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low oil pressure reading - intermittent

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I searched through a lot of the old thread on 'low oil pressure'.

A little scary - the guage reads '0' for a while - then bam - jumps up to the right reading, and behaves normally.

Then I go to start it a day later - sits at '0' again - then bam - all fine. If I rev it over 2000rpm while the guage reads '0' the 'check engine' idiot light comes on (as it should).

I am assuming this is a bad sending unit - starting to go - but thought I would ask for other people's experience. I would hate to find out that there actually could be a situation where the real oil pressure would be intermittent....


Lou Senko

Austin, TX

more, more, more....

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Could be a bad sender or just a loose conection. Check your connections and put some di-electric grease in there, you may have to recrimp the connectors a little to get a snug fit.

Or it might be a sticking gauge in the dash.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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I have the opposite problem . . . the oil pressure runs fine and then all the sudden it will ease its way up about 3/4ths up the guage . . . then settle back down, seems to do it at about 80 mph when i hold her steady there on the highway . . . thought maybe it was overcooling . . .but that seems like a stretch . . . it was happening mostly in the mountains when the temp was around 30 F . . .

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Lou,

I would remove the sender and then spray some carb cleaner into the orfice. Flush it several times as there may be something in their clogging it affecting its response. One thing I tried on my Twin Turbo Z was I drilled the orfice slightly larger. It fixed the sluggishness dramatically and gave INSTANT oil pressure response. If you are resigned to replacing it this is something I would try before calling JAE, etc for a replacement. If you do drill it out make sure you flush it with cleaner REAL good, and be careful not to drill beyond just the orfice opening.

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Hi all,

My turn for a couple of oil questions. This is a shot of my oil pressure gauge (obviously) (sorry about the quality- fone) but what I am concerned about is where the gauge is indicating. I presume the gauge is in bar. At idle yesterday coming back from airport, 28 deg C day, no real traffic to talk about, but sitting at lights at idle, pressure dropped under last line on gauge. Slight rev lifted the gauge up to between first and second lines. I also get tappet rattle on start up until oil pressure comes up. I am going to get the part number etc off the oil filter to confirm it has a check valve in it. Just wondering if gauge is indicating correctly?

Have not checked oil pressure with independent gauge as yet.

Thanks,

Michael

26122008001.jpg

Edited by ramjet

All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

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Ryco Part number is Z89A, "with anti drain-back valve". Though my belief is, (I could be wrong) that with the filter mounted on it's side rather vertically the "with anti drain-back valve" is never going to work. So it will always take a couple of seconds for the oil pressure to come up from a cold start. But I would do an oil and filter change, I use Castrol Edge Sort 10/60. At idle cold the neddle is almost off the gauge to the right, at operating temerature, (hot) again at iddle it will be at about 3/4s.


Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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Hmm Roger.

My gauge never gets past the half way point on the scale. Time for investigation unless there are other S4 drivers that get the same thing as me?

Michael.


All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

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Your gauge is calibrated differently to mine, mine goes from zero to 5. which doesn't seem to correlate to yours if it is bar? If I were nervous, and I would be, I would attach a real live pressure gauge, then I would know beyond doubt what pressure there is, rather than what an electric gauge is telling me.


Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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The manual says .35 bar at idle, 2.4 bar at 3,500rpm and 3.1 bar at 6,500rpm which seems to correlate with the marks on the gauge.

I will be getting hold of a real gauge to see what is going on. Also not sure what the PO was running as far as oil went. His mechanic did everything for him. Will contact PO and get hold of his mechanics name to see what he can tell me if anything.

Will also check spade connectors as well. All the obvious things before thinking the worst.

Edited by ramjet

All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

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I have read a lot over the the years about oil pressure reading with the esprit I bought my first esprit 1995 which was 1989 turbo seem to have low pressure readings and ever had any problems,. Now on my 2 esprit which is also 1989 but SE still see this low pressure readings. Especialy when it is very cold out like 5 F outside. Its take a long time to the gauge to come off 0 and low presuure light will only come on when you rev off 1000rpms. still no problems . I am not sure if the espirit guage is just more acurate than others showing us the ture reading or are others just less acurate not telling us of the truth of low pressure on start up with a cold engnie??

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in traffic just over the 1st white mark and when accelerating 3/4 of teh way up. (also 3/4) of the way up when cold otherwise normal driving is 1/2 the way up although i need to check the belt (get around to that some time this week)


It's Oogies turn to boogie

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Michael, your oil pressure photo correlates with mine at the same temperature and idle speed. Also never goes past half, 4 bar, except on start up when cold. With our summer weather run at least a quality 15-50 oil.

The filter should have both an excess pressure relief valve and anti-drainback flap. The last is half useless since the filter lies flat so oil in the top of the can can drain back to the sump after a while. There's an old post of mine where I cut open, photographed a few filters and the forum discussed this.

The excess pressure valve is only there if the filter becomes clogged due to never being changed. Or for those who top up their oil and never bother to drain and change. Doubt that would apply to these cars.

A worthwhile mod could be a remote filter held upside down with a thermostat bypass for the oil coolers.


DanR

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Michael, mine looks same too. When hot the readings are lower than when cold, naturally. When I start her up it takes at least 3-5 seconds before I get any reading at all. On advice of Steffen ar R&B I got the diameter of the oil pipe going up to the cylinderhead narrowed, to keep more oil in the crankhousing at higer rpm. Mine is now limited at 8100 rpm....

There was a good thread on Oils a while back, actually explains a fair amount about the pressure readings. I still use the Lotus prescribed 10W60 Castrol RS.... :)


Olaf S400 project www.esprits4.de

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Sorry to bring this one back to life but i have the exact same problem as you lou start up the esprit gauge shows almost no pressure, light rev oil light comes on.It stays like this unless i move the car somewhere even if its just around my car park then gauge springs back to life like normal? did you find the problem with yours?

