850 Turbo, 95, stumbles during hard acceleration-turbo

Post by **john_dakins** » 21 Feb 2010, 09:09

Hello. Thanks for the site - I'm a user and supporter with this issue:
My car starts and runs fine, but under strong acceleration, as in when I peg the turbo needle, it chugs, sputters, stumbles and recovers only when I reduce the gas. It seems more prominent at higher speeds, say jumping on it at 65 - 70 mph, but it will behave that way at lower speeds also. However, if I am gentle - it will climb to faster speeds than I want to drive without missing. Recurring error codes include Turbo boost regulation, front heated oxygen sensor, slow response, rear heated oxygen sensor compensation and catalytic converter efficiency, with the oxygen sensor and catalytic converter cropping up most often. This happens so frequently that I have been ignoring them. I will reset them, it will be fine, then I'll jump on it a little and the codes will come back. My backyard skills are above average, but not expert. Any advice will be appreciated - if you suggest dealer work would you also give me a price idea?

My 95 850 turbo has 160K miles and a dealer installed "used" brain about 16 months ago. No changes / modifications except for that, which I suggest isn't the issue.

Thanks!
John

Post by **Ozark Lee** » 21 Feb 2010, 09:49

A couple of questions:

What kind of spark plugs are you using and what are the specific code numbers that you are pulling?

...Lee

Post by **john_dakins** » 21 Feb 2010, 10:03

Lee,

Bosch and the codes are: 414,443, and 435 mostly. Plugs changed a couple years ago, perhaps longer. Wires before that, 4 years or so.

Joe Hurless · Post by **Joe Hurless** » 21 Feb 2010, 20:24

Sounds a bit like an airflow issue. Check all of your turbo hose connections (sometimes these are loosened to do work to the car, like replacing a radiator), as well as air hoses between the air mass meter and throttle body, pretty much just check anything with a hose clamp on it, haha.

If this is an air mass issue, which it could possibly be, there is a neat little trick that will often fix the little sputtering problems your having. Pull the electrical plug that connects to the air mass meter. Inside the plug you will see little metal contacts. Grab a small pick tool and push those little connectors to the middle so they will contact better when you plug it back in. Try it, its free and easy and sometimes makes a big difference.

volvee850glt · Post by **volvee850glt** » 21 Feb 2010, 22:03

Check for any disconnected vacuum lines. My 850 was doing what you described and i found a vacuum line came off. And it ran fine after i put back on. Just idea I don't think that would be pulling any codes though.

xb corp · Post by **xb corp** » 21 Feb 2010, 22:49

does it spits fire when it sputters? if yes, look at the fire color, if it is yellowish orange...they you have problem with lean fuel ratio since you said "dealer has change the used brain"..seems to me they might changed it to a wrong ECU..or wrongly chipped the brain..

i had it before, i changed the plugs, cables, distributor cap & arm..but still no improvement. check compression and loose vacuum..no improvement...until i did dyno, finally it showed very lean mixture.

the knock sensor will send signal to ECU to cut the fuel supply to prevent damage, so when it goes normal again the fuel will surge in suddenly and this split second event that creates sputters & spit fire.

Post by **matthew1** » 22 Feb 2010, 00:04

Joe Hurless wrote:Sounds a bit like an airflow issue. Check all of your turbo hose connections (sometimes these are loosened to do work to the car, like replacing a radiator), as well as air hoses between the air mass meter and throttle body, pretty much just check anything with a hose clamp on it, haha.

My guess also. I had this happen jumping on 36 going from Boulder to Denver 2 years ago (at night, ugh). Same description as yours, only the problem would manifest much sooner, with much less throttle. Otherwise, it sounds identical.

I limped to a gas station at 40mph max, and after 40 minutes of looking and listening (and smelling) around the engine bay I discovered it. The large air hose to the intake had worked loose, but only half. Looking at it from the top, after removing the black plastic throttle cover, you wouldn't notice it. But when I felt around it's lower half it was obvious half the hose's lip had worked free of the clamp and was admitting unmetered air. The way I found it was by sound, while working the throttle in the engine bay. I could hear the air getting sucked into that area.

Luckily I had a long standard screwdriver with me and fixed it. It was a bit of a fight, and I'm much better at it now.

I remember it set the CEL, but I didn't get the codes because it went away that same night.

0menu0 · Post by **0menu0** » 24 Feb 2010, 23:07

john_dakins wrote:Hello. Thanks for the site - I'm a user and supporter with this issue:
My car starts and runs fine, but under strong acceleration, as in when I peg the turbo needle, it chugs, sputters, stumbles and recovers only when I reduce the gas. It seems more prominent at higher speeds, say jumping on it at 65 - 70 mph, but it will behave that way at lower speeds also. However, if I am gentle - it will climb to faster speeds than I want to drive without missing. Recurring error codes include Turbo boost regulation, front heated oxygen sensor, slow response, rear heated oxygen sensor compensation and catalytic converter efficiency, with the oxygen sensor and catalytic converter cropping up most often. This happens so frequently that I have been ignoring them. I will reset them, it will be fine, then I'll jump on it a little and the codes will come back. My backyard skills are above average, but not expert. Any advice will be appreciated - if you suggest dealer work would you also give me a price idea?

My 95 850 turbo has 160K miles and a dealer installed "used" brain about 16 months ago. No changes / modifications except for that, which I suggest isn't the issue.

Thanks!
John

My 1994 850t5 started doing the exact same today. Checking my intake hose(s) and vacuum lines in the morning.

Post by **john_dakins** » 11 Mar 2010, 08:20

It is help like I got here that makes it easy to donate another $25.00 to the cause, which I just did. I've been a fan of this site for quite awhile, I know it is expensive to keep it up and running and I also know it is a bargin for me to get help here rather than pay a dealer. Now to the results:

Last weekend it warmed up enough for me to get under the hood. I changed the air cleaner, just because. I cleaned the connections on the air mass meter as suggested. I didn't find any loose hoses with one exception - there is a plastic hose that runs from the radiator to a box, (for all I know that is the turbo charger)

that sits between the washer reservoir and the cooling system expansion tank. A couple years ago this broke in half at the accordian and I duck taped it. The tape was getting pretty brittle, so I cleaned it up and gave it a new duck tape bandage. One of those things, or a combination worked - because it runs like a new car now, and doesn't sputter.

Thanks!
john

Post by **jblackburn** » 11 Mar 2010, 10:04

there is a plastic hose that runs from the radiator to a box, (for all I know that is the turbo charger)

That's its brain!!! The air intake hose for the ECU box is deteriorated on almost all of them. I don't know why they put that accordion thing in the hose in the first place. I'm willing to bet your problem was with the MAF sensor itself, but all that matters is that it works now, right?