'02 V70 2.4T more misfires

mouseskowitz · Post by **mouseskowitz** » 23 Feb 2017, 04:53

So, I thought I had this fixed. A while back I blew the spark plug on cyl 2. Had a local shop put in a hilicoil and look at the other cyl. They said everything was fine. It really hasn't been driven much since then until today. It's running rough and has had misfires on 3, 4 and 5. Not sure if the misfires for 2 are pre or post fix since the codes hadn't been cleared. I cleared the codes and took a drive up the block. The misfires on 3 and 5 showed up again.
The exact codes that are coming up are "ECM-3503 Misfire, at least one cylinder - Catalyst damage" and ECM-3533 and ECM-3553 Misfire cylinder * - Catalyst damage.
Any ideas where to start trouble shooting when I get some time to dig into this?

Post by **abscate** » 23 Feb 2017, 05:23

New plugs and coils first.

Check for 12vdc at the coil connectors, and their condition

Check compression across the board.

Misfire codes take several cycles to clear, so clear them with either reader or battery disconnect

Alldata doesn't list the ECM-35x3 code but I'm sure they are the cylinder specific code for 3503, with x being the identified misfire cylinder.

Make sure you count the cylinders from the right end...BTDT..

mouseskowitz · Post by **mouseskowitz** » 23 Feb 2017, 15:30

"Check for 12vdc at the coil connectors, and their condition"

How do you do that? Unplug them with the engine running?

Post by **abscate** » 24 Feb 2017, 00:42

Voltmeter, unplug each one and Turn on ignition to POS II

I'll link to the pin assignment thread

v70_Lush · Post by **v70_Lush** » 01 Mar 2017, 10:33

While you are checking those coils, check the plug connection to the throttle body and make sure that connection is secure and that the wires are in good shape. Its an easy thing to check that could help.

I have the same year and model. That connector and those wires are old.

mouseskowitz · Post by **mouseskowitz** » 06 Mar 2017, 18:52

I checked the wires and the voltage, 11.70-11.72. Then I took the coil packs out. There is standing water in two of the plug wells. Me thinks that is the problem. I'll have to call the shop that put the helicoil in. I'm guessing they tried to wash some of the oil that was on top of the head off. Since they made the problem they can fix it. Then I hope it'll go back to running like a Volvo should.

Post by **abscate** » 08 Mar 2017, 04:28

Just suck it out with a vacuum, or blow it out with compressed air as best you can, then remove plug and let it dry out.

You should have battery voltage at coil, 11.7 is too low.

mouseskowitz · Post by **mouseskowitz** » 09 Mar 2017, 01:23

The shop dried it out for me and it seems to be running great! Now that it actually has power I have to watch how hard I step on the gas. Is the voltage something to really worry about at the moment since it seems to run well now?

Post by **abscate** » 09 Mar 2017, 07:38

Your battery should be over 12 volts and the coil supply terminals should be close to it, like within 0.1V

More loss than this means something isn't right. Wires, terminal, relays are all things to check via wiring diagram