ozzy

I'd fitted my SPA digital gauge donkey's ago, including the Oil Temp sender, but since the Oil Pressure needed the alternator removed to fit I put this off until I found out how to do it properly.

Well last night I installed the Oil Pressure sender and plugged the signal wires into my gauge and finally started to monitor the temp & pressure.

I started the car last night and check for any oil leaks - thankfully it was dry as a bone. Pressure peaked round 118lb and the temp steadily rose to around 60 degrees C before I switched off for the night.

Started the car this morning and the pressure jumped around from 92, 85, 93, 90, 95, etc. whilst temp steadily climbed from around 20 degrees C.

Again checked for leaks whilst the car warmed and still nothing.

Jumped in a drove to work (20min motorway). Temp climbed steadily all the way to around 86 degrees C, but the Oil Pressure would jump between 85lb do to 65lb, but on average it was around 80.

Came off the slip road to first set of traffi lights and the low pressure light flashed as it dropped below 30lb's. A blip of the throttle saw it jump back to 70, but as soon as the revs dropped it shot back down again.

I pulled into the office car park (it's right off the roundabout) and it sat idling around 22lbs (but still jumped as high as 25 and as low as 20).

I popped the bonnet expecting to see oil everywhere, but the engine's dry with absolutely no leaks around the senders.

I checked the oil level on the dipstick and it's at the 2nd small hole (I don't have my owners manual in the car, so can someone confirm what the levels are?)

Help, I'm very paranoid now. Maybe it's just a duff sender or the signal/connectors are faulty

Stefan

pban

Ozzy

I have SPA oil temp/press gauge and the oil pressure at idle in a little over 2 bar (approx. 30 psi) and I use Mobile 1. I know that various oils influence oil pressure a little. Hope that helps.

Paul

ozzy

Hi Paul,

What does your SPA gauge read? lbs and degrees C or have you set it for something else?

I read last night after I fitted the gauge that the oil will affect the reading, but my worry is the wild swing. I really would like to know if this is normal behaviour or not.

Does your oil pressure stay relatively constant on idle or is it jumping all over the place like mine does?

Stefan

pban

I have the SPA setup to read bar and degrees C. Normal-ish temp is anything between 80-100 degrees C, max I have seem is 106 degrees. To be honest I can say buy how much the pressure jumps around as I haven't sort of watched it. I'll have a look tonight on the way home though. I have the low pressure on the oil set to 1.9 bar I think and occationally you get the odd flash from the warning light but this is set loads higher than the standard low pressure which which is 10 psi I think. What oil are you running?

Paul

alcazar

iTrader: (2)

Do you mean it jumps around when you hold the engine revs constant?
Mine is on a Defi gauge: it idles at 2bar, jumps up very quickly on revving the car to about 6bar with the engine hot, and as much as 8bar with it cold. I use Mobil 1.
The only time I see it change, is a very small flicker, less than 0.2bar if I sustain high speed.
Alcazar

ozzy

Yes, if the car sits idling (at constant rpm), the gauge still jumps around. This morning when cold it went 94.8, 93.3, 92.9, 95.1, 91.2, 93.6 (then I gave up writing them down).

The pressure is never stable. Constantly moves around like that (albeit it at higher or lower values).

Since theirs no leaks, I can't see the car actually having a problem. All I did was remove the alternator, alternator belt and OE pressure sensor. All was re-fitted and I checked the belt tension and made sure there were no leaks.

Is the gauge reading correctly or is the sender/wiring duff?

Stefan

[Edited by ozzy - 9/22/2003 10:43:26 AM]

AlanG

It could also be how the sampling rate is set for the gauge.
Reduce the sampling rate to say once a second and see how it looks.
If it samples several times a second the readings can look very *jumpy*.

And reduce the accuracy you read on the gauge i.e. set for say 84psi on gauge and forget the 84.Xpsi

Alan

[Edited by AlanG - 9/22/2003 10:42:01 AM]

ozzy

bar? was that in 'real' money

OK, the gauge is set "as-is" straight out the box. Alan mine measures in lbs and degrees C. Did you specify bar or did you change the gauge readings or are you just converting yourself?

Stefan

AlanG

Hi Stefan
Just edited my last post.....hmmm..

You can set the gauge yourself for whatever you want degrees centigrade or fahrenheit, Ibft or bar etc

You'll find it in the manual

Alan

AlanG

Same with sampling rate etc.
If you want to give me a bell tonight i could take you through it if you don't have a manual.

Alan

ozzy

ah, that's what it's for

OK, I'm starting to **** pebbles instead of bricks now

I guess if the car's been 100% (had it's 60K service last week) and there's no leaks, then what the gauge is telling me could simply be the setup or false readings.

Is that a logical and safe assumption?

Stefan

ozzy

Thanks Alan. I'll check the settings in the manual and if I'm stuck (or just stupid) I'll give you a call.

Stefan

AlanG

Sounds like set up.
It actually tells you in the manual about setting up sampling rate to take away the worry of readings jumping about and giving you the jitters..... ....

