96 850 Turbo: Codes P0302 P1310 - problem ONLY during idle

insession · Post by **insession** » 28 Apr 2022, 10:09

As of late, I've gotten codes P0302 P1310 at the same time. The car runs and accelerates just fine while driving, turbo kicks in fine too. The rough running only shows up while idling, and in gear. It's smooth in P and N, but jerky while idling in gear (with foot on brake). I delete the codes, but thus far they've come back.

A visual inspection doesn't show any cracked/loose hoses. Cables/plugs/rotor/cap are pretty new.
Does this point straight to the IAC? I've cleaned it a few years ago, it had been gunked up. Any pointers greatly appreciated.

Peter

Post by **ZionXIX** » 28 Apr 2022, 12:44

Misfires can still happen with new wires. Pull the wires off of the distributer 1 at a time and check for corrosion. If clean, then pull the distributor cap off and check for any signs of wear or corrosion.

insession · Post by **insession** » 28 Apr 2022, 14:15

Thanks ZionXIX - will look. But wouldn't a straight-up misfire show during driving/acceleration as well, not just during idling?

Post by **Clemens** » 28 Apr 2022, 15:08

it could, but not necessarily. Usually I've had bad idle or cutouts under high rpms, but betwenn 2000 and 3000 all of my p80s ran smooth even with well worn ignition parts.

insession · Post by **insession** » 28 Apr 2022, 15:58

Copy. Will look into it tomorrow or the next day and report back.

insession · Post by **insession** » 30 Apr 2022, 10:35

No corrosion on wire ends at distributor, but enough dark/rough areas on rotor and all cylinder brass points. Gave it all a good clean and will see if/when codes may show again. Idle upon reassembly is calm and steady, have not driven it yet.

It's possible that I didn't get high enough quality parts last I replaced all the plugs/wires/cap/rotor. I did get NGK (54120) RC-EUX023 Plugs, Bosch 03371 Distributor Cap, Champion RC8WYPB3 (9801) Iridium plugs, and a Standard Motor Products GB-368T Distributor Rotor.

Peter

Post by **scot850** » 30 Apr 2022, 10:56

Parts suppliers of many of the parts can give variable outcomes. NGK wires can work or not. I have read more with issues fitting them but then you only hear from those with issues!

I would only recommend Bougicord (Volvo)

I wouldn't use Champion plugs, only Bosch, OE Volvo or possibly NGK. The most important think is for them to be gaped correctly.
Plugs are not always gaped consistently or correctly for Volvos. I can never remember what the gap is, I think it is 0.028"

Rotor arm only Bosch brand from a reputable supplier. Too many knock-offs out there these days.

Hopefully your adjustments with what you have work well now!

Neil

454cid · Post by **454cid** » 30 Apr 2022, 11:08

scot850 wrote: 30 Apr 2022, 10:56
Rotor arm only Bosch brand from a reputable supplier. Too many knock-offs out there these days.

Rotor arm? I've never heard that combination of terms before... are you speaking of ignition?

Post by **misha** » 30 Apr 2022, 11:25

Gap is critical for turbo engines...it must be 0.026-0.028.

Spark plugs...Volvo (set of 5) for turbo engines,NGK iridium properly gapped or cheap copper Bosch or NGK properly gapped..nothing in between and nothing fancy...since it will not run properly with anything else.

Cap & rotor MUST be Bosch,spark plug wires Bougicord.

You might want to read this:
http://volvospeed.com/vs_forum/topic/96 ... /#comments

insession · Post by **insession** » 30 Apr 2022, 12:52

Thanks guys!

I imagine Neill meant distributor rotor when he said 'arm'. And yes, that will be my next replacement with a Bosch one.

Plugs had been gapped at 0.028 by me recently.

Peter