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94 850T check engine light while accelerating

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

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henrysin44
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Year and Model: 1994 Volvo 855 Turbo
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henrysin44

Re: 94 850T check engine light while accelerating

Post by henrysin44 » Thu May 14, 2020 6:29 pm

misha wrote: ↑
Thu May 14, 2020 5:17 pm
henrysin44 wrote: ↑
Thu May 14, 2020 3:55 pm
...That would definitely explain why my headlights would be dim until i started driving.
You had a good luck that your battery was in good shape.
Since you ran a car with low voltage charging system...i would suggest to remove negative battery terminal for a few hours in order to reset car's management system and all bad things it could catch because of low voltage.

After that,perform a re-learning procedure for ecu and check voltage output on battery terminals.
Re-learning procedure:
http://www.volvotips.com/index.php/850- ... rocedures/
I'll give that a try, your probably right especially sense the CEL was on only during load.
http://shealabs.net
Daily driver Black 1994 Volvo 855 2.3L Turbo - manual swapped, turbo swapped, green injectors, custom M4.4 Tune, de-catted, custom two-tone interior, V70R seats & rims
Teal 1994 Volvo 855 2.5L N/A Manual Transmission (the back up daily and parts car) - Runs and Drives but the engine knocks
Silver 1997 Honda CRV 2.0 AWD - its in a very sorry condition, but drives
Silver 2003 Subaru Forester 2.5L N/A AWD - Leaks everything

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henrysin44
Posts: 113
Joined: Sun Apr 12, 2015 4:14 pm
Year and Model: 1994 Volvo 855 Turbo
Location: Guilford, CT USA
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henrysin44

Re: 94 850T check engine light while accelerating

Post by henrysin44 » Thu May 14, 2020 8:07 pm

misha wrote: ↑
Thu May 14, 2020 5:17 pm
henrysin44 wrote: ↑
Thu May 14, 2020 3:55 pm
...That would definitely explain why my headlights would be dim until i started driving.
You had a good luck that your battery was in good shape.
Since you ran a car with low voltage charging system...i would suggest to remove negative battery terminal for a few hours in order to reset car's management system and all bad things it could catch because of low voltage.

After that,perform a re-learning procedure for ecu and check voltage output on battery terminals.
Re-learning procedure:
http://www.volvotips.com/index.php/850- ... rocedures/
Gave it a try but unfortunately im still getting a CEL under load only....this is weird....car starts faster now though
http://shealabs.net
Daily driver Black 1994 Volvo 855 2.3L Turbo - manual swapped, turbo swapped, green injectors, custom M4.4 Tune, de-catted, custom two-tone interior, V70R seats & rims
Teal 1994 Volvo 855 2.5L N/A Manual Transmission (the back up daily and parts car) - Runs and Drives but the engine knocks
Silver 1997 Honda CRV 2.0 AWD - its in a very sorry condition, but drives
Silver 2003 Subaru Forester 2.5L N/A AWD - Leaks everything

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erikv11
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erikv11

Re: 94 850T check engine light while accelerating

Post by erikv11 » Fri May 15, 2020 9:05 am

Number one hypothesis here is knock under load. I'm not sure how to track that down but some ideas are to make sure the engine is not running lean, that the knock sensors are connected and mounted, that you are using proper octane fuel.
These users thanked the author erikv11 for the post:
henrysin44
'95 854 T5-R, Motronic 4.4, 185k
'96 855 NA, 145k
'98 S70 NA, 220k (living out west)
'98 V70, T5 tune-injectors-turbo, LPT engine, 286k
'06 S60 R, 167k
'99 Camry V6 :shock: 125k
gone: '96 NA 850 210k, '98 NA V70 182k

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henrysin44
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henrysin44

Re: 94 850T check engine light while accelerating

Post by henrysin44 » Sun May 31, 2020 1:32 am

erikv11 wrote: ↑
Fri May 15, 2020 9:05 am
Number one hypothesis here is knock under load. I'm not sure how to track that down but some ideas are to make sure the engine is not running lean, that the knock sensors are connected and mounted, that you are using proper octane fuel.
Just got back from a 10 day road trip and the CEL is still doing its thing. Ill check for vacuum leaks and start filling up with premium (been using regular ever sense the pandemic started). I put new copper spark plugs (runs a little smoother) and double checked the big 3. Really hoping to solve this one
http://shealabs.net
Daily driver Black 1994 Volvo 855 2.3L Turbo - manual swapped, turbo swapped, green injectors, custom M4.4 Tune, de-catted, custom two-tone interior, V70R seats & rims
Teal 1994 Volvo 855 2.5L N/A Manual Transmission (the back up daily and parts car) - Runs and Drives but the engine knocks
Silver 1997 Honda CRV 2.0 AWD - its in a very sorry condition, but drives
Silver 2003 Subaru Forester 2.5L N/A AWD - Leaks everything

scot850
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scot850

Re: 94 850T check engine light while accelerating

Post by scot850 » Sun May 31, 2020 1:24 pm

Never run a turbo on regular particularly under load or on the highway. Quickest way to get burnt valves.

Have you tried swapping in used knock sensor? How worn is the distributor shaft? I'll have to go back through this long thread to see what parts you have swapped out.

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

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henrysin44
Posts: 113
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henrysin44

Re: 94 850T check engine light while accelerating

Post by henrysin44 » Sun May 31, 2020 4:35 pm

scot850 wrote: ↑
Sun May 31, 2020 1:24 pm
Never run a turbo on regular particularly under load or on the highway. Quickest way to get burnt valves.

Have you tried swapping in used knock sensor? How worn is the distributor shaft? I'll have to go back through this long thread to see what parts you have swapped out.

