Abs and glow plug light errors,blowing 80 amp fuse.

[Bozwell2201]

Hi all,newbie here,i,ll dive straight in,i have a daewoo musso 2.9td 1999,and its developed a fault,the abs light is permently on and i have no glow plug light and its a mare trying to start from cold,ive had it a 5 garages local to me,four of them started crying because they couldnt scan it,the 5th bless him has got the furthest yet he found the 3rd glow plug cable was touching the engine and causing the 80amp abs fuse to blow,he straightened the end out which is attached to glow plug and i had both lights doing what they should been great for 4 days now its blown fuse again and in back to square 1,has anyone any ideas where i go from here,im thinking its now the cable could be shorting out somewhere but m guessing,cheers all.

 

[shaun1]

I'm no expert on Daewoo glow plugs but if a cable was damaged and had just been 'straigtended out' then I would be looking there again for the problem. Its probably time to replace that glow plug and or loom (and check the others wbilst you are there). I imadgine the loom could be salvaged from a breakers or possibly the ends rebuilt by an auto electrician with the correct crimp tools.

 

[Bozwell2201]

Hi shaun1,thanks for reply,the guy did bench test all plugs and they were all good,he replaced no3,because when he tested it it blew the fuse on his tester,id replaced the plug myself a week earlierxwhen my problems originally started,and i must of twisted the cable,but what sounds funny to me is the problem was already there,so dont understand why mechanic said the cable was touching engine and blowing fuse,am i right in thinking a fuse will blow because theres a short or bad ground,electrics is such a minefield very confusing.

 

[SparkyChick]

If it's a single core connected to the glow plug, then yes if the copper core of the cable (or a connector attached to it) touches the engine it will blow a fuse because the core will be carrying 12v and the engine will be at 0v (assuming of course it's a negative earth arrangement).

 

[Bozwell2201]

Thanks for that sparkychick,looks like i,ll be checking the glow plug loom out this weekend then.oh joy.

 

[shaun1]

It may well be that the insulation on the wire has become brittle and cracked near to the glow plugs because of the heat from the engine and glow plugs.

 

[Bozwell2201]

Cheers again shaun1,i suppose i should expect brittle wires due to age of vehicle,luckily its only a shortish loom,cheers again bud.

 

[PEG]

If the same fuse is blowing,it would indicate a fault on the same circuit.
Although glow plugs usually fail open circuit,on occasion,they can short,internally. Is this a Merc engine?

 

[Bozwell2201]

Yes it is the merc engine,a few have laughed when ive said that and said have fun they fault for fun,i can see this being a bigger job than first thought.

 

[ruston]

Most of the electrical major problems I have worked on of late have been mercs with a bit of age .
It has usually been the naff harnesses. The wire turns to dry string.
As you have found out it usually affects other systems too.

 

[Bozwell2201]

You are not wrong there,cant wait to start delving on the wiring,im hoping for an easy fix,a dodgy wire in the loom i hope, if not the crusher will sort it once and for all. Lol.

 

[ruston]

Just trace it back , start where there is heat and where there is obvious corosion. Routing around manifolds , that sort of thing .
Glow plugs is not the end of the world , just keep chipping away.

 

[Bozwell2201]

Cheers ruston,gets abit disheartening when its been going on for nearly a month,i,ll keep going its challenging.

 

[Bozwell2201]

Just had the 5th mechanic tell me he doesnt now no why the 80 amp fuse keeps blowing he doesnt reckon its a short in the wiring because his two wire and fuse homemade tester doesnt blow after he straightened the cable out,he said he thinks its drawing to much ampage,and said try disconnecting on glow pkug and see if that works,baffled.

 

[ruston]

Are all the glow plugs new?
Do you have an ohmmeter to accurately test the plugs ?

 

[Bozwell2201]

Hi yes ive got a metre,i changed all 5 a year ago,all good till a month ago did the ohm test 3 and 4 had high readings 55+,so changed them the rest 0.6,which apparently i should be looking for,but thats when problems started my glow plug light went out completely abs light came on permenetly,been nightmar3 ever since,the last test i did,i got .
no1 0.2 no2 0.2 no3 0.6 no4 0.6 no5 0.2,not been able to do another yet as ive ran out of fuses used 12 upto now doing tests it blows everytime i do preheat cycle on ignition,when the 80 amp abs fuse blows i dont get power to glow plug relay,sone fuse blow straight away sone tahe 6 turns of the ignition cycle waiting forcmore fuses now before i can carry on.been looking at doing an overide manual switch in the cab if its possible taking the relay out of the equation..

 

[shaun1]

Dis you measure the glow plugs with each one disconnected from the loom? If those 3 glow plugs are 0.2 ohms they will be drawing 60a each. Sounds like they have failed short circuit. Did you replace them with pattern parts? Perhaps they have not been manufactured to the same standard as the originals.

 

[Bozwell2201]

No tested them connected,i replaced all 5 from europarts,was told just make sure they were 11.5 v which they were cant remember the make though,should i test unconnected aswell then and what sort of reading should i look for.

 

[shaun1]

Ah yes if you test them connected to the loom you will be measuring the resistance across all 5 of them at once. Disconnect and check each one. I'm not sure exactly what the resistance should be, but looking online it seems that 0.6ohms is about right.

 

[ruston]

Yes take them out to test them individually. Try the circuit with them out to prove no short in harness . Euro parts are not renouned for quality parts either . Get a decent set if they are not reading as they should .
It is as @PEG said earlier . If you are blowing fuses at that rate you could have a shorted one.