Narrowing down misfire
 

I have a misfire on cylinder 5 that may be an injector.

Can anyone point me to a company that will test it?

Or, an obvious thing would be to swap two injectors around and see if the misfire follows the injector. I know that the high pressure metal pipe should not be re-used but in practice can I get away with it just for testing purposes?
If so do the injectors need to be coded to the ecu?

It's a XC70 2006 D5 (185).

Thanks
Joe

Swapping injectors around is a time consuming exercise , by far the quickest is to get the ECU codes read & this will point you in the right direction . Common rail engines are not like earlier style diesels , you could search the link & see if there is a member close by who can read the ecu for you

http://www.zeemaps.com/map?group=280351

I strongly advise against opening up the fuel system , unless you are familiar with common rail systems , mainly due to the very high pressures present in the fuel rail .

Thanks.
The codes were read but I don't have them to hand. They point to the swirl system being broken internally (not just the plastic link) and EGR problems plus odd reading on injector 5.
I was planning on opening up the manifold to sort the swirl and replace the hard pipes at that point.

I'm a reasonable mechanic but not experienced in the common rail. I am aware of the dangers hence asking the question - what do you think, if I use new pipes??
Joe.

If you take care undoing them , you can normally use them at least once more .
Personally fix the swirl & clean the EGR , clear the codes & see what happens next . Becasue common raisl are fickle creatures , the misfire may go away on No.5 injector

God luck

Yes, that's what I'm hoping - but my thinking was that if I swap 2 injectors around first and the misfire follows the injector it helps me plan a bit more.
Thanks
Joe

When is the cylinder misfiring ??

I would clean the intake and EGR (New O ring and gasket), change the fuel filter and fill the housing with Liqui Moly Diesel Purge (Read the instructions about varying the idle RPM), then take it for a Sunday morning motorway session or Italian tune up.
Also remove all the fuel injection system connectors, spray with contact cleaner and refit, just in case the misfire is electrical.

As a general rule I would never touch the injectors until after changing the fuel filter, using a direct feed injection cleaner and doing some WOT time, unless one was obviously leaking from a blown seal or cracked feed.

It is generally running rough rather than just misfiring at say WOT and I can't remember what the report said exactly about the misfire. I'm a few thousand miles from it for the next couple of weeks as well, so i can't look it up ! The garage found no leaks btw.

So I will sort out the obvious problems (EGR, Swirl), new filter, purge, clean and then see how it is performing and pull new codes then .
Thanks for the the pointers.

Joe

XC 70 D5 misfire
 

Someone can help me. I can not find fault. Volvo D5 2008 XC70. The engine works idle when working freely and after a moment it starts misfiring in it without burning in one of the cylinders. If I start to turn on electric consumers like a rear window heater, conditioner, dipped beam, fog lights, driving beam, seat heater, then the engine immediately works perfectly at idle. If I shut out one of the consumers, for example a driving beam, then the engine starts to misfiring at the instant that one of the cylinders will not work.
What I have checked and changed:
I double checked the nozzles and placed the other nozzles for the third time (no changes)
I drove all the wires from the control unit to the sensors to all of them and opened it, and found some of the wires that I had stripped off of the insulation. Repair them (no changes)
I exchanged fuel rail pressure sensor, fuel rail regulator, injection pump, injection pump regulator, crankshaft sensor, camshaft sensor. (no changes)
I checked the toothbelt condition and timing marks (all ok)
I removed the valve cover and checked the camshaft wear and the rocks were not broken (everything is ok as new)
I checked the compression
1 cil 28bar
2 cil 29bar
3 cil 30bar
4 cil 30bar
5 cil 30bar

Help someone with smart advice.

You will need to get the hidden fault codes read.

Janis,

I'm no expert on these engines, but this does sound like an electrical problem. If you haven't already done this, it might be worth checking the battery voltage when the misfiring is occurring. Then turn on enough electrical items to stop the misfire and measure the voltage again.

It's possible that the alternator voltage may be poorly regulated and is rising too high when there is little current being drawn. Excess voltage may upset the ECU. Turning on electrical equipment then causes the voltage to drop into a more normal range and everything is happy.

This may a complete red herring, but it's an easy check to make.

Hope this is of some interest.

Martin