2004 XC70 Starting and cruising trouble - dealer no help

[shiloh51933]

I'd stick with the factory spec Bosch, I've had issues the factory spec NGK/NTK plugs/o2 sensors with Volvo vehicles...just a suggestion. I mention the plugs because it's a good possibility, I know you mentioned an issue smelling fuel fumes. Just because the CEL hasn't illuminated doesn't mean you don't have recorded data concerning your issue. If your EVAP monitor hasn't set but the I/M monitors are finished running there course that could very well be your issue. Either way nobody should have to keep there windows closed while there driving due to fumes. If you don't have a good OBD2 scanner I would invest $200-$300 bucks on a decent scanner. This dealership only evaluated your vibration concerns and didn't investigate your fuel problem? There's a check valve in the fuel pump, that being said the fuel system does hold a little pressure when you key off. You can try to let the FP prime itself a bunch of times by keying on without cranking motor, after about 5 times of listening to the FP prime itself you can try to crank her over and see if she starts right up. A fuel pressure gauge would be quite useful at this time.

[BigNerd]

I got to work today to change the plugs and inspect the coils.

The removed plugs were NGK double iridium, and seemed tired but serviceable. The gaps had opened to about .043, which is pretty darn big compared to the specified .028. The only really remarkable finding was that the #3 plug hole had filled with oil. I was not happy with the condition of the coilpack on that cylinder, and sadly it tore as I was cleaning it. I don't have a replacement on hand at the moment, so I cleaned it as best I could and re-installed - for now...

That flooded plug hole was probably misfiring, and the engine did seem to run quite a bit better with the new plugs. The plugs were definitely a worthwhile investment of time.

I also checked the fuel pressure. When operating its at a steady 55psi. After shutting down, within 30 seconds the pressure is already down to 25, and within 2 minutes the pressure has returned to 0psi. Whatever device is responsible for holding pressure in the fuel rail - its not working.

I have no idea how to read date code on the coils. The pictures are attached. I would appreciate any input.

I still have some vibration under high load - maybe a motor mount?

[Cuba]

Highly recommend one of these http://www.stahlcar.nz/diagnostic-tools ... oothswitch
You leave them in without battery drain. Torque pro seems to work well with it.

[Cuba]

Highly recommend one of these http://www.stahlcar.nz/diagnostic-tools ... oothswitch
You leave them in without battery drain. Torque pro seems to work well with it.

[abscate]

Nice clear photos. These belong as the gold standard for posts!

Those plugs are worn out, so replacing them is good. The date codes on Bosch stuff. Are year plus a toggling month ( I've forgotten the code) but those are original 2003 ( MY 2004) coils so replace the one that one oil soaked as a start. Let's defer the vibration until you get that part. The vibration is still going away when you lift, right?

[BigNerd]

After a few days with the new spark plugs I can sadly say that my problem isn't completely fixed. I still have vibration under load sometimes, and occasionally pretty bad. However, it's much smoother when not misfiring. The plugs were definitely not wasted effort or money.

I think the next step is to change all the coils. I realize that they may not all be bad, but because of their age, and how long they tend to last, I think its reasonable to expect multiple failures soon. They've survived 165000 miles, that's pretty extreme for a component like an ignition coil.

I'll post another update following the coil work.

[E Showell]

I had hard starting and vibration in my 04 XC70 at c. 165 K miles. Replaced plugs with genuine Volvo and all coil packs with Bosch. Ran like a top afterward. You're right on schedule for a complete replacement. You can replace a coil at a time if cash is tight, but I tend to do them all at once for peace of mind.

And Steve is right. The date code starts with year '04 and W = week, so I am thinking 12th week of '04, or end of March. Definitely OE. They don't owe you anything. You'll be amazed at the difference on replacement.

Parts guys at my local dealer, Bridgewater Volvo in NJ, said a lot of the techs run mid 2000s XC70s.

I really like mine. Super comfy and drives pretty well. I don't care for the plastic cladding, but I don't have to look at it when I'm driving.