IPD sale XeMODeX - Experts in Volvo Electronics Free shipping all USA - Experts in Brakes
Did you know? 🤔
Logged in users can get email notification of topic replies Log in or register (free).
Amazon Link Buy anything with this and it helps MVS!

1998 S70 Runs fine cold, misfire when hot at low revs bad KAE fuel relay Topic is solved

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

scot850
Posts: 5785
Joined: Mon Apr 05, 2010 2:46 pm
Year and Model: 2000 V70 R
Location: Calgary, Alberta, Canada
Has thanked: 9 times
Been thanked: 193 times
Canada
scot850

Re: Runs fine cold, misfire when hot at low revs

Post by scot850 » Tue Feb 20, 2018 3:16 pm

It is possible, but If the wiring is not damaged, I can't see it being an issue unless it managed to get into the joint some how.

I know I have had problems getting the ABS module connector apart when it has not been disturbed for a long time. Wish I could actually get my hands on the connector to tackle it.

Those wires from NGK are possibly part of the issue. We only ever recommend OE brand or OEM Bougicord due to so many issues with other branded part just not working.

Other parts should be good.

Neil.
2000 V70 R - still being an endless PITA
2006 XC70
2003 Toyota 4Runner V8 Limited
2015 Kia Sportage EX-L
1993 850 GLT -Sold
1998 V70 XC - Sold
1997 Volvo 850 SE NA - Went to niece in California - Sold
2000 V70 SE NA - New project and test bed - Sold

User avatar
abscate
MVS Moderator
Posts: 20567
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 290 times
Been thanked: 909 times
Trinidad & Tobago
abscate

Re: Runs fine cold, misfire when hot at low revs

Post by abscate » Tue Feb 20, 2018 3:17 pm

An OXS won't cause a huge misfire like this. Are you getting codes? The Short term fuel trim will run out of limit if the OXS is totally bad, which will pop a P0171 code.

Start at the coil and look for battery voltage, and then fault trace the ignition system all the way to the plugs. You just can't assume parts are good, you have to remove them, look at the wear surfaces, and correct.A bad rms is probably from crankcase over pressure, which will blow oil in the distributor cap.
Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW
Link to Maintenance record thread
Link To Volvo Glossary

User avatar
WhatAmIDoing
Posts: 756
Joined: Sat Jul 30, 2016 1:13 pm
Year and Model: 1998 S70 T5M
Location: North America
Has thanked: 66 times
Been thanked: 56 times
Canada
WhatAmIDoing

Re: Runs fine cold, misfire when hot at low revs

Post by WhatAmIDoing » Tue Feb 20, 2018 3:21 pm

Pulled distributor, very little moisture/oil around the edges where it mates with the block. Inside looks good, no arcing, maybe the slightest trace of moisture. Would think there would be some kind of rubber seal to keep dirt/water/oil out. What do some people do to keep moisture out of the distributor?
'98 S70 T5M - 276,000+mi - forever a project
'99 S70 "AWD" - 220,000+mi - wrecked :cry:
Knows enough to be dangerous :wink:

User avatar
WhatAmIDoing
Posts: 756
Joined: Sat Jul 30, 2016 1:13 pm
Year and Model: 1998 S70 T5M
Location: North America
Has thanked: 66 times
Been thanked: 56 times
Canada
WhatAmIDoing

Re: Runs fine cold, misfire when hot at low revs

Post by WhatAmIDoing » Tue Feb 20, 2018 3:31 pm

abscate wrote:
Tue Feb 20, 2018 3:17 pm
An OXS won't cause a huge misfire like this. Are you getting codes? The Short term fuel trim will run out of limit if the OXS is totally bad, which will pop a P0171 code.

Start at the coil and look for battery voltage, and then fault trace the ignition system all the way to the plugs. You just can't assume parts are good, you have to remove them, look at the wear surfaces, and correct.A bad rms is probably from crankcase over pressure, which will blow oil in the distributor cap.
Missed your post somehow. I misplaced my good code reader, and my spare took a dump (so did my multimeter). Going to limp the car to an auto parts store this evening. Car had PCV done when I bought it. Passes glove test. Theory is the seal just deteriorated.
'98 S70 T5M - 276,000+mi - forever a project
'99 S70 "AWD" - 220,000+mi - wrecked :cry:
Knows enough to be dangerous :wink:

User avatar
WhatAmIDoing
Posts: 756
Joined: Sat Jul 30, 2016 1:13 pm
Year and Model: 1998 S70 T5M
Location: North America
Has thanked: 66 times
Been thanked: 56 times
Canada
WhatAmIDoing

