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Seafoam...now idle is horribly irregular

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo's stylish, distinctive P2 platform cars sold as model years 2001-2007 (North American market year designations).

2001 - 2007 V70
2001 - 2004 V70 XC (Cross Country)
2004 - 2007 XC70 (Cross Country)
2001 - 2009 S60
2003 - 2007 S60 R
2004 - 2007 V70 R

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priapism
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Seafoam...now idle is horribly irregular

Post by priapism »

2001 S60. I ran Seafoam through the intake per the instructions here: https://www.matthewsvolvosite.com/2010/0 ... -followup/. Lotsa smoke! The idle was irregular before (drops, then rises) but now it drops so low as to almost stall every "cycle". The interior lights dim and everything. Did I break something?

CEL light is on, but it has been for a while (trans is bad, getting fixed soon) so I've been ignoring it. I pulled the code now and it's reading PO237, low input voltage for the turbo? I reset it and it comes back on immediately.
Titan LE : S60 2.4t : 91 325i : Spec E30 #33

jblackburn
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Post by jblackburn »

Hold the idle steady with your foot and check the alternator's output voltage. Low voltage can cause all kinds of weird things to happen.
'98 S70 T5
2016 Chevy Cruze Premier


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priapism
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Post by priapism »

The alternator reads perfect, right around 14.5-14.8 or so when idling. Battery is strong, 12.5v.

It idles perfectly when cold but the idle gets all wavy when it's warmed up. Drops to 6-700 the pops up to 1k. Every so often it drops so low as to make the whole car judder. Man, I thought seafoaming the intake was supposed to FIX this.

Codes come back immediately after clearing too. 237 and 236. Ugh!
Titan LE : S60 2.4t : 91 325i : Spec E30 #33

JRL
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Post by JRL »

May have messed up the MAF
(Or it was going bad and this helped it along)
Mod note. Jim passed away in early 2022, his contributions to this forum are immortal, and he is missed. RIP

2000 V70R Black, 144,000 miles Wife's R.
2007 V70 2.5T White/Oak 111,000 MILES. Polestar tune, IPD bars, rear spoiler, dark grey Thors, DWS 06, HU850, sub.

priapism
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Post by priapism »

I was wondering about that. I'll pull it and clean it while it's sitting anyways.
Titan LE : S60 2.4t : 91 325i : Spec E30 #33

JRL
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Post by JRL »

CAREFULLY
Mod note. Jim passed away in early 2022, his contributions to this forum are immortal, and he is missed. RIP

2000 V70R Black, 144,000 miles Wife's R.
2007 V70 2.5T White/Oak 111,000 MILES. Polestar tune, IPD bars, rear spoiler, dark grey Thors, DWS 06, HU850, sub.

skeeter123
Posts: 35
Joined: 5 December 2009
Year and Model: s60, 2004
Location: USA

Post by skeeter123 »

Those codes could point to the MAP sensor; maybe the seafoam didn't agree with it, or maybe you could check the wiring/connector to the MAP.
Hope this helps.

check out:
https://www.matthewsvolvosite.com/forums ... r+#p135453

priapism
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Post by priapism »

JRL wrote:CAREFULLY
No kidding...

Yeah, I touched the sensor when I picked it up, think I broke it. Ha! It's much worse now. Time for a new MAF. I was thinking I should probably replace it anyways.
Titan LE : S60 2.4t : 91 325i : Spec E30 #33

priapism
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Post by priapism »

New MAF, idle still goes up and down, though not too much. Guess I need to clean the throttle body by hand. Looks like it's a pain to get to as well.
Titan LE : S60 2.4t : 91 325i : Spec E30 #33

JRL
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Post by JRL »

You need to remove the TB to properly clean it
Make sure you buy a new gasket
Mod note. Jim passed away in early 2022, his contributions to this forum are immortal, and he is missed. RIP

2000 V70R Black, 144,000 miles Wife's R.
2007 V70 2.5T White/Oak 111,000 MILES. Polestar tune, IPD bars, rear spoiler, dark grey Thors, DWS 06, HU850, sub.

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