Stalling problem - 94 850 turbo

tomellis · Post by **tomellis** » 02 Dec 2009, 20:47

Yesterday I got a phone call from my son. He had just left swim practice, and the car (94 850t) had stalled shortly after leaving the parking lot. I told him to try to restart the car, and it started and ran fine so he drove home. Since the car seemed to be running fine I was not too concerned.

Today when he was leaving school it took 4 tries to start the car - VERY unusual! He drove to swim practice without incident, but once again as he was leaving the car stalled, and this time he could not get it to start again. He told me that before it died it was idling very poorly. So off I went to rescue him.

When I got to where he was parked, I tried to start the car. It started quite easily, but was running very rough unless I kept it at >1200 rpm. When I let the car idle down the engine was not happy, very rough and surging, almost like not enough fuel. I ran the car out of gear (with my foot on the gas) until it was fully warmed up, and then tried to let it idle again. Stalled out almost immediately unless I upped the throttle. At this point the cold and dark (and son who needed dinner) made my decision pretty easy - car is currently being towed home by AAA so I can give it more attention tomorrow.

The car had been running really well recently, so this catches me off-guard. I had just replaced a bad intercooler hose a few weeks ago, along with most of the vacuum hoses, and the car was running better than it had in a long time. After hearing the symptoms, does anyone have some ideas of where I should begin? All ignition parts (cap, rotor, wires plugs) were replaced just over a year ago, along with fuel filter.

As always, thanks in advance for any help and advice!

Post by **confused_al** » 02 Dec 2009, 21:32

Try to pull your trouble codes;
http://volvospeed.com/CheckEngine.php
read first then clear them, start car again read again for most recent codes;
https://www.matthewsvolvosite.com/forums ... hp?t=10758
post back so the experts here will give you more advise.
BTW, are you getting right fuel pressure?
GL!

Post by **polskamafia mjl** » 02 Dec 2009, 22:04

Loose or missing vacuum hose, maf problem. Could be hole list of easy to fix things. Do you have a CEL on? Like confused_al said, pull the codes and post them here and we'll see what's up.

Post by **jblackburn** » 02 Dec 2009, 22:07

My first guess would be the MAF sensor. Mine went kaput immediately, but when it went on my Buick, it ran exactly like you describe, hard starting and unable to idle.

Try taking the plug off, and see if the idle/running smooths out (you will throw a check engine light for this). If this helps, take it off and clean it and the plug with electrical contact cleaner, then letting it air dry. DONT TOUCH THE WIRE INSIDE!

tomellis · Post by **tomellis** » 02 Dec 2009, 23:30

I'll pull the codes in the morning and post them. I was also thinking MAF, but the only time I've had one fail before (on an Audi turbo) the symptoms were much worse than this.

Thanks for the help!

Post by **polskamafia mjl** » 02 Dec 2009, 23:53

Audi's aren't tanks. lol

Post by **jblackburn** » 03 Dec 2009, 07:23

If there's no engine light on, you may not have a code, but go ahead and try to read them anyway in case its something else. Mine didn't post one when it went. If disconnecting the sensor makes it run better though, there's your problem!

tomellis · Post by **tomellis** » 03 Dec 2009, 13:18

OK, here is where I am now. I first tried to start the car without doing anything else first, and had no success. I pulled the codes (and cleared them), and did get a 1-2-1 for missing MAF signal. I then pulled the plug on the MAF sensor and the engine started right up, ran for about 5-10 seconds and died. I started it again and this time kept my foot on the gas, idling 1200-1500. Engine ran for ~10 seconds and then tried to stall unless I pumped the gas. I then pulled the codes, and this time I got a 1-2-1 and a 3-2-5 (memory loss). Cleared the codes, reconnected the plug and started again. Got engine running by giving it a lot of gas, but it really wanted to stall.

So what is the verdict? Starting was much better with MAF disconnected, but engine still would not idle. Is this normal? Or do I need to look for something else?

I am now going to pull the sensor and clean it as described by jablackburn to see if this helps. What the heck, it's worth a shot!

Post by **jblackburn** » 03 Dec 2009, 13:30

Hrm...if it still won't run after you clean it, poke around your turbo/air intake/vacuum lines and look for leaks. It sounds like you have a huge air leak somewhere if it still won't run in limp mode. I forgot to reconnect a turbo air hose after doing some work once

, and my car would only start (and then run horribly) giving it lots of gas.

tomellis · Post by **tomellis** » 03 Dec 2009, 13:46

Cleaned the sensor thoroughly, replaced and no change. If the MAF sensor is simply dead, isn't this what I should expect? Or do these not really "die", only get dirty, which cleaning should fix?

Back to look for any big leaks, but since I just replaced a bunch of hoses I'd be surprised if I find one. Unless, of course, I didn't fasten something correctly and it has worked its way loose.......