Re: Runs fine cold, misfire when hot at low revs

Post by WhatAmIDoing » Tue Feb 20, 2018 5:47 pm

Borrowed a code reader. 5 Stored codes, 0 Pending, in order: P0141, P0136, P0440, P0410, P0108. Don't know how I didn't get a P0300, which is what I was expecting. I know P0141 and P0136 is from the downstream O2 sensor being disconnected. P0440 is evap system malfunction, this one comes and goes. P0410 is for secondary air pump, comes and goes, need to do SAS delete. P0108 - MAP Pressure Circuit High Input is new. My money is on this one, which means I'm looking for a vacuum leak or a short due to water.
'98 S70 T5M - 276,000+mi - forever a project
'99 S70 "AWD" - 220,000+mi - wrecked :cry:
Knows enough to be dangerous :wink:

User avatar
abscate
MVS Moderator
Posts: 20567
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 290 times
Been thanked: 909 times
Trinidad & Tobago
abscate

Re: Runs fine cold, misfire when hot at low revs

Post by abscate » Wed Feb 21, 2018 10:24 am

Clear codes, see what comes back. That P0108 could be a ghost.
Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW
Link to Maintenance record thread
Link To Volvo Glossary

User avatar
WhatAmIDoing
Posts: 756
Joined: Sat Jul 30, 2016 1:13 pm
Year and Model: 1998 S70 T5M
Location: North America
Has thanked: 66 times
Been thanked: 56 times
Canada
WhatAmIDoing

Re: Runs fine cold, misfire when hot at low revs  Topic is solved

Post by WhatAmIDoing » Wed Feb 21, 2018 11:01 pm

Cleared codes. P0141, P0136, P0440 came back. Knocked some debris out of the air filter, resat the MAF connector. No change, misfiring and stumbling when hot. Decided to pull the fuel pump relay and pop apart the housing before pulling all the plugs and wires. PCB was fried and several solder joints were touching. Not sure how the engine was even able to start. Plugged in a spare Volvo relay. Initial start was a bit rough, then it evened out and all is good now. KAE relay failed in 4000 miles, bought itself a one way ticket back to FCP.
'98 S70 T5M - 276,000+mi - forever a project
'99 S70 "AWD" - 220,000+mi - wrecked :cry:
Knows enough to be dangerous :wink:

User avatar
abscate
MVS Moderator
Posts: 20567
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 290 times
Been thanked: 909 times
Trinidad & Tobago
abscate

Re: Runs fine cold, misfire when hot at low revs

Post by abscate » Thu Feb 22, 2018 4:07 am

If you talk to FCP, without using the internet, you might get the KaE piece of poop upgraded to a Decent relay for a nominal charge

Thanks for closing up the report!
Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW
Link to Maintenance record thread
Link To Volvo Glossary

User avatar
WhatAmIDoing
Posts: 756
Joined: Sat Jul 30, 2016 1:13 pm
Year and Model: 1998 S70 T5M
Location: North America
Has thanked: 66 times
Been thanked: 56 times
Canada
WhatAmIDoing

Re: Runs fine cold, misfire when hot at low revs

Post by WhatAmIDoing » Thu Feb 22, 2018 9:30 am

abscate wrote:
Thu Feb 22, 2018 4:07 am
If you talk to FCP, without using the internet, you might get the KaE piece of poop upgraded to a Decent relay for a nominal charge

Thanks for closing up the report!
Just did. :D Genuine Volvo on the way. Let this topic be a warning to anyone thinking about buying a "cheap" fuel pump relay. This was the 3rd KAE I've burned through. Fortunately, the first 2 came with the car. :lol:
'98 S70 T5M - 276,000+mi - forever a project
'99 S70 "AWD" - 220,000+mi - wrecked :cry:
Knows enough to be dangerous :wink:

scot850
Posts: 5785
Joined: Mon Apr 05, 2010 2:46 pm
Year and Model: 2000 V70 R
Location: Calgary, Alberta, Canada
Has thanked: 9 times
Been thanked: 193 times
Canada
scot850

Re: 1998 S70 Runs fine cold, misfire when hot at low revs bad KAE fuel relay

Post by scot850 » Thu Feb 22, 2018 11:28 am

Glad the lateral thinking on your part found the root cause. Well done and hopefully plain sailing for a while!

Neil.
2000 V70 R - still being an endless PITA
2006 XC70
2003 Toyota 4Runner V8 Limited
2015 Kia Sportage EX-L
1993 850 GLT -Sold
1998 V70 XC - Sold
1997 Volvo 850 SE NA - Went to niece in California - Sold
2000 V70 SE NA - New project and test bed - Sold

Post Reply
  • Similar Topics
    Replies
    Views
    Last post