2001 V70 2.4T inconsistent startup issues

[prwood]

Following up from a previous thread where I was trying to track down a coolant leak, I'm now trying to diagnose some issues with inconsistent startup. I worked on this some last night, and basically sometimes the car will start up and run with no issues, while other times the engine dies after its first cranks, or starts sputtering after a minute.

This morning, the first startup of the day went smoothly, but after a couple of minutes idling, the engine started surging, and I started hearing popping/puffing sounds. I shut the car off, and then tried starting it back up, but on the next few attempts, the engine would start and then immediately stop.

I checked everything I could see from the top of the engine bay, but didn't see any hoses or pipes disconnected, or any electrical connectors disconnected. I haven't gone under the car yet. The sound almost sounds like the exhaust is popping.

Luckily I was recording the whole thing, and I uploaded a video with the highlights and lowlights to YouTube, in case you want to hear and see for yourself:

https://www.youtube.com/watch?v=vPY-nn7Ynis

Any suggestions for what to look at?

[oragex]

Just a side note, I think the cover of the ECM box with the hole in it, usually it has a tube going into the bumper to suck 'fresh' air which has to cool down the ECM modules. If the tube is missing, the small fan inside will suck hot air from the engine which does nothing to cool down the ECM modules.

Could it be the a/c pulley bearing has seized? Quite common to go bad past 100k miles. Or maybe the compressor itself was lacking oil and seized (less probable). Maybe try removing - or at least un-tensioning the serp belt and check all pulleys by hand.

[prwood]

Just a side note, I think the cover of the ECM box with the hole in it, usually it has a tube going into the bumper to suck 'fresh' air which has to cool down the ECM modules. If the tube is missing, the small fan inside will suck hot air from the engine which does nothing to cool down the ECM modules.

It's funny you mention that - I've always wondered about that port on the front of the ECM box. Thing is, on my car at least, the port doesn't actually open to the inside of the box - it is blocked on the inside and there is no fan inside. Looks like a plastic boss that you would need to cut out. So it looks like it has the option for something to be hooked up. Not sure if it's present on some configurations and not others.

Could it be the a/c pulley bearing has seized? Quite common to go bad past 100k miles. Or maybe the compressor itself was lacking oil and seized (less probable). Maybe try removing - or at least un-tensioning the serp belt and check all pulleys by hand.

That sounds like a good thing to check, and would also explain the intermittent nature of the problem. I'll take a look tonight.

[prwood]

If it is the bearings seizing, is that possible to fix without replacing the whole compressor assembly?

Also, would it be possible as a temporary fix to get a shorter serpentine belt to bypass the ac compressor?

[prwood]

Update:

* Removed the serpentine belt and found that I could turn the AC compressor pulley freely.
* Reattached serpentine belt and attempted to start the car. It started up fine and ran for about a minute before doing the sputtering thing again, and then stopping. During the time it was sputtering, I did notice that it looked like the clutch was running intermittently... freezing maybe every 10th revolution. Eventually the engine stopped.
* After this, I tried starting up the car twice, and both times the engine started and immediately stopped. The third time, it started up with no issues and has been idling just fine for nearly 30 minutes.
* I read over here: http://forums.corral.net/forums/#/topics/91656 (definitely not Volvo, but I'm assuming the AC principles are the same) that the clutch wouldn't cycle if there wasn't adequate refrigerant pressure. That got me thinking, so I got out the gauge attachment I had left over from filling another car's refrigerant to try measuring the pressure on this car. I already had the engine running with the AC on and the windows open to prevent the compressor from cycling, so I measured the pressure on the low pressure AC port. According to the gauge, with an ambient temperature of 80F, the PSI should have been between 40-50. In my case it was down at 32. I'm hesitant to believe that having the pressure 8psi below the range could cause the kind of problems I'm seeing, but I suppose it would be worth a shot to try charging the system. It is blowing cold, so I know it's working in general... but maybe it's still affecting it? I'm wondering if there are certain conditions, for example maybe it's more likely to happen the first time I start the car if the AC is already turned on, vs if I start the car up with no ac running, then engage it later...

In any case, I've been idling with the AC running for 45 minutes now. I think I'm going to leave it running and drive over and get some refrigerant at Advance, charge it up to the top of the range, and then see what happens when I let it cycle.

Any other thoughts?

[Daveliz99]

I'm not the best mechanic in the world, but i also have a 2001 2.4T. If any of the intercooler pipes are loose, the engine will die right away. I had a lot of problems out of the pipe that goes over the engine. The couplers more specifically. Make sure the ends on those aren't deteriorated and leaking. That's probably not it in your case because you can run fine at times, but mine had similar symptoms when the ends of the original rubber couplers had been chewed up over time.

When you crank it and it is running okay, what happens if you get on it?

I suppose you don't have any messages in your center?

I don't know anything about air conditioning, but like you said, I can't imagine low freon doing that.

[jonesg]

puzzling, I'd leave the AC off for now to try and isolate the problem.

The fitting on the front of the Ebox was for older versions that took fresh air into the box to cool the computer.
If you lift the PS pump there will probably be an elec fan which draws cooler air from the cabin.

