87 5KTQW injector cooling fan problem

[Paul Meyers]

Ok. I bow to your obvious understanding of this area. When the battery is
up, the car starts very easily. I could just be a weak battery. It's several
years old. The battery tested good at Checker Auto parts, but could be weak
anyway. I'm going to leave the injector fan sensor disconnected until I
actually get a vapor lock some time. Why run the fan unless there is
actually a problem to solve. Dave Head told me that he had run his car all
over the south without ever having an injector fan installed without once
encountering vapor lock. Anyway, it's good to know that the injector cooling
system isn't the culprit. I will look elsewhere.

It's entirely possible that Audis would run hotter here in the Utah desert,
since we're also at altitude (over 4000 feet) and the (cooling) air is
thinner, allowing for less effective heat transfer in the radiator, etc. In
the summer, the average daytime high here is over 90 degrees. I noticed my
fan was running during an extended period of idle. I just didn't know why.
Now that the daytime temperatures are in the 60s, the fand rarely runs at
all.
Thanks for the help.



-----Original Message-----
From: Ameer Antar [mailto:ameer at snet.net]
Sent: Monday, October 16, 2000 12:25 PM
To: quattro at audifans.com
Subject: RE: 87 5KTQW injector cooling fan problem


I actually don't think anything is wrong w/ yer fan. Mine works fine and is 
the original one from '84. The fans could go bad if lots of dirt gets in 
there, but you would notice a big current drain. Measure the current the 
fan is draining by using an ammeter directly on the fan's ground or 12v 
wire. This will tell you if the fan is the culprit, eliminating other 
issues. I don't know about others, but the audi inj. cooling fans aren't 
bad...no need to stock up. And there's no need to pay for something that 
ain't broke, while you can spend on something that is...

If the fan shows up at few amps, look somewhere else. It's not like the fan 
is actually running all the time or for even extended periods. In fact my 
inj fan rarely goes on while driving around. I have seen it go on w/ the 
ignition, but only when it's been idling in summer. Mine usually shuts down 
a few minutes after parking the car. Is your engine bay temp too hot? It 
might be all kinds of other problems like a vac. pump or self-leveling 
pump, or 100 other convenience items that is broken and draining your 
system. Do you have trouble starting? Maybe something is up w/ the starter. 
I've seen a car unable to start cuz of corroded starter and batt. cable 
ends. A multimeter is really helpful in diagnosis, that way you can at 
least see what shape the battery is in vs. different points in the wiring. 
just my thoughts...good luck.

-ameer
'84 5kT


At 02:05 PM 10/16/00, you wrote:
>Thus, the system is working "as designed". It's no wonder that the injector
>cooling fans wear out. What could they have been thinking? Ok. I'd better
>stock up on the fans. I'll likely deal with the electrical problems by
>increasing the alternator output voltage to 14.4 amps by using an Avi
>alternator. That should provide enough "headroom" to charge the battery
even
>if I have some voltage loss between alternator and battery. I have already
>replace the swaged connector between alternator and battery. Thanks.
>
>Paul Meyers
>Gray 87 5KCSTQ 1.8bar eurolights fuchs 145 kM, needs loom transplant
>Pearl 88 5KCSTQ 1.8bar eurolights fuchs bilsteins 125 kM 2pc-em k24 turbo
>Metallic White 87 5KTQW eurolights bilsteins 191 kM daily driver
>Blue 86 5KCSTQ parts car
>
>
>
>-----Original Message-----
>From: Ameer Antar [mailto:ameer at snet.net]
>Sent: Monday, October 16, 2000 11:59 AM
>To: quattro at audifans.com
>Subject: RE: 87 5KTQW injector cooling fan problem
>
>
>actually audi designed it so the fan can go on at any time, w/ or w/o
>engine running. Although the after-run relay connects to the same power
>supply as the inj. fan, the inj fan has it's own relay #15. The two
>circuits are only sharing the same power source, but they each have their
>own circuits. They are both getting power through fuse 21 and also thru
>wire dist.#20. After that the power is split to each circuit. Even though
>what you say makes sense, this is what audi came up w/.
>
>It sounds as though yer having some other kind of problem though. I never
>had a problem related to the cooling fan. Maybe the sensor is being
>overheated b/c it's too close to the engine/exhaust. Maybe your having
>battery, wiring, or charging issues [check alt. belt...] It could be a bad
>motor too. Check how much current the fan is draining. I have no idea what
>it should be, but I think it should definitely be under 8A...more like 2A
>or so. If not, your batt. is dying on you b/c of something else. Check the
>current drain on the batt. w/ the ignition off, as was discussed
>recently...good luck.
>
>
>At 12:43 PM 10/16/00, you wrote:
> >This is really important. Can you verify for me that the injector fan
runs
> >all the time when the engine is hot, even when the engine is running? I
> >thought that it only ran when the ignition was off. Otherwise, wouldn't
>this
> >wear out the fan unnecessarily? Why would you want it on when the engine
> >runs, since the fuel itself cools the lines. Isn't this all about vapor
>lock
> >after the engine is shut off? Am I wrong here?
> >
> >Paul Meyers
> >Gray 87 5KCSTQ 1.8bar eurolights fuchs 145 kM, needs loom transplant
> >Pearl 88 5KCSTQ 1.8bar eurolights fuchs bilsteins 125 kM 2pc-em k24 turbo
> >Metallic White 87 5KTQW eurolights bilsteins 191 kM daily driver
> >Blue 86 5KCSTQ parts car