Help please, '88 5KCSTQ needs at least 3 hrs rest!

[Louis A. Mulieri]

Dear Ian,

Thanks for your relaying your experiences. Your interpretation of the 
short rest / long-crank problem sounds logical. Did you actually fix the 
problem by change the injectors or can they be cleaned to stop leakage 
via gas additive? I hesitate to try popping them out 
because it looks like one needs to almost take the whole intake manifold 
off to get to them what with all the turbo stuff packed around.


Also, I would think there should be black smoke out the tailpipe during 
and shortly after a galloping/hesitating start at the end of the long 
crank I need after an hour rest. Did you have rich mixture smoke after 
long-cranking starts? Also, I can leave the car untouched for 3 days and 
still, it will start normally on first try. Kinda hard to believe that 
leaked fuel would still be there after that long. But it does jibe with my 
original observation that I would have the long cranking spells after an 
overnight rest last summer whenever the temperature was above 78 F 
outside.

Since I never see black smoke I assumed the long cranking could be due to 
lack of fuel in the injecor lines but ruled this out because running the 
fuel pump by jumping the relay for a minute before and during starting 
does not reduce the cranking time. 

However after your report I'm questioning my logic here. I could 
be wrong by assuming I don't have a flooded engine and that the trouble is 
empty injectors/lines because I assumed the empty injector 
tubing would be filled when the fuel pump has been pumping for a minute before trying to start
even though the air-flow plate/lever is not elevated due to inadequate 
air intake at normal cranking speeds (i.e., that's why the cold start 
valve is needed on these engines). Do you think empty lines will not be 
filled while pump is delivering but air intake plate is not elevated?

Thanks for helping me,
Lou
 
 On Tue, 2 Dec 2003, Dr. Ian McArthur wrote:

> Mine did this too.  It was leaking injectors.  When the car sits over night
> the leaked fuel acts as a choke, like the sixth injector, so the car starts
> fine.  When left for a short time, the leaked fuel tends to flood the
> engine.
> 
> My other 88 5TQ has used (slightly leaking) injectors and acts like yours,
> only not so long a crank time.  Probably because my injectors are not
> leaking as badly as yours.
> 
> I checked mine for leakes by pulling them out and taping a clear 35mm film
> can over each injector.  I wrapped the tape tight enough to prevent most
> evaporation.  It is easy to tell how bad they are leaking.
> 
> Ian
> 
> -----Original Message-----
> From: quattro-bounces at audifans.com
> [mailto:quattro-bounces at audifans.com]On Behalf Of Louis A. Mulieri
> Sent: Sunday, November 30, 2003 6:57 PM
> To: quattro at audifans.com
> Subject: Re: Help please, '88 5KCSTQ needs at least 3 hrs rest!
> 
> 
> My 1988 5KCSTQ cranks a loooooong time if I try to start it after a 1 hr
> cooldown from normal driving temperature. Sooner than 1 hr and it starts
> in a few seconds but from 1-2+ hrs after normal running it cranks up to 1
> min before firing a few cyls and then stumbles along for another 15-20
> seconds before coming to life. 3-hrs or overnight rest and it starts
> instantly so it seems unlikely to be leaky injectors.
> 
> I had long cranking even after overnight rest this summer whenever the
> outside temperature was above 78F.
> 
> There are no fault codes registered. Energizing the fuel pump with a
> jumper wire (pump sounds good) for 30 sec before and during turning the
> key to start does not eliminate the long crank time during the 1-2+ hr
> slow-start period.
> 
> I replaced the fuel filter underhood and checked fuel delivery rate as
> well (750 cc/30 sec as per Bentley).
> 
> I suspect the temperature sender that signals the cold start valve
> controller may be erroneously indicating "warmed-up engine" when it's
> cooled down for 1-2 hrs when it should be indicating "cold engine".
> 
> >From Bentley I concluded the likely temp sender was the double-spade
> terminal one pointing toward back of engine out of the top goosneck and that
> it
> should be a resistance unit rather than a thermal switch. Ohmmeter check
> revealed open circuit between terminals as well as from each terminal to
> ground. Jumping the terminals with a fixed, 1 kohm resistor did not
> eliminate long cranking.
> 
> Ordered a new one (22 mm brass hex housing with red dot on nylon
> base of terminals and 9 mm threaded end into block, stamped: 07-93 and
> 110-97, 130 C max). The new one also reads open circuit regardless of
> ice-water or flame exposure. I'm confused as to whether the new sender is
> bad or that I'm not looking at the right one on my engine.
> 
> There are two other temp-like units screwed into the water jacket in this
> area. A small one with a single spade terminal screwed directly into the
> head ahead of the top goosneck and a large, 4 or 5 terminal socket one
> pointing downward from underneath the top gooseneck.
> 
> Can anyone help me to identify which sender is the one used by the
> computer to control when to pulse the cold start valve and what it's
> temp-resistance readings should be and/or what other causes there could
> be?
> 
> Thanks for ideas,
> Lou
> 
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