V70 S70 Fuel injection problem.

Greetings all,
I have a 1997 V70 20V with 248,000km. I developed after washing the car a
really bad miss or what I thought was a bad miss followed by a really bad
smell. My mechanic found that number 1 injector was pouring the fuel in at
max volume ie the solinoid was fully open all the time. This caused the
Lamba Sond light (L) to come on. He then warned me about the dangers of
washing 850 / V70 motors - they don't like water particularly. After much
mucking around, new plug wires, distributor cap and rotor (all were original
and needed replacing anyway). The problem was still there. He removed the
ECU for the Fuel Injection and cleaned the contacts and this solved the
problem.

But only for a week, and the first sign of uneveness of the motor at idle in
gear started again. Then the light came on, then back to the rotten egg
gas. After checking for any shorts and resistance problems and going
through everything thoroughly, the only thing left was a new ECU for the
Fuel Injection. $960 Australian plus labour, and this solved the problem.

But only for a week (1100km), and the problem was back, number 1 injector
again filling number 1 pot with fuel. Because I was now 350k's from my
mechanic went to Volvo in Brisbane who squeezed me in and found the fault
was in the wiring harness. There was a bad connection (intermittent) in the
wiring loom. The problem area was between the bottom of the electric fan
and the engine. There is a part of the wiring loom which goes into a square
shaped section for about 10cm - and the problem was there in one of the
connections. $125 later the problem was all solved.

I'm not annoyed with my mechanic because he spend a huge amount of time on
this intermittent fault, and there was nothing more that could have been
checked out. When we discovered exactly where the problem was, you could
make it run perfectly by moving the harness, and then you couldn't get it to
play up again. I just thought this information might be useful someone else
in Volvo-Land who doesn't now need to spend $1500 when $125 would do fine.

My mechanic paid the Volvo bill, which was very good of him. Also he
changed the oil (fully synthetic) each time, just to make sure that the oil
wasn't too contaminated by all the petrol going through (and it was a lot of
petrol). And when he did a compression test all five cylinders came to
170psi. Not bad for a motor with 248,000km.

Happy motoring.
Jeff

 

Thanks for sharing

 

Definately worth knowing and a starting place to start looking for the
cause, if you have strange short / open circuit type faults with the fuel
injection eg an injector stuck open all the time.

Tim..