Technical Earth strap check?

[1stDucato]

Learned here - thanks, folks - that poor starting performance can be due to bad connection between gearbox & chassis. Not that confident about removing strap to check it I was thinking of seeing if connecting a jump lead in parallel would improve things. lf it does, I might then be motivated to attempt the replacement of the braided earth strap. Is this a plan ?

 

[varesecrazy]

Learned here - thanks, folks - that poor starting performance can be due to bad connection between gearbox & chassis. Not that confident about removing strap to check it I was thinking of seeing if connecting a jump lead in parallel would improve things. lf it does, I might then be motivated to attempt the replacement of the braided earth strap. Is this a plan ?

Yes,

Just ensure you are actually on metal at either end

 

[1stDucato]

Yes,

Just ensure you are actually on metal at either end

Thank you for your interest, @varesecrazy. Executing the plan didn't give a conclusive result but your response plus the cumulative effect of fiddling around in the area gave me the confidence to extract the earthing strap. To my untutored eye it doesn't look that bad even though the label is consistent with it having been on the van since it was built. Are the attached photos clear enough for you to give your opinion for which I'd be most grateful. I will of course be cleaning the contacts as well as those on the van & protecting them with e g. Vaseline.

 

[NeilDD]

1st pic' shows signs of green Verdigris towards the lower end.
Probably water ingress where it goes into the crimp terminal

 

[1stDucato]

1st pic' shows signs of green Verdigris towards the lower end.
Probably water ingress where it goes into the crimp terminal

Thanks for that. I'd noticed that the strap was fitted with the 'open' side of the 'to be crimped' terminals uppermost which seems to invite moisture ingress. After soaking the ends in white vinegar for a bit & then lathering with 'Nocorode' red jelly, I re-installed it the other way up (this also meant the engine-side terminal sat flush on its mount whereas before the vertical lip on one edge of it was downmost & had prevented contact over all the two surfaces). Dissapointingly all this resulted in only a marginal reduction in cranking duration.....

 

[lycopersicum]

Not sure the vinegar would help as wires need to be smooshed together to make a good contact. So if the crimps were oxidized, they would need re-crimping after cleaning to improve the connection. I wouldn't expect just soaking in vinegar to do much, and acid residues could in fact hasten the demise of the braid.

But, it's possible that the strap wasn't the problem. Can you measure the voltage drop across the strap while cranking with a multimeter?

 

[Communicator]

Learned here - thanks, folks - that poor starting performance can be due to bad connection between gearbox & chassis. Not that confident about removing strap to check it I was thinking of seeing if connecting a jump lead in parallel would improve things. lf it does, I might then be motivated to attempt the replacement of the braided earth strap. Is this a plan ?

I am wondering what you mean by poor starting performance? My 2.8jtd typically takes about 3 compression strokes prior to firing. I reason that this is acceptable, because it it needs to receive a pulse from the camshaft sensor to determine the stroke, before injecting fuel. The cranking rpm is a different matter, but improving it could mask a failing injector that has excessive leak off.

 

[1stDucato]

Not sure the vinegar would help as wires need to be smooshed together to make a good contact. So if the crimps were oxidized, they would need re-crimping after cleaning to improve the connection. I wouldn't expect just soaking in vinegar to do much, and acid residues could in fact hasten the demise of the braid.

But, it's possible that the strap wasn't the problem. Can you measure the voltage drop across the strap while cranking with a multimeter?

Thanks again. I knew the Nocorode gell is formulated to neutralise acidity so that's why I thought the vinegar would be a reasonable play to get rid of any hidden corrosion. The crimps did seem to be quite tight afterwards. I'll need to wait for another pair of hands to be avaliable in order to make the measurement you helpfully suggest. But as you say this strap might not be the problem after all....

 

[Communicator]

Thank you for your interest, @varesecrazy. Executing the plan didn't give a conclusive result but your response plus the cumulative effect of fiddling around in the area gave me the confidence to extract the earthing strap. To my untutored eye it doesn't look that bad even though the label is consistent with it having been on the van since it was built. Are the attached photos clear enough for you to give your opinion for which I'd be most grateful. I will of course be cleaning the contacts as well as those on the van & protecting them with e g. Vaseline.

With acknowledgements to Motorhome Fun Forum. See attached photo of failing earh strap

 

[1stDucato]

I am wondering what you mean by poor starting performance? My 2.8jtd typically takes about 3 compression strokes prior to firing. I reason that this is acceptable, because it it needs to receive a pulse from the camshaft sensor to determine the stroke, before injecting fuel. The cranking rpm is a different matter, but improving it could mask a failing injector that has excessive leak off.

I've been instinctively cautious about cranking the engine more than 3 or 4 times & have generally found it takes 2 such attempts to start but sometimes it can be 3. We've only had the van for a couple of months & not used it much so maybe this isn't surprising; it does tend to start promply up to ~12 hrs after a run ( the battery has been tested & given the thumbs up). Your comment makes me wonder whether there is in fact anything to worry about....

 

[1stDucato]

With acknowledgements to Motorhome Fun Forum. See attached photo of failing earh strap

Well if that's a failing strap...! It looks much better than mine (although my connectors are now much cleaner than these). Thank you.

 

[Communicator]

Well if that's a failing strap...! It looks much better than mine (although my connectors are now much cleaner than these). Thank you.

It has orange cuprous oxide on the centre section., which is an indication of overheating.

 

[Communicator]

I've been instinctively cautious about cranking the engine more than 3 or 4 times & have generally found it takes 2 such attempts to start but sometimes it can be 3. We've only had the van for a couple of months & not used it much so maybe this isn't surprising; it does tend to start promply up to ~12 hrs after a run ( the battery has been tested & given the thumbs up). Your comment makes me wonder whether there is in fact anything to worry about....

You could consider a failing injector, as discussed on another thread.

 

[1stDucato]

You could consider a failing injector, as discussed on another thread.

Thanks. Maybe it's just been helpful to have ruled out the earth strap issue....