  >> Any ideas? Is there a way to check fuel pressure on these engines (NG)?
>  >> Radek.
>  >>
>  >>
>  >> ----- Original Message -----
>  >> From: Radek
>  >> To: quattro at audifans.com <mailto:quattro at audifans.com>
>  >> Sent: Monday, August 01, 2011 9:46 PM
>  >> Subject: No start condition - 1988 90Q
>  >>
>  >>
>  >> In need of help again, my son's 90q is out of commission again.
>  >> Here is what he reported:
>  >> when trying to start the car, at the first or second crank he heard
> a bang (a snap, something sounding mechanical) and smelled something
> weird under the hood. The smell, he said, smelled of friction.
>  >> The car kept cranking, but no start. Came back home on a flatbed.
>  >>
>  >> Here is what I checked till now:
>  >> - starter cranks the engine
>  >> - timing belt is OK
>  >> - valve train is moving (took rocker cover off to see if sprocket is
> not sheared)
>  >> - has good compression
>  >> - timing belt alignment is OK (crankshaft to camshaft)
>  >> - distributor turns
>  >> - smells of gas when cranked
>  >> - seems to have spark (checked with wire touching enging block)
>  >> - coil resistance checks out OK
>  >> - Hall sensor works (blinks a diode)
>  >>
>  >> Where to look next? I'm going to blink out error codes tomorrow,
> mosquitoes chased us out tonight.
>  >> TIA
>  >>
>  >> Radek
>  >>
>  >>
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