1999 V70XC Turbo Chugging/RPM Up/Down ETM, MAF,other

richc233 · Post by **richc233** » 29 Jun 2014, 19:24

A month or so ago the car was having trouble when first started/intermittently, chugging when starting from a stop, the RPM going up and down with steady gas pedal pressure. After driving a few minutes it seemed to go back to normal. It now is much worse, and the RPM go up and down with steady pedal pressure, ie: if you are driving at 30-40 mph and try to hold the RPMs at 2000, every couple of seconds it goes down to 1500, then back up, over and over. It will get up to higher speeds and seems to accelerate OK after it is over 2000 rpm or so.

I initially posted this in the ETM forum but realized that it could be something else so I am posting here (don't know how to delete the other post). I have read the details, checked the Xemodex flowchart, and the problem I am having does not seem to point to the ETM but I am not sure.

It didn't have any codes or check engine. I disconnected the MAF sensor then started it up today to see if that would help, then it seemed to drive fine for several minutes so I thought the MAF sensor was the problem. I reconnected it and it had the original problem, BUT when I disconnected again it had the problem again - not sure if warming up affected the problem. I also took the sensor out and cleaned it with some contact cleaner, though it didn't look very dirty, but still has the same problem.

I didn't find other posts with these same symptoms, so I am a bit stuck here. Not sure if the car would Run properly with the MAF disconnected, or if the MAF is the problem.

Any help would be GREAT!

Thanks,
Rich

Post by **abscate** » 30 Jun 2014, 03:56

If the ETS light is not ON your electronic throttle body (ETB) is probably ok. The ETS bulb has to be working of course.

Spark plugs and ignition coils are all the tuneup parts that get replaced on these cars.

Checking fuel pressure at the rail will confirm fuel pump is ok.

Cleaning the ETB is a big project on a turbo but that would be next.

richc233 · Post by **richc233** » 30 Jun 2014, 07:45

I am thinking the throttle body cleaning will help...hopefully! Do you think the easy way, spraying Seafoam cleaner that I have seen in posts, would do it. I am thinking that if it at least works somewhat better I will know it is the problem and can then consider removal of the throttle body if needed.

Thanks,
Rich

Post by **abscate** » 30 Jun 2014, 07:56

I think most recommend removing the ETB to clean on a turbo. Its a big job, but too much solvent will kill the ETB and then you are in for a 1000 USD repair.

How many miles are on the beast?

Do you have a white label (original) or yellow label

ETM?

richc233 · Post by **richc233** » 30 Jun 2014, 09:40

The miles are actually real low, only about 60,000 (not home now to check), my wife uses it around town. Maybe I can get the air intake pipe off to at least look inside, see if it is dirty, and clean it off with some cleaner to see if it affects the problem. Not sure if it will be possible, have to look at it again.

Thanks,
Rich

Post by **abscate** » 30 Jun 2014, 10:32

The intercooler piping has to be put back on TIGHT - I once spent three weeks chasing an intercooler leak which gave horrendous running and made me think I had blown the whole motor up.

richc233 · Post by **richc233** » 04 Jul 2014, 13:11

I didn't get to try and clean the throttle body, looks like it will be difficult to get to under the car though! I tried the car again to see if I could narrow down when the problem is occurring - also it has about 80,000 miles not 60. The other question I never answered was the ETM, which is original with the white label.

Started up the car, and it seems to drive fine for about 5 minutes. After warming up, and starting from a stop, the car is jerking/chugging as it gets up to speed and RPMs go from 900 at idle to 1000-2000. It seems that when it is going around 40mph on a straight road, and the accelerator is steady and RPMs around 1500, it has the problem. It feels as if I was taking my foot off the pedal and then pushing it again, and it goes down to maybe 1200 then back up to 2000. If I accelerate harder from a stop, it speeds up fine, with maybe a little hesitation at first. Also, accelerating hard when the problem occurs, it goes to higher RPMs fine.

I don't recall when the spark plugs were replaced, and the coils have not been replaced - I don't know if could be as simple as one or both of them causing a problem. Do you recommend replacing coils if they are working properly, and would I have a Check Engine light if there was a problem with one?

Thanks,
Rich

Post by **abscate** » 04 Jul 2014, 13:37

The coil trouble code is one of the least reliable to show up if a coil is bad,in my experience. I jumped my 1999 with a charger pack, and one week later a coil pack failed and it took me a long time to track it down. I documented some measurements on the coil packs if you search under my user name and keywords 1999 coil T5

Post by **precopster** » 04 Jul 2014, 13:52

XeModex have a tutorial for turbo ETM removal posted on their website. It's about 45 minutes to remove and about 35 minutes to replace plus cleaning time. On yours the cable will be routed behind the starter bracket.

Removal is really the only way to clean, especially for the inner side of the throat bore behind the butterfly valve....lots of baked on gunk

richc233 · Post by **richc233** » 04 Jul 2014, 14:00

You think the gunked throttle could be the cause? I was looking at some other posts and someone had said that the springs for the throttle are strong would not be affected much by buildup. Thanks for the additional info guys.