All,

Our 01 XC 70 with 72K on it has developed an irritating issue. The worst part is that it is intermittant at best.

Ok, here we go. When we are driving the car on the open road on flat or slighty hilly terrain at times it will feel like the engine hesitates for a quick second and then catch up again. It almost feels like a flat spot in the power band. The best way to describe it is if you picture yourself driving and are constantly taking your foot off the gas and reapplying it several times a minute to maintain a constant speed.When it does it, it is more pronounced with the cruise control on. The irritating part is that it happens only once in awhile, and you never know when it is going to occur, but when it does happen, it only occurs in the 68-62 MPH band. Slowing down or speeding up makes it go away or at least become less pronounced.

Idida full tune up on the car about 8,000 miles ago along witha timing belt change, and I changed the transmission fluid (with the proper Mobil 3309 fluid) about 5K ago. I also changed the bevel gear oil about 5K ago as well. Oh yes, Volvo replaced the ETM at 59K due to the dreaded "reduced performance" issue we all know about.

The car starts and idles fine, revs freely, no unusual noises, and no check engine light or stored codes in the computer. The transmission shifts fine, except it does shift a bit firm when cold, and it always seems that it "short shifts" from 3rd to 4th under brisk acceleration.

Any ideas, I really woiuld like to get to the bottom of this.

Thanks,

Glenn

 

I would try cleaning the throttle body and see if that helps it.

 

Never thought of that....definitely worth a shot. Now for the really embarrassing question (for me at least)

Is there a good step by step set of instructions posted on how to doit? I have done something similar on a few Hondas but never a Volvo. Itried the search, but nothing clsoe came up. Since this is the wife's car I want to make sure I do it correctly.

Thanks Tech,

Glenn

 

Ok, doing the search again with different parameters I was able to dig up some info. Correct me if I am wrong, but it looks like I just need to take off the inlet hose and clean the throat and butterfly on the throttle body. I'm planning on using carb cleaner, any problems with that?

 

Carb cleaner is fine.
Removing the intake hose will get you to it but the throttle body is under the intake.
You might want to get a gasket and remove the throttle body to clean it good.

 

Works for me.....Thanks Tech

Glenn

 

No problem.

 

Ok, I probably sound like a complete idiot, but how do you get to the throttle body on this engine? I just spent a half hourfollowing the air intake ducting from the air filter box and the turbo piping, but they both look like they go to the back and theunderside of the motor toward the turbo. Please don't tell me that is where the throttle body is as well? All the other cars I have worked on have the throttle body on the top of the motor. So..................

Cananyone give me a quick step-by step? Sort of an idiots guide to the throttle body? I have removed and cleanedthrottle bodies on GM's, Ford's and Honda's but this motor looks like a different animal.

Thanks,

Glenn

 

The throttle body is mounted under the intake. The pipe goes from the throttle body to the intercooler on the drivers side.
It is a pain to get to the clamp to loosen it.
You will need a 1/4 drive ratchet and 7mm socket it really helps if you have a short socket as well.

 

Thanks Tech, I'll give it a shot in the morning.

 

Ok, I couldn't wait until the morning <grin>. I went out to the garage to look at the car just to see if I could get an idea of what I need to do. From what I can tell, I think the Throttle body is mounted by the ETM, under the intake and on the front right sideof the motor (as you are standing in front of the car looking at the motor),is that correct?

Looking with a flashlight I can see the yellow stickered ETM on the car and if the throttle body is by that, it looks like I would have to remove the big plastic pipe that goes across the top of the engine, and the flexible hose that attaches from the big plastic pipe to the lower right front of the car.

It also looks like there are a few other things to remove to get room to work on it.

Either that, or I am completely lost.

Glenn

 

The ETM Yellow sticker is the throttle body.
You only have to remove the pipe from the ETM to the Intercooler.

 

That sounds a little easier and clears it up for me.

Again..........thanks tech,

Glenn

 

No problem anytime.

 

have u performed recall 155?? u may be able to save some money and time if u haven't done so... extended warranty for throttle unit may be available for repairs. If u really need to clean it on your own spray carb clean on a clean cloth and wipe it clean instead of spraying directly and soaking throttle unit wet.