1998 V70 (almost musical) plastic-like clicking sound?

Post by **theWIFES_S70** » 05 Nov 2015, 11:24

Hey guys, anyone have any clue what this sound might indicate? Happened shortly after having a flashing/blinking check engine light... (This is my brother's car and I'm trying to keep him in the P80 family!)

I told him to clean out the Mass Airflow Sensor...
Also told him to check out the connections to the idle air control valve...
Tune up (plugs, wire, rotor, cap) was done about a month ago...
He did do a fuel injector cleaner thing (are there any that are really bad for our P80s?)...

Here's a video of the sound:

Thanks guys!!

Post by **regent** » 05 Nov 2015, 11:43

The sound in the video distinctly points to a high-voltage arc; I think at least one cylinder keeps 'missing' because of that. I would take look again at the ignition components first (could be a loose ignition wire at the dist. cap or plug)

Post by **theWIFES_S70** » 05 Nov 2015, 11:55

Thanks for the reply, Regent. Really appreciate it! I was going to suggest that he take apart all the plugs and install each with a little dialectric grease to the sure.

Post by **regent** » 05 Nov 2015, 11:59

You are on the right track!

jcdillin · Post by **jcdillin** » 05 Nov 2015, 12:06

Wow, is it just the video or does the EGR valve really move around that much? Shown at 00:13.

The other thing I would check is to pull the distributor cap and check to make sure one of the screws isn't backing out. That really sounds like something is hitting.

Post by **theWIFES_S70** » 05 Nov 2015, 13:00

So the plugs have been pulled, #1, #4, #3 look pretty burnt. (No way they should be this burnt...). My brother did run some "STP Fuel Injector cleaner" through this car. Could this all be related somehow?

Post by **theWIFES_S70** » 05 Nov 2015, 18:04

Also, could this occur if the Mass Airflow Sensor was cleaned improperly? I think he unhooked the air filter box and just sprayed cleaner into the MAF (it needs a special torx!) and then turned the car on... This is wrong, right?

Post by **Ozark Lee** » 06 Nov 2015, 07:15

Just spraying the MAF is the proper way. You never want to scrub it or even touch it in any way.

I get nervous looking at it too hard.

Make sure the spark plugs are properly gapped. The spec is 0.028" and error on the tight side.

...Lee

brunocerous · Post by **brunocerous** » 06 Nov 2015, 08:19

regent wrote:The sound in the video distinctly points to a high-voltage arc; I think at least one cylinder keeps 'missing' because of that. I would take look again at the ignition components first (could be a loose ignition wire at the dist. cap or plug)

Thank you so much! It does appear to have been a loose ignition coil wire. I had inadvertently knocked into it when removing the air box.

brunocerous · Post by **brunocerous** » 06 Nov 2015, 08:22

jcdillin wrote:Wow, is it just the video or does the EGR valve really move around that much? Shown at 00:13.

The other thing I would check is to pull the distributor cap and check to make sure one of the screws isn't backing out. That really sounds like something is hitting.

Crazy thing is, it's much worse in real life, at least two or three times faster than it appears in the video. The video frame rate couldn't catch the high-speed vibrations. Any idea what I could do to fix that? New motor mounts?