What happened? -- S70 T5 140K

mar601 · Post by **mar601** » 14 Apr 2016, 10:42

I was just driving and all of a sudden the car lost power and I pulled over. It almost stalled and I had to floor it just to keep the engine running. I kept it floored for maybe 15 - 20 seconds, then bam it went full throttle and smooth. I drove home (about a 5 minute trip) and it was incredibly responsive like never before. Like a new car. -- YET -- I never sensed a power problem before and the mileage has been good, around 19.5 city. I use 93 octane, do fuel
cleaner, synthetic oil etc. I did have a PCV rebuild about 2000 miles ago at the Volvo dealer, which I thought made a big difference in performance and made my mpg go up as well.

Now -- what do you think happened? It sounded like it was constipated or a a clog somewhere. Can something "blow out" and then this happens? is it common? The turbo maybe or maybe the PCV job wasn't 100% ?

What's your best guess? -- thank you

Post by **scot850** » 14 Apr 2016, 11:04

The problem here is we would only be guessing. That can become very expensive in un-necessary repairs very quickly.

Guesses would include:

1) Fuel pump relay failing
2) Ignition switch issues
3) Fuel pump failing
4) Cam sensor failing or routed too close to the distributor
5) Cam shaft seal failing causing oil to get in the distributor
6) Bad/failing coil

and the list could go on.

Check with the local autozone or such and see if they have a code reader that will work on a 98 Volvo and see if they can pull any codes. Take a note of them if they can and report back. Or talk to the dealer but that will be the more expensive route.

Neil.

mar601 · Post by **mar601** » 14 Apr 2016, 11:28

Neil -- thanks much. It didn't throw any codes ( ! ) I have an OBD reader

mar601 · Post by **mar601** » 14 Apr 2016, 11:30

Also, I HAD been getting a growling sort of diesel engine noise at around 1000 rpm all winter -- which went away past week with warmer temps ?

Only at 1000 rpm and could get noisy as hell.

mar601 · Post by **mar601** » 14 Apr 2016, 11:31

I'll replace the relay and I know the ig switch is good.

mar601 · Post by **mar601** » 14 Apr 2016, 11:32

I have yet to drive it more but assuming it "doesn't" happen again, then what would you summize?

Post by **polskamafia mjl** » 14 Apr 2016, 11:44

Immediate loss of power on a turbo car usually happens when a boost pipe pops off but its not going to fix itself so I don't know what to think.

Post by **regent** » 14 Apr 2016, 11:57

Our cars are famous for being overly receptive to electrical gremlins.
Anything from a battery on the go to a poor contact could be the source of an intermittent misbehaviour like what you described, with or without setting any codes.

In addition to the ignition switch, I would do a nice visual/hands-on inspect at the battery terminals, the input at the main fuse box, ground straps, etc. Sometimes a slight tug or wiggle at the connections while the engine is idling may help re-enact the problem.

Just be safe and keep tools, fingers, sleeves, neck ties (and in that order) clear from belts, pulleys, and fan that may be in motion when you decide to do that

mar601 · Post by **mar601** » 14 Apr 2016, 13:51

Just going to drive around the neighbor hood tonight and see what happens -- ig switch should be good because i replaced it last year -- will exercise the relays and may report back. Can the fuel pump be "sketchy" or does it usually just go bad and that's it ?

Post by **BEJinFbk** » 14 Apr 2016, 14:11

Might be something as simple as water in the gas.
For a buck or so, throw some Heet in there.