Replaced Ignition coil Misfire cylinder #1

Fishinmagician · Post by **Fishinmagician** » 20 Jul 2021, 14:34

New to this forum and new to Volvo' s as well.

Actually I've had some experience with older Volvos; good friend had a couple P1800s, I owned an early 70s(?) 211 and later an eighties 4 door.

If I remember right I think the 211 had twin carbs that needed balancing every so often.

I digress. Just bought a 2001 (had reams of maintenance/servic records) V70 2.4t.

Shortly after I bought the car I drove some friends to the airport (about 40 miles, mostly freeway).

Shortly after dropping em off the cruise control quit workin and car started to vibrate, especially @lower rpms/under load and the CEL came on.

Few days later took the car to autozone and scanned for trouble codes and the printout said misfire cylinder. #1.

After a lil research I bought five new plugs and a Bosch ign coil.

Replaced the coil and plug on cylinder 1 and no change...

Took car to local repair shop and they said that I had a bad #1 coil...verified (so they say...) by swapping w/ cylinder #2.

Wife went to parts store and bought a no-name-brand coil. Installed coil and same result.

Miscellaneous trivial info:
Car seemed to run rougher while driving it home from the shop than when driving it to the shop?!! It even sounds different.

Visual inspection of wiring revealed nothing. I'm gonna find a wiring dia. ( I hope), buy a multimeter and check associated wiring.

What are the odds of receiving two bad coils?

If wiring is good would the next most likely suspect be the ECU (Computer, black box, etc.)?

Thanx in advance for any help.

Take care and stay safe
Roger

Post by **vtl** » 20 Jul 2021, 18:05

Check the compression.

There's a guy on ebay who sells homebrew Volvo engine wire harnesses.

Fishinmagician · Post by **Fishinmagician** » 20 Jul 2021, 19:15

Thanx, VTL.

Compression check just moved ahead of metering the wires.

Appreciate you takin the time to read n reply.

Take care,
Roger

93SCMax · Post by **93SCMax** » 20 Jul 2021, 19:29

Hope you bought Volvo OEM plugs or Bosch plugs.

Ground point for coil is critical to be clean and tight (bolt holding coil in place and cylinder head interface).

OEM or Bosch coils only. I'm still running my originals.

Wiring is still suspect.

I have a hard time trusting your mechanic if they say it's the coil but you have a new Bosch coil. Could it be an E-bay counterfit?

Make sure your battery is well charged and not the problem.

Fishinmagician · Post by **Fishinmagician** » 20 Jul 2021, 23:00

Thanks fer takin the time to help me out, it's greatly appreciated.

Bosch plugs and Bosch coil. Coils in the car appear to be original.

Bought first coil from rock auto. Wife bought the second coil from autozone.

Scrupulously cleaned ground. Car has 250k miles.

Gonna pick up a multimeter and dig up a wiring diagram, and verify good continuity and perform a compression check. Hopefully get it done tomorrow.

Thanx again fer the assistance.

Take care,
Roger

Fishinmagician · Post by **Fishinmagician** » 20 Jul 2021, 23:05

Also have trouble believing that I wuz unlucky enough to have purchased two bad coils.

Will post results of compression and continuity checks.

Thanx again fer the assistance

Post by **oragex** » 21 Jul 2021, 06:14

If a coil, spark plug or injector is bad it's easy to check it. Check the rear block ground wire just behind Cyl #1. For the cruise control, it may be a vacuum issue so check all hoses around the turbo, or sometimes the brake switch sensor at the brake booster.

Post by **abscate** » 23 Jul 2021, 03:22

Two issues ofoutofboxquality ( OBQ) coils would be unlikely , but you could have a bad spark plug.

Move everything from cylinder 1 to 2 systematically to see if the fault code moves. Yes,it will pay pretty quickly to have a code reader.

Wiring and ECU faults on these cars are about as rare as gold capped hens teeth

Fishinmagician · Post by **Fishinmagician** » 23 Jul 2021, 08:16

Thank you, empty nester. Odd, I was gettin ready to buy some spark plugs fer our corolla wagon (1995, w/ 360k miles!), and had the same thought about the spark plugs.

Have been a lil busy gettin ready for the upcoming salmon season, so probably won't get to the cars til the weekend.

Since we just bought the volvo I'm plannin on doing a compression check on all the cylinders and checking the wiring and installing new plugs.

I bought cheapo Bosch copper plugs, not sure of the advantages of the fancier ones w/multiple ground electrodes/shapes, exotic metals etc. or if they are worth the extra $$. I usually replace spark plugs frequently so figure the copper ones will be best.

Wonder if $15 ea spark plugs give better (as in unmistakably noticeable) performance and/or gas mileage. They do, apparently, have "longer life" but seeing how easy they are to change in this car I figured that they're not needed.

Love yer signature(?), empty nester -- I have for several years now enforced a limit on estrogen levels in my house, garage, etc.

Sorry, I do tend to ramble a bit...plus it's 7 am here in the great Pacific Northwest and I haven't finished my first cuppa coffee!

Hope yer having a great summer

Thanx again for takin the time to share yer thoughts

take care
Roger

Post by **vtl** » 23 Jul 2021, 08:24

Volvo turbo engines are picky for plugs. Original plugs would be the safest choice, they are good for well over 50k miles.