Intermittent stalling

[vtwinpilot]

Hi all,

New to this forum. I belong to a couple of other Volvo forums, and to put it mildly, they're lame. Hardly any threads are answered, yet lots of views. I guess people just read them and either don't have anything to offer, or don't want to. Not sure, but I'm dismayed and thought I'd try my luck here. With that, here goes....

My 2006 has been stalling intermittently for 6 mos or so. At first, it was accompanied by erratic idling at a light. So first things first, I replaced the plugs with OEM Volvo plugs, as it'd been two years since the last plug change. The choppy idle totally went away, the stalling did not. It happens maybe once a week or two. Or this week, it happened once a day for three days straight. It almost always happened within the first 10 mins of having left the house. I almost was able to say that it always happened with the A/C on, but this week it happened with the A/C off.

It's my wife's car so I don't drive it much. These past 6 mos have been fairly hot here in Atlanta, but I'm not sure that has anything to do with it. About 3 mos ago, after it stalled, it threw a CEL, and the code was a P303, indicating a misfire in cylinder 3. Aha!, I thought, must be a bad coil. I swapped the #3 and #4 coils, hoping it'd then throw a P304 code. It didn't.

I replaced the coils anyway, given the car has 175k miles. I also cleaned the MAF and intake. The air filter is relatively new.

Googling and researching, it looks like these areas are potential things to look into and consider, more or less in order of ease/cost, from easiest/cheapest to hardest/expensive:
1. Camshaft position sensor
2. Crankshaft position sensor
3. Fuel pump relay
4. Fuel filter
5. Fuel pump

I've looked for the relay but can't seem to find it. Also, I looked for the fuel filter under the passenger side and it's not there, so I must have a model that has it in the tank.

Any thoughts/recommendations most appreciated. Also, I have the 5 old ignition coils that I'm happy to give to whoever wants them. I know for a fact four are good, and I suspect that the #3 coil is still good too. I'd just ask that you pay for shipping (I'm in the U.S.).

Many thanks in advance.

[b1mcp]

OK, this is not specific to your car or even Volvo.

I had a very similar issue to yours some years a go with a Jag XJS. It would stall and not restart after a 5-10 mis driving if I had to stop at traffic lights/give way etc. If I was just driving without stopping all was fine.

After several diagnosis efforts I found a dead spot on the engine temperature sensor. When it reached a certain temperature it just went open circuit and then when a bit hotter it recovered. If that open circuit coincided with me having to stop it stalled. It would not restart until it either cooled down or heak soak raised it's temperature.

It's easy to check with a voltmeter and usually easy/cheap to replace, so worth a look.

Even better, use an OBD tool to check live data and see what is happening with sensors when it stalls.

[oragex]

To the original poster, which engine and which year is the car ?

[vtwinpilot]

Originally Posted by oragex

to the original poster, which engine and which year is the car ?

my 2006, 2.4l b5244s

[VOLVOBOY]

Hi.
If you have a fuel pressure sensor on the fuel rail try swapping this out or doing a fuel pressure test as this is a known weak point.
As you are in the states I assume you have automatic trans. If it is a manual however, the clutch pedal position sensor can come adrift / fail and cause similar symptoms.

[oragex]

Originally Posted by VOLVOBOY

Hi.
If you have a fuel pressure sensor on the fuel rail try swapping this out or doing a fuel pressure test as this is a known weak point.

It's a good starting point. I would also look at the PEM (google). The FPS can be brought from fcpeuro, the PEM used off Ebay ($50)

May also watch the temp needle, see if it moves smoothly when the engine is warming up. May also check the connectors at the sensor - it's at the thermostat housing, speaking of which, at 180k miles it may need replaced - here's how to simply test it www.youtube.com/watch?v=sOjfjCIemVY

[vtwinpilot]

Thanks, good suggestions all. I'll look into them and post up results. I've also ordered a new camshaft position sensor to start ticking things off the list.

[vtwinpilot]

Coincidentally, the car stalled today, but unlike most times in the past few months (except once when it generated a P0303 code), the CEL came on, and it's P0089. The car started right back up, as it always does.

Looks like these are the possible causes:
• Faulty fuel pump
• Fuel line restricted
• Faulty fuel pressure sensor
• Fuel pressure sensor harness is open or shorted
• Fuel pressure sensor electrical circuit poor connection
• Faulty fuel pressure regulator

Volvoboy, looks like you were on the right path. I'm leaning toward the fuel pressure sensor. My other car - a Prius - just suffered a failed fuel pump, and when it failed, the failure was immediate and permanent. The car wouldn't start back up. That's not the case here.

While I have a basic OBDII scan tool, I think I should invest in a more advanced one that reads live data, etc.

Should I invest in a fuel pressure gauge? Or should I concentrate on maybe testing the FPS? Or given it's relatively low cost, perhaps I should just replace it.

[VOLVOBOY]

Hi.
I`m glad that you`re getting somewhere with this.
Personally, I think some test gauges are always a useful bit of kit to have.
If you were to pressure test the fuel system first it will quickly tell you that if the system pressure was good then the sensor is at fault , and if the pressure is bad the pump or regulator are at fault.
I suggest that you check all the induction pipework and vacuum piping for leaks first. If you have a turbo check the waste-gate actuator and bypass valve for leaks/operation.
Engine earth leads can also cause all kind of weird behaviour so that`s worth a look too.
Keep us posted on how you get on.

[vtwinpilot]

Originally Posted by VOLVOBOY

Personally, I think some test gauges are always a useful bit of kit to have.

Engine earth leads can also cause all kind of weird behaviour so that`s worth a look too.

Yup and yup, absolutely, right on, man. I'm on it...