1994 850 - Stalling, Acceleration Issues

jjs70pdx · Post by **jjs70pdx** » 17 Aug 2014, 12:15

I've noticed over the last three or four months, the following symptoms. They are not an every day occurrence, although it seems to be happening more recently in the last few weeks: not much power on acceleration, the gas pedal is all the way down and it feels like the gas pedal is slipping or there is some sort of hesitation (if that makes sense?).

Yesterday I was driving home and the car stalled three times, at about 30-40 second intervals. It started back up fine each time, and I let it sit for a few minutes after the third stall. I was able to drive it home but the check engine light is now on. Any advice on what to troubleshoot would be appreciated.

Background on the car: I have owned it almost a year. Going on almost 195k. Engine compression is strong, and it's a non-turbo if that matters.

Post by **regent** » 17 Aug 2014, 12:38

Throttle position sensor would be my first suspect

Post by **erikv11** » 17 Aug 2014, 12:40

You will want to get the code(s) read, find out what the message is from the CEL. Report the actual code (e.g. P0300) here we can perhaps give more specific help. Oh, your car has a diagnostics box, you can read them yourself.

Offhand it sounds a bit like a MAF problem, though I agree could be TPS. Try unplugging the MAF and then start up the car and take it for a drive. Are the symptoms gone? Note this will set a CEL with a MAF code, so may as well try it before reading and clearing the codes.

jjs70pdx · Post by **jjs70pdx** » 17 Aug 2014, 15:37

Erik,
I just looked over the records for the car before I purchased it last October. The previous owner replaced the MAF and air mass sensor just before I got the car - in September 2013. Also the crankshaft pulse speed sensor in Feb. '13.

Given this info, would you still recommend removing the MAF and driving? It seems doubtful that it would go out soon, especially considering I drive the car very little - mostly on weekends or to run a few errands during the week so I haven't put much mileage on it. I will read the codes and let you know what I find.

Thanks,
Jessica

jjs70pdx · Post by **jjs70pdx** » 17 Aug 2014, 16:15

I tried the on-board diagnostic unit (Test Mode No. 1) and it looks like it's coming up with code 1-2-2. What issue does this point to? From what I could find online it showed air temp sensor. Was I supposed to diagnose via Test Mode 2 instructions instead?

Post by **erikv11** » 17 Aug 2014, 18:26

What brand is the MAF (MAF is the air mass sensor)? If it is a Bosch, then I agree it should be fine and it is wise to look elsewhere. If it is not, then unfortunately all bets are off, non-Bosch MAFs can be bad right out of the box, or in a week, or sometimes not for a year ...

Here is a thread with some relevant MAF info FYI: https://www.matthewsvolvosite.com/forums ... =1&t=57684

That 1-2-2 code doesn't help much, alas. Are you sure it wasn't 1-2-1? That would be a MAF code. Once you are sure of the code, clear it and see if it comes back, then read it again.

jjs70pdx · Post by **jjs70pdx** » 19 Aug 2014, 10:23

Not sure on the brand, I will check it this evening. I noticed from the previous owner's records that he had two receipts for MAFs - one for an aftermarket $45 one and one for a Bosch.

I checked the codes again and am still getting the 1-2-2 code. After watching some videos on using that built in diagnostic box I realize perhaps I am doing it incorrectly. I had it connected to the B side, #2. Please confirm which side and number it should be hooked up to read the codes.

jjs70pdx · Post by **jjs70pdx** » 19 Aug 2014, 20:15

The MAF is Bosch brand. Receipt from previous owner confirms it was purchased in Sept '13 just before I bought the car and I have since put maybe 5k miles on it. I retested the codes again and got a 1-2-1 code from A2 initially. Other codes as follows: A1, A6= 1-1-1, A3= 1-4-1, A7= 1-2-2. Tested A2 again and second time around it read 1-1-1. Do I need to clear the codes and try again?

Post by **erikv11** » 19 Aug 2014, 20:34

I don't know the OBD1 codes at all, I will have to look those up. But yes, it is good to clear the codes and see which ones come back first. Some of them could have been there a while and may be red herrings.

jjs70pdx · Post by **jjs70pdx** » 22 Aug 2014, 11:10

I cleared the codes last night and the CEL is off. I took it for a very short test drive (5 mins) and it seemed fine with no stalling. How long do I need to drive it for to reset any codes that would come up?