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Old 10-10-2018, 02:45 PM   #1
Pumba
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Question Chippet 850 T-5 - Boost issue

Oi there lads..

I got a '96 850 T-5 (B5234T) with white injectors and a stg 3 chip, it's got a ****ton of power and goes like a bat out of hell..

But if I floor it (pedal to the basement) it'll start - well sounds like studdering and it kinda halfway cuts out..
It'll start doing it at about 3300-3500rpm..

It's only doing it when at full throttle and not if I accelerate at 3/4 throttle, even if I go to 5000+rpm..

Could it be the boost protection kicking in or could it be that I'd need a bigger downpipe than 2.5" ?
(as far as I have been able to figure out, the boost protection shouldn't kick in with a sgt3 chip, or am I totally lost here?)

Hope someone in here got the "Guru"-sign lit

Best Regards
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Old 10-13-2018, 11:58 AM   #2
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Check the condition and gap of your spark plugs. IIRC the factory gap is .028. If you're running more boost you may want to narrow that down to .026.
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Old 10-15-2018, 02:36 PM   #3
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Check the condition and gap of your spark plugs. IIRC the factory gap is .028. If you're running more boost you may want to narrow that down to .026.
Could that really be the issue ?
The boost on this one is set to 18psi (1.24bar)

The manufacture of the chip says they don't have any boost protection fuel cut installed at all, so the issue gotta be somewhere else..

I have ordered IK20TT Iridium plugs and new cables, hope to get them within the next few days, I'll make sure to check the gap on them then..
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Old 10-17-2018, 04:36 PM   #4
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I've had the exact same experience with my former 850 T5. Altering the gap on my spark plugs fixed it instantly. I'd start with the known 5 cylinder issues you can fix for free.
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Old 10-17-2018, 06:58 PM   #5
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I have just adjusted the gap on the plugs to .026. and sure enough it did indeed help some, but at full boost there's still some slight stuttering.
I'll make sure to check the gap on the new plugs I have ordered before fitting them and hope that and the new cables will fix it..

Thanks a bunch for the hint guys, I'm kinda new to these "newer" cars ;)

Another thing if you lads knows, is the only way to make the engine run richer ECU work ?
The plugs where a lot whiter than I like to see and as far as I know that indicates that it's running to lean..
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Old 10-17-2018, 10:48 PM   #6
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You could even try going to .024 or .025.
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Old 10-18-2018, 03:43 AM   #7
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You could even try going to .024 or .025.
I'll give it a try ;)
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Old 10-18-2018, 07:22 AM   #8
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I would not use iridium plugs. Copper core NGK B7KRE are what most of us use, colder heat range.

Get a wideband. An 88c tstat will run a little richer.

Who is this tuner?

18 psi on what? TD04?
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Old 10-18-2018, 08:58 AM   #9
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I would not use iridium plugs. Copper core NGK B7KRE are what most of us use, colder heat range.
10-4 I'll try that then. (hope I still got time to change the order)

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Get a wideband. An 88c tstat will run a little richer.
Ok, feeling like a total noob here, but a fuel/air mix controller or ?

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Who is this tuner?
it's a reprogrammed BSR chip.

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Originally Posted by ErikS View Post
18 psi on what? TD04?
Yes the 15G.. I know it can't take the punishment in the long run and wanna replace it with a 18t or 19t. But that's also a bit of a cash issue..
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Old 10-18-2018, 09:25 AM   #10
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A wideband sensor and gauge will let you know if your air to fuel ratio is safe.
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Old 10-18-2018, 10:01 AM   #11
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10-4 I'll try that then. (hope I still got time to change the order)

Ok, feeling like a total noob here, but a fuel/air mix controller or ?

it's a reprogrammed BSR chip.

Yes the 15G.. I know it can't take the punishment in the long run and wanna replace it with a 18t or 19t. But that's also a bit of a cash issue..
You can also just run the OEM Volvo copper plugs, they are fine.

Thermostat - 88C - allows the car to run a little richer under boost.

https://www.amazon.com/Stant-45378-S.../dp/B000C80AFK

BSR is old technology, no way should you be running 18 psi on a 15g, way out of its efficiency range.
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Old 10-18-2018, 11:59 AM   #12
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Quote:
Originally Posted by ErikS View Post
I would not use iridium plugs. Copper core NGK B7KRE are what most of us use, colder heat range.

Get a wideband. An 88c tstat will run a little richer.

Who is this tuner?

18 psi on what? TD04?
This

Worn cap/rotor/wires/plugs will do the same. Oem only or you’ll be replacing crap all the time

Also
15g at 18psi pushes a lot of hot air.


Bit of a cash issue you say? Then stop making your car worse. Get out of college and get a job then start to do it right
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Old 10-18-2018, 12:55 PM   #13
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Bit of a cash issue you say? Then stop making your car worse. Get out of college and get a job then start to do it right
Unnecessary judgement is unnecessary.
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Old 10-18-2018, 01:52 PM   #14
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Quote:
Originally Posted by Jack View Post
This

Worn cap/rotor/wires/plugs will do the same. Oem only or you’ll be replacing crap all the time

Also
15g at 18psi pushes a lot of hot air.


Bit of a cash issue you say? Then stop making your car worse. Get out of college and get a job then start to do it right
Hopefully he did a stage zero before the mods. These cars are sensitive to worn ignition components when you start modding them.

Last edited by ovlov760; 10-18-2018 at 02:14 PM..
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Old 10-18-2018, 02:57 PM   #15
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Had similar issues with B5204T2 (2.0l version) with 16T #7 angled exhaust flange @ 18-20 psi.
We gapped plugs down to 0.020" (0.50mm) and this cured the issue.

Stage 0 of course!

Last edited by 8DOM8S8AN; 10-18-2018 at 04:56 PM..
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