XC70 injector leaking internally? Topic is solved

jkatz · Post by **jkatz** » 11 Jun 2021, 08:20

I’m really close to stage 0 with my 2007 XC70, but I’m chasing a difficult hot start. I think an injector is leaking internally but I can’t say for sure.

In the morning the car starts immediately, as it should. If I drive it, turn it off, and 1 hour later try to start it it takes 6-7 seconds of cranking, then when it catches it takes another second to come up to idle RPM. The tach doesn’t jump or anything weird, it really acts like it is just flooded.

After a hard start if I turn it off after starting, wait 1 minute, then try to start it again it starts immediately, suggesting that it was indeed nearly flooded and has burned out the excess fuel.

If in the morning I turn the key to position II rather than start it and pressurize the rail, then wait an hour, it is hard to start. This suggests it is not heat related.

The car has a new plugs (Bosch platinum), fuel pump (Bosch), filter (Mann), and pressure sensor (Bosch). No smell of gas at any time. I just put the new FPS in last week, there was a small amount of black sediment in the rail when I pulled off the old sensor.

Last weekend I drove it, waited 2 hours for it to cool enough to touch, then pulled all 5 plugs to check gaps (all 0.027”, very uniform), sniff for gas, and check color. Color looked good and I was surprised that none of the 5 looked sooty or smelled of gas.

There are no codes for misfires or O2 sensor. I just cleared the FPS high/unexpected fuel pressure codes from the old FPS, I should drive it and check to see if they returned. I didn’t do a fuel pressure leak down test, but with a new FPS I monitored pressure with my iCarSoft scanner for 10 minutes after shutdown and it dropped from 58psi to 37psi, which seemed pretty fast for it to fall but I can’t say it would have fallen below 20psi if I had waited another 10 minutes.

At this point I feel confident that one of the injectors is leaking but I can’t figure out which one. I’m considering replacing all 5. Is this what you folks would do? It doesn’t seem like a common issue. Is there any other way to tell which is leaking? It looks like with the steel gas line I can’t really pressurize the rail after pulling it from the manifold, right?

Post by **kallekula** » 11 Jun 2021, 10:32

Does the ECT sensor work properly? Check with your reader if water temp nr is realistic.

jkatz · Post by **jkatz** » 11 Jun 2021, 10:39

Ah, I should have mentioned that water temp looks good (190F) and the thermostat and ECT are brand new.

Also the throttle body is freshly cleaned, and I can hear the stepper motor working if I use the pedal when the motor is off but key is on.

Turning the key on and letting the rail come up to pressure before starting doesn’t change the pattern of symptoms.

I haven’t checked the timing belt but like I mentioned it does start when hot if its only been sitting a few minutes.

Post by **jonesg** » 11 Jun 2021, 12:22

You could try removing and putting the injectors in containers to find the leak.
I'd order new seals ,O rings, before pulling them out.

Post by **volvolugnut** » 11 Jun 2021, 12:43

This method is recommended in old 240 manual to check for leaking and bad spray pattern. Use glass or clear plastic bottles to see the spray patterns. Test all injectors at once while all connected to the fuel rail.
volvolugnut

jkatz · Post by **jkatz** » 11 Jun 2021, 12:46

I’ve seen pictures of containers taped together to compare injector output. How do people pressurize the fuel rail to do this test? My car has no pressure regulator/absorber, the steel gas line plugs directly into the fuel rail, and it seems unlikely that I can extend it and not make a huge mess.

Post by **jonesg** » 12 Jun 2021, 05:02

Pull the rail and use compressed air at 60 psi.
Or fab a short section of fuel tube.

jkatz · Post by **jkatz** » 12 Jun 2021, 05:50

Thanks for the video. I have the 5 o-rings that came with my IPD PCV kit (“have”: they are somewhere in the garage), I will give this a try. I had no idea I can actuate an injector with a 9v battery and a spare pigtail connector. Maybe I’ll do the leak test, then back flush.

Post by **jonesg** » 12 Jun 2021, 13:22

depending which area of vermont you're in, it might be worth a drive to Hollands salvage in N. Billerica MA, lots of v70 volvos at that pick n pull. I snip all the connectors I can get at, you could snag some spare injectors on a fuel rail, prices are very cheap.
Hollands is close to I 93.

jkatz · Post by **jkatz** » 12 Jun 2021, 14:27

I am in the NW corner near Burlington, sadly the boneyard nearest me stopped letting customers pick our own parts last summer.

When I did the PCV refresh this winter I lost a rectangular gasket from inside one of the injector connectors so I bought one of these as a donor from Rock Auto, it should be useful for this task:

https://www.rockauto.com/en/catalog/vol ... ector,2577