First post!

Need any advice I can get on this. My 97 850 has issues starting up after it has been parked for more than a couple hours. The first turn of the key rotates the engine, and then it tries to run but it is very rough and typical putters out. The second try always starts it fine. Never happens after it has been running awhile.

I get a check engine light of 0172 which could mean the following:

-Fuel bressure or Mass Air Flow sensor
-Oxygen sensor Defective
-Ignition misfire repair
-Fuel Injector Problem

In response to these issues, I just replaced the following with new parts:

-Ignition Coil
-Spark plug wires
-Distributor
-Distributor Rotor
(Spark plugs changed last summer)


My question is, what would you do next? What is the probable cause of the start up/check engine light issues?

 

Any vaccum leaks?

 

Eh, that's unfortunately one of many things I don't have experience with a car. Hopefully my Haynes manual has something on it.

 

The symptoms are classic for a bad check valve in the fuel pump.

If you can geta fuel pressure gauge you need to start the car and then shut it off and observe the fuel pressure reading. It should remain high, if it quickly drops off the check valve is bad.

I'm at the cabin and don't have all of my resources to search by the code.

...Lee

 

P0172 also corresponds to following OBD-I codes:

2-3-1, 2-3-2, 2-3-3

If it weren't for the fuel pump, see attached. It seems like you may need Volvo scan tool but some test may be done without it. As to the vacuum lines, there is also a vacuum junction under the black throttle area cover held by one Torx screw. Check that area as well.


JPN

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Thanks for the help. Today I will be working to correct this issue. HOWEVER, something else happened that will hopefully narrow down this issue. I NEED your help though.

When starting the car the engine was somewhat sporadic, as it would not accelerate smoothly. It would pick up speed and then in an instant seem to down shift. It was very hard to pick up speed.

Does this help narrow down the culprit? A BIG THANKS.

 

I may be out in left field here, but when I had similar symptoms, it turned out to be a defective coolant temperature sensor. After running the car a bit does the temperature gauge ever get to the mid scale? Do the cooling fans work, or stay on all the time. Just another direction to look