Oil light flashing up

[ewenmaclean]

Hello again,

I had a problem with the sender for my gauge when I first installed it - you might be able to calibrate it as I could with mine. If it's reading above 0 at e.g. 2000 rpm, I would see if it the gauge has a screw calibration thingy at the back. If you do, get a wet reading for a tick-over when fully warm and calibrate it from there.

Ewen

[Rich Tea]

Hello Kevin, Ewen

Thanks for your posts.

Glad to hear the wet readings were similar to Kevs, that's some peace of mind. I did think about a capilary gauge but assumed it would be difficult running copper pipe all the way from the back to the front (a wire sounded easier). On the cheapness front it was only £25 for the electric one so not too bad, but I did have to buy the remote T-piece which was about the same again.

Ewen

After a running the engine a bit longer I now get readings below zero and still no warning light (i checked and the light does work), there's definitly something not right with the gauge or the sender.

I was thinking about sending it back but I'm encouraged by your calibration suggestion. Perhaps you can tell me more. The instructions that came with the gauge were quite poor so are of no help. The only feature on the sender is the single stud coming out the centre (where you attach the electrical cable). The only thing I can imagine that could be adjusted is the first nut that sits on that stud. Is that what you're suggesting, or was your sender different?

Cheers

Rich

[pocolow]

My 1.6td has an electrical gauge and when warm reads around 20-25 psi on tick over and 40 psi at around 30-40mph on the flat.

[ewenmaclean]

Hi Rich,

With my gauge I had to go inside the electrics and there was a potentiometer there (like a very small volume control or some such), and I turned it until it read the same as the wet gauge. It is also possible in your case that the gauge and sender are just the wrong types - in which case it might be an idea to send it back. I remember also that some senders have opposite polarity to others depending on what gauge they expect, in which case it will read about 7 bar at tick over and decrease to 5 when revving! I'm afraid I don't know the insides of a Tim gauge so can't really help with that.

I'm sure the wiring is all correct and good, but it'd be worth checking the connection to the sender is good, the earth is good there through the t-piece (my extended alluminium t-piece doesn't conduct earth from the engine block), and that you haven't accidentally got a bit of an earth leak on the wire going from the engine bay to the gauge - e.g. losing a bit of plastic sheathing and rubbing against bare metal....

Ewen

[Rich Tea]

Ewan,
Thanks for your reply.

Can I ask did you do your adjustment on the sender or on the gauge?

The TIM sender has a swaged joint on it so the only way into it is via the insulated washer around the stud, I'm not convinced there's access for fiddling purposes though. I'm not sure if I can get into the gauge itself, it might be worth a look.

Ref your other suggestions,

I have to assume the gauge and sender are compatible as the TIM one is included with the gauge in the same box, so I've got to assume they match.

For the sender earth I drilled a hole throught the rubber lined P clip and put a self tapper through it into the T- piece. I checked the conductivity and it is earthed ok.

I've run two different cables from the sender (one directly through the van) to the sender to the gauge and they give the same reading so no risk of an earth leak.

I'm still fighting it, I'll let you know where I go from here.

Cheers

Rich

[ermie571]

Hi mate,

although I don't have any op issues at the moment, this thread has been very interesting reading.
Could I ask a favour? That you take some pics of your op sender and guage, and its fitment?
Huge thanks

Em
xx

[Rich Tea]

Hello Em,

Will take some pictures next time i'm at the Van (it lives in storage about 8 miles away). You may have to be patient I'm afraid as I'm not likely to get anywhere near it until the weekend at the earliest busy week at work and dark evenings don't give much opportunity to play during the week.

As I said somewhere before, I seem to have more time to talk (and worry), than I actually have to work on it.

I may need some tips on adding photos to the forum as I've not tried it before.

Cheers

Rich

[syncrosimon]

The cheapest fix for this is to make sure that your tick over is set at the right speed.

I run my bus on fully synthetic which gives noticeable lower oil pressure at tick over, I have set off the warning light by dropping the tick over rpm below 650rpm.

If you don't use the bus very often, or park her on a slope you are much more likely to hear the valve clatter. If when the engine is in regular use you don't get clatter then I would not worry about this.

The clattering can be reduced by regular use, and re-setting of the hydraulic tappets.

The other thing that can cause the oil light to come on is submersion in water, but I don't suspect this is an issue with your bus!!!

For a gauge this is what i did.

Here is the m10 x 1 extension hose about 70 cm long.


Here is the dual sender for gauge and warning light.


I have a oil temp, pressure, and a lambda probe up front.


Hope it is a simple fix.

Simon.

[ermie571]

Simon,
thanks for those pictures...certainly makes it plainer for me.
Does that sender do the oil temp as well as the pressure, or do you have another sender for that? Is the original sender wiring attached to the one in your hand? Sorry for all the numpty questions....

