2002 C70 HPT spitting and sputtering above 3k rpms.

RSM-GA · Post by **RSM-GA** » 26 Jul 2014, 19:12

Hopefully, someone has experienced my issue. My 02 C70 HPT coupe will religiously start "cutting back, sputtering and loses power" any time the car gets above 3000 rpms. It feels like a fuel issue but cannot isolate. It has not set any codes, no check engine light comes on. I was at my local Volvo dealer today for over six hours trying to isolate issue. We have replaced the fuel filter, drove it with fuel pressure gauge hooked up (very minor fluctuation when it happens), we changed spark plugs, we changed out the turbo control valve (the one on the airbox). We removed the rear oxygen sensor for reference, cleaned throttle body and briefly checked the hoses. Still nothing changes the fact once you hit the 3000 rpm range, it will start cutting back. And the ETM has already been replaced and new programming installed. I have had the car for 2 months and it has done this since day one. It currently has about 137,000 miles on it. Does anyone have any idea on this? I am out of of options and ideas as is the three technicians at the dealer. I am fortunate to know someone there and they are willing to go the extra steps to look into it.

Thanks for any help and ideas!
Rob

Post by **shaker_chi** » 26 Jul 2014, 19:40

Maybe the issue is air and not fuel. I know seems easy, but have you check all the hoses to the turbo, intercooler, etc? Maybe try to pick up a used ECU on ebay and throw it in. On my S70 T5, I had an issue with a hose that wasn't tight enough and when I gave it some gas it would sputter. Just a thought.

RSM-GA · Post by **RSM-GA** » 26 Jul 2014, 19:50

My thoughts too! I asked the technician about this when he had the hoses off and he says he checked most of the hoses and all appeared to be in good shape. Maybe I will go out in the morning and check them again when it is cool.

RSM-GA · Post by **RSM-GA** » 27 Jul 2014, 09:29

Nothing unusual about hoses, they appear to be in good shape.
This has me befuddled!

Post by **erikv11** » 27 Jul 2014, 11:17

Good chance there is a leaky CBV diaphragm on the turbo. Have the tech (or yourself) pull it out and if you can't see an obvious small tear or hole, hold it up to the light and check for thin spots.

RSM-GA · Post by **RSM-GA** » 28 Jul 2014, 08:15

Just finding it hard to believe that dealer is at a loss on diagnosis on this too! Problem is duplicated but unsolved!

Post by **erikv11** » 28 Jul 2014, 11:52

Yeah, I hear you. A Volvo dealer shop rarely deals with old cars like these, so the techs often don't know to check the long-interval wear items. If you are lucky you get one that has been there a while, rather than freshly trained ...

RSM-GA · Post by **RSM-GA** » 30 Jul 2014, 09:29

Any possibility this could be an exhaust issue? When it was in the air, I noticed the mid-section of the exhaust pipe (between convertor and muffler) had been replaced with a section of galvanized pipe. The convertor and the muffler seemed excessively hotter (not cherry red) than normal. Just a thought.

Rob

RSM-GA · Post by **RSM-GA** » 30 Jul 2014, 14:47

Ok, just had it at the local indy. They are telling me the exhaust (muffler) needs replacing as it is obstructed. He states he checked the temperatures inlet/outlet at converter and there is like a 40 degree difference but when he checked at the muffler the temp at the muffler was like about 200 degrees hotter than the converter! Now I am stumped!!!

FirstS40 · Post by **FirstS40** » 26 Aug 2023, 06:42

RSM-GA

Did you come up with a solution on your C70?