Engine: B5254: ECM 3503 Misfire at least one cylinder

[100K+]

Driving back home today, long uphill perhaps 1 in 10 to 1 in 8. Its very long and open so it invites a run and a zoom. Even the Jazz can make 50mph. Today was a bit different, doing 60ish half way up I became aware of a misfire, which became more sever the harder you pushed. So I poodled home and checked with DICE.
At this time there were no warning lights, but there was a big misfire and a well felt vibration through the car.
ECM 3503 misfire at least one cylinder Emission Agitation.
ERM 3513 misfire cylinder no1 emission agitation.
ECM 3523 misfire cylinder no2. emission agitation.

So I removed the plugs and coil packs from cylinders 1+2 and swapped them with cylinders 4+5 ( cleaning all plugs before refitting cos they were silver hairy catapillars -very dirty)
Retesting showed showed the yellow engine light, ( 1st time seen today) the misfire on cylinder 1 was cured, but cylinder 2 misfire remained, and to be honest the misfire appeared to be no less harsh
Forum research suggests the DICE sometimes misinforms which cylinder has the misfire, and an old fashioned substitution is the better way to resolve this issue. The only thread I found was from 2018 where a similar problem existed (V70 T5) and the OP's solution was
replace all spark plugs
replace all coil packs
replace associated wiring loom.
= problem fixed.

The plugs I understand and will do that next week ( genuine volvo) but i am unsure about coil packs and associated wiring loom. Is there a way to check these things out??
The OP from 2018 appears to have left the forum.

Cheers
Bob

[100K+]

Today replaced all spark plugs - no change still misfire on cylinder 2.
Swapped again multiple coil packs into cylinder 2, misfire never moved always cylinder 2. Assuming coil packs are not a coded item - could find no way that VIDA/DIce allowed item to be coded. Removing the coil pack connectors caused a "no signal " DTM so I'm now assuming the coil pack wiring is OK.
Also swapped a couple of fuel injectors into cylinder 2; again no change to misfire. On each occassion misfire confirmed by removing coil pack wiring and listening for engine note change, then doing similar with a random cylinder and hearing a significant change. Assume too that injectors are not coded and don't need recoding. If I have got this wrong someone please tell me.
Where I go from here and what to check next I don't know, I'm struggling to get my brain round this.
Any comments/suggestions as always most welcome.

Cheers Bob.

[VOLVOBOY]

https://www.dtcdecode.com/Volvo/ECM-3503
Which seems to suggest that if it`s not ignition it`s fuel related.
Apart from what`s listed in the above a dodgy Lambda sensor is a possibilty.

[ASt85]

Originally Posted by VOLVOBOY

https://www.dtcdecode.com/Volvo/ECM-3503
Which seems to suggest that if it`s not ignition it`s fuel related.
Apart from what`s listed in the above a dodgy Lambda sensor is a possibilty.

Take a very close look at the coil connectors - they can fail where the connection on the "prongs" is intermittent.....

and having had a dodgy new Volvo plug for my T5 - try a new genuineplug in pot 2.

[100K+]

Originally Posted by VOLVOBOY

https://www.dtcdecode.com/Volvo/ECM-3503
Which seems to suggest that if it`s not ignition it`s fuel related.
Apart from what`s listed in the above a dodgy Lambda sensor is a possibilty.

Have read that volvo dtc code list, and have worked my was through it. I am currently waiting for a compression tester to arrive, as I have read some reports about cylinder bore cracking and low compression would be an indicator of this ( as it would a blown head gasket) However as yet there are no signs of oil in the header tank, or white smoke from the exhaust.
A dodgy Lamba sensor would I would have thought, thrown a DTC code ( which my VIDA/DICE is not showing) even if the MIL was not lit.

Originally Posted by ASt85

Take a very close look at the coil connectors - they can fail where the connection on the "prongs" is intermittent.....

and having had a dodgy new Volvo plug for my T5 - try a new genuineplug in pot 2.

This was another point I was arriving arriving at - the wiring harness, as regardless of how many things I change - plugs, coil packs, injectors the No2 pot always constantly does not fire, and the only constant I can see is the wiring to the coil pack of No2 pot ( which ever coil pack/injector/spark plug I use.) - I even re used old plugs (genuine volvo)I kept from a previous plug change miles ago. ( its a poor old man thing from a time when I sometimes could not afford new gear, and needed to keep the old "removed" in case of failure of the new. )
However, VIDA/DICE is noticing each time I remove No2 pot coil pack lead, with the engine running and throwing A DTC of "no signal coil pack 2" or similar.

To check those connectors - assume a pin in the wire away from the connector as one connection is the way to go one this?


Cheers
Bob

[ASt85]

If there is a break in the wire it is most frequently where the loom passes through the rubber "grommet" at the right hand end of the coil cover plastic plate - the wire is made just that little bit too short to absorb the rock in the engine as the engine mounts and bushes wear, so that end of the loom gets stressed - you can buy the connectors and new pins, or in some cases, ready made coil connectors with a length of wire attached which is long enough to join to the loom outside the coil cover plate.

see the post which has Lee Siggers contact number https://www.volvoforums.org.uk/showthread.php?t=297226

It is worth contacting Lee, who runs h2f connectors - he might be willing to make them up.

https://www.ebay.co.uk/usr/h2fconnec...88.m1543.l2754


I've pm'd his contact details to you.

[100K+]

Today I got hold of a compression tester and the results do not make good reading:-
Cold Engine "Dry" Test

Cylinder 1 108
Cylinder 2 Nil, nada, zilch. - hence the misfire.
Cylinder 3 110
Cylinder 4 not tested - over engine turbo pipe prevented access.
Cylinder 5 106.

So pick your poison

Head gasket; Split cylinder; or carboned up value gear.

Bottom line having spent lots of money just before Christmas ( turbo + driveshaft) is it time to cut my loses and scrap the thing???

Cheers
Bob

[jeremycolley]

You might as well pull the head off and see what's happened before you weigh it in for scrap - assuming you have the time... if not it's a judgement call to weigh up how much the car is worth as it stands, what the cost of repair will be - ie engine swap against the the cost of a comparable car.

[MisterGee19]

Originally Posted by 100K+

Today I got hold of a compression tester and the results do not make good reading:-
Cold Engine "Dry" Test

Cylinder 1 108
Cylinder 2 Nil, nada, zilch. - hence the misfire.
Cylinder 3 110
Cylinder 4 not tested - over engine turbo pipe prevented access.
Cylinder 5 106.

So pick your poison

Head gasket; Split cylinder; or carboned up value gear.

Bottom line having spent lots of money just before Christmas ( turbo + driveshaft) is it time to cut my loses and scrap the thing???

Cheers
Bob

Any coolant system pressurising issues? If not it sounds like a burnt valve?

[IainG]

Hi
Just a couple of thoughts for discussion.
If the compression is zero on one cylinder.
Would a head gasket cause that? Would need to be a big bit of the gasket to have failed. I would normally expect some reading with a failed head gasket?
Again a crack in a liner, surely there woud be some pressure?
Have you tried a wet test? Would help point to top or bottom of the engine.
If top could be a valve
If bottom could be worse?
Just a few thoughts,

If a wet test didn't improve the reading I would certainly have a look at the valves, nothing to loose if you have the time.
You also can sometimes see if a valve is sticking open ( although not a burnt valve) from under the rocker on some engines.

Iain