Cold start issues continue (84 4000 quattro)

[Johnny B]

The injectors & seals are all brand new from the engine rebuild. I felt around and each feels tight, but I have yet to blast em with chemtool (ran out over the weekend). My new vac tubes are arriving today, after install I will be thoroughly checking every vacuum related part under the hood including each injector seal. 

Yes, it definitely sounds like a lean situation to me as well. The thermo-time switch on the back of the cylinder head has yet to be replaced (and is the original from before the engine rebuild). The previous owner had gotten this switch mixed up with the temperature sender I just replaced, and contacted me yesterday to state that he never touched the one on the back of the head. I'm assuming because of its price they never replaced it (normally $90). 

Without testing the CSV, I went ahead and ordered one (dealer closeout, got it for over 50% off @ $40). I figure, I dont mind spending $40 on piece of mind, and if it doesnt turn out to be the problem, the old one would have failed sooner or later (and might as well save 50% while I can!). It's also due to arrive this week, and I will toss it in and continue on my adventure here. 

After hearing a ur-q owner state he had the same symptoms and corrected this by adding a manual push button to the CSV inside the car, the thermo-time switch may just be my problem. For what its worth, it was roughly 42* outside this morning w/ wind, so definitely cold enough for the CSV to run for a few seconds. Also, the previous owner had stated they leaned the mixture out a tad for smog purposes. I dont believe it's too lean for driving (as the engine temps stay low, no pinging or spark knock) but having a lean mix on top of not having the CSV help out on cold start would create one hell of a lean situation on start (plus me tapping the gas pedal would create a vacuum sucking in a chunk of more air killing the motor). I will be re-tuning the fuel metering plate with the procedure outlined on Huws Audi Garage once my new (digital) voltmeter comes in. 

Im hoping for the best, and will keep everyone posted on the progress. Thanks to all for the help! 

Johnny


> From: theloves at localaccess.com
> To: ekellock at gmail.com; pre95 at live.com; quattro at audifans.com
> Subject: Re: Cold start issues continue (84 4000 quattro)
> Date: Wed, 11 Aug 2010 10:46:17 -0700
> 
> or leaking injector?
> ----- Original Message ----- 
> From: "Ed Kellock" <ekellock at gmail.com>
> To: "'Johnny B'" <pre95 at live.com>; <quattro at audifans.com>
> Sent: Wednesday, August 11, 2010 10:23 AM
> Subject: RE: Cold start issues continue (84 4000 quattro)
> 
> 
> > Have you checked the injector seals?
> >
> > Touching the gas and having the engine die sounds exactly like a too lean
> > situation.  On my 85 urq I went around and around and found that all my
> > injector seals were loose.  We removed each injector and just tightened 
> > each
> > seal and cured what amounted to a serious vacuum leak.  They're not all in
> > hoses.
> >
> >
> > Ed
> >
> >
> >
> > -----Original Message-----
> > From: quattro-bounces at audifans.com [mailto:quattro-bounces at audifans.com] 
> > On
> > Behalf Of Johnny B
> > Sent: Wednesday, August 11, 2010 7:07 AM
> > To: quattro at audifans.com
> > Subject: Cold start issues continue (84 4000 quattro)
> >
> >
> >
> > Well thus far no luck. I have scoured the engine compartment for vac 
> > leaks,
> > fixed one which corrected my high idle, but still have my cold start 
> > issue.
> > The coolant temperature switch came in yesterday (that mounts between
> > cylinders #1 and #2 on the bottom of the coolant neck leading in to the
> > head), I installed it and this morning, still a bad cold start.
> >
> > Once the car is started, my idle is rock solid, does not wonder, and I 
> > have
> > good power up to ~5k which seems fine for a JT. No running condition 
> > issues
> > once started. I did notice this morning when it first started, I touched 
> > the
> > gas pedal to bring the R's up and it simply died. I restarted and let it
> > idle for ~30 seconds and all apparent running conditions went away.
> >
> > Someone had mentioned the fuel pressure regulator could be at fault,
> > specifically the "warm up regulator on the fuel head" which I am uncertain
> > as to what he means. There are 2 "fuel regulator" pieces near the fuel
> > distributor, the vacuum regulated piece mounted towards the front of the 
> > car
> > in front of the fuel distributor, and the FPR mounted directly to the fuel
> > distributor that has 2 wires leading to it.
> >
> > Any insight greatly appreciated, I know I have said it but it's very
> > annoying having a car that is otherwise well sorted and good running with 
> > a
> > bad cold start.
> >
> > Johnny
> >
> >
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