944 1984 2.5 lux. Oil pressure sensor problem, rough start and oil pressure valve question

james944 · Mar 11, 2013

Hi, I've had my 944 for coming up to a year and I am really enjoying getting to know the car. It's a 1984, 2.5 Lux model

When I bought the car it had a split in the oil cooler housing (after some research i found this was a common fault in the original part, so I had a newer design fitted). The new housing wasn't aligned with the special tool as we couldn't get hold of one. We did our best to get it in shape and didn't have any problem with the car until recently. The work was done 9 months ago. Everything worked after the new housing, pressure release valve and pressure sensor had been re-fitted.

Only recently in the last month or so the oil pressure gauge has become erratic, bouncing from 1 to 5 bars, some times settling but mostly flickering. It could be a bad ground but I just wanted to hear if anyone had any other ideas and if you know where the exact grounding is for the oil pressure sensor. Also at initial start up the car starts fine but until the engine becomes warm it sounds quite rough, if you gently put your foot on the accelerator its fine but it doesn't like to idle until its heated up.

One last thing, I salvaged the 'new' oil cooler housing from a breakers yard and it had the newer style oil pressure relief valve in it. My 944 still has the spring loaded valve in it. Could i simply put the newer solid one in it place?

Any help would be greatly appreciated. Thanks, James

andy watson · Mar 11, 2013

James,
Hi and welcome, owned her for a year and your 1st post!! where you been [

] sorry I can't help with the problem someone will be along soon who can no doubt,
If you don't already know we do like pics [

]

james944 · Mar 13, 2013

I have looked at adding a picture but it has to be 20 KB for a profile image. My files are all far to big for that. I know nearly a year already, you can see I signed up just to get some information from another thread back in August.

No-one seems to know what to do to help me though! Are there experts of people who may have dealt with a similar issue?

Mike_Pollock · Mar 13, 2013

Hi James
Not sure about the car but email me the pic to A9XXC@aol.com and I'll sort it out so you can use it .

944Turbo · Mar 13, 2013

Not sure on the compatibility of the 2 oil pressure relief valves, but if the gauge is flicking I expect the problem is with the gauge - earth problems are not unheard of on the instrument pod. Low oil pressure will not affect the idle particularly, bad earths might though! there are several earth pints around the foot wells and there is a big one at the rear of the engine.

good luck,
Tony

hotblack944 · Mar 13, 2013

ORIGINAL: james944
One last thing, I salvaged the 'new' oil cooler housing from a breakers yard and it had the newer style oil pressure relief valve in it. My 944 still has the spring loaded valve in it. Could i simply put the newer solid one in it place?

There are two types of "newer" style OPRV, one of which is a retro-fit for the original style. There's a good write up here (the cheeky blighter has even nicked one of my pics):

http://944foot2thefloor.blogspot.co.uk/2010/07/how-to-remove-and-replace-oprv-oil.html

944 man · Mar 13, 2013

My 1985 series one had a revised OPRV fitted in 1994. The usual symptom for series one OPRV trouble, was very low oil pressure at tickover which quickly rose to 3-4BAR when the engine speed was increased to 1,000RPM.

Simon

james944 · Mar 14, 2013

Thanks for your help guys. I will conduct a oil pressure test to check too see if it is the gauge that's faulty. And hopefuly diagnose that my groggy start is from a low oil pressure

Looks like I'm in luck with the 'newer' style OPRV as it is the shorter one that my model engine would require. Thanks for that link to the website hotblack944 it was really helpful