just rebuilt my first motor and fired it up (finally!) for the first time...

both the oil pressure sender and coolant temp sender are brand new. bought a set of new gauges (omega kustom), but as soon as i start it up both oil and temp gauges peg high.

i had initially installed both senders with teflon tape -- directions with gauges said that could prevent ground and recommended teflon paste, so i pulled both and removed tape and added dap of paste.

the gauges (though meant for a ford) came with both senders, but they don't fit this 351W.

do all senders use the same values?

thanks in advance.

 

No, the Ford senders will most likely not have the same resistance as the aftermarket senders. You need to either adapt the aftermarket senders to your engine, or install a resistor between the Ford senders and the meters.

I am having to do this myself right now, and the trick is to find the correct resistor to get accurate readings on the meter. There could be additional complications to that, as I have no idea of the response curve of the aftermarket meter vs Ford's, so a simple resistor may not be sufficient.

 

adapted the sending units which came with the gauges and still the same problem... grrrr.

rented a mechanical oil pressure gauge yesterday just to be sure — now i can at least put my mind to ease knowing oil is good; just gotta figure out how to make the gauges work now.

 

I don't like reviving old threads, but the above question was left unanswered. I might also have an oil pressure problem, and I hope a new sender will be the fix. My 1985 F150 300 plow truck will show normal on the gauge and when I am done plowing the driveway (takes about an hour), the gauge will be at the low position as if the engine wasn't running. I never remember to look at the gauge while plowing.

 

When the gauge read normally, was the engine still cold? And after your plowing is done, and the reading is low, is the engine much warmer? In that condition, have you tried revving the engine to see if the pressure increases?

Cold oil will always show higher pressure at lower rpms, but will thin out as it warms up, generating lower pressure at the same idle rpms. But even when warm, if your oil pump is working well, or if the engine's clearances haven't grown too much, a rev to higher rpms should bring up the pressure.

If it's a stock gauge, you may need to hold the rpm for about a minute as they are heavily damped, and will respond slowly.