gricec

Have an early 85 that I am running rotella 15w-40 in with a porsche oil filter.

When the car is hot and after running it pretty hard the oil pressure at idle reads around 1 - 1.25 bar. When I press the gas it will peg at roughly 2500rpm. On a normal run I get around 1.5 -1.75 at idle. To me this seems a little low although I have no lifter clatter and the idiot light has never come on.

Cold idle the guage is pegged. After about 5 miles of driving I get 3 bar at idle which progressively lowers to the usual 1.5 -1.75. It also takes about 5 seconds for the guage to read the full 5 bar on a cold start

Also when I turn on the accessories lights etc I lose over half a bar of pressure. is this normal. i have cleaned all the grounds bar the two under the dash

The sender is new and i have cleaned the OPRV to no difference. Im also thinking of putting in some castrol 20w-50 to see if that makes any difference.

Is this all within normal range or should I start prepping myself for some work. I am thinking could be the pickup tube if anything

luftpirate

I have not noticed any accessories affecting gauges in my early 85 and I believe everything is currently working as it should. I would start with cleaning ALL the grounds, then purchase a cheap aftermarket mechanical oil pressure gauge to validate the stock gauge.

This thread should get you started.
https://rennlist.com/forums/924-931-...g-grounds.html

gricec

yeah I have got to most of the grounds. just have to do the ones under the dash.

What is your warn idle oil pressure ?

VirginiaF1

Howdy!
I run fresh Rotella dino 15w-40 and hot idle is 3.5bar..

New OP sender, cleaned grounds, new oil cooler kit and correctly installed/tested OPRV...

Cold (50F ambient) idle is 4.75... 3k revs = 5bar till water temp hits ~170F.

We conjectured last year whether my oil journals are 240,000 mile-clogged resulting in higher pressures than you are seeing?..

gricec

Thanks for the response.

Mine is quite a bit lower than that when warm. The cold is the same though.

My old 84 used to idle at around 2 with castrol gtx.

Ben951S

Your owners manual tells you this... also mentions it's okay to be so low and have the occasional warning light flicker... all in the owners manual.

gricec

Ok back to looking at grounds.

A couple of months ago I replaced the DME as a couple of pins were fried. When I replaced the DME i noticed that pin 19 on the harness was burnt. This is a ground according to the electrical diagram but it seems like that 16 & 17 are also grounds. The car has run well apart from this possible ground issue for the last 3 months. If the DME cannot ground through Pin 19 would this cause an issue or would it ground through the other grounds.

Excuse my lack of electrical knowledge.