cossie

I drive a 1990 C2 Tip, on standstill traffic earlier the oil pressure light suddenly went ON and pressure was around .25 or almost 0, then I noticed that my idle speed was kinda low - it sat on the 2nd line below the 1000 RPM mark (is that 400 rpm??) on either "D" or "N". Oil level was in the middle, oil temp at 9 o'clock, no stalling, no miss, RPM was stable - in short everything was fine except for the oil light & low RPM. The low idle dropped that low whenever at full stop - so the oil pressure would light up every time. What can be causing this?

I just brought out the car for a spin after a month in storage and this happens. Previously, given the same traffic condition my oil pressure was slightly below 1 bar (around .8) and idle speed at the middle of the 1st & 2nd line under the 1000RPM in "N" and slightly lower on "D".

Since oil pressure is a variable of idle speed - I am thinking that there is nothing wrong with any of the oil pressure components and it is just caused by the low idle. Having said this, can I increase the idle by turning the screw on the throttle linkage rest stop? This way I achieve the correct idle speed and likewise increase oil pressure - thus avoiding the oil pressure light turning ON again next time.

Thanks for your inputs.

Rocket Rob

As far as I know, you cannot adjust the idle speed. Its controlled by the DME via the ISV (idle stabilization valve). When the oil pressure / RPM is low, does the oil pressure come back up to normal if you raise the RPMs slightly? If yes, the I would say your internals are probably ok.

FeralComprehension

I believe if you look in the owner's manual you'll find a statement that an intermittent op warning light at hot idle is ok.

Blown Away

Before you try and adjust idle speed at the linkage, suggest you check other things first given it was previously fine.
Two lines under 1000 rpm will be 600 - a bit low.

I don't know much about TIPs and how it links with the engine electronics.

Check your distributer belt hasn't broken aned clean up all the electrical terminals on the injectors, and all those little electrical plugs on the engine including the ISV and the oil pressure switch which is burried on the top back centre of the engine behind all the intake stuff.

If that doesn't work, suggest you try and get it plugged in to a diagnostics system and see what that throws up.

Rob.

cobias1

+1 on the diagnostic. Maybe its getting rid of the old gas that was in it while in storage. With the car being in storage for a month I would look towards a diagnostic, and maybe dme reset if nothing is obviously wrong via sight check and fresh fuel doesnt make a difference.

Navaros911

Don't adjust your idle through the cable. The 964 is not supposed to work that way. As stated before, the electronics take care of it.

Have the fault mem read. Check if the idle switch "clicks" when you release throttle all the way. Easy to do in the engine bay without the engine running. Get someone to step on the throtle and gently ease off... You should hear a click.


Had the same issue as you are describing and it was remedied after cleaning the ISV, replacing a seal between the air flow meter and the airfilter housing and cleaning the AFM. Can't say what it was, but it wasn't doing giving me warnings anymore after it.

Good luck.

NateSaJack

Hi I get this when engine at temp, on warm to hot days when I stop at lights, the moment I pull away the warning light goes out. Did a lot of research when it first happened as it did worry me, result, perfectly normal so I don't give it a second thought anymore.

cossie

Just an update...

I temporarily fixed the issue by unplugging the oil cooler fan sensor socket - hence, the fan always runs at high speed. In this 90' weather I now maintain my oil temp around 8'o'clock and oil pressure around .9 at idle. No more oil pressure light coming on...

Question: is it ok to keep this set-up?

Vandit

You can use a resistor to lower the fan engagement point.

More here
https://rennlist.com/forums/964-foru...n-by-212f.html

and pics from my thread here, halfway through the 1st post.
https://rennlist.com/forums/964-foru...ew-months.html

HalV

^+1... I also get this on hot idle when stopped. Goes away when I pull away. I have a LWF and the idle always seems a tad low.

Quadcammer

even at 600rpm, you should be seeing close to one bar of oil pressure. That is the bigger concern here. Raising the idle fixes a consequence and not the root cause.

what oil are you running? I would manually verify the pressure as the gauges aren't terrible accurate.

HalV

I'm not sure if you're addressing your question to me or the original poster, but I use Brad Penn 20W50. I am seeing at least one bar of pressure normally, but as you said, the gauge isn't terribly accurate and bounces around a little. I don't know if it's the sending unit or the LWF that causes it to bounce. In any case, other than this issue the pressure reads fine, so I'm not too concerned.