Em
xx

[ewenmaclean]

Hi Rich,

I used a cheapo gauge as I happened to have it, and a separate sender - I got into the electrics and fiddled with it and now it reads the same as the wet gauge. It sounds like that's not an option with yours. If you're getting different reading from wet and electric and your earth is good then if you ask me it's a faulty sender or gauge. If you've got a potentiometer around (v cheap from maplins e.g.) then you could test the gauge is at least working by connecting the sender to earth through the potentiometer pins. I can't find any info on the TIM gauges but mine operates between 10 and 180 Ohms, as do the VDO gauges I think so that's probably a good guess. Fairly easy check both gauge and sender if you've got a multimeter and the wires are all already in place.

Let me know if that makes any sense or not! It does seem to me that either the gauge or the sender are wrong.

The advice from Syncrosimon is reassuring, but it don't think it explains the difference in values between wet and electric... perhaps I'm wrong.

Ewen

[syncrosimon]

Em.

Yes the oil pressure sender has an output that connects to the VW loom, and an output for the gauge. the oil temp comes from my oil cooler plumbing, but can be taken from the front oil pressure switch, by replacing it with a temp sender. If you have a gauge then this is ok.
oil temp is yellow wire, and monitors oil temp on its way to the oil cooler.


Ewen.

No I don't think it does explain the difference?

Rich.

The other cause of flashing oil light and other malfunctioning warning lights is the dash pod loom plug, but this would normally make your light flash until you wriggle the plug and get good contact. You can reach up underneath the dash and press the plug in, or remove and pry out the contact tangs in the plug so that it grips the blue contact tape on the dash pod side a bit tighter giving better contact.


PS I get around 12 psi on tick over when hot. This is very sensitive to RPM and will leap up with the merest waft of throttle (hence why tick over rpm is so critical). At cruise speed of 70 mph I will be getting 3 bar or 43 psi. I use the fully synthetic for cold start oiling, on cold start with dinosaur oil most of the oil is dumped back into the case by the oil pressure relief valve and little flow gets to the bearings. With the thinner fully syn you should get more oil flow around the engine, this is at the expense of hot tick over, which I am not to bothered about. When the oil cooler thermostat opens I can see a marked rise of around 7 psi in the oil pressure as the cold oil is used by the oil pump. (I only see this when the oil cooler is first used, and it does not use it round town, just on flat out or fast running) It is amazing how only 20 seconds of flat out will bring the oil temp up 10 degs or so.

[Rich Tea]

Cheers for all the replies.

I use a similar remote T-piece as Simon has, the sender looks a bit different though (one terminal not two). My T piece and sender is mounted on the left hand side of the engine bay, as far down as I could go without drilling in to the box section. The 500mm hose is just long enough (with some free play).

I've had plenty of problems with the 14 pin connector but it isn't applicable here as the oil light has been cut out of the PCB by a previous owner and another seperate light has been wired in (low rpm low pressure only). They cut the cable from the 14 pin connector to do this, so this can not be a factor. This is one reason why I want a properly functioning gauge (to keep an eye on both the low and high rpm low pressure warnings) for peace of mind. I think the fact the gauge is out of wack is stressing me more than not knowing.

Having though a bit more about Ewans tip, I think I remember a small hole in the centre of the back of the gauge with what looked like a small white nylon socket just visable. Could this an adjustable potentiometer? Unfortunately I can't play until Friday, so I'll have to patient.

Cheers all

Rich

[ewenmaclean]

Rich,

Small nylon socket - that 'might well be it! You might even have got the little pin to adjust it when you bought the gauge.

Failing that, do have a go at measuring the resistance of the sender and the gauge though - knowing the values when cold and warm would be very useful.

I suspect it's reading too high, and forgive me if this is all obvious, but do this: connect the middle pin of the potentiometer to earth, then connect either end pin to the sender pin at the gauge, AS WELL as the original wire - leave the third remaining pin unconnected. As you move the dial on the potentiometer the oil pressure will read between min and max.

If it's reading too low, then put the potentionmeter in series - i.e. middle pin to the sender unit, one of the end pins to the gauge sender wire.

Unfortunately the first solution will work to calibrate the result well at one value but quite possibly not at another since the rate of change will be logarithmic, and probably the sender has a linear change function.

Ewen

[Rich Tea]

Hello Ewen,

I got down to the Van on Friday and had a look at the back of the gauge. The Nylon socket was there but it's nothing to do with a potentiometer, it has a little brass disk at the bottom of it which had a small indent in the middle of it (looks like one of those reset buttons you poke with a ball point pen). Pressing it had no affect.

It sounds like you know your way around electronics, I hope you won't be dissapointed but I gave up and removed the gauge without any further checks. I'm convinced its at fault so I'm sending it back to where I got it from. Hopefully there will be no problem with getting a replacement.

For Em,
The photos you requested. You can see the braided hose of the remote T-piece running down (behind the wires) to the engine. The regulat pressure sensor is screwed into the top and sender is the big can coming out ot the side of the T-piece.

SENDER.jpg

DASH.jpg

I hope it helps.

Cheers

Rich

[HarryMann]

Could you (did you) mention where you sourced those parts (senders, tee etc) from (please)?