Alan

Hakon

ozzy, try changing the pressure setting to bar and then have a look. As the spa system is very accurate to .o bar/psi it may look like its fluctuation greatly when in fact it really isnt. On idle, hot or cold (bar) i get a little fluctuation in the .0 scale but not the real numbers.
I think the red back light offsets the green dash very nicely
Hope it helps
Gervase

ozzy

Ahoy Gervase,

I'm off out for a run, but I'll try changing all the settings when I return.

What have you guys set as your alarms for min/maximum for pressure and temp?

Cau Stefan

ozzy

Me again.

Ok, I changed some of the settings on the gauge and turned the HR1 (high resolution ch1) setting to off.

I can't see any settings in the manual to adjust the sampling rate other than that one.

Anyway, in PSI mode it still jumps about 88, 92, 95, 89, 92, 88, 93, 95, 93, 91, 88, 94, 89, ..... and so on.

As I approach my exit (after about 20mins driving) it's dropped to around 70 (it's settled around that mark, but still jumps about as above).

Then as I brake off the slip road, it drops (well plummets) down to (and hovers) 20-25 psi. Alarm is set @ 24psi/1.7bar IIRC so starts flashing like made. If I blip the throttle it shoots back up to 40-50.

On idle it bounces around 22-25 psi. I changed it over to bar and it reads 1.8, 1.6, 1.7, 1.8, 1.6, 1.7, 1.8, ........

Car drives fine, feels fine and sounds fine

Stefan

pban

Ozzy

Checked last night for you

At idle it fluctuates between 2.6 to 2.9 bar @ 75 degrees C using Mobile 1.

Paul

ozzy

Paul,

What Oil would a Dealer normally use? or are they all different?

Stefan

pban

Stefan

Thats could be anything but worth finding out as it will affect the oil pressure. I know Bob Rawle said that he saw an increase by 1 bar when using Motul.

Paul

Hakon

Hi Ozzy,

Just been out to check my oil pressure values for you.
My98, castrol rs 10w-60

Cold idle. at 22c i get between 6.72 and 6.81 bar fluctuations or 97.47 - 98.77 psi

Hot idle. 84c... btw 2.88 - 3.08 bar or 41.77 - 44.67 psi

I have set my low pressure alarm to 1.9 bar. 27.6 psi
Hot oil temp set to 110c, i have only seen 105 once on a prolonged 100 mph + motorway run.

pressure convert http://www.convert-me.com/en/convert/pressure

Hope it helps
Gervase

ozzy

Thanks Gervase.

OK, I understand that the type of Engine Oil used will affect the readings and you guys have been very helpful setting some benchmarks.

What I don't understand (and what is worrying me most) is my readings seem to fluctuate so widely and my Hot oil pressure seems very low compared to you guys.

I'll take a video clip of my readings and you guys can hopefully see for yourselves and see if I'm being paranoid over nothing.

Thanks,

Stefan

nom

Leaping about quite a bit is normal - and the downside of digital guages! In the grand scheme of things, the fluctuations you are getting don't sound out of the ordinary.
Oil type makes a whopper of a difference. If you have a dealer-supplied cheapo oil in there, your oil pressure is likely to vary more than if you have a good oil; also, idle pressure will be lower.
I can't remember at what point it all happens, but at some rpm or other the pressure should stop rising - the oil flow is mechanically driven, so at idle it will be/should be lower (except at start-up when the oil is thicker, which is a good thing! ).

Switching your readout to bar will make the readout a lot less 'nervous' as a bar is so much larger.

If I were you, seeming that you've checked for leaks, etc., I'd take whatever is going on now as 'ok' and then just watch for changes - particlarly when above 2,500rpm or so (again that rpm when things should settle would be helpful here ). Basically, if you're on the motorway cruising & the guage reads about the same as usual (6.5 bar or so?), you're ok. If you look one day & it's down to 4 bar, something's up!
Also, you'll find you want to standardise on your oil more. It's suprising how much the oil pressure can fluctuate - at a service we ran out of Motul so stuck in some of the 'approved' Esso (Shell?) semi-synth & the hot idle pressure dropped from the usual 2.8 bar down to 1.9 - gave me a shock, that did! Shows the advantage of a good oil . Motul went in rather sooner than when I first planned

[Edited by nom - 9/23/2003 1:12:54 PM]

ozzy

Cheers Nom.

I'll ask the Dealer just what gloup they stuck in the car and at least that'll give me an idea as to what the readings should.

I guess I just don't know what should be normal for my car. If someone says they're reading 6 bar and mines 2 bar, then that's bound to raise my eyebrows

There's definitely no signs of leaks around the pressure sender - I was meticulous over that.

Stefan

pban

Stefan

I watched the pressure on mine for a while then decided at the level for the LP warning so it a little lower than the average low, it flickers sometimes especially when crawling in traffic but at least I will get as early a warning as possible to any trouble.

Paul

[Edited by pban - 9/23/2003 4:43:00 PM]

ozzy

Yes?

pban

You are just too quick mate!

ozzy

quicker than sh!te off a shiney shovel

pban

I would check the oil type you have been given by the dealer though.

Paul