volvo fh12 cuts of

[dimitar22]

Hello I have preoblem with volvo fh 12 1997 year , it cuts out while
driving it starts to lose power than the engine kills, after that when you try to blead out the fuel system there is air in it, the truck has no fault codes tested with vcads, i checked all the hoses from fuel tank to cylinder head they are all ok, what might be the probelm.

Please help me.

[hercamp]

well ..if all sistem is ok ...and dont have connection with problems ...problem can be inyector...I ve seen a couple with same problem and after that ..change all inyectors to try and works perfect.

[dimitar22]

I cant change inyectors i 'm not shore if that is the problem problem mostly occurs when driving up hill.

[batpepi]

the problem is from gearbox kleme for tachograf
try to clear it and will see

[hercamp]

mm....well thats sound different ...to fuel problem like a friend say before ..can be tacograph or speed sensor...but without fault code check air connection..maybe you lost air turbo pressure at high rpms...

[RSwire]

I've had hair like cracks in fuel line flares suck air into system but not leak fuel, also a cracked fuel tank pick-up tube.

[baburs]

95% it is standard problem, in non return valve, on D12A it is situated on a fuel line 5 cm higher of starter(cost 20 euro). Just look impact and you would understand why it is his problem.
After you take him off try to breast through it if breast in both sides you find problem...
p.s. Don't take of injectors before test of this valve ,seems it is not problem of injectors...

[emercia]

I use to work at Volvo here in South Africa and now have 6 of these Fh12 420 D12A trucks myself. I agree with baburs, it sounds like a non return valve problem. Check them all, i think there is two on the fuel pump, one above the starter, and another one at the head. Also check at bottom of fuel pump there is a hole, little one, if it is wet, change the fuel pump. had this problem before where it sucks air in there. Also make sure that the fuel lines are connected correctly to the fuel pump. Again, as baburs said, i dont think it is a injector problem, but after you have checked everything I would replace the orings that go around the injectors, on these older volvos they tend to go hard and break.Good luck!
Mike

[dimitar22]

Thanks to all problem solved the first problem was the non return valve as baburs said, the second problem was the pick up pipe from the tank it was pluged with parafin from the fuel.

P.S when i was testing the truck the turbo boost pressure stayed in yellow field no meather what i do the boost pressure newer reached in green field is it normal?

[baburs]

P.S when i was testing the truck the turbo boost pressure stayed in yellow field no meather what i do the boost pressure newer reached in green field is it normal?
To test it good truck had to be loaded and move to a hill...
When truck is standing it is nearly impossibly to test it by computer..
So what you see mean nothing(normal or not)...

[hanzem evr]

deleted post

[STK340]

speed limited at 1500rot/min for me was VECU unit malfunction,that on fm7 from 2000 year,
regards