1999 XC70 Engine running on 4 cylinders

Dynamic D · Post by **Dynamic D** » 13 Dec 2013, 07:05

Hello,

I have a 1999 XC70 Volvo that is running on 4 cylinders and the engine doesn't want to run over 2000 RPM. Last tuesday I drove it up to my mechanic and after 20 minutes of driving, the fifth cylinder came back to life and the car was behaving as normal. They changed all the coils and that "fixed" the problem until this morning.

I don't know if that can be related, but 2 weeks ago, before the cars started to have this problem, I got a few check codes that were pointing to the O2 sensor. I changed the sensor and the radiator that started to leak.

My mechanic doesn't know what the problem is. Can anyone help me find the problem ?

Thanks !

Post by **Ozark Lee** » 13 Dec 2013, 09:49

What were the code numbers?

It seems like overkill to change all of the coils when only one cylinder wasn't firing.

...Lee

Post by **abscate** » 13 Dec 2013, 10:47

Pull spark plugs and, if you haven't changed them recently, out new ones in.

My guess is the coils were fine and you might have a bad plug that might have been bumped good again

Dynamic D · Post by **Dynamic D** » 16 Dec 2013, 20:16

Hello,

The codes were P0133 and P0030 or P0031 (my memory is not good on this one).

I tried a few things tonight:
I've look carefully at the cable going into the coils and found that one of the cable was pinched (black cable going into cylinder #3). I remove the connector to the coil and checked if the middle pin of the connector had continuity with the motor (grounded) and it was ok. So for me it doesn't seem to be problem.
Next, I only had 1 spark plug in my garage, so I tried to see what cylinder isn't working. To do that, I unplugged one coil at a time and see which one would make no difference on the way the motor was running. I expected that if unplugged a good one, the motor would not start. Unfortunately, the motor is quite robust and none of the coil unplugging made a difference to my ears.
Next I tried to unplug all the coil and just plug one at a time. I though that by trying to start the engine, if the spark plug was bad, there would be no fire. I had this only with cylinder #3, so I changed the spark plug on that cylinder, plug back all the coil and started the engine. The engine is still vibrating a lot, it sounds bad and I have the yellow ETS light on.

In short, the problem is still there. I left the engine running like that for about 10 minutes to give a change to the battery to charge a little bit and at the end the engine was still working bad.

I don't know what else I should look at, so any suggestion is more than welcome !

Thanks again,

Post by **phils94850** » 16 Dec 2013, 21:05

Sounds like you did the correct procedures, you need to try and figure out a way to see if you can either swap coils and make the dead cylinder change, if none of that works then it may be an internal issue which would require a compression test..

Post by **erikv11** » 16 Dec 2013, 21:34

I can't think of any bad compression scenarios that would come and go like that. I like the idea here of troubleshooting the ignition etc.

Are you saying all of the coils are new? What brand are they (not sure why I am asking that)? What brand are the plugs (definitely sure why I'm asking that)?

Post by **phils94850** » 17 Dec 2013, 05:22

I missed the come and go part.. has he checked to make sure he doesn't have a bad injector causing the issue ?

Dynamic D · Post by **Dynamic D** » 17 Dec 2013, 06:26

Hello Phils,

Last week, when I drove the car to the garage, after about 20 min, the engine started to work perfect just like magic.

How do I check for a bad injector ?

Post by **erikv11** » 17 Dec 2013, 08:54

Check the wiring, make sure each injector is plugged in.

But otherwise it is just like checking a plug or a coil pack: you swap the position of the injectors around, see if the problem follows an injector to another cylinder.

Look at probably any PCV job video, there is a good one at the FCP web site that shows very clearly how to pull the injectors. It is easy to do, basically relieve fuel pressure, unscrew two bolts holding the fuel rail, unplug injectors, pull rail straight out, swap injectors around in rail, reinstall. Watch to make sure the little rubber seals don't fall out of the intake manifold. Very lightly grease each injector o-ring with vaseline upon reinstall.

What kind of plugs are in there?

Post by **cn90** » 17 Dec 2013, 09:01

A note on cosmetic cover (the cover with Torx bolts) in car with direct ignition, leave the cover out if possible.
During installation, if one is not careful, the cover may pinch some wiring that feeds the individual ignition coil(s).

You need to read the thread below...

Car won't start after replacing spark plugs!
https://www.matthewsvolvosite.com/forums ... hp?t=29712

Another read:
http://volvoforums.com/forum/volvo-s60- ... use-72249/