Oil starvation, cooler and pump

[campbellju]

Whilst out testing the car recently and looking at maps etc, After I've accelerated hard in 5th upto around 5Krpm and back off, I get what appears to be terminal oil starvation. The oil pressure light comes on almost as soon as I back off and I can see the oil pressure drop. On all 3 times its happened I've reacted very quickly and engaged the clucth/neutral shortly followed by killing the ignition. Hopefully no damage so far. It only appears in 5th though at high load, not 4th or below???

My guess is its the oil cooler that is mounted at the front right (like Nissan WRC) with 1/2" pipes and a thermostat in the middle. My guess is at the engine speed/load, the pump is working so hard that when you come off the power its cavetating or something and stalling. I can re start the car with in 30s and its fine. I was discussing the problem with a friend but we both agreed its not something you experimant with.

Anyone heard of this before?
Jim

 

[neil240z]

maybe the gears are worn in the pump and are slipping at high rpm?

Neil

 

[campbellju]

Maybe. Its a new pump though after the build (cicra 5K) so I'd be surprised. Its something where testing could be dangerous.

 

[neil240z]

oh right, if its a new pump then thats highly unlikely.

 

[Boooooost]

My engine picked up on a big end I'd been having intermittant pressure faults. My oil cooler was front mounted and I had a new oil pump too. You def want to sort it or youll end up with a pile of bits like me

 

[pulsarboby]

your sump pans not bent is it? as this will obstruct the pick up filter at high rpm, or the pickup filter maybe blocked which will do exactly the same thing

 

[campbellju]

My engine picked up on a big end I'd been having intermittant pressure faults. My oil cooler was front mounted and I had a new oil pump too. You def want to sort it or youll end up with a pile of bits like me

That does it then, the oil cooler is getting disconnected. Its not a chance I want to take until I can find out more info.

What were the details of your fault and how did the your big end finally fail? Was it a catastrophic failure or just got worse and worse until it was always knocking?

Was it a newly re-built engine as well as the pump?

Cheers,
Jim

 

[campbellju]

your sump pans not bent is it? as this will obstruct the pick up filter at high rpm, or the pickup filter maybe blocked which will do exactly the same thing

I don't think so but if I still see it after the cooler comes off then the sump might be next.

BUT..... you might be on the right lines, removing the cooler, changing the oil and FILTER can only help as the filter might be blocked. After all, I am asking it to flow more oil as its travelling further.

Good thinking PB

 

[pulsarboby]

not the oil filter but the pick up filter in the sump pan im talking about!
they are very close to the bottom of the pan and pick up every little bit of crap there is floating about.
reckon thats the first thing to check.
it will take no longwer than half hour to do!

 

[campbellju]

Yep, I understood what you meant. I was just thinking the filter could be blocked too as its been given some punishment recently. I'm also expecting it to flow 15% more oil to the front of the car and back again through the cooler.

Once the oil is out it won't take much longer to check the bit you're talking about too. I'll have to look at the service manuals to see where it is on our cars. I can't picture it in my mind.

 

[pulsarboby]

undo the black bit right at the bottom of sump the actual pan!
then youll see it straight away, it looks like a big tea strainer:-D

 

[campbellju]

Yep, just saw a picture of it, I remember it clearly now. It will have been cleaned at the time of the re-build but that will have given it plenty of opportunity to pick up crap.

Another idea is that at high rpm, beacuse of the cooler, I'm getting a low level in the pan. The oil is all pushed to the back though under acceleration. Back off the throttle though and what little is left rushes to the front leaving air and a WTF from the oil pump.

Stupid or sensible?

 

[stumo]

possible

 

[Fast Guy]

I'd have thought if that was the case tho, it would be more likely to show up in 5th gear last as it's the slowest accelerating gear, ie it would definately happen in 1-4th.

 

[campbellju]

Yep good point, well presented.. My thinking was that in 5ht more oil has time to get pressurised into the oil cooler. (The Thermostat only blocks in the inlet to the cooler rather than the outlet).

Anyways, the cooler is coming off next time and the sump filter is getting cleaned.

I'll see where I go from there.

Thanks for all your thoughts.

Jim

 

[Boooooost]

It just let go no knocking before hand made hell of a noise when it did tho.

 

[Trip]

bringing this old thread alive again.

Hey Jim, did you find a solution to this. I have an identical problem though not on 5th gear.

 

[campbellju]

I did but nothing to do with the oil in the end. It was some mapping weirdness that caused the car to stall at high revs on the overrun. When the engine stalled all the warning lights came on but as soon as you dipped the clutch it bump started again. It was the flash of red lights that made me panic and post up.

 

[Trip]

I did but nothing to do with the oil in the end. It was some mapping weirdness that caused the car to stall at high revs on the overrun. When the engine stalled all the warning lights came on but as soon as you dipped the clutch it bump started again. It was the flash of red lights that made me panic and post up.

Thanks Jim. It is perfectly what my symptoms are. But mine is running on standard ECU, injectors and MAF :doh:.