Surge under load?

[frank_a]

My 02 with 113,000 miles seems to be having a surge issue. During warm weather, 80 degrees or more, while driving up hill or accelerating hard onto a highway the power surges. It almost feels like the turbo is is coming on and off. It usually occurs over 2500 rpms.

I just had the mass air flow sensor cleaned and it didn't help.

Any advice on what might be the cause?

[JRL]

I had the same deal with my 02 S60 AWD several years ago under these same circumstances.
After Keystone Volvo (who are good) could not find anything, I gave up and lived with it.
Only happened under load, at higher speeds and in warmer weather.
Yours sounds a little worse but I can't help you

[billr99]

My 02 with 113,000 miles seems to be having a surge issue. During warm weather, 80 degrees or more, while driving up hill or accelerating hard onto a highway the power surges. It almost feels like the turbo is is coming on and off. It usually occurs over 2500 rpms.

I just had the mass air flow sensor cleaned and it didn't help.

Any advice on what might be the cause?
Yep, I have it too and I've been trying to dial it out for the last couple of years. Considering that it occurs at higher temp and lower humidity (well, lower than usual for us here), I would suspect its a mixture under load problem which would be somewhere in the software.

Cheers,

Bill

[JRL]

Probably running a bit lean and there's no real fix for that unless you (AFTERMARKET) tune the ECU ($800-$1000)

[sjonnie]

Probably running a bit lean and there's no real fix for that unless you (AFTERMARKET) tune the ECU ($800-$1000)
Dirty injectors? Low fuel pressure? I mean not everybody's car has these problems so why would it be an ECU issue?

[JRL]

I doubt I had any of the above (it was a low mileage, well serviced car)
I really don't know.
It seldom occured, plus it was my wife's car and the only time it happened is when we went on a trip, me driving at higher speeds, car loaded up (weight wise) and accellerating under load (up hills, very high speed passing, etc), so I didn't really worry about it.
The major leadfoot I sold it to never mentioned it, so it was a rare occurence and in fact, unless you were a very sensitive driver, most people would not notice anything.

I think they all do it, (at least 2002's) it's just most drivers don't notice it

[billr99]

It is not the first time I've ever run into it over the years and it has occurred with any number of makes. With the EPA regs and desire to promote a certain MPG level, the stock tune is set to run pretty much on the edge of lean. All it takes to create a surge condition is a humidity level, air temp, fuel mix, or any one of the involved sensors to be off just a wee bit from ideal. Doesn't take enough to throw codes either. In theory the software should account for it, but I've had it happen with the most basic injection systems that were around 20 years ago and systems newer than what is on my '02 XC. And as JRL has stated, it occurs under a fairly specific set of conditions. In fact, my surging occurs under the same conditions he has described, hence my suggestion that its just part of the stock setup.

In the old days such as in the old K-Jetronic systems, you could adjust a bit of it out. These days the OEMs and the State have pretty much taken that ability away unless you go to a custom tune. Just another one of those modern "advances" we all have to put up with.

Cheers,

Bill

[sjonnie]

driving at higher speeds, car loaded up (weight wise) and accellerating under load (up hills, very high speed passing, etc)
I can't say I've noticed anything like that in my '02. Going uphill with boats and gear on the roof and more in the back at say 75mph (2800rpm in 5th), it'll boost to 10psi then back-off and hold 8psi without a problem. I don't observe any obvious fluctuation in power, although maybe it's too subtle for me ;) I do run premium gasoline though, I wonder if that could be the difference?

[billr99]

I can't say I've noticed anything like that in my '02. Going uphill with boats and gear on the roof and more in the back at say 75mph (2800rpm in 5th), it'll boost to 10psi then back-off and hold 8psi without a problem. I don't observe any obvious fluctuation in power, although maybe it's too subtle for me ;) I do run premium gasoline though, I wonder if that could be the difference?
I've done both regular and premium and have also noticed it after a reset or some time after a reset. It is a subtle surge, at least on mine, and it goes away when its cooler or when the air is more humid. I have tried just about everything I can think of but I do have new intake tubes and vacuum lines to put on so I'll see if that helps at all. I'm also going to install IPD's CBV to see if that might do something.

Cheers,

Bill

[Aviator]

My way of thinking is....the apple doesn't fall far from the tree. It's entirely possible that the TCV (turbo control valve) is struggling given higher air temps. For the price of a TCV, I'd be tossing one in. As far as leaning out and having to live with it, and all that talk about mapping......nonsense; dirty injectors, low fuel pressure.....you'd have performance issues all the time under any condition. Eighty fahrenheit is nothing compared to way hotter places on this earth, and I'm sure that would have been taken into account when engine controls were being developed for these cars.

Dave.

[billr99]

It's entirely possible that the TCV (turbo control valve) is struggling given higher air temps. For the price of a TCV, I'd be tossing one in.

Been there and have done that with no change. I have periodically run Seafoam thru the gas to try and keep the injectors clean and the MAF has also been cleaned. Plugs new, coils changed about 25K kms ago, clean air filter, etc. Only thing I haven't done, but its coming, is new vacuum lines but my thought there is that those would cause a problem regardless of temp and humidity and would be more a load problem.

I'm open to suggestions. As I said, I have seen this before, even on carb'd cars, that were emission controlled and it is a lean condition. Back in the days when things could be tweaked a bit, richer setting (slightly bored out jets or a tweak of the mixture screw on the K-Jetronic systems) took care of it. Usually improved the mileage too.

Cheers,

Bill

[lexefx]

I think they all do it, (at least 2002's) it's just most drivers don't notice it

When my 2002 would surge, it was because I hadn't synced the sidedrafts that week... lol [thumbup]

[billr99]

When my 2002 would surge, it was because I hadn't synced the sidedrafts that week... lol [thumbup]

Ah yes, if it could only be that easy. A bit of hose and a careful ear was all that was needed to do a decent tune. Sigh......:(

Cheers,

Bill

[frank_a]

Thanks for all the replies everyone.

I was planning on running some Techron in the next tankful. Then change the spark plugs. The TCV would be next but if it hasn't worked for others, I many not bother.

Could this have anything to do with the newer ethanol fuel?

[JRL]

Could this have anything to do with the newer ethanol fuel?

Naw, this was back in 03-04

[billr99]

Thanks for all the replies everyone.

I was planning on running some Techron in the next tankful. Then change the spark plugs. The TCV would be next but if it hasn't worked for others, I many not bother.

Could this have anything to do with the newer ethanol fuel?

I saw it when I lived in Ohio which typically was running 10% ethanol at most of the stations I went to (i.e. BP). But I've also seen it in Canada (ON (PetroCan and Shell) and NS (Irving and Ultramar) which typically have no ethanol content or any other oxygenators as far as I know.

Cheers,

Bill

[sjonnie]

I was planning on running some Techron in the next tankful. Then change the spark plugs.
Both very good ideas. I run Techron at least 3-4 times / oil change. Advange Auto parts were selling the 12 gal treatments at 2 for 1 a while back. Otherwise Walmart have them for $6 a pop. Spark plugs are great idea too. 30K is the max life for Volvo plugs, Bosch Super Plus are OEM equivalents for $1.50 ea.

[BillAileo]

I use Techron as well. The containers sold locally now say they will treat up to 15 gal versus the 12 gal rating on older bottles.