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Can low oil pressure cause the engine to stall?
the dave - 7/8/07 at 06:04 AM

Question as per the title..

..upon braking i see the oil light come on then i struggle to stop the engine from stalling, and this isn't even under heavy braking.

I have a 2ltr silvertop zetec with twin 45 webers.

[Edited on 7/8/07 by the dave]


nick205 - 7/8/07 at 07:39 AM

It sounds like you need to baffle the sunp to stop the oil from sloshing around under braking (and accelerating and cornering). That should sort the low oil pressure warning problem.

The stalling is probably not related and is more likely to be related to the carbs and float settings


JimSpencer - 7/8/07 at 08:26 AM

Hi

Sure its not the other way around?

i.e. when you brake it's trying to stall and as the revs drop to stalling point you then lose oil pressure, that would be much more normal.

I would think fixing the stalling may cure both?


nick205 - 7/8/07 at 08:37 AM

Very good point - hadn't thought of it that way around!


andyace - 7/8/07 at 11:49 AM

If its the stall causing the oil pressure to drop could you not recreate this without moving by getting some high revs and then taking your foot off the accelerator quickly, the sudden drop in revs would cause the stall and drop the oil pressure.

Also you are dipping the clutch when you brake hard arent you


the dave - 7/8/07 at 03:30 PM

dipping the clutch, yes, cuz i want to change gear

I'll try and recreate the stall, but i've only ever seen it when the engine is hot.

Spoke to someone from raceline, and they don't think it would be oil related, and basically said it could be something wrong within the engine itself.

In all honesty, it's been an annoying problem as is getting beyond my knowledge, my current thoughts are get a stock blacktop to replace it and a raceline sump. Short of that i am clueless.


ChrisGamlin - 7/8/07 at 03:51 PM

It very unlikely to be anything "physical" wrong with the engine itself, its almost certainly going to be electrical or fuelling related so changing to a stock engine and putting on a different sump is not going to help assuming you planned on keeping your current electrical / fuel setup.

What does it idle at normally? This is not specific to Zetecs but this kind of problem is quite common on injected cars and can often be related to something like a blocked breather somewhere in the intake system, a faulty sensor not picking up the engine revs/throttle position correctly, or a dodgy MAF sensor meaning the fuelling is incorrect.

If you list your engine spec and what ignition / fuelling / intake system etc you use I expect people may be able to point you in the right direction.


the dave - 7/8/07 at 04:09 PM

At the moment it is as follows:

2.0ltr zetec
Tiger ERA Sump + Pickup
Tiger Fuel tank + facet fuel pump
Weber 45 DCOE carbs
Filter king regulator
Alpha ECU + loom+tps (came in silver kits with carbs)
Tiger Lightened flywheel.

The only work on the engine was a water pump and ARP conrod bolts, plus sparks and HT leads.

Hope this may trigger someones thoughts


Macbeast - 7/8/07 at 04:24 PM

Lightened flywheel, eh ?


C10CoryM - 7/8/07 at 04:29 PM

Its not anything mechanical, and the only time oil pressure will stop the engine from running is if there is a low pressure kill switch. Not likely to have one on your car. Very likely its fuel related.

When you go to re-start what happens? Do you need to pump the gas pedal? Clear flood it?
I am not too familiar with the webers, but common causes of stalling on braking are:
Low float level, high float level (floods), fuel being pulled away from the idle mixture ports, or just an improperly adjusted idle mixture.
I switched carbs on my camaro and one of them only had idle mixture in the front bowls, on heavy braking after a hard run the fuel would be pushed forward away from the idle ports making the engine lean and stall. Had to go back to the other carb which had 4 idle screws to fix that. Slightly thirstier engine than a zetec though
Cheers.


thomas4age - 7/8/07 at 07:50 PM

Yes it does!

I have a 4age 16v engine sitting in a corner, that used to be in my striker, but is enourmously worn out that no oil presure is present at all at idle and only very little on rpm. comming of idle the digital gauge goes quickly down from 10psi to 0.4 and then it decreases slower uptill the point the gauge has shown 0.0 for about 4 seconds and then it stalls

I initially had the plan to hammer the thing till it aint want to go no more, but restarting it infront of every stoplight became a little embarrasing

it's now replaced with a nice 20V and maybe I should send the 16 back to toyota for them to do a long term wear damage investigation on.

thing is, it just kept on going without loosing any power, I recall doing about a 1000mls before I got tired of the thing stalling every idle moment. still doing nice laps on track whith enourmous rattling noise but it wouldn't throw a rod (which would have hung nice on the wall of shame in the garage)

so in short YES very much!

You need to baffle your sump ASAP to keep oil around the pickup. I have a speedon shortened sump on my 20v and the light won't come on unless I put it agaist the wall i think.

[Edited on 7/8/07 by thomas4age]

ps: the grinding noise on startup was also something you couldn't mis even if you where in another closeby town hahaha.



[Edited on 7/8/07 by thomas4age]