Just recently my gas gauge started acting erratic. Fluctuates up and down. I think there may be a bad ground somewhere. The connector at the top of the tank feels tight. Also noticed the windshield wipers will sometimes move really slow. Sometimes they run at normal speed. I think that too may be a bad ground. Running voltage is a consistent 14.2 so no problem there.

Where do the ground straps for these accessories connect to the frame? I want to start checking there first. I'll take any other suggestions you have in tracking this stuff down.

Thanks

 

Hmmm - these two issues could be unrelated. Your 14.2 reading shows your alternator/charging system to be OK. Fuel sending units have history of intermittent/faulty operation as they age (I've replaced the sending unit once on my 1988). I'd check the connections for the wiper motor, age might be affecting that too.

 

Thanks for the reply Cusser. I might tap a bypass ground wire in from the harness plug at the fuel sender and another at the wiper motor harness. Doing that will ensure they are grounded good. If the problems persist, then I suppose I'll need to look at the wiper motor and fuel sender themselves.

But if anybody has a list of all the ground strap locations, that would be a big help.

Thanks

 

As for the intermittent slow wipers, I think its the wiper motor. I used my FLIR thermal imaging cam on the wiper motor. Its 46 degrees outside here today. I ran the wipers for about 5 mins and they really slowed down. Shot the motor with the cam and it's getting pretty hot. So, slow movement means its laboring and the increased temp confirms it.

So, in searching for a replacement motor it look like they are not readily available. Rock Auto does offer a rebuild service for $90 although I might try a local service for that. Or, I may try rebuilding it myself once I find alternatives to bail myself out if I mess it up.

Anyone know if other vehicles also use this wiper motor? That would increase my chances of finding one in a junkyard.

Here's the FLIR image showing the bearing hub at 160 degrees. Im sure internally its hotter. The temp of the bearing hub is transferring from the stator I believe.

 

I took the wiper motor apart. Nothing burnt or broken inside but it was pretty dirty like old electric motors tend to get. I cleaned it up, lubed the bushings and put it back together. It works much better now.

i ensured good ground for the fuel sender and no improvement. I think its the sender. Rock Auto was out of stock but Amazon had one. :$80 and i ordered it.

I also ordered a vacuum advance unit for the distributor since the one on the truck has a leaking diaphram.

 

To replace my fuel sender, I tilted the truck bed up for access. I removed the three large bolts on passenger side (17mm socket, very tight) and loosened the three on driver side. I removed fuel filler hoses/assembly. Then I used a 2x4 and a floor jack to raise up/tilt the truck bed. When replacing the sending unit, I used stainless steel hex head screws from Ace Hardware to replace the original Phillips one.
See https://www.streetsource.com/wiki/67...er-replacement
See https://www.streetsource.com/threads...er-replacement

 

I thought that there were 8 total number of bolts that hold the bed on, not 6 -- 4 on each side.

 

Cusser, I previously replaced the rear leaf spring bushings. Man was that a tough job. Initially I wanted to lift the bed to get at them easily. Unfortunately, two of the bed mount bolts were seized. I soaked them for days with PB Blaster and I had a 3' breaker bar on the job. The would not budge. To avoid the risk of breaking the bolts off I abandoned the idea of lifting the bed and sweated the job out from underneath.

Subsequently, I fixed the typical leak spot at the rear of the gas tank which required me to drop the tank down from the frame bracket anyway. The leak is fixed and holding good. Since the tank has already been down recently, It will be easy enough to do the same for accessing the fuel sender.

Thanks for the suggestion anyway.

 

I have a 1/2" electric impact wrench from Harbor Freight, and I used that for initial loosening of the 6 big bolts. My '88 is a Cab Plus, had 6 big bolts; wrote this all down then, Yes, I replaced my leaf spring bushings too. See attached file.

 

Fuel sending unit came in the other day. I plugged it in to the harness under the truck and moved the are to various positions. The gauge worked. I wanted to confirm it was actually the sending unit before I begin the work. I'm gonna be installing it this morning.