2001 V70T5 205K miles: Bucking and lack of power over 60mph.

carboncow · Post by **carboncow** » 15 Apr 2015, 10:55

OK...3rd car and doesn't get the love it should

Today tried to drive to work on the freeway and when the engine was put under load to pass or go up hills then it started to buck pretty bad. No CEL and I have not had time to get it home to put on Vida Dice.

It seems the issue is directly related to "load" which makes me think fuel filter and/or pressure regulator?

When I got down the country road to work I decided to get on it hard and the RPMs shot up 1K (maybe kick down) but no increase in speed...

How about a bad cat converter?

I guess I'll know more when I run the diagnostics but trying to get some ideas to rule out some options or correct bad logic.

Maybe even the tranny giving up the ghost...bucking at load?

Since it's been the neglected 3rd car we've lived with a few things that may give additional info...

1. O2 sensor on top of cat has been bad for a couple years. Cleared CEL a couple weeks back and has not returned but still showing bank1 trim issues on VD
2. One of the timing advance solenoids shows up from time to time on VD too.
3. The tranny has been crapped for 3-4 years. It has flares at 2-3 and 3-4 only when hot and only around town. Otherwise it's been a pefect highway commuter all these years.
4. Who knows when fuel filter was last done!
5. ETM is perfect and the MAF has been cleaned. ETM passes Vida Dice test perfectly when I was trying to solve an issue last week when the air temp sensor popped out.

Post by **vtl** » 15 Apr 2015, 11:05

2 can be skipped tooth on a t-belt. Or bad solenoid itself. If you disconnect it, how it feels?

I'd check fuel ramp pressure under load, should be almost 100% stable with very little variation.

One more possibility is bad TCV.

carboncow · Post by **carboncow** » 15 Apr 2015, 11:11

VTI,

I forgot to mention that turbo pressure has been terrible for the last 3 months. I'm assuming TCV is the turbo control valve? It's basically been driving like a non-turbo car!

How does one check "fuel ramp pressure" under load? Values with Vide Dice while driving or high RPM while stationary?

I have not tried to disconnect the solenoid yet...I'll try tonight. Does disconnecting it send it to a value that is generic (like a MAF or O2) and thus may stabilize the situation?

Timing is an option...as I'm to embarrassed to tell how many miles I'm over on doing the belt! I was supposed to sell this car off this spring w/o putting money into but I've loved it for my daily beater.

Post by **vtl** » 15 Apr 2015, 11:35

carboncow wrote:I forgot to mention that turbo pressure has been terrible for the last 3 months. I'm assuming TCV is the turbo control valve? It's basically been driving like a non-turbo car!

Dead TCV can result in non-turbo car feeling.

How does one check "fuel ramp pressure" under load? Values with Vide Dice while driving or high RPM while stationary?

Connect fuel pressure gauge to the rail (I meant to say "rail", not "ramp") and push the pedal few times while looking at the gauge. You can compare that to what VIDA shows you, rail pressure sensor can be bad too.

I have not tried to disconnect the solenoid yet...I'll try tonight. Does disconnecting it send it to a value that is generic (like a MAF or O2) and thus may stabilize the situation?

Yes, it will disable variable timing at all.

carboncow · Post by **carboncow** » 15 Apr 2015, 17:09

vtl wrote:
I have not tried to disconnect the solenoid yet...I'll try tonight. Does disconnecting it send it to a value that is generic (like a MAF or O2) and thus may stabilize the situation?
Yes, it will disable variable timing at all.

I think we have a winner!

I got in the car cold (less then 2 minute warm up) and took off to our maintenance facility up the road (1/8th mile) and you could tell the car wanted to stumble even at lower speeds/loads.

Pulled the cover off, disconnected the VVT and drove home 55 miles on the freeway...ran just fine. prob unrelated (I still have low turbo pressure and will discuss in another post) but I think the VVT may have been my bucking under load issue.

Now I've heard many talk about replacing the VVT solenoid and it appears pretty easy but is that in fact the issue? I read one post where the tech says the solenoids almost never fail but something about being the pulley (?!?).

Does Vida Dice have a procedure/cycle for testing the functionality of the solenoid?
When the VVT was throwing codes before did that take the VVT offline for future driving and thus the issue never showed up until I reset codes a couple weeks past...and forever reason it's not throwing a code and putting it in "generic mode"?

What is the disadvantage of leaving the wire off the solenoid? emissions and power?

Post by **vtl** » 16 Apr 2015, 11:07

The car does not have circuits to test VVT operation directly.

I'd buy a new solenoid gasket(s), took solenoid(s) off, disassemble and clean them. Gasket has mesh filter on it, it may get clogged, as well as solenoid may become sticky due to sludge residue.

VVT hub died in my 2002 V70, but the car didn't loose power - it was causing annoying resonating sounds when engine was passing 1450..1600 RPM range.

carboncow · Post by **carboncow** » 16 Apr 2015, 12:52

Thanks clean it is.

I did watch a video that showed a sound was the need for a new VVT too...I do have some sounds in that area but most likely from neglected pulleys/tensioners! I'm guessing when the Volvo Tech said the solenoids don't fail...like you said they just need a good pull and clean.

Will report back once done.