misfires and sputtering 1998 V70

volvooh · Post by **volvooh** » 23 Jul 2009, 07:58

Two nights ago, the V70, with 155,000 miles on it, began sputtering and missing when sitting at stop lights- especially when the A/C was engaged. The problem persisted with in hesitating and missing on take-off, and eventually through a misfire code (P0305). Since it was raining that night and very humid, I suspected sparkplug wires. I purchased a new wireset and plugs and after installation, it ran like a champ. Until last night when it started again, albeit to a lessor extent.

It has started missing at traffic lights again, but has not thrown a code yet, but I am quite sure it will.

My next step is to replace the cap and rotor- any other thoughts like fuel or vaccuum issues?

I was also considering adding a bottle of JB to clean out the injectors.

volvooh · Post by **volvooh** » 24 Jul 2009, 08:47

Just to add to this...

After changing out the wires and plugs, it seems to be isolated to when the volvo is sitting at a traffic light in "D" and especially with the a/c running. So it appears that under a load at idle is when it is most notable.

I do notice a slight hesitation when I "rev" in neutral. Once it is rolling, it feels like it runs fine with plenty of power.

SilverBullet · Post by **SilverBullet** » 24 Jul 2009, 08:54

I have a 99 V70 XC and i got the P0305 code.. I replaced the plugs and it still was there.. Check your coil pack.

Post by **songzunhuang** » 29 Jul 2009, 23:27

I hope you are able to track this down. Our family's 1998 V70 T5 is also throwing misfire codes with the same symptoms you are describing. I am getting misfire codes on ALL the cynlinders. I have replaced the plugs, wires, cap, rotor, and it's still misfiring.

I took it to Specialized Auto (supposedly Volvo experts) and they charged me $100 for diagnostic and told me they found nothing. After several months and more problems, I broke down and took it to Smythe Volvo in San Jose (where we bought the car) and they charged me $200 and told me they found nothing. However, they recommended that I change to Volvo OEM plugs for $56 a set. They wanted to charge me $200 installed. They are insane. I bought the set and put them in myself.

Yeah, you guessed it. I still get the misfire. What's going on!?
As for the coil pack. Is this something for the entire ignition or is it specific to each plug? If it's each plug then I don't think this is the problem I am having as ALL my cylinders are misfiring. I can't imagine each individual pack would fail at the same time.

If it's the Big thing that connects to the distributor, that would make more sense, but that is an expensive part that I don't want to replace unless I am sure. Since it is electrical, I can't return it once I install it.

Post by **Ozark Lee** » 30 Jul 2009, 04:44

Your '98 has a standard coil and distributor setup with one coil. The later models have a coil for each spark plug. With the single coil versions you can often see if the coil is the problem by looking at it in the dark. When the coil breaks down you can often see faint blue arcs from the coil itself to the frame.

...Lee

Brutus Maximus · Post by **Brutus Maximus** » 05 Aug 2009, 22:31

If you do need to replace your coil, I recommend the MSD Blaster coil setup from IPD. Yeah, you can buy the coil cheaper from Summit or other online sources, but you won't get the custom coil bracket or coil wire. I was amazed at the difference the replacement coil made, from idle all the way through the range. Took just half an hour to install, and it works flawlessly. Well worth the money.

Another consideration is that you could have gotten some water in your fuel. I'd try running a can of Berryman B12 through the tank. Besides being a potent fuel system cleaner, it contains hygroscopic isopropyl alcohol, which is the best agent available for removing water contamination.

FCPEURO · Post by **FCPEURO** » 06 Aug 2009, 13:30

Another thing to consider would be your fuel pump. It could be going out on you.

Post by **songzunhuang** » 19 Aug 2009, 22:37

OK, it's been a while and the problems continue. The stumbling happens most when the car is idling and in gear. It's not so bad that the car dies, but it sure doesn't give you a feeling of security.

Since this began, we have driven on a few rather long roadtrips (4 hours each way) and the car made it just fine. Under acceleration and at freeway speeds, there's nothing wrong at all. So I think this eliminates the fuel pump issue. I can't imagine it'd survive 8 hours of driving without issue if the pump was failing, correct?

Ozark Lee - Wow! I just went out in the garage tonight and tried your little trick. Boy was there small blue sparks on both sides of the coil. I can hear a faint popping sound when I get close to it. So it looks to me like the first order of business is to replace that coil.

But the story doesn't end there. A a new code was thrown - P0172. It looks like there was a rich mixture at some point. From my research on this and other website, the issue seems to point to a vacuum leak of some kind. Oh my, how am I supposed to track that down and why didn't the dealer find any of this in the multiple visits (and charges) that have happened.

So it looks like my first course of action is to replace the coil. Then comes the vacuum leak. So where do I start? Is my diagnosis correct? How can I test for this before embarking on a journey of replacing a maze of hoses? Does anyone have a diagram I can look at to start?

Thanks for all your kind help.

NickD · Post by **NickD** » 20 Aug 2009, 11:18

I just had the exact same problem on my 1998 S70. I did a full tune-up last night (plugs, wires, cap, rotor, air filter) and the problem is fixed. I was getting a "mixture too rich" and assorted "misfire" codes. I suspect it was the cap and rotor (they looked pretty beat up), but I'm glad I did everything because I should be good for another 130K miles (yep...everything original until last night).

Nick

Post by **Ozark Lee** » 20 Aug 2009, 14:14

How can I test for this before embarking on a journey of replacing a maze of hoses? Does anyone have a diagram I can look at to start?

Usually there is a vacuum diagram under the hood. If you have a turbo we have a picture of the routing in the database. I always just start at the vacuum tree and go from there. The line line on the end of the intake manifold is the "usual suspect".

...Lee