2004 s60r misfire dead cylinder

swedehast · Post by **swedehast** » 18 Feb 2018, 10:50

Driving my daughter to airport my car made a " peculiar " sound, then ran rough all the way home. Idle is poor, engine only smooths out when revs are up. Codes showed random misfire cyl 3 and 5. I erased all codes and re-ran, showed misfire cyl 3. I swapped coils and still got misfire code cyl 3. Then I sequentially unplugged injectors as car idled. At cyl 3 little change ( all others cyl saw an additional drop in rpm )Installed new OEM injector cyl 3, car still runs rough and when I sequentially unplugged injectors ( again ) only cyl 3 saw no real change in rpm. Peculiar though the analyzer is NOT now showing code for cyl misfire ???? Car has not blown any white smoke, nor used any oil or coolant, at least to a noticeable extent. Do I have a " mechanical " issue ( bad valve or ? ) at this point or is there still something " electronic " that could be the cause. Thanks all.

Post by **jimmy57** » 18 Feb 2018, 11:16

A quickie test would be to remove the starter relay in the fuse box in engine bay and fashion a jumper or use a remove starter switch to bridge 30 to 87 as marked on relay and identify the terminals where it was removed. If it cranks over is an even beat then it has more or less equal compression and reduced likelihood of mechanical issues. If it has 4 beats and a faster single beat then that cylinder has low compression and you have likely joined the burnt valve club.\
You may already have heard what I'm referring to when cranking it over but if it starts quick it is harder to sense it.
(my money is on burnt valve)

Post by **rspi** » 18 Feb 2018, 13:02

Interesting test Jimmy57.

Welcome to the club...

Post by **rspi** » 18 Feb 2018, 13:02

viewtopic.php?t=74239&start=10

Post by **abscate** » 18 Feb 2018, 19:58

Check the 12 D.C. Supply on the number 3 coil and make sure it is near battery voltage.

If that's ok, you need to do a compression test on all cylinder to evaluate rings and valves

swedehast · Post by **swedehast** » 04 Mar 2018, 22:00

Thanks to all, sorry for delay in updating

Cyl 3 is dead. A local shop that works on a lot of these tells me pretty sure its a " dropped valve seat " Owner says he's seen many of these, not just on Volvo's and he doesn't regard it as unusual ( any longer )

He asked if I hear a little rattle on start up and intermittent ( yes ), he says that's almost confirmation.

Hence engine is toast.

Post by **wizechatmgr** » 05 Mar 2018, 01:32

Have them toss a borescope in and verify. Should take 10-15 minutes tops.

Dropped valve seats shouldn't be intermittent...

Post by **RickHaleParker** » 05 Mar 2018, 03:03

Get a second option. A dropped valve seat does not intermittent. They are talking about a piece of metal out of place.

Have them toss a borescope in and verify. Should take 10-15 minutes tops.

You know of a Borescope/Endoscope with mirrors that can look back almost 180° ?

I have a USB Endoscope that came with a attachable mirror. The mirror optics where so crappy I tossed the mirror.

Post by **oragex** » 05 Mar 2018, 06:12

That rattle might have been a lifter trying to say something... Better catch these in time, it's easy to hear them tap by listening close to the engine head. Surely, previous owner had neglected oil changes. There is also this R forum, http://forums.swedespeed.com/forumdispl ... 2004-2007)

I drove a Nissan with a lifter knocking all day long, but when the valve went (was driving uphill) it didn't make any noise, just sudden loss of power, vibrations and check engine.

I would also check the spark plug.

Post by **erikv11** » 05 Mar 2018, 17:11

Don't call the engine toast without a compression test. And run away fast from a shop that does.