1998 Volvo S70 bad misfiring

[rising]

Okay I'll check dates tonight when I'm home and unless they are new I'll replace with proper boogies

[rising]

Okay still haven't had a chance to check dates on the wires but I noticed a few things. One is after the coil the codes went from random misfires on all cyl to just cyl 2.

But I'm also getting a p0172 system too rich. Is that just from the unburned fuel from cyl 2? And now that its just one cyl are there any other steps to take to narrow it?

PS. There is an audible clicking/tapping noise when I press the accelerator that isnt there at idle. Could that be something? Sounds almost spark like

[erikv11]

For misfires specific to one cylinder

- check the plug, swap it to another cylinder see if the problem follows
- could be the #2 plug wire is bad
- could be the electrical to the #2 injector, switch the electrical leads for #2 and #1 see if the code follows to #1 (all injectors pulse at the same time)
- could be the #2 injector is bad, you can swap injectors without much trouble but need to be careful

p0172 is almost always a vacuum leak, e.g. did you check the little elbow on the passenger side of the intake manifold? Tucked in behind the power steering pump, use a flashlight to peer in there.

[rugbygrrl_15]

Hey Rising,

Did you steal my car? No wait, I was having the same problem a few months ago, including the P0172 code. OMG this may be a real pain in the neck to troubleshoot, just warning you. With my car, I ended up replacing the EGR exhaust valve 1026122 and that cured the problem but there were many worn out rubber elbows and hoses too, which I also replaced.

This is how you may want to go about it:
Check the fuses
Check ALL rubber elbows on the vacuum system they deteriorate and vacuum tubes.
Then systematically check all the items in the PAIR system

Unfortunately, I would bet the P0172 code is the darn Exhaust valve ($175 @ dealership) the inside of my valve was caked with carbon and had condensation on the inside which likely made it seize.
But, it could be a cracked elbow:)

S


Let me know if you need a diagram where all the buggers are located.

[rising]

Hey Rising,

Did you steal my car? No wait, I was having the same problem a few months ago, including the P0172 code. OMG this may be a real pain in the neck to troubleshoot, just warning you. With my car, I ended up replacing the EGR exhaust valve 1026122 and that cured the problem but there were many worn out rubber elbows and hoses too, which I also replaced.

This is how you may want to go about it:
Check the fuses
Check ALL rubber elbows on the vacuum system they deteriorate and vacuum tubes.
Then systematically check all the items in the PAIR system

Unfortunately, I would bet the P0172 code is the darn Exhaust valve ($175 @ dealership) the inside of my valve was caked with carbon and had condensation on the inside which likely made it seize.
But, it could be a cracked elbow:)

S


Let me know if you need a diagram where all the buggers are located.

Haha well idk was your car a 98 beige glt that was misfiring badly? If so maybe we swapped by accident
I'd love to see a diagram! That might help a lot. Though I have been over a lot of these hoses. Where do you get replacement elbows? Can I just order a whole new vacuum system? Lol might be easier.

Come to think of it I did get a code awhile ago that was something about the waste gate input too low or something. I cleared it and it never came back..

Also checked the plug wires today and they appear to be Bosch units. Didn't look new but didn't appear to be in bad shape. Until I tried to yank the #2 wire and it came apart on my hand... :/

Right before that mishap however I did unplug the #2 injector and it didn't seem to do any thing. No drop in idle at all. So that cylinder definitely isn't firing. The others showed a drop. Plugging 3 into 2 didn't seem to work either.

So I'm going with wires first and then I'm going to start digging through the vacuum system. Really starting to think about parting this car out though with all the other misc problems..

[rising]

Hey Rising,

Did you steal my car? No wait, I was having the same problem a few months ago, including the P0172 code. OMG this may be a real pain in the neck to troubleshoot, just warning you. With my car, I ended up replacing the EGR exhaust valve 1026122 and that cured the problem but there were many worn out rubber elbows and hoses too, which I also replaced.

This is how you may want to go about it:
Check the fuses
Check ALL rubber elbows on the vacuum system they deteriorate and vacuum tubes.
Then systematically check all the items in the PAIR system

Unfortunately, I would bet the P0172 code is the darn Exhaust valve ($175 @ dealership) the inside of my valve was caked with carbon and had condensation on the inside which likely made it seize.
But, it could be a cracked elbow:)

S


Let me know if you need a diagram where all the buggers are located.

Haha well idk was your car a 98 beige glt that was misfiring badly? If so maybe we swapped by accident
I'd love to see a diagram! That might help a lot. Though I have been over a lot of these hoses. Where do you get replacement elbows? Can I just order a whole new vacuum system? Lol might be easier.

Come to think of it I did get a code awhile ago that was something about the waste gate input too low or something. I cleared it and it never came back..

Also checked the plug wires today and they appear to be Bosch units. Didn't look new but didn't appear to be in bad shape. Until I tried to yank the #2 wire and it came apart on my hand... :/

Right before that mishap however I did unplug the #2 injector and it didn't seem to do any thing. No drop in idle at all. So that cylinder definitely isn't firing. The others showed a drop. Plugging 3 into 2 didn't seem to work either.

So I'm going with wires first and then I'm going to start digging through the vacuum system. Really starting to think about parting this car out though with all the other misc problems..

[erikv11]

Oh my, if you already know #2 is definitely not firing at all then we misunderstood the level of misfire. You're going to want to check compression on #2, that doesn't sound so good ...

[RigsPGT]

My misfire codes along with P0172 were the result of a broken elbow in the passenger side, next to the PS pump on cyl 1 intake runner. It's a little pain to get a new one in and the only way to replace it is by using some long needle nose pliers. After that, car ran like a champ!

[rising]

Okay just replaced the spark plug wires and no dice. It probably needed them but that's another $60 down the drain into this car. I pulled the number two injector (second from the passenger side... That's #2 right?) And the misfire didn't change, but did change when I pulled all other wires. Switched #1 onto #2 and it stayed just as crappy as when number #1 got pulled. So I pulled the fuel rail and swapped #1 And #2 injectors. Repeated the test and I got the same results. #2 showed no change in idle when pulled. #1 #3#4 and #5 all showed a change.

I guess a compression check is next but it sound like I am just going to have to sell off some of these parts and recoup some losses and junk the car.

[erikv11]

Yeah, this sounds like a burnt valve on #2 (you have the numbering right). A compression test will be very telling if it is.

You can drive it around town with #2 not firing, just unplug the #2 fuel injector wire to keep unburnt fuel out of the cat.