2000 V70xc Loss of power and/or stall

zinman · Post by **zinman** » 12 Sep 2014, 09:31

My V70 with 150k miles runs well much of the time, starts easily and has generally been reliable. Over the past couple of months it will just lose power and be unresponsive to throttle position. A couple times on the highway, it was as if the car went suddenly into neutral. It coasted for a while then seemed to find itself again. Twice after running fine, it refused to start for ten minutes following refueling. It started, if I remember, after about 5 minutes of trying when I flooded it while turning the key. Once it stalled at a red light and restarted after 10 minutes.

I replaced two ignition coils in separate incidents this summer when the car ran rough and the code said which cylinder was misfiring. Three of the five coils have been replaced in all. This was an instant fix.
There was also an O2 sensor code which I have learned to ignore as indicative of some other issue, and one that said turbo control valve. (P1237 on generic scanner)

Two weeks ago on the way to work and only a couple blocks from home it lost power and would not restart. The only way it would even start to turn over was by flooding it and turning the key, but ultimately no success.

I had it towed to the local mechanic.

Remembering the code and feeling uneasy about my recent experiences with loss of power, I ordered a turbo control valve which was on sale from IPD for about the same price as the OEM and a MAF sensor, knowing it is a common cause of many ailments. The parts were en route when the car died.

After ignoring the car for a week and a half with parts in hand, the mechanic gladly agreed to install the MAF and turbo control valve. He said it started for him and he drove it around the block. I asked if it started before the MAF was installed. He said, "Yes." He will be installing the TCV today since there isn't that much time into it. I asked if he would replace the vacuum lines that go to the valve since I believed they are more likely bad than the valve itself. He seemed reluctant to do this.

Anyway, most likely I'll be on borrowed time again. Could this be an issue with the fuel delivery in some respect? I fear a fuel pump on the way out. Anyone have suggestions on what to look for?

I should mention that I have a Xemodex throttle body and oddly, it was replaced under warranty when the original failed after only a year. If it means anything, when my car stalled this last time, I popped the hood thinking I'd disconnect the MAF sensor and see if it made a difference. I saw that I needed a torx screwdriver to unplug the connector so that didn't happen, but the throttle body was making a high pitched sound. The tech at Xemodex said this indicated a correctly functioning part when I removed the fuse and then reinserted when we were troubleshooting the part they eventually replaced. Maybe the key was just in the on position when I opened the hood and it is normal but I thought it worth mentioning.

This site has saved me a bundle in the past, and I am very grateful. I'm fond of my Volvo and I think the mechanics are being sensitive to not do repairs that approach the total value of the vehicle. They know I like to do whatever I can myself. That said, I think it really takes another Volvo owner to know the issues that are likely to arise. Thanks for your time and talent.

alex7 · Post by **alex7** » 12 Sep 2014, 10:22

That's what mine started to do. I put a lot of new stuff on then ran ok then started back running bad. They told me to check the fuel pressure I found my was good the would drop. The check valve was going out on mine but they are telling me that its all one. I read that it need to be around 40. I would check that first..

Post by **rspi** » 12 Sep 2014, 10:35

Follow the codes. I would replace the balance of the ignition coils, if you have 2 or 3 bad, then the other 2 are right behind them.

Vacuum lines and hoses are a good thing to check and replace. So many of them are old, torn, etc. A lot of time the TCV codes are related to holes and tears in intake tubing, especially in turbo cars.

Post by **timmybdaddyof3** » 12 Sep 2014, 16:16

I would agree with rspi -if 3 packs died, the others are following - as standard practice unless we know how old they all are i push clients to do them all at once or sign the disclaimer acknowledging they will be back for more- i would also be a little nervous about the mechanic - I try to be sensitive, but as a shop owner I quote high to cover the cost of my reputation, what your car is worth is ultimately up to you.
As a standard practice i urge customers to replace any line we might be touching...my mentality is this - I don't want you coming back into my shop complaining that the part was installed incorrectly or whatever because a cheap piece of rubber failed...99% of the time if the customer doesn't want to pay the extra couple of bucks I eat it in the name of reputation.

The same symptoms are typical on older Audi 5 cyl turbos when the intercooler piping starts to fail- they dont run right once they warm up, they will stall and not restart, and they will all of the sudden lose power, then act like nothing happened....Cant recall having to deal with failing lines on a Volvo, but its a thought.

Post by **abscate** » 12 Sep 2014, 18:35

It sounds like your car is going into limp mode. The accelerator pedal isn't mechanically connected to the engine on the 1999+ cars, it sends electrical signals to the electronic throttle body (ETB)

Pumping the gas pedal on an ETB car isn't entirely fruitless, your right foot does get exercise.

