[V8] Fuel never reads Full

[Mike Arman]

>: [V8] Fuel never reads Full
>To: "urq" <urq at pacbell.net>, "V8" <v8 at audifans.com>
>
>Who's got the best writeup on fixing/repairing the V8 cluster?  I've got
>mine out to replace some bulbs, and want to see what else I should
>check.
>Chris


Turns out it really isn't a great big deal once the cluster is out. 
Remember you have to pull the top dash pad and the top of the "trim box" 
around the steering column to get the cluster out. You do not have to 
disconnect or disable the air bag to do it, either. Steering wheel stays on.

The wire connectors (three or four of them) have snap locks which you have 
to withdraw before they can be unplugged from the back of the cluster. The 
snap lock looks like a plastic "bridge" which fits lengthwise over the 
plug. Grip it with your fingers and pull it (gently) directly away from the 
cluster (it does NOT come off the plug), and then the plugs will come right 
out. You may need a small, flat screwdriver for some additional gentle 
persuasion - be careful!

Lay the cluster face down on a towel, and remove the phillips screws that 
hold the various back covers on. There are a couple of multi-pin edge 
connectors - one in the middle of the large cover, and one or two on the PC 
boards themselves.

The usual suspect is the green multi-pin edge connector between the large 
and small boards. Using a jeweler's loupe (Harbor Freight, $1.99 set of 
three) of about 5 power, examine the solder joints where the pins go 
through the boards.

Dollars to doughnuts you have cold solder joints there, and they are easy 
to see with the loupe - the cracks are VERY obvious. The underlying problem 
is that these boards are assembled on a wave soldering machine, and 
everything is soldered at once. If the machine is set hot enough to 
properly solder the pins on the edge connectors, everything else melts. If 
it is set cool enough to keep the most fragile parts intact, the pins don't 
get hot enough to make a good solder joint - and we get all kinds of 
strangeness from the instrument cluster. (On my V8, the fuel and temp 
gauges would intermittently drop to zero, the interior light would either 
not come on, or stay on, and I got random autocheck complaints about oil 
pressure and lord knows what else. Fixing the connector pins ABSOLUTELY 
CURED *ALL* OF THEM in one whack.)

Use a soldering pencil (about 35 watts, max) and ROSIN core (electronic) 
solder, resolder all the pins. Make sure you don't create solder bridges, 
this does take a small amount of skill, and if you are not comfortable 
soldering PC boards, don't do it - find someone who can, and who you can 
trust. Remember if the cluster gets screwed up, the car CANNOT be made to 
run . . . so be careful.

There are a couple of edge connectors which will need this treatment, but 
the green one between the two boards is the most likely suspect. When you 
put everything back together, this is a good time to change all the burned 
out dash lights (and you won't believe what they cost), and use contact 
enhancer on all the edge connectors and anything else that doesn't get out 
of the way in time.

Don't put the dash pad back on until you are SURE you have everything 
working right.

The whole job is perhaps a couple of hours - the hardest part is finding 
the various screws that hold that dash pad in place. Check over the other 
wood trim bits on the dash - you will find some loose ones - they are held 
on to their metal mounting brackets with a few tiny, tiny wood screws, 
which fall out, but can usually be found wedged between the bracket and the 
cast dashboard cross-member. (So *that's* what those tiny wood screws are!) 
Use some good glue (Pliobond is good) to glue the brackets to the trim, 
then put the screws back. The screws alone are inadequate, which is why 
they fell out. The Pliobond keeps it together forever, and the little 
screws hold things in alignment.

This exercise accomplishes three things - all the "ghosts" in the dashboard 
will be gone, the instrument lights will all work, and a BUNCH of squeaks 
and rattles around the dashboard will also go away.

Best Regards,

Mike Arman
90 V8, not just a car, an ADVENTURE!




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