Two Sensors Die at Once? 98 v70 T5

[erikv11]

Yes the FPR will be down by the passenger axle, before the fuel lines come up over the engine.

It is not the one in the picture shown by mrbrian but it looks similar to that, just doesn't plug into the fuel rail.

The rubber vacuum lines will be quite worn down there, be prepared to replace the one you disconnect from the FPR.

[WagonLagan]

Disconnect the vacuum hose at the fuel pressure regulator. You don't have fuel shooting out of there do you?

I'm back! It definitely got worse again.

I found the FPR, but I need help determining which things to pull, which to plug, etc. There's about 5 vacuum tubes to account for, which is more than I was expecting.

Also, I've included a video of what happens sometimes when I start it cold in Park. It spikes straight up to 2500 RPM. The RPM drop when I put it into Drive. When this happen is when I smell a lot of gasoline.
https://vid.me/SCjde



I've numbered the vacuum hoses below, and I'm hopeful someone can give me some more guidance before I just start pulling hoses off and screw something up.

FPR Numbered.jpg (2.43 MiB) Viewed 1076 times

Thanks a ton for the help everybody.

[erikv11]

2, 3 and 4 are all fuel lines, don't mess with those. 1 is the vacuum line.

If you can disconnect it at the clamp in the bottom left corner off of 1a, that might be the easiest way to check for a strong fuel smell without trashing things. That's assuming the plastic fitting is just an open connector, no little check valves or anything inside. Or rebuild all of the vacuum lines. Those FPRs down on the rack are a real hassle to deal with, a couple weeks ago I needed to disconnect one of the fuel lines there (to replace it, coming from the filter to the FPR) so I ended up opening that clamp up and taking it apart.

[mrbrian200]

#1


If this were a Siemens ECU, after ruling out a vacuum leak I would associate the racing idle with a combination failure of the TPS and ECT. On Bosch I don't know-- However if the idle speed returns to normal if you disconnect the IAC that would suggest you don't have a vacuum leak, or at least not a major one.

[WagonLagan]

2, 3 and 4 are all fuel lines, don't mess with those. 1 is the vacuum line.

If you can disconnect it at the clamp in the bottom left corner off of 1a, that might be the easiest way to check for a strong fuel smell without trashing things. That's assuming the plastic fitting is just an open connector, no little check valves or anything inside. Or rebuild all of the vacuum lines. Those FPRs down on the rack are a real hassle to deal with, a couple weeks ago I needed to disconnect one of the fuel lines there (to replace it, coming from the filter to the FPR) so I ended up opening that clamp up and taking it apart.

Thank you for the fast response erik. I have very little time to work on this, and it's so helpful to know what my next step is so quickly.

I'll probably plan on replacing all the vacuum lines and fuel lines there that I can reasonably access after I fix this. They certainly look rough.

Will report back after I screw with line 1.

Side note, why does the FPR seem to look so different from the FPR I found on FCP?
https://www.fcpeuro.com/products/volvo- ... 0280160554

[erikv11]

That's the FPR that plugs directly into the fuel rail. There are a few different fuel setups, return versus non-return, and then the hole in the fuel rail can either have a "pulse dampener" or the FPR itself. The different setups have different hose configurations, too (OK of course).

BTW you can also check the vacuum line 1a where it connects to the intake manifold, for strong fuel smell. Will make things much easier/quicker. If you smell only a hint of fuel there, the FPR isn't dumping extra fuel into the intake. I would check it after operation.

I would follow that other line 4 back to the rear, it may be vapor not fuel I am no longer so sure of my previous call on that particular hose (the rest is correct, and the plastic fitting is definitely just a hollow connector). I was assuming 4 is fuel return.

[WagonLagan]

I removed line 1 entirely from the FPR, put a paper towel under that and the disconnected vacuum hose. Started the car, let it run and watched, saw no fuel escaping. Revved the engine, went back under and saw/smelled no fuel on the paper towel.

Does this rule out the FPR? Are we back to vacuum leak?

... if the idle speed returns to normal if you disconnect the IAC that would suggest you don't have a vacuum leak, or at least not a major one.

It's deciding to idle stable right now. I tried disconnecting and reconnecting the IAC.
When disconnected it idles at ~1200 RPM
When connected it idles at ~ 900 RPM
Does that give us any leads brian?

Keep in mind the FPR vacuum tube is still detached.

[WagonLagan]

I removed line 1 entirely from the FPR, put a paper towel under that and the disconnected vacuum hose. Started the car, let it run and watched, saw no fuel escaping. Revved the engine, went back under and saw/smelled no fuel on the paper towel.

Does this rule out the FPR? Are we back to vacuum leak?

... if the idle speed returns to normal if you disconnect the IAC that would suggest you don't have a vacuum leak, or at least not a major one.

It's deciding to idle stable right now. I tried disconnecting and reconnecting the IAC.
When disconnected it idles at ~1200 RPM
When connected it idles at ~ 900 RPM
Does that give us any leads brian?

Keep in mind the FPR vacuum tube is still detached.

[mrbrian200]

Question: 1b goes to the evap purge solenoid yes/no? If so 1a would be better yes, though disconnecting 1a doesn't isolate the FPR. If disconnecting 1a makes a difference you'd reconnect 1a and disconnect at 1. Between the two you'd be able to figure out whether it was the FPR or the evap system dumping fuel into the IM.

[WagonLagan]

I removed line 1 entirely from the FPR, put a paper towel under that and the disconnected vacuum hose. Started the car, let it run and watched, saw no fuel escaping. Revved the engine, went back under and saw/smelled no fuel on the paper towel.

Does this rule out the FPR? Are we back to vacuum leak?

... if the idle speed returns to normal if you disconnect the IAC that would suggest you don't have a vacuum leak, or at least not a major one.

It's deciding to idle stable right now. I tried disconnecting and reconnecting the IAC.
When disconnected it idles at ~1200 RPM
When connected it idles at ~ 900 RPM
Does that give us any leads?

Keep in mind the FPR vacuum tube is still detached.

I have to head to work now, but I'll have some more time to play with it tomorrow. Maybe try to do a more thorough smoke test if you guys think that we're back to vacuum leaks.