Troubleshooting

[Ben Swann]

The reason I asked about the warmup is I have had several that basically started up -
VROOM and ran fine a few minutes into warmup.  Then shortly into the drive or idling,
the car would start running like crap and stalling out.  Took me awhile to figure it out
then, but now is one thing I'd check right away, especicially if I did not just replace
it.  If the car starts OK but runs like crap when it goes into closed loop operation,
then disconnect the oxygen sensor and see if it runs better.  
 
I've had bad O2 sensors make the car sound like it was going to throw a rod or like the
the lifters were all collapsed.  Makes the engine run so bad like there is a totally
different problem and you end up chasing tail checking compression, replacing lifters -
all of course after replacing vacuum lines, messing with timing, etc.
 
Let us know what you find.
 
Ben

  _____  

From: Ben Swann [mailto:benswann at verizon.net] 
Sent: Saturday, January 08, 2011 5:02 PM
To: 'Vincent Gelinas'; 'quattro at audifans.com'
Subject: RE: Troubleshooting


Bad fuel?  Lifters?
 
Does it start and run OK when cold and begins to run crappy after warmup?
 
Ben

  _____  

From: Vincent Gelinas [mailto:vrgelinas at gmail.com] 
Sent: Saturday, January 08, 2011 4:49 PM
To: Ben Swann; quattro at audifans.com
Subject: Re: Troubleshooting



Okay to recap I have replaced - battery, coil, cap, rotor, plugs, wires, fuel filter,
and fuel pump. I drove it around for a while just waiting for it to cool down so I could
restart when it stalled (under any sort of moderate load, even while revving hard in
neutral). My water temp gauge never worked but my oil temp will go up to the first hash
mark above the bottom number (60c?). Now when I go to start, it will crank and then
sound like a cold diesel. Tick. Tick. Tick. Firing but slowly and not on all cylinders.
Are our cars particularly sensitive to low/bad fuel? I can take vids and post them on
youtube or something. Would that help?

On Jan 8, 2011 4:36 PM, "Ben Swann" <benswann at verizon.net> wrote:
> 
> Vincent,
> 
> You might want to recap what you have done and what overall symptoms you are having. 
> 
> Some things to try/confirm..sometimes a little starting fluid directed into the intake
> manifold can reveal if there is or not spark. You might need to remove a vaccume cap
to
> spray in there, and I think there is a vaccuum port on the side of the throttle body -
> use the one inside the throttle - closer to the cylinders.
> 
> Remember the fuel pump is ignition primary triggered. You can try to jumper fuel pump
> hot and prime the injectors by lifting the air fuel plate up - either with 3mm allen
> wrench inserted in the adjustment hole, or remove filterbox and lift plate up by hand.
> When pump is running, you should hear a sqeal as fuel goes through injectors. Don't
> overdo it as you will flood the engine. If there is resistance on lifting the plate,
> then you may have clogged differential pressure regulator.
> 
> You should be able to verify spark - crank with primary coil lead connected to plug
and
> ground metal casing - I use a large alligator clip, but somehow connect the spark plug
> to ground. You should see good healthy spark. If so then see if spark is making it
> through wires to the plugs - could just be a bad cap or rotor.
> 
> Compression would need to be very bad or almost non-existant if there is no running at
> all. That would be a broken timing belt or slipped crank pully - not usual.
> 
> You can revise what you said to be - air, fuel, spark, compression -all in the correct
> amount at the proper time. Then the engine will run correctly.
> 
> This engine is picky about having intake fully sealed in order to draw in air and lift
> the plate while cranking.
 <snip> > Some troubleshooting tips here: http://www.gtquattro.com/FAQ.html
> 
> 
> [Date: Sat, 8 Jan 2011 13:07:28 -0500
> From: Vincent Gelinas <vrgelinas at gmail.com>
> Subject: Troubleshooting
> To: "quattro at audifans.com" <quattro at audifans.com>
> Message-ID:
> <AANLkTimk8Y3iKs7jvVVgc4ULD4EtAkNnyRqQbnZ53DgM at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
> 
> Okay so I know the four things that an engine needs are fuel, air, spark,
> and compression. Engine is NG in 1989 90q. I know I am getting fuel and
> air.
 <snip>