1996 850 GLT Wagon Stalling at High RPMs and Over Bumps

Volvo_Lover · Post by **Volvo_Lover** » 28 Jun 2015, 03:53

Hi there, fellow Volvolians! I have a 1996 850 GLT Wagon that is stalling when I give it too much gas and especially when I hit bumps. The CEL lit up about 6 months ago so I bought an OBD II scanner that read a set P0120 code. Apparently a P0120 may indicate a TPS fault, so I removed it, cleaned it (it was filth-y!) and reinstalled it but I'm still stalling. I also stall at high speeds or high RPMs (lots of gas), but especially when I hit bumps. I understand this may imply a loose electrical connection, so I tightened the battery connections (they're taught, as is the TPS), but still stalling. I'm also feeling some latency from the engine when I give it gas, especially at high speeds. Sometimes this precedes stalling. I'm usually able to restart the engine immediately, sometimes without stopping; other times I have to wait a few minutes. I have 100k miles on the odometer and other than the above issues there doesn't seem to be anything wrong. At idle there is some sputtering, but never stalling. The service [SER] light illuminates on ignition and stays lit about 3 minutes. I used my scanner to clear the P0120 code and the SEL has not returned to stay, although it does illuminate prior to stalling. The arrow light also illuminated the last time I stalled, but that was its first appearance. I've combed the threads on this (magnificent) site, but have yet to find one that pertains to this particular situation. I'm hoping someone here can give me some direction, any help is much appreciated.

Post by **abscate** » 28 Jun 2015, 04:45

Welcome to MVS!

A frequent cause of this is loose ground wires...and there a lot of them to check on this car. They look like metal braids and the connections to the engine block and frame get corroded. I think there are some under the battery too, so you might have to remove that to check those.

When was the last time the consumable ignition parts were replaced? Spark plugs, wires, cap rotor, coil?

Volvo_Lover · Post by **Volvo_Lover** » 28 Jun 2015, 15:12

The ground wires on the engine block ARE corroded, I'm going to replace them today. I checked under the battery platform, there is one insulated ground wire that had a dirty contact; I hit it with cleaner. I don't know how old the ignition parts are... at least as long as I've been the owner, about 4 years.

Post by **E Showell** » 28 Jun 2015, 18:09

I've never replaced my ignition coil. My factory-trained Volvo mechanic said either they work or they fail. I've got 291K miles on my original coil and have never changed it. Can't say the same for plugs, cap, rotor & wires. Plugs are 30,000 mile maintenance items and wires shouldn't go beyond about 50K. I usually do cap and rotor when I do plugs.

I alway use Volvo plugs, Bosch rotor and cap and Bougicord wires and haven't had a problem with ignition components. Others on here have used different (cheaper) plugs without adverse consequences, but I wouldn't use anything other than Bosch for the cap and rotor and Bougicord for the wires.

Just for kicks, if you have a set of Bougicord wires in the car now, they generally have a date code on them. Might be fun to see just how old they are.

Post by **abscate** » 29 Jun 2015, 03:35

To clean electrical ground, you have to remove the bolt, wire brush both parts to shiny metal, reattach, and then apply grease or something to keep water out. The part you see when attached makes no electrical connection, the problems arise underneath.

4 years at 15000 mile average is 60000 miles or more. Time for some TLC!

Volvo_Lover · Post by **Volvo_Lover** » 06 Jul 2015, 04:51

Good ideas here. I bought her off the first owner, who took very good care and even payed to have the dealership do the tune-ups. Not sure how old the plugs, rotor or wires are but I'll check for a date. Embarrassed to ask but what is a cap? I decided to spring for a new Bosch TPS since that was what the computer indicated in the first place, and I haven't stalled since! I've been over bumps, on the freeway, never stalled. Yesterday the CEL flashed it's ugly head but didn't stall and the CEL has not stayed lit. Hoping I've fixed the main problem, seems that way as yet.

Sommerfeldt · Post by **Sommerfeldt** » 06 Jul 2015, 06:47

Hey.

The "cap" is the distributor cap, seen here:

They crack or deteriorate, causing all sorts of ignition BS.

- S

Post by **E Showell** » 07 Jul 2015, 04:49

And when you replace the distributor cap, you have to be very careful about the plug wire routing. You need to make sure the wires go to the proper plugs or the spark won't arrive at the designated cylinder when the fuel/air charge does.

Volvo_Lover · Post by **Volvo_Lover** » 10 Jul 2015, 14:18

Ok got you, I came across that when I was diagnosing the stalling. So far so good, still no stalling and no CEL since that one time I mentioned earlier. Hoping this is it for now. Changing the distributor looks doable so I may invest in that next. Running much better for now. Thanks for the support!

Post by **E Showell** » 10 Jul 2015, 14:30

When you change the cap, you must also change the rotor or you are simply wasting your time.