After cylinder heads job and new oil pressure sender the gauge started showing lower than before reading. After the first drive today it started dying and now “check gages” appears intermittently with the gage showing 0. Also check engine light appeared, it was 43 esc code. I disconnected the oil pressure harness and the needle showed the maximum reading. Put back the old sender and it’s the same. Any ideas?
Yep. I chased that for awhile.
I had 4 problems at the same time but only code 43.
In no particuler order,
1. when I pulled the starter I caught the knock sensor harness and wrecked that goofy plug that goes into it.
When I looked at it,
The center of the knock sensor was completely loose from the brass and the plug was broken.
2. The factory copper mesh ground strap that goes from the back of the passenger side head, to a stud on the firewall and then to the frame was rotted and crumbled .
I replaced them with cheap battery cables from walmart.
Bolting that cable to the back of the head is pretty much impossible unless you pull the distributor.
Especially since the people who had the warrenty on my spine went out of business long ago.
My 94 has a bracket on the back of the head.
I cleaned the paint off of it and thru bolted the cable.
Be carefull aboit that firewall stud. It is only 10mm and you dont want to pull the threads off.
3. A cheap and intermittantly failing fuel pump relay.
The part callout for these trucks is a 15 amp relay.
Echlin makes a 30 amp relay.
It isnt about needing a relay that can handle 30 amps.
It is because the contacts are made from solid copper instead of copper plated steel, and the relay is cast from "virgin" plastic instead of old soda pop bottles.
Less likely to arc fuse toghether and less likely to heat deform.
4. failed thread sealant where the oil sensor pipe threads in.
They didnt "clock" those fittings at the factory, they glued them in with thread sealant.
Not Loc-Tite that is not the same product.
Thread Sealant.
Mine was about a good 270 degrees out from pointing when it bottomed.
The sealant had failed and it puked oil.
A sure fire test for this is if ypu can thread the oil pressure sensor on to the fitting and then twist it to line up where you need it.
If it that fitting moves, that sealant s bad.
Never ever never try to fix that with teflon tape or gas tape.
You really dont want any of that in your bearings or in your oil pickup.
Mine was so far out of clock that I bought the thread die and carefully a little at a time recut the threads untill I was about 40 degrees out of clock and then pulled it, sealed it, and then tightened it down and aimed it where I needed it to be in order to get the pressure sensor back on using the sensor socket and drop head ratchet I had available to me.
You probably dont have to get that crazy
Mine was just way out of whack
If that fitting is loose, pull it, clean the threads, glue it back exactly where you need it to point at in order to get the sender and your tools back onto it and then leave it alone to cure for at least 24 hours.
That is how I got rid of the dreaded code 43.
And always keep in mind that if you get a check gauges light on an obd1 they will not restart from a "key on" position.
You always have to go back to "key off" before you try to start again.
