1990 F150, inline 6, 5 speed.

Hi all. I haven't posted for a while, but always appreciate the more active forum members. I have perused the older posts to some extent on these issues, but wanted to run it by everyone.

Brief history - this truck was abused, hard, in it's previous life. I have been working on getting it up to a reasonable standard since I bought it.

Fuel Gauge:
The fuel gauge has never worked properly for either tank. The fuel pump was dead in the front tank, so I replaced it first with a used one, then in an effort to make the gauge work, with a new one. The gauge typically reads empty, but sometimes switches to 3/4 or so. I have run the tank dry with the gauge staying at 3/4, so fuel level isn't necessarily represented accurately when the gauge is above empty. The gauge doesn't really bounce, just moves to it's spot and stays there. When I switch tanks, sometimes it moves to a new spot.

The archive says that the fuel selector solenoid, at the frame, may be the culprit. My other guess would be wiring.
Here is the thread I got my information from.
https://www.ford-trucks.com/forums/1...-problems.html


Oil Pressure Gauge:
The oil pressure gauge maxes out and stays maxed out as soon as the truck is started. I have replaced the sensor, with no change. I initially thought someone had put a high pressure pump in there, but nothing else on the truck was maintained, so why would they do the work on that? With no other information, are there any thoughts on this?

Thanks

 

It's possible that you have an instrument cluster problem. If you have one without a tach, this might be a good excuse to upgrade.

Otherwise, it's likely two separate issues. On the oil pressure "gauge", it's not really a gauge - it's an "idiot light" masquerading as a gauge. It sounds like something may be grounding out and pegging the needle.

 

Thanks for the quick reply. The speedo, tach, and temp gauges are all seemingly working, at least as near as I can tell.

In a brilliant move, when I replaced the speedometer gauge (wasn't the problem...but replaced the whole speedo system) I did the gas gauge as well, but not the oil gauge. I have one, it just didn't make it in and I wasn't in a hurry to take off the many tiny torque screws to get in there again.

I will get back into the dash and replace the oil pressure "light", checking to see if I can see anything that might cause a ground. I can try swapping out the gas gauge again as well. It wouldn't be the first time I put in a bad part picked from the parts yard...