Look down under the intake manifold and tell us if the label on the ETB is white or yellow. Follow the BFH ( big fat hose) coming up from near the bottom of the radiator, which the turns right under the intake manifold and ends at a black box. That's the ETB.

My gut says that is the root of your problems on this car

On edit - got this backwards, i think. charge air pipe feeds to bottom of intercooler, and top feeds to ETB

zinman · Post by **zinman** » 12 Sep 2014, 21:24

Thanks. I'm familiar with throttle body issues as I experienced it twice; replaced it twice. It isn't limp mode like I remember where the car stays at low rpm and won't go faster than 20 mph. I went with the highly regarded Xemodex modified throttle body, supposedly an improvement over the stock. It failed after a year, but they stood by their guarantee and overnighted a new one. In both cases, the ETM light was activated.

I can't disagree with the suggestion of replacing the remaining coils and would if I can get my car back from the mechanic. He told me it is now running terribly. I suspect they largely ignored it for two weeks then rushed to finish it when I paid a visit and they discovered it really does not drive well. When the mechanic started it for me this afternoon, it started quickly but idled rough like it did before it finally threw a misfire code. He said it wasn't doing it before. Maybe those remaining original coils are kaput. I have read too much not to believe that the vacuum hoses around the intake could be deteriorating. I'd replace them, too (if I could drive it home a half mile away). The mechanic thinks its a blocked exhaust or catalytic converter but I just don't think it is likely.

I'll give the mechanic another day. Honestly, they are nice guys but I don't think they want to spend the time with cars like mine and they are too generalized. I have more faith in your collective wisdom. It's similar to, "Nobody knows the kid as well as the parent." I'm optimistic it may be a simpler remedy. I certainly won't authorize an estimate for a new catalytic converter.

Again, thanks for your help.

Post by **timmybdaddyof3** » 12 Sep 2014, 22:43

Not buying into a bad cat unless you have had other major symptoms (rattling in the exhaust, running rich and the rotten egg smell)...and assuming you are stock with a rear 02 if it went you would usually get a code for it.

I am still thinking a vacuum or plumbing issue...

zinman · Post by **zinman** » 13 Sep 2014, 02:47

I thought the same thing about the sulfur smell from the catalytic converter being bad and I've pounded on it when I removed the drive shaft. (Yes, I had the prop shaft failure, too.) The only rattling was the heat shield. The only O2 sensor that ever registers is the one before the converter.

I never really looked closely at the turbo setup so I'll have to peek at a parts drawing for the intercooler plumbing. It also didn't seem to be a problem with the 2.4 L 5 cylinder, at least on this forum. I've had so many of the other probable issues.

Wish I could find my spare key. I'm tempted to go there with those last two coils and a can of carb cleaner to spray around. I wonder if he'd let me... I wouldn't charge him for it.

Post by **timmybdaddyof3** » 13 Sep 2014, 22:48

Yeah, on the Audi 2.2l 5cyl turbos they call it the "Michelin Man hose" that runs from the intercooler outlet to the throttle body, they are prone to slowly splitting, and when they do things get real inconsistent and wierd

zinman · Post by **zinman** » 16 Sep 2014, 12:01

Okay two weeks later and $300+ in diagnostics and tow, here is an update. Drove it home from the mechanic with low power. Put in two remaining coils, and it runs noticeably better already. I'm about to run to the dealer for some new spark plugs.

Discovered I botched my PCV repair of a year ago. Shortly after my "repair" I discovered a serious oil leak. Never could positively identify the source because of obstructions. With today's coil replacement I see, which the mechanic pointed out, the tube to the top of the cylinder head is nearly severed from the screw style clamp I used. I suspect the same problem or a cracked hose by the flame trap. Anyway, it has to be redone but since I tackled it already, it isn't so intimidating. I think I'll use spring clamps. I was dreading an oil pan gasket but thought it a strange coincidence, especially since it was supposed to relieve pressure on the engine seals and gaskets. Right after the PCV replacement it ran better than ever with much improved milage.

Could these cracked PCV elbows and such contribute to the running conditions I've experienced, or is it more like I'm just putting out excessive pollution in the form of oil and non-combusted air/fuel?

The mechanic also told me he ran a wave test on the fuel pump and said it showed a slight unevenness in the AC wave pattern but was not extreme. Do I need to think about replacing the fuel pump? Should it be done preemptively? Or do I say, "It ain't broke. Don't fix it?"