Good evening,

I will apologize in advance for the long post and THANK YOU all for sharing your knowledge.

I am losing my hair with my 2001 Volvo S40. My CEL popped on with accompanying sputtering/loss of power. New spark plugs fixed a similar issue in 2009 and I thought that if I would just replace the plugs, I would be all set. Wrong.

Didn't have time to fix it myself this time so I took it to a shop who does work on my buddy's 2000 V40 and had good reviews. His diagnostic test read P0304 (cylinder #4 misfire) and he replaced my plugs as I asked. According to the mechanic, my plug wires and coils were OK.....HOWEVER.......he told me that the "wiring harness" that connects to the ignition coils is corroded and needs replacement, adding that Volvo doesn't sell this wiring as a replacement part. He added that my car will continue to sputter until those "electrical connectors at the coil" are replaced. To quote his estimate I need the "electrical, female connectors to attach to each ignition coil". Does this make sense to any Volvo mechanics or handymen out there? I have not had luck locating these wires online or over the phone, or even figuring out what the heck it is I need to fix this!!!

I made the mistake of not checking the mechanic's work after getting my car back 3 weeks ago. Just an hour ago I popped the plastic engine cover off and desired to inspect my plugs/wires/coils/wires myself, just to gain a better understanding of what I exactly need to replace. What I have discovered is my WORST NIGHTMARE! Not only is the area where the plugs are covered with bits of crumbled plastic from the corroded wire housings, but there is a substantial amount of OIL pooled up in the nooks around the coils and plugs! I have been using Q-Tips to absorb this oil and get the crumbled bits of plastic out. I also found that the mechanic used electrical tape to sloppily fasten the wires/clip to the ignition coil, the one that is closest to the oil reservoir cap. I am assuming that these are the wires that he is telling me need replacing.

I clearly have a number of issues going on here. I have been tirelessly reading Matthew's Volvo Site blogs and forums to determine what to do to remedy this issue. UGH! Any and all correspondence is appreciated!!

With sincere thanks,
-Aaron

2001 Volvo S40 163,000 mi
1991 Volvo 240 265,000 mi
1986 Volvo 240 DL 195,000 mi

 

The codes arent always correct when it comes to marking which plug is misfiring.I had the same code and what do you know the #2 side of the coil was out.Measuring the resistance on the didnt help either as it did show they are good.This coil feeds the #2-#3 cylinders.The lose electrical feed connection can and will kill the coil.I just mentioned the very same problem in another post.I ended up removing the plastic parts from around the leads and connected them naked to the coil.
The oil on top is most likely a leaking at the filler cap.For temporary fix you can remove the rubber seal and turn the inside out which a bit more soft still and will give you a little time to get the new seal.No need to buy the entire cap.
The broken off plastic pieces are normal at this age.Go to AZ or any part store and get this sleeve.Mechanic should have fixed it the right way instead of using the tape which is useless at that temps.
Buy two new coil if you never replaced them you'v got lucky so far it is time.

 

Thank you for the reply!

I have spent the last 2 hours cleaning the area around the coils & plugs as it was pooled with oil and plastic bits. The mechanic clearly did a sloppy job and said he wanted to replace the entire wiring harness.

So you believe that new coils should fix this problem? I have never changed them, so it would be a good time at 165k!

 

I wouldn't change the coils until the coil connectors are fixed/replaced.

Take a good look at the coil connectors. You may find a part number molded into them.

As far as the oil goes, remove the timing belt top cover and check the timing belt area. Oil is either coming from a leaking oil filler cap gasket (P/N 1275379) or from a leaking VVT pulley. If it's the VVT pulley there will be oil in the timing belt area. Third possibility is a leaking cam seal due to a blocked PCV system.

 

Thank you migbro. I am planning on replacing the timing belt next week so perhaps these gaskets/pulleys will also be addressed.

If the PCV system were blocked, causing a leaking cam seal, am I up the creek or can that be repaired?

Thank you again!

 

Oil on top of the motor is usually clogged PCV system. This system should be replaced every 100k. You can read a lot about it in the 850 section, not sure if there are a lot about in other forums even though they all have it.

A new oil cap seal is cheap.

 

Definitely replace the coils and wires if they have never been replaced. For me they are a 100k mile item but I've had them fail with less. They ohm good but still have issues where the spark will jump to the head and short instead of to the plug. Same with the wires, they ohm good but short to the head past the spark plug tube seal where you can't see it.

As written above, you can manually push the female wire connectors onto the male coil connectors. The plastic holder is nice but it's not really required to get a good connection. Mine have never slipped off. A simple pair of wire pliers will do the trick.