Check Engine Light Flashing - Noticeable Vibration

[mrscullini]

I just got another update from him. He now says about five working days, because he can't do all the work himself, he has to take it by a machine shop to have some stuff ground down. Also, my timing belt was replaced last week.

And thankfully we do trust this guy, he's been working on our Volvos since we moved here (about 18 years ago) and we've bought a total of five used Volvos from him throughout the years.

it is good to have a trustworthy mechanic. i would definitely ask him what other work should be done.

the tb should be just fine.

the valve seats probably have to be ground and/or replaced.

[JRL]

it is good to have a trustworthy mechanic. i would definitely ask him what other work should be done.

the tb should be just fine.

the valve seats probably have to be ground and/or replaced.

Needs a valve job. You just don't put a new valve back in and close it up for one thing, that would be very penny wise and pound foolish, etc

[coolwhipdefuser]

Needs a valve job. You just don't put a new valve back in and close it up for one thing, that would be very penny wise and pound foolish, etc

I'm pretty sure it's getting a valve job. I'll have to look at the sheet of what he wrote down again. He's not starting work till tomorrow anyway.

[JRL]

I'm pretty sure it's getting a valve job. I'll have to look at the sheet of what he wrote down again. He's not starting work till tomorrow anyway.

The question is why?
Even with those miles this is not a usual Volvo engine problem and in fact this is the 1st time I ever heard that happening

[mrscullini]

Needs a valve job. You just don't put a new valve back in and close it up for one thing, that would be very penny wise and pound foolish, etc

nice to see your tackful responses have not waned.

what part of my response suggest that only a single valve should be replaced? i am suggesting that since the head is off, which is a rather involved job, that other components, potentially not related to the valve burn should be considered.

[mrscullini]

nice to see your tackful responses have not waned.

what part of my response suggest that only a single valve should be replaced? i am suggesting that since the head is off, which is a rather involved job, that other components, potentially not related to the valve burn should be considered.

to better illustrate my point, it would be foolish to replace a manual transmission without serious consideration of replacing a clutch, as the labor to replace a clutch is the same as the labor to replace a transmission.

[JRL]

nice to see your tackful responses have not waned.

what part of my response suggest that only a single valve should be replaced? i am suggesting that since the head is off, which is a rather involved job, that other components, potentially not related to the valve burn should be considered.

Newer said you said anything.
Just making sure he does a valve job which is the cheaper part of the deal.
Not talking to you, so don't talk to me

[uk_v70r]

Short version:

1. Had same exact symptoms
2. Diagnosed #4 misfire
3. Replaced coil and plug
4. Problem solved

Moral: use OEM parts


Long version:

Coincidentally, my 1999 v70r had exactly the symptoms you gave on my way to work about two weeks ago....very noticible vibration, drop in power, check engine light on and intermittantly flashing when the engine was loaded.

I made the 19 mile trip on into work then "gently" drove it home that afternoon. I too suspected a miss. So I diagnosed it by disconnecting the coil plugs (clips into the top of each coil) individually, one at a time (with engine running), to see which cylinder was missing. Every time I would unplug one of the coils, the idle would get much rougher--except for when I disconnected #4.

So, maybe I had a bad plug or bad coil or worse. I ordered a new set of 5 Volvo OEM plugs and one coil ($50) from fcpgroton.

I've just installed the new set of plugs and the new coil on #4 and the problem is cured. No vibration and no check engine light (I reset by disconnecting the battery).

I have an idea of the root cause or at least a significant contributing factor. I recently (<1000 miles back) replaced my plugs. I had always used Volvo plugs (pregapped) but this time I bought the NGK "platinum for turbo" plugs from fcpgroton, about $12 each.

The NGK plugs are excellent quality I'm sure, but I fouled up by not properly gapping them. After installation I noticed some different numbers on the individual NGK packages (like a -045 on the end). The end number corresponded to the preset gap. Without relooking it up, the specified gap for the Volvo is something around .032" but the plugs provided from fcpgroton came pregapped at over 0.04 (they weren't all the same but all were too large.)

So, knowing the gaps were too big, I should have immediately removed the plugs and regapped---but I put it off and then forgot about it. I believe that the larger than spec gap (and therefore, the larger than spec impedence) led to premature toasting of the coil. I haven't done any autopsy of the old coil and don't intend to , but I think my slacking about not regapping and not going OEM caused my problem.

[bugjar]

Along the same lines as this post...I replaced my plugs last weekend (OEM). My car purred before this and then after (+/- 50 mi.). I started getting a misfire that I could feel. This was in cylinder #5 (that's what my CEL told me). I pulled the plug yesterday and the ceramic looked to be scored or cracked, could this be the reason? A faulty plug? Going to swap this out tonight I just haven't heard of plugs being bad I guess. I should Probably just use Ockham's razor anyway.

[bugjar]

It was a bad plug. I guess this means that even if it is OEM it may fail prematurely (like after 200 miles).