Did it throw any codes?

[prwood]

Hey Dave, it's always good to run into someone with the same model and hear experiences. Regardless of whether you consider yourself the best mechanic. I like to think that all of us are together on a learning voyage about Volvo.

The turbo charge pipe going over the engine was one of the first things I thought of, because I have had issues with it coming disconnected in the past. However, I checked and it seems pretty tight. I haven't checked the intercooler pipes in front, though. Will check that tomorrow.

When I crank it and it's running ok, and I accelerate, everything is fine. Literally. It's like nothing was ever wrong. Typically, if I have a problem, it's immediately when I start up, or within two minutes of starting up.

I was able to start it up earlier tonight, and drove around for quite a while with no problems. I finally parked and shut it off and went into a store for about 20 minutes, and when I came out, it started up okay, but after two minutes of driving, the engine started surging, then went into limp mode, and shortly thereafter the engine stopped. I pulled over and was able to restart the engine, and drive home (another 10 minutes) with no problems at all....

I do have messages in the message center: "Engine System Service Urgent" and "Engine System Service Required". The really weird thing is, though, that the only code I'm getting is a P0455, which is an evap code that always comes back ever since I've owned this car. No misfire codes or anything else.

I'm not the best mechanic in the world, but i also have a 2001 2.4T. If any of the intercooler pipes are loose, the engine will die right away. I had a lot of problems out of the pipe that goes over the engine. The couplers more specifically. Make sure the ends on those aren't deteriorated and leaking. That's probably not it in your case because you can run fine at times, but mine had similar symptoms when the ends of the original rubber couplers had been chewed up over time.

When you crank it and it is running okay, what happens if you get on it?

I suppose you don't have any messages in your center?

I don't know anything about air conditioning, but like you said, I can't imagine low freon doing that.

[prwood]

puzzling, I'd leave the AC off for now to try and isolate the problem.

The fitting on the front of the Ebox was for older versions that took fresh air into the box to cool the computer.
If you lift the PS pump there will probably be an elec fan which draws cooler air from the cabin.

Did it throw any codes?

It didn't throw any codes when the problem happened, oddly enough. The only code stored or pending is a P0455 large evap leak which has always come up since I've owned the car. It makes me wonder if whatever is happening is occurring inside a system that doesn't have sensors.

I can also tell you that when it goes into limp mode, the throttle position is forced to 20% and stays that way. In a previous thread it was suggested that perhaps the fuse for the accelerator position sensor was blown, which would cause the computer to be unable to sense the pedal's position, and therefore hardwire the throttle to a drivable but safe position. But, I have checked all fuses and none of them are blown.

Tomorrow I have the whole day to work on the car. I'm planning to change the timing belt/tensioner/pulley/water pump (because I just discovered the previous owner never had those changed, and it has 212k miles on it now...). So while I'm doing that I might as well pull other stuff apart and make sure everything is clamped down to spec. Maybe also remove the ETM and clean it (I did this last summer, but maybe it's needed again).

I also have plans to either clean or replace the PCV system, as I've been experiencing symptoms of PCV issues for quite some time (smoking dipstick, inflating glove test on the oil filler neck, oil leaks, burning through oil). I'm thinking of trying to remove, clean w/carb cleaner, and replace the system tomorrow, since I have plans to be working on the car all day anyway and won't have time to do that amount of work again for another month, and no place local sells all the parts I'd need at a reasonable price. But maybe I'd be better off just putting it off another month when I would have time to order the parts and another free weekend to work on it.

[prwood]

Update:

Did some controlled testing tonight: I did a test drive on a 5-minute circuit around my neighborhood that includes one strip where you can go pretty fast if you're so inclined. I did five minutes because I knew that in the past few days if it has failed, it failed within the first two minutes, so I wanted to be sure to give it at least that much time, but not so much time that it would take all night.

I did three sets of three drives each with a one-minute rest in between, during which I shut the engine off and took the key out of the ignition. The first set I did with the AC turned off, the second set I did with the AC turned on, and the third set I did with climate control in fully automatic mode.

The results?

All nine startups went flawlessly, the engine hummed along each time as though nothing was ever wrong. No codes were thrown. The message center on the dashboard still reported "Engine System Service Required," but I get the impression that's something I can't turn off myself.

Here is a summary of the conditions that changed since the issues I had driving earlier this afternoon:

1. For this afternoon's drives, the car had been sitting for 8 hours. For this evening's drives, the car had only been sitting for 3 hours.
2. The air temperature dropped from 80 during this afternoon's drives to 71 for this evening.
3. After I got home from this afternoon's drive, I added some refrigerant to the AC system, topping it up to the max acceptable range listed on the gauge.

Not sure which of those, if any, made a difference.

The other possibility I'm wondering is whether the ECU is recalibrating to compensate for some sort of issue, and that's why it's been gradually getting better since I disconnected the battery while working on the coolant system. In that case, it would be nice if I knew what the issue was...

Also: I realize a five minute drive, even nine of them, doesn't really put the vehicle through its paces, so I'll need to do a full road and highway test tomorrow.