Volvo EC55 goes up in smoke

[Muz]

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Was trying to fix an electrical fault .. machine was blowing the 80 amp battery fuse, but could I find where the short was ? .. well... not until it burst into flames. The wiring loom runs under the engine mount and had chaffed through causing the grounding

Said loom was covered in oil from a hydraulic burst which is actually what I got called out to fix .. only for this electrical problem to appear at the same time.

We managed to get the electrical fire put out reasonably quickly, but all 16 wires in the loom got totally burned. It was panic for a moment or too, the machine started its self up during the fire and I had already removed the fuel cut off solenoid so had to stick my finger into the injection pump to shut it off before disconnecting the battery .

Ive rejoined the loom but she still isnt getting power to the cut off solenoid or the primer pump to feed the fuel system so wont start off the key yet .. I can bridge that circuit and she starts and runs fine .. but I cant seem to find why that section of the loom isnt getting power .. theres no damage anywhere else, and Ive replaced all the relays and glow timers etc etc .. any ideas guys ?

[Garry]

Hmm ... I assume the multiblocks are just a temp


Obviously (he says!!) the line is dead from somewhere .. have you got a schematic for the loom ?

[ianoz]

I guess just because it shorted and damaged wiring there does not mean the is not another spot it did the same thing . If you have power getting to the repaired section ,i would run a temperary wire from the repair joiner to the starter . If it starts , the problem is in the loom in that section ..Ian .

[Muz]

I spoke to one of Volvo's tech guys today who has helped by giving me a proper schematic, and it looks like power is not getting to the fuse box for that circuit, and is controlled by a master relay else where. I have run a temp wire to prove this, but ofcourse the engine wont shut off from the key, so I need to get that circuit up again .. so thats tomorrows job .. hauling the dash out next .. fun .. fun

And yes .. I'll solder the wires once I'm certain theyre connected the right way ..

I priced the rear loom section from Volvo and it was £370+VAT .. for about 1m worth of cables ?

[Garry]

I guess just because it shorted and damaged wiring there does not mean the is not another

Agreed .. could well be a melt or something elsewhere .. but hopefully that master relay will be the weak spot

[ianoz]

My Hino truck has a fault in it somewhere . Power comes up to the fuse box with about 50 other wires in the loom .Now ,it does not do it all the time but go to start it and the electric shut off won't go to the run position . Now to start it , i had to get a live power wire and put it on the fuse .Now you say ,that makes sense. But the UHF radio is also on the same fuse , so radio is always turned on with the ignition ,so put power to the fuse radio comes on ,got it ?. Well put the wire to the fuse radio came on , but the power wire slip out of the fuse ,but radio kepted working Turned the key engine fired up . . Got me buggered .

[Muz]

My Hino truck has a fault in it somewhere . Power comes up to the fuse box with about 50 other wires in the loom .Now ,it does not do it all the time but go to start it and the electric shut off won't go to the run position . Now to start it , i had to get a live power wire and put it on the fuse .Now you say ,that makes sense. But the UHF radio is also on the same fuse , so radio is always turned on with the ignition ,so put power to the fuse radio comes on ,got it ?. Well put the wire to the fuse radio came on , but the power wire slip out of the fuse ,but radio kepted working Turned the key engine fired up . . Got me buggered .

MIght have a fix for you on that one if I read you right the solenoid that controls the fuel supply on the injection pump has 3 wires going to it usually ... one is the earth the other two do two different jobs .. the main one energises the pull mechanism to allow fuel throu during engine start .. the second is a 'hold' current that keeps the plunger pulled out whilst the engine is running .. when you throw the key to stop.. you cut the power to the hold circuit,.. the plunger springs back and cuts the fuel and your engine stops running your radio might be on the hold circuit as its a constant live like a lot of things governed by the key switch

[FrankB]

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Was trying to fix an electrical fault .. machine was blowing the 80 amp battery fuse, but could I find where the short was ? .. well... not until it burst into flames. The wiring loom runs under the engine mount and had chaffed through causing the grounding

Said loom was covered in oil from a hydraulic burst which is actually what I got called out to fix .. only for this electrical problem to appear at the same time.

