850 GLT 1997 Misfires etc.

spacecadetcharlie · Post by **spacecadetcharlie** » 21 May 2009, 11:28

Long time reader, first time writer, but all the responses to others' posts have been extremely helpful to me in the past. (apologies if this is a rethread; if it is please point me to the correct thread and I will happily read read read)

I am trying to sell my 97 850 GLT wagon (sadness! 160k miles and still drives sweetly) and of course the check engine light is on. This has been a problem for a while so I'll give you the history:

8 months ago I got a misfire on a cold start in Colorado, during which the engine shut down. However, I now live in Houston and the warm climate offers no shut downs, though apparently the engine still misfires on start-up. The problem has never affected driving the engine once it was warm, save once or twice, but I still get the codes (to follow). I have:
1. Replaced all the spark plugs, and set to appropriate gaps.
2. Used a billion fuel system cleaners (well, maybe 6 or so)
3. Cleaned the MAF.

However I get the following codes to this day and don't want to be ripped off by a mechanic I don't know.

P0172 - Fuel system for bank 1 too rich
P0440 - Malfunction exists in the EVAP (emission control system)
P0305 - Misfire in cylinder 5
P0300 - Multiple random misfires
P0304 - Misfire in cylinder 4
P0301 - Misfire in cylinder 1

Based on my non-mechanic logic, the only real common (potential) problems could be fuel injector issues and/or vacuum leaks. But since the car drives like a champ I never bothered with it.

Any ideas? Is this a no-brainer? Or something that only a qualified mechanic could piece together? I hope it isn't an O2 sensor. Yikes! Any ideas?

Post by **Ozark Lee** » 21 May 2009, 13:43

Welcome to MVS as a for real poster,

The misfire codes may be legacy codes. Clear them and see if they come back. The P0172 is likely a vacuum leak, I use a propane torch to try to find leaks but you can also use carb cleaner. If the misfire codes do come back I would start with the cap, rotor and wires. Don't cheap out on any of those items or you will have more trouble then you had before. Bosch for the cap and rotor and Bougicord for the wires.

...Lee

jyossarian · Post by **jyossarian** » 22 May 2009, 06:18

I hate to admit to it, but I drove around for the last 3 months getting a MIL for misfires in cylinders 2,4,5. I kept resetting the light and hoping it would go away, because my normally reliable indy mechanic had just replaced the plugs, wires and cap. The wires are not OEM and I figured, from the advice at MVS, that that was the problem. I had just about resolved myself to the fact that I was going to get the light until the next time I shelled out $60 for new wires.

Yesterday I was checking fluids and randomly decided to also check the plugs. It seems as if the plugs were never gaped. They were about .045 - I assume that's the "out of the box" gap.

My point is: Unless you personally checked the gap on your plugs, don't assume that the last guy did it right.

spacecadetcharlie · Post by **spacecadetcharlie** » 22 May 2009, 10:53

Wow, thanks for the tips!

I was hoping vacuum leaks for some of it. I'll check those and get back to you.

I did gap the plugs by myself. Maybe I'll ask the mechanic here to double check my work. My brother also suggested I might be getting short in the wires leading to the plugs... but with misfires on 3 cylinders that seems unlikely, right?

The engine is over 10 years old so the vacuum leaks seem the most obvious problem. I know my turbo is dead, could that be causing some issues as well?

milesursogood · Post by **milesursogood** » 02 Oct 2009, 20:55

just got my 1st volvo a week ago. would like to learn more about my car, '97 volvo 850 t5 wagon. what are codes? and how does one use it? i ask you b/c you seem to have a lot of knowledge in the forum. thanks.

Ozark Lee wrote:Welcome to MVS as a for real poster,

The misfire codes may be legacy codes. Clear them and see if they come back. The P0172 is likely a vacuum leak, I use a propane torch to try to find leaks but you can also use carb cleaner. If the misfire codes do come back I would start with the cap, rotor and wires. Don't cheap out on any of those items or you will have more trouble then you had before. Bosch for the cap and rotor and Bougicord for the wires.

...Lee

Post by **Ozark Lee** » 03 Oct 2009, 07:41

just got my 1st volvo a week ago. would like to learn more about my car, '97 volvo 850 t5 wagon. what are codes? and how does one use it? i ask you b/c you seem to have a lot of knowledge in the forum. thanks.

Welcome to MVS. The codes are standard OBD-II codes on the models after 1996. They are read by a specialized automotive code reader and they indicate which system on the car is "unhappy" when the Check Engine Light comes on. For each code there is a series of tests to determine the source of the problem. There is an OBD-II port located under your coin slot in front of the shifter where the scan tool plugs in.

Many auto parts stores will read the codes for free or you can simply buy a code reader, you can pick up an economy model that will read and reset the codes for around $40.00 at Harbor Freight. They make fancier code readers that will display real time engine performance data but that of course comes with a higher price tag.

The ultimate is the Volvo Scan Tool or the VIDA system but they cost more than you likely paid for your car. The Volvo specific tools read error codes for everything from the seats and the climate control to the engine.

...Lee

Post by **jtp** » 03 Oct 2009, 13:24

Back to what spacecadetcharlie was saying cuz I'm dealing with the same problem: couldn't the rich mixture be the result of the misfires, i.e. not all fuel being consumed in combustion and so registering as too rich on the way out of the exhaust?