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Roger, your oil pressure is fine. According to the manual (from memory) the pressure is allowed to drop to .4 bar-ish. The red line on the dial is at 1 bar so in fact the needle can drop into the red by half and still be okay (according to the manual). On a hot day mine will sit at .7 bar (in the red) at idle ,and will go to 2 bar with revs.

I believe on the S4 the sender is rated at 0-5 bar and the dial is rated at 0-7 bar - so that's one of the problems.

Edited by s4simon

Simon  (94 S4)      My Esprit will be for sale in late 2017

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I have a slightly odd problem. The oil gauge on my SE seems to be behave pretty normally, but when hot at idle sits just above the red section of the gauge. When I say just, I mean literally almost on the red. Based on some of the above comments that may be normal. However, when I rev the engine either out of gear or when driving, the red oil light comes on when the revs are rising (ie engine under acceleration) between 1400 and 1600. Always at these revs, never more or less, and not when the revs are falling. Any thoughts? The car has had a recentish oil change and the level is on Max.

Robert

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the warning light comes on whenever your gauge reading is in the red and the rpms exceed 2000 (i believe).

I have a low oil pressure readin g on startup for about 15-20secs, and if I rev it the warning light come on until the pressure gauge runs up into the normal range.

it does seem normal to have low pressure once warmed up - but I would be concerned if it went into the red....


Lou Senko

Austin, TX

more, more, more....

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Think this all goes to show the cars are all different, strange coincidence but just before I came on line I tokk my car out for a spin, started it up and I always let mine tick over for 2 or 3 mins before acelerating, today like a number of other instances the oil pressure gauge read zero for about 20 secs, I touch the acelerator to get it just above 1000 rpm and sh ...t the red light came on. then it went out and the pressure came up to normal, ie 1/2 way up the gauge.

This car has always been like this, I guess with the check light problem i get a bit paranoid.

I thinks its just normal, just do not rev the car as soon as you turn the key. Its simple!

Dave

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Guys, thanks for your help.

Quickr

The oil pressure never actually drops into the red.

Dave

Yes, I get low pressure on first start, and the red light comes on for a few seconds until the pressure jumps to normal. Like you, I am sure that is normal.

However, what I am talking about here is after a 20 mile run, say. Car is at full operating temp. I pull up to traffic lights and oil pressure drops to just above the red section (nearly crossing into red, but not quite). No red light while idling. Then when I pull away, as the revs get to 1400, red light comes on and stays on until revs get to 1600, then it goes out. It happens in all gears at the same revs (ie 1400-1600) irrespective of road speed, but only under load, never on the overrun.

Does that make sense?

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Mine is only on start up from cold, once its warm the pressure drops to just above red line on tick over - thats normal I think.

Red light at medium revs when hot, no, i'd be a bit concerned. Check switch as previous member suggests.

Dave

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Here's what is in the Service Notes...

Oil Pressure Tell Tale

This red tell tale is provided to warn of dangerously low engine oil

pressure. To prevent unnecessary concern at idle, an engine speed relay is used

to enable the circuit only at engine speeds above 1600 rpm. If the oil pressure

falls below 1.4 bar (20 psi) at any time above this engine speed, the tell tale

will light.

On,early cars, the tell tale is linked to the warning lamp check module such

that the tell tale will light when the ignition is switched on, and should go out

when the engine is cranked. On later 'revised harness' cars, no check module is

fitted, and as a lamp test function, the tell tale is linked to the battery

non-charging tell tale and should glow when the ignition is switched on. On

these cars, if the lamp lights together with the battery tell tale at engine

speeds above idle, it is likely that the fault lies in the charging system.

Oil Pressure Gauge

This gauge is calibrated in bar units and registers oil pressure as detected

by the sender unit in the oil gallery cover at the rear of the RH side of the

block. Under normal running conditions when the engine is warm, the gauge should

register not less than:

0.35 bar at idle; (5 psi)

2.4 bar at 3,500 rpm; (35 psi)

3.1 bar at 6,500 rpm. (45 psi)

Readings will increase when the engine oil is cold, and there is no cause for

alarm if very high readings are indicated after start up in cold weather.


1995 S4s

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Jim

That's realy helpful.

Attempting to apply some logic to this, does this mean that it is more likely to be a fault with the engine speed relay which is allowing the light to come on below (but never above) 1600rpm?

My logic being, these notes seem to suggest that, provided the oil pressure is 0.35bar or greater at idle, Lotus were not concerned about oil pressure unless, above 1600 rpm, pressure fell below 1.4bar. This means the oil pressure light is set to trigger at a pressure of less than 1.4bar, but is inhibited from registering this below 1600rpm by the engine speed relay. Therefore, pressure of less than 1.4 bar is normal below 1400 rpm, but a fault in the engine speed relay is allowing the light to register pressure below 1.4 bar at a lower rpm than is normal?

Is that logical?

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Very interesting reading for a new owner with oil pressure readings in the red!

The odd part is that if your oil pressure falls below 0.35 bar at idle, I expect the oil light won't come on since the speed relay is not enabled. I can get a very brief flicker of the oil light when taking off from a stop light, that must be when I pass 1600 rpm and don't quite have the 1.4 bar built up yet.

I'm going to tap into the oil feed line to the turbo to record the actual pressures on a gauge, just for peace of mind.

To prevent "unnecessary concern at idle" they should have put the red line on the gauge at 0.35 bar instead of at 1.0 bar.............I get concerned when I see gauges reading in the red zone.

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Manually checking the pressure for peace of mind is a good thing to do IMHO.

Here's how I did it recently on an engine I had just rebuilt:

IMG_1983.jpg


1995 S4s

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