2001 S80 T6 Surging under hard acceleration

Woody70 · Post by **Woody70** » 07 Oct 2008, 20:14

Hi all. My first post, and first Volvo. Need to tap the brain power of the S80 turbo guys for some suggestions. My 01 S80 T6 has 76,000 miles, and thusfar has been a pretty good car by maintenance history. Still had the typicals: ABS module (too bad I hadn't heard of Victor then), and the ETM was replaced and latest software update done by a dealer without even having to ask, no other mods that I'm aware of. Only problem I'm having is VERY noticible power surge under hard acceleration. It doesn't do it under moderate push, only when your foot is in the floor. I read on some past postings of possibilities like the ETM, various software issues, etc causing this, just need some other poss causes. Anyone dealt with this one? The car runs great; smooth otherwise, 30+MPG, no lights, no hick-ups. You push it, the turbos kick in and it feels like 300hp, then two seconds later it backs off, then kicks up again, on and on and soforth. Almost like its overboosting and the wastegates are opening up to vent. Any advice?

Post by **vegasjetskier** » 08 Oct 2008, 19:19

Check the hoses to the Turbo Control Valve. Also, you might want to replace it, either with an OEM or an IPD aftermarket unit. Here are the IPD directions on how to replace it; they will show you where it is and how the hoses hook to it:

http://www.ipdusa.com/uploads/sku_files/13184_INST.PDF

Post by **MadeInJapan** » 08 Oct 2008, 19:41

Good suggestion on the IPD unit. I've replaced the ones in both our S70 and V70 with this and it made noticeable differences, especially in terms of smoothness all the way up the power band. If that's not it, you might be in for the ETM again. How many miles has it been since the first replacement?

Woody70 · Post by **Woody70** » 08 Oct 2008, 20:03

Thanks guys. I had thought about the boost control valve and was looking up availability and price earlier today. Didn't see one on IPD, will look again. The ETM was replaced about two weeks ago, maybe 150 miles. I wasn't having any issues with it before it was replaced. I took the car to the dealer for ABS issues and they changed it while it was there and did the software reload. Nice folks these, but $$$$$. I'll be doing my best to learn as much as I can about the car for future maintenance. I'm like most in that I'm pretty good with cars, just unfamiliar with these so far. Like I said, car runs very well, just surges under full boost. So, the ETMs that are being used as replacements are nothing more than new (functional) ones? Nothing in the way of improvements?

Post by **MadeInJapan** » 08 Oct 2008, 20:26

Check your plugs and wires, ignition coils at your plugs as well. When plugs start to wear out and the gap becomes larger then spec, sometimes what you describe can occur.

Woody70 · Post by **Woody70** » 09 Oct 2008, 03:55

Thanks again. I'm sure some general tune-up stuff couldn't hurt. I love the car. I think I'm hooked, just hope I can continue to afford to be. I'll post any improvements or otherwise.

Woody70 · Post by **Woody70** » 14 Oct 2008, 12:12

OK. So I've learned a few things. I did buy and install an IPD boost control valve (and tried as best as could to follow the "learning" protocol). It DID make a difference, but the difference it made was smoother and more responsive power up to a point. The surge is still there. Maybe not quite as noticeable. I took it back to the dealer, and took a ride with one of the techs. They're pretty good guys I must admit. I spent about an hour visiting with them and talking about the possibilities and they rechecked the ETM. All of the advice offered here was repeated plus a look at the PCV system. They were quite impressed with how the car runs and said it is one of the best they've seen performance wise. For some reason I was under the assumption (don't ask) that the wastegates were VACUUM actuated, when in fact they are manofold PRESSURE activated. I did both vacuum and pressure leak-down tests on the wastegate circuit; all good and the actuator rods move the gates. I changed the plugs just for giggles, what came out looked good and was within spec for gap. Coils look good, no visual evidence of malfunction, and the car just runs too dang smooth. I know that if I'm going to look at real boost parameters and attempt any adjustments,

I need a boost guage, just no way around it. Am I being a little too expectant given that this is a "luxery" car and all? Any more things I might consider?

Post by **MadeInJapan** » 14 Oct 2008, 16:00

If you're doing this much stuff on your car yourself, I would highly recommend the boost gauge. I added mine on the S70 for well under $100 including the pod and it looks terrific. I know that Lucky over at IPD is working on a nice looking pod for the P2 cars which would include yours. Keep your eyes open and you'll be able to add something that will look like a nice upgrade to your interior as well as be functional at the same time.

Woody70 · Post by **Woody70** » 24 Oct 2008, 08:59

Just an update for those interested. The S80 T6 seems to have smoothed out a little more under full boost since replacement of the TCV. Maybe it just needed a little longer to "learn." The car is running great. The "position bulb" warning has come up a couple of times, but all bulbs seem to be working, so I'm pretty much ignoring it for now.

77.5k miles on it now. Transmission flush/fluid change will be next I think. No record of it having been done in the past. If the tranny is a weak point on these cars, what are folks typically seeing as a problem (specifically)? The IPD website sites customers as running their computer flash at 300+ hp with no problems.