Neil.
Good to know! I knew it wasn't a great thing to do but I don't want to get burnt valves. I haven't swapped the knock sensors, but wouldn't faulty knock sensors store a code? What do you mean by distributor shaft, cam shaft? I replaced the distributor cap and rotor last summer and everything looked good.

As an update I gaped my new plugs at 0.26 (from 0.28) and filled my empty tank with premium, now the check engine light only comes on during WOT and almost WOT, or if not in the appropriate gear.
http://shealabs.net
Daily driver Black 1994 Volvo 855 2.3L Turbo - manual swapped, turbo swapped, green injectors, custom M4.4 Tune, de-catted, custom two-tone interior, V70R seats & rims
Teal 1994 Volvo 855 2.5L N/A Manual Transmission (the back up daily and parts car) - Runs and Drives but the engine knocks
Silver 1997 Honda CRV 2.0 AWD - its in a very sorry condition, but drives
Silver 2003 Subaru Forester 2.5L N/A AWD - Leaks everything

scot850
Posts: 6059
Joined: Mon Apr 05, 2010 2:46 pm
Year and Model: 2000 V70 R
Location: Calgary, Alberta, Canada
Has thanked: 12 times
Been thanked: 230 times
Canada
scot850

Re: 94 850T check engine light while accelerating

Post by scot850 » Sun May 31, 2020 7:24 pm

Have you changed either the cam or crank sensors in the recent past?

If your distributor shaft (the shaft with the rotor arm on it) is worn it can accelerate the wear on the rotor arm causing spark drop off or damage to the distributor cap.

Have you checked inside the distributor cap recently to make sure there is no moisture or oil from a leaking cam seal in there?

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

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erikv11
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erikv11

Re: 94 850T check engine light while accelerating

Post by erikv11 » Sun May 31, 2020 10:00 pm

The knock sensors rarely, rarely, rarely go bad. However the wire to them can be come frayed, so it is definitely worth checking the connections. Since they never go bad I have no experience with or reading about knock sensor codes but yeah, I too would expect a bad one to set a code.

Neil's point about ignition parts is a good one, especially since plugs may have made a difference. What is the vintage on the plug/coil wires? They have a date code stamped on them.
'95 854 T5-R, Motronic 4.4, 185k
'96 855 NA, 145k
'98 S70 NA, 220k (living out west)
'98 V70, T5 tune-injectors-turbo, LPT engine, 286k
'06 S60 R, 167k
'99 Camry V6 :shock: 125k
gone: '96 NA 850 210k, '98 NA V70 182k

User avatar
henrysin44
Posts: 113
Joined: Sun Apr 12, 2015 4:14 pm
Year and Model: 1994 Volvo 855 Turbo
Location: Guilford, CT USA
Has thanked: 1 time
Been thanked: 3 times
Sweden
henrysin44

Re: 94 850T check engine light while accelerating

Post by henrysin44 » Tue Jun 02, 2020 8:05 am

erikv11 wrote: ↑
Sun May 31, 2020 10:00 pm
The knock sensors rarely, rarely, rarely go bad. However the wire to them can be come frayed, so it is definitely worth checking the connections. Since they never go bad I have no experience with or reading about knock sensor codes but yeah, I too would expect a bad one to set a code.

Neil's point about ignition parts is a good one, especially since plugs may have made a difference. What is the vintage on the plug/coil wires? They have a date code stamped on them.
Ill take a look, the OEM plug wires came from a pre coil pack V70 T5 at a scrap yard, they look quite good in and out but that could be the weak link as every other ignition component, besides the coil, is new.

Today i finally got around to installing an exhaust, it was just a down-pipe prior, and with the car now quiet i was able to notice the light comes on when it hits max boost, and when that light comes on the boost pulls back a few PSIs, something i didn't notice when the car was insanely loud.
http://shealabs.net
Daily driver Black 1994 Volvo 855 2.3L Turbo - manual swapped, turbo swapped, green injectors, custom M4.4 Tune, de-catted, custom two-tone interior, V70R seats & rims
Teal 1994 Volvo 855 2.5L N/A Manual Transmission (the back up daily and parts car) - Runs and Drives but the engine knocks
Silver 1997 Honda CRV 2.0 AWD - its in a very sorry condition, but drives
Silver 2003 Subaru Forester 2.5L N/A AWD - Leaks everything

User avatar
henrysin44
Posts: 113
Joined: Sun Apr 12, 2015 4:14 pm
Year and Model: 1994 Volvo 855 Turbo
Location: Guilford, CT USA
Has thanked: 1 time
Been thanked: 3 times
Sweden
henrysin44

Re: 94 850T check engine light while accelerating

Post by henrysin44 » Tue Jun 02, 2020 8:06 am

scot850 wrote: ↑
Sun May 31, 2020 7:24 pm
Have you changed either the cam or crank sensors in the recent past?

If your distributor shaft (the shaft with the rotor arm on it) is worn it can accelerate the wear on the rotor arm causing spark drop off or damage to the distributor cap.

Have you checked inside the distributor cap recently to make sure there is no moisture or oil from a leaking cam seal in there?

Neil.
Well the engine has about 366K on it so i wouldn't be surprised to find oil in the distributor cap, ill give it a look.
http://shealabs.net
Daily driver Black 1994 Volvo 855 2.3L Turbo - manual swapped, turbo swapped, green injectors, custom M4.4 Tune, de-catted, custom two-tone interior, V70R seats & rims
Teal 1994 Volvo 855 2.5L N/A Manual Transmission (the back up daily and parts car) - Runs and Drives but the engine knocks
Silver 1997 Honda CRV 2.0 AWD - its in a very sorry condition, but drives
Silver 2003 Subaru Forester 2.5L N/A AWD - Leaks everything

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