2004 S40 Ignition Coils replaced, car won't move.

[bustedvolvo27]

Hello all, first I'd like to say that I have searched for solutions to this problem on this and other sites, and have found nothing so far. The problem:

It all started when I accelerated a little too hard, and the check engine light came on as a result. Went to the local Autozone, got the OBD II code: First solution, change the spark plugs. Simple enough, I changed and installed new ones with the correct gap (0.0315"). Worked like a charm for about two weeks. Check engine light came back on, and I started having hiccuping when I came to an idle position (known as misfiring I'm sure). Went back to the Autozone, had the code read again, and the suggested solution was to change the ignition coils. Now I did so earlier today, and the car started ok, but there is a constant rumbling in the engine, the whole car vibrates slightly and the worst part is, I put it in reverse for a test and it does nothing, the RPM needle even stays idle.

I was told that the wiring sequence for the connectors should be 1-4 and 2-3. The wires as far as I know are in securely and correctly. Seeing as how I can't even get it to the shop, what should I do?

NOTE: I bought replacement parts from http://www.autopartswarehouse.com and they are exactly the same as the manufacturer parts.

[kcodyjr]

Accelerated a little too hard? BS. Something was ready to let go. Otherwise, you can stand on the pedal all you want and reasonably expect it'll take it.

What kind of replacement spark plugs did you get? I don't know the S40's 4-cyl well, but the 5-cyl engines are pretty touchy about spark plug types.

Any chance it might be sucking air around one of those replaced plugs, or maybe a vacuum hose got knocked off while you were working near it? If all else fails, spray some carburetor cleaner or starting fluid around. If it revs up, you've found a vacuum leak.

[bustedvolvo27]

Well I can believe that something was definitely ready to go, I just meant that accelerating hard is what initiated the problems. I believe the replacement plugs were these:

Re-Post: Autolite XP Iridium/Spark Plug (Replacement Plugs)
Link: http://www.autozone.com/autozone/parts/ ... 896883_0_0_

I'm sure the hoses are ok, I was pretty careful going about replacing the parts. The funny thing is, the car will start normally, but accelerating/leaving it idle does nothing but cause intense rumbling.

[kcodyjr]

OK, I'm not sure those plugs were a good idea in a non-turbo. Hoping someone that's tried them chimes in.

Have you reset the adaptives? Disconnect the negative battery cable and touch it to the positive terminal for ten seconds.

[bustedvolvo27]

I have not done that, and I'll let you know the result. Sorry for being such a noob; what will that do exactly, "resetting the adaptives"?

[kcodyjr]

The engine computer keeps a memory of fuel trim settings and a bunch of other fiddly details. When something is changed that can affect mixture or ignition, best practice is to wipe out that memory.

[bustedvolvo27]

Well, I tried that, same problem. Although, the negative cable barely reached the positive terminal. Any other ideas?

[kcodyjr]

What exactly was the code being thrown?

[bustedvolvo27]

If I remember correctly, it was P0300 -- Misfire, at least one cylinder -- Start-up

[kcodyjr]

That's all? How wonderfully vague. Next time, see if you can find someone with the Vida/DiCE, rather than using the generic scanner that AutoZone has. I suspect the Volvo-specific codes will be more revealing.

That said, there's a strong chance the plugs you picked aren't really compatible. It's also possible that it's running lean due to either an undetected vacuum leak or plugged fuel system. That would also be revealed by examining the ECU trim settings.

There's also a chance there's moisture in the fuel tank - no reason to assume all your woes are due to the same cause. I'd dump in some Heet, some Techron, and about half a tank of premium, and see what happens.