Oil pressure issue Duratec after wet sump refit

[Chris300]

Hate to ask for further help on this...

Background: car is a Supersport R 210, Duratec, wetsump. Link below is my previous forum post where i refitted the sump after a weld and had an oil pressure problem and the sump was leaking oil around the seal. Following advice given, i believe the sump is fitted correctly now and the sealant pattern was the issue (thanks John and 7 Wonders for sending the info needed).

https://www.caterhamlotus7.club/forum/techtalk/sump-heat-spot-and-sealant-pattern

The problem now, is that when i turn on the ignition the oil pressure gauge moves to zero from its lowest point (think this might be normal). When i turn over the engine the needle shoots to the highest point and then back to zero and stays there. So turned engine off straight away. There are no leaks visible. I have checked other posts (site:lotus7.club duratec oil pressure) and couldn't see anything the same, but does this sound like the sender unit is faulty? 

Edit: uploaded video as a gif though didnt work. Here is a video with sound, but will be a temporary link link: https://linksharing.samsungcloud.com/uZ15RjFUWxWG

Thanks!

[Jonathan Kay]

"I have checked other posts (site:lotus7.club duratec oil pressure) and couldn't see anything the same... "

Good search strategy. But I now use "site:caterhamlotus7.club term1 term2... ". The old sitename does work but I don't know if using the new sitename finds more.

Jonathan

[Jonathan Kay]

I know that modern Sevens flick their instrument needles, but does that happen at Ignition ON or when the engine turns over? Is it the same for all of the instruments, including the oil pressure gauge, and has it always done it?

Does it have a separate sensor for an oil pressure warning light?

...

With traditional senders and gauges you can test the sender and the gauge separately. Disconnect the sender from the loom.

1 To test the sender set a multimeter to resistance and if there are two terminals on the sender measure between them and if there's one measure between that and earth. Measure at rest and as the engine turns over for a bit.

2 To test the gauge: turn the ignition ON. Touch the signal wire which connects to the sender to earth and watch the gauge as you do this.

Please will someone correct this if it doesn't work with modern senders and gauges.

Jonathan

[Jonathan Kay]

Thanks for adding the video.

I think that's a traditional all-analogue set-up.

So any flicking to full scale deflection is abnormal.

And testing the sensor and gauge as above should work fine. 

(And I'd get on with identifying a replacement sender and supplier in parallel... Redline?)

Jonathan

[Chris300]

Thanks Jonathan. Added a video to the post showing the issue more clearly. All instruments to seem to flicker with ignition ON. Not sure if there is a separate sensor, will see if i can work that out later today. Will also have a go at the tests suggested, thanks, and will keep an eye on any additional comments on testing the modern gauges. 

[Chris300]

Thanks, our messages crossed. Will do the tests. Also thanks for updated search term :)

[Jonathan Kay]

Crossed posts.

: - )

Jonathan

[Tony Whitley]

I fitted a mechanical gauge to my wet sump Duratec and it goes over 100 PSI with new oil when cold which disconcerted me somewhat but it's been fine for thousands of miles since so I'm not that surprised that yours goes full scale - what did it go to before you had your sump problem?  The way it goes below zero shows an electrical problem and probably the oil pressure is fine - my previous K Series did it once on the M3 but that turned out to be the alternator coming loose and resting on the pressure sender connection!

[Amos91]

Unplug the injectors, then just turn it over for a little bit and see if the gauge comes back to normality. 

[Chris300]

Hi Tony,  before sump issue it was completely different behaviour would idle at about 1.5 to 2 bar and go as high as about 6 with full revs. 

[Chris300]

Thanks Amos, will add that ti list of what to try and report back 

[Chris300]

Hi Jonathan, have tested the sender. Found difficult to do in situ so took out. Has four pins. Looking top down in photo, the two bottom pins have continuity, but not sure if thats the correct result?

Tested signal wire of gauge with ignition on and when earthed needle goes to highest point, so seems good. 

[Jonathan Kay]

I don't know how the four pin sensor works. I'll have a look in the archives. Can you get the wiring colours from the connector?

This diagram is labelled as being for the Stack dash but I'd guess that it's what you've got.

And do you have a separate sender/switch for an a low oil pressure warning light on the dash?

Jonathan 

 

 

[John Vine]

Hi Chris,

That gauge behaviour is very odd, and certainly abnormal. 

It would be good to test both gauge and sensor before you embark on costly replacements. 

Is your sensor a Caerbont PTR5000-4N-12SPR?  If so, I could lend you my old one (replaced when I went mechanical), together with my old gauge (like yours but with silver dial).  Note that I'm abroad at the moment, but could probably ask my neighbour to dig out the bits and post them to you. 

JV

[Chris300]

Hi Jonathan, there is an additional light it's thisndash setup:

Here is picture of connector:

Green, black and orange/green 

 

 

[Chris300]

Hi JV thanks for reply. Tested gauge, as in connected signal wire to earth with ignition on and it shoots from lowest reading to highest. Guessnthat means its doing what it should? 

Working on test for sender with Jonathan and any pointers would be appreciated. Thanks for offer to borrow the sender, where you based? Cheers

[Jonathan Kay]

Thanks

https://www.caigauge.com/documents//pdfs/pressure-transducers-383.pdf

(That's PTTR rather than PTR but it makes sense.)

Jonathan

[Chris300]

Thanks Jonathan, great bit of info. So my gauge looks to be ok and pin 1 and 2 have continuity on the sender when connected.

Have seen videos of testing diaphram with air and also in water. Could also give that a go possibly. There might be a weep on the sump at weld, just cleaned and will look later. Guess that shouldn't interfere with preasure, if very slight? 

If sump is leaking will have to bite the bullet for a new one. Or used good condition possibly. It's a bugger! 

Thanks  

[Chris300]

Also this is the sender I took out:

[John Vine]

#16 and #19:  That looks like a Variohm Eurosensor rather than a Caerbont, so I'm afraid my sensor wouldn't fit your connector. 

A full sweep on earthing confirms the gauge is working ok.

JV

[Chris300]

Thanks JV

[jbcollier]

Go and buy a cheap mechanical gauge.  Test it against a bicycle tire pump to get an idea of how accurate it is.  It doesn't need to be accurate, just consistent.  Hook it up and start the car.

Same behavior?  STOP  There is a mechanical issue in the engine.

[John Vine]

#13:  That image shows a round connector, which is what my Caerbont sensor has.  I don't know whether the loom wiring for the Variohm would be the same, but my guess would be yes.

#22:  I'd go a stage further and suggest converting to mechanical permanently, using the Think Auto OPG100. It would provide much more accurate and reliable pressure readings.

JV

[John Vine]

#23:  Looking more closely, that wiring diagram (in #13) is a bit misleading.  The round (Stack) connector shows four wires, while I'm pretty sure my non-Stack round Caerbont connector has only three, and probably the same as Chris' Variohm. (I can't check at the moment.)   Also, the non-Stack connection is via two spades -- I definitely don't have those.

JV

[Chris300]

Thanks Jbcollier, think I might head down machanical route