Ok update. We finally had a forklift mechanic come out and found its a bad computer causing all of our problems. Hooked up a harness to the distributor to cut out the cpu control and the machine fired up no problem ran smooth just like before.

Thanks for everybodys help on here

We bought the new sending unit off of ebay. The next one will come from our hyster distributor. Right now we can not crank the engine long enough to test because of the kick back or we are goig to destroy another starter. When I pulled the motor there was another nose cone in the bell housing which means this is not a new problem but worse than what I have seen it do in 18 months

Where did you get the new sender?
You said you have 45 psi oil pressure when running?
the sender is a simple switch, [not a variable resister like it would be with a gauge,] which should be dead short with that much engine oil pressure and dead open with no oil pressure. Your 'new' sender tests as -bad-, in my book.
get the right PN sender from your local Hyster forklift dealer, and give it another go.

I would definitely hook up a manual pressure guage to verify it has pressure. If it does then put the sensor back in and use your continuity meter and check the sender while cranking the engine.

Ok I'm back, so I replaced the wrap around dash unit. The oil pressure gauge is working lift was still shutting down due to low oil pressure. I ground out the wires on the sending unit and the lift will stay running. I tried using the old and new sending units same outcome with both. Should I invest in another one? I shut the lift down and when I go to restart and is very hard restarting and the engine has a lot of kickback during the whole starting process. Sometimes it will fire right off.

Any more ideas???? about ready to call a tech that can scan it with the laptop.

Thanks

I have already replaced the sending unit and traced the wires to make sure there wasn't a short somewhere. I have ordered the circuit boards for the dash now just waiting for the parts. I'll keep posting on what I find

just replace the sender
they are cheap enough and are known to be flaky and leak oil
i have had them check good but the pressure was borderlined and the sensor was worn enough to cause it to not make properly even though it would test good.

IF that does not fix the problem then yes... you have other issues but from my experience they are not common with these engines and the oil pressure circuit. It's generally the oil sender unit.

since oil pressure sending unit seems to be working I started following the wires to make sure there wasn't a bad connection or a broken wire and ended up in the dash. the pressure gauge also reads no pressure. Could it be a bad circuit board in the dash???

I just hooked a pressure gauge up and it stays constant at 43 psi. It ran longer this time and the oil pressure light came on and then went off but did eventually come back on and kill the motor again.

Does anyone know what the resistance should read on the sending unit while the motor is running or have any more ideas.

I have read they should read between 35 and 50ohms so I was considering buying a 40ohm resistor and seeing if the lift will stay running

I agree w/ fixit- seems like a a lot of running time before an oil pressure drop.

The light with the oil drop is low oil pressure warning. Maybe you could "t" a pressure gauge on where the sender is and watch what the pressure is doing.

the engine only runs for about 30 seconds and no I tried keeping the rpms high and it does the same thing and shuts down

How long does the engine run at idle before this issue starts? Does holding the RPM above idle have an influence on how long it runs?

Ok I installed the new oil pressure sending unit and nothing has changed. Not running it is reading about 240ohms and while running 120ohms. Prior to the engine shutting down what I believe to be the oil pressure light comes on (an oil drop with an arrow on each side pointing at it?) it shuts down then I can feel the safety cutoff solenoid close. Any more suggestions?

There are two. I have a new one coming crossing my fingers