Oil pressure switches

[arrowheadracing]

Just replaced another switch today. Same symptoms as last time, stalling, wouldnt start , would start and die, then just crank. No fuel pressure. This is the second one in three months. Have you guys run into this problem. I was thinking of just carrying a spare, along with my spare pmd and lift pump. By the time I am done collecting spares, I ll have a complete rebuilt motor in the bed of the truck ready to install. Just seems like these 6.5s eat alot of same parts time after time. Also is the 96 oil switch the same as a 95 ?
Todd

[Hye]

I wonder if you have an intermittant short somewhere that's burning the oil switch contacts or maybe a lift pump that's going bad. There are some aftermarket relays that have stronger contacts. Check with Kennedy.

[BrentN]

For my information, does the 99 Engine suffer from the oil pressure switch problem or had GM rewired things?

[More Power]

We're re-running an article that appeared on the site a few years ago about Oil Pressure Switch (http://www.thedieselpage.com/features/sutsos.htm) reliability. Might want to have a look.

Along with the introduction of the piston oil spray blocks in late 1996, we saw a reduction in hot idle oil pressure. A side effect of lower oil pressure is that this can coincide with the set point for many oil pressure switches. In these cases, idling can cause the switch to cycle excessively, which causes a short switch life.

MP

[nvmtnlion]

Thanks for re-running that! I have been looking at putting a relay to relieve the OPS since I got this truck. I see someone already did the thinkin' part.

[Kennedy]

A non functioning lift pump will typicaly NOT cause stalling or even startup issues provided there are no air leaks. You will typically notice an inop. lift pump under heavy load.

Coming VERY soon, I'll have a lift pump control ckt that uses it's own OPS and only "senses" the switch position. It also runs the pump at at keyup for prime function, and has a manual activation switch for bleeding filters. Last round of prototype ckt's have been tested, and now the wire length details are being finalized...