oil pressure lost

[hummer_maxxer]

hey, i got an 89 ranger with the 2.9 in it and once it warms up it losses oil presure when reving under 1500. what goin on??? i only use this truck for trail rides and mudding so its not a big deal turning the truck off when i aint driving but its annoying. would i just be able to turn up the idle to 1500????

 

[IMenriched]

Do you have a factory sending unit for reading the oil pressure??....if so...they are notorious for giving false information. Best bet would be to get a nice mechnical guage to see where you are really at.

there is a screw near the throttle body/plate....& it looks to be a Idle stop....but...it is not , it is to set the corrtect voltage for the TPS....messing with that could alter overall runnabilitly. In other words you maybe scaraficing performance in another rpm band/range...and on the trail...that may not be desireable.

it would be alot of work but some have placed a thin washer in the pressure valve on the oil pump to boost oil pressure. but that would require dropping the pan and removing the oil pump...etc. note of caution...to thick of shim/washer and you'll blow the oil filter up

 

[BillupsOMally]

Shimming the oil pressure relief spring worked for me, but don't be too surprised if it doesn't work for you. The theory behind why it won't help is solid.

If you do go through with it though, I tried 4 washers under the spring the first time, that resulted in my oil filter getting pushed right off the truck. The second time I tried 1 washer, there was very little improvement. The third time round I tried 2 washers, that fixed my low oil pressure, but it's not as high as spec says it should be. (I'm not surprised considering I checked the rod bearings and they were probably toast more than 100 000 ago. ie. BAD.)

After the first failure, I didn't even bolt the oil pan back on before testing the second time, I left the motor lifted off the mounts, and just held the oil pan, with old gasket, in place with a jack underneath it. This made reshimming the spring after failure #2 a 5 minute job. Being that lazy is a terrible terrible idea though, and I wouldn't recommend trying it, because if you do I guarantee the sky will fall, ending life as we know it.

I have a 2" body lift which made the whole job very quick and easy. You could probably do it start to finish in about an hour.