Injectors misbehaving but trying to understand the numbers

[CitroJim]

Ahh, now I did not appreciate the CAN bus was talking directly to the glowplug relay Darren... I was thinking it was a straight on/off control line rather than a digital signal...

In that case, 2.6V is reasonable...

Sorry for writing a total load of rubbish in my last post - I'm good at that

Does Diagbox shed any light?

[darbuck]

Not at all Jim they keep changing how they control things to make it more difficult for the likes of us on older models you would be completely correct. Diagbox says p1350 and when I run relay activation it says open circuit

[Paul-R]

This has rung a little bell for me. IIRC measuring each side of the data wires to earth should give values that add up to exactly 5v
So 2.6 should be matched by 2.4v on the other. But you should never see exactly 2.5v on both as this indicates a short between the two sides somewhere. I hope I've remembered that correctly. Or closely enough.

[Vic Evans]

So got the ride on turning over it starts and runs for a couple of seconds and then shuts off. I think the carb needs looking at so will have to take it off and clean it up. I do have to change the carb bowl every few years. there's a weird size o ring in it that I can never find a replacement for and the carb bowl is only about 30 quid delivered and I get 4 or 5 years out of it normally and it comes with a new gasket so something else to get this month.

Try the carb adjusting screws.
One of my strimmers had this problem so I stripped, cleaned & rebuilt the carb. umpteen times but problem still existed.
Left it at our local service place & when I collected it the guy said all it needed was a tweak of the mixture screw. I'd never thought of that as it was running ok(ish) the last time I'd used it.
He started it up to show me it was now OK & charged me 5€

[darbuck]

Thanks Paul and Vic both very good bits of knowledge.the only problem is I don't where to look for the other half of the 5v as it were

[darbuck]

Has anyone any tips on testing the relays themselves

[darbuck]

This has rung a little bell for me. IIRC measuring each side of the data wires to earth should give values that add up to exactly 5v
So 2.6 should be matched by 2.4v on the other. But you should never see exactly 2.5v on both as this indicates a short between the two sides somewhere. I hope I've remembered that correctly. Or closely enough.

Hi Paul when you say 2.6v and 2.4v my understanding of CAN is a square wave signal as such so you have 2.6v positive and 2.4v negative. Am I correct in this thinking?

[Paul-R]

...the only problem is I don't where to look for the other half of the 5v as it were

Data wires are usually a twisted pair so follow along the pair and keep testing. You can get break-out boxes as well.

I will have to look this up in case I am badly misremembering things.

https://www.ebay.co.uk/sch/i.html?_nkw= ... 40&_sop=15

[darbuck]

Hi Paul, I must be wrong then on the CAN network thing. The control wire is single. The wire I was calling the diagnostic wire is the ignition wire I have discovered.

[CitroJim]

This has rung a little bell for me. IIRC measuring each side of the data wires to earth should give values that add up to exactly 5v
So 2.6 should be matched by 2.4v on the other. But you should never see exactly 2.5v on both as this indicates a short between the two sides somewhere. I hope I've remembered that correctly. Or closely enough.

Hi Paul when you say 2.6v and 2.4v my understanding of CAN is a square wave signal as such so you have 2.6v positive and 2.4v negative. Am I correct in this thinking?

That's the way I'd understand it, yes...

Has anyone any tips on testing the relays themselves

Yes, have a look at the wiring diagram and if you can replicate the control signal(s) and any other needed conditions then a bench test is potentially possible...

Do you have the relevant wiring diagrams Darren? If you do, if I could see them it may help me answer the above question a bit more fully...

[darbuck]

Hi Jim I will root them out for you

[CitroJim]

Hi Jim I will root them out for you

That'll be good Darren

[darbuck]

Hi Jim, I think this is what you are after.

[CitroJim]

Thanks Darren, I'll take a look in a bit

[darbuck]

Excellent thanks Jim