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Jim B
Jim B, ASE Certified Technician
Category: Volvo
Satisfied Customers: 1243
Experience:  40 years Import and domestic AAA Approved Shop owner 30 yrs
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2001 Volvo S40 1.9T keeps missing on cyl #2 - P0302

Customer Question

recently bought a 2001 Volvo S40 1.9T. Starts fine and idles fine except for the occasional stumble. Revs up no problem. Under load however it has no power and keeps missing. Hooking up a codereader I constantly get code P0302 - miss on cyl#2. It previously also threw P0107 but replacing the MAP and boost sensor cleared that up. No difference in how it runs though. No difference after replacing the fuel pressure regulator either. Connected one of those lights inline with the sparkplug and it does miss on cyl #2. I already cleaned out the idle motor with brake cleaner, cleaned and regapped the plugs (OEM) to 0.75mm which look fairly new, swapped the #3 and #4 coils around and same for the wires. Just for good measure also then replaced the #3 coil and wire (as it goes to #2 as well). No difference whatsoever. I also noticed that I may have a new MAF. Hooked up this plumbing rig I made to my air compressor to listen for air leaks. Seems to hold some pressure, there is a very slow leak but don't think it's the issue. Sometimes a little quicker and sometimes barely accelerates. Any ideas?
Submitted: 5 years ago.
Category: Volvo
Expert:  Jim B replied 5 years ago.

Hi Customer. Thank you for asking your question on JustAnswer.

 

What is the engine compression on that cylinder?

What is engine vacuum at idle?

 

 

 


Thank you again for trusting us with your problem. Please reply as soon as possible so that we can finish answering your question.

Check back in later ,

 

Jim B

Customer: replied 5 years ago.
Hi Jim

Thanks for your prompt response. It settles to 20Hg at idle (though haven't had a chance to see if there's any boost yet) and up to 25-30Hg lifting off throttle.

My compression tester doesn't go deep enough for the spark plug opening so will see if I can get another one to test it tomorrow.

Also, if kept below 2-2.5k rpm at light throttle, it at times hardly misses, while at others (often after a hwy run) stumbles so badly that it barely accelerates.

Will get back to you re the compression to see if it's a valve issue.

Cheers,
Alex.
Expert:  Jim B replied 5 years ago.

We had one that had a bad crank position sensor. It was giving a bad signal to ecm and kept getting a misfire on #5. Not sure if that is your case but we need to keep it in mind.

Did you try a new plug by chance, does not happen too often but will lead you in wrong direction. Does not sound like a weak cylinder it would be a dead miss at idle. This acts like the old cars when the points would bounce... New cars have crank and cam sensors.

Might not be easy from my end but I will help as much as I can. Sure would like to see on a lab scope. But let's do the basics first. Jim
Customer: replied 5 years ago.
Hmm... maybe for the crank sensor. I did swap the plugs around when I cleaned them and it made no difference, the miss stayed on cyl#2. They look to be fairly new as well. When the map was bad, after a while the ECU would report a miss on all cyl's but now it's only and always P0302. Another thought I have is the temperature sensor but there isn't really a consistent difference in how it runs between hot and cold. Will do a compression test on all cyl's anyways just to rule that out. I know Audi's but with this Volvo need to lookup every sensor to find out where it is. There is also a check valve with a connector coming off it just at the intake to the turbo, disconnecting it seems to make no difference at all nor brings up any new codes. Not sure what it's for though.
Expert:  Jim B replied 5 years ago.

Here is some ammo for you

 

 

graphic

 

 



  1. Engine coolant temperature (ECT) sensor
  2. Ground terminal
  3. Coolant level sensor
  4. Camshaft reset valve
  5. Turbocharger (TC) control valve
  6. Engine speed (RPM) sensor
  7. Camshaft position sensor (CMP)
  8. Brake pedal sensor
  9. Outer temperature sensor
  10. Power supply terminal
  11. Fuse box
  12. Relay box
  13. Mass air flow (MAF) sensor
  14. Canister purge (CP) valve
  15. Intake air temperature sensor
  16. Boost pressure sensor
  17. Ignition coil
  18. Injector
  19. Throttle unit
  20. Knock sensor (KS)
  21. Engine cooling fan (FC) control module
  22. A/C pressure sensor
  23. Engine control module (ECM).

Jim

 

Customer: replied 5 years ago.
Fantastic! Thanks! BTW not that it's really relevant but it seems to boost to about 7psi which I believe is normal for the low pressure set-up on the car.

Also, correct me if I'm wrong but doesn't it need to reference the the crank sensor to start? Do you happen to know if the crank sensor might be on the transmission bell housing? Is there a resistance check that can be done accross it? Will go hunting for it on the car tomorrow.
Expert:  Jim B replied 5 years ago.

graphic

Inductive sensor with a permanent magnet Resistance 125.5 ±17 Ohms

2 wire sensor. Produces an ac voltage signal.

 

Customer: replied 4 years ago.
I ended up fixing the problem completely by switching to new copper core plugs. Weird! But works great now! Thanks much for your help! Merry Christmas!
Expert:  Jim B replied 4 years ago.
Glad you got it fixed. thanks Jim B
Jim B, ASE Certified Technician
Category: Volvo
Satisfied Customers: 1243
Experience: 40 years Import and domestic AAA Approved Shop owner 30 yrs
Jim B and other Volvo Specialists are ready to help you
Customer: replied 2 years ago.
FYI the problem came back after a few thousand kms and switching to new plugs would fix the problem for a bit but it would always come back. I ended up swapping a couple of the coils and it ended up fixing it. Thanks much! ...now for the EVAP CEL that just turned on...
Expert:  Jim B replied 2 years ago.
coils do fail at times. thanks for getting back to mejim

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