We managed to get the electrical fire put out reasonably quickly, but all 16 wires in the loom got totally burned. It was panic for a moment or too, the machine started its self up during the fire and I had already removed the fuel cut off solenoid so had to stick my finger into the injection pump to shut it off before disconnecting the battery .

Ive rejoined the loom but she still isnt getting power to the cut off solenoid or the primer pump to feed the fuel system so wont start off the key yet .. I can bridge that circuit and she starts and runs fine .. but I cant seem to find why that section of the loom isnt getting power .. theres no damage anywhere else, and Ive replaced all the relays and glow timers etc etc .. any ideas guys ?

Volvo eh? ........ Sumitomo originally If I'm right ? well it might be worth saving ... good job it wasnt JCB .. I wouldnt have put the fire out

[ianoz]

MIght have a fix for you on that one if I read you right the solenoid that controls the fuel supply on the injection pump has 3 wires going to it usually ... one is the earth the other two do two different jobs .. the main one energises the pull mechanism to allow fuel throu during engine start .. the second is a 'hold' current that keeps the plunger pulled out whilst the engine is running .. when you throw the key to stop.. you cut the power to the hold circuit,.. the plunger springs back and cuts the fuel and your engine stops running your radio might be on the hold circuit as its a constant live like a lot of things governed by the key switch

Problem is Muz ,that the power was not getting to the fuse box to go down to the shut off . Power is not like water kink a hose over water can't get through . Kink a wire and the power will still pass .What was happening , put live power on to the fuse ,then take it away it would work , It was like the electrons on how ever you want to put it were blocked from coming through send power back through the wire, the power would then come through.. I ended up cutting a jumper wire from just before the loom enters the cab ,and splicing it in to where it goes into the fuse box .Fixing that problem . Have had problems since with the shut off ,As you said the power is constantly on for the off position and the on one .

It would start up OK ,but when it came time to shut it off the motor to the cutoff would keep running , pull the stop cable then let it off before the engine stopped .Had to climb under and hold the actuator to stop it . Pulled it apart to find one of the wires had broken .But by the time i had finished soldering it back on the other two decided to let go .Soldered them back on and all is good once more .Ian .

[ianoz]

Volvo eh? ........ Sumitomo originally If I'm right ? well it might be worth saving ... good job it wasnt JCB .. I wouldnt have put the fire out

AHHHHH , your another disappointed JCB owner i take it frank ? What is your tale of woe . Ian .

[Dan]

AHHHHH , your another disappointed JCB owner i take it frank ? What is your tale of woe . Ian .

I think we could all take a view on the ones we would have left to burn .. some Volvo's aint to clever either .. dont ask me how I know .. but I think muz just found out the hard way .. sorry m8

[Muz]

Yaaaaaaaaaaaaa .. fixed it


Sodding 15A fuse in the box looked fine to the eye but was buggered

Hmm .. I ve done this job for long enough to know that things arent as simple as that though

I think something else is up

but ofcourse it will only show when I go on holiday and costs me £500 to sort just when I cant be there .. maybe time to sell the machine

[ianoz]

Sometimes its the simple things , Other times it is just the machine from hell testing you words . Ian

[Muz]

Sometimes its the simple things , Other times it is just the machine from hell testing you

Yep .. I could spend about an hour telling you a 'shortened' version of everything I tested or checked :angry: and in the end it came down to fused that 'looked' ok but wasnt

I have run and tested it for ages and every thing works perfectly .. so I guess I must have sorted it

Ofcourse this isnt strictly a Volvo ofcourse .. its a Sumitomo machine badged by them when they bought them over

[Muz]

Just an update for you fellas .. thats a good few months this gal has been out on hire now and 'touching wood' .. not a sniff of trouble .. picking her up tomorrow from a job where shes been on a pecker down a shaft .. maybe thats a contradiction in terms for some of you guys