High Boost Misfire Help Update: Misfire fixed, now jb4 issue

dm874 · 05-13-2015, 08:06 AM

Hey guys,
Recently I decided to play around a little with the user adjustments on map 6 on the JB4 and increased my peak boost to 17 psi.

On the regular map 6 and 5 I was hitting 15-16 psi No problem, and No misfires.

But with the increased boost to 17 psi I started to get a Misfire Only on cylinder 1 when I would do a WOT pull in 3rd gear (in the higher rpm range).

Any ideas of what it could be? It's just on one cylinder. I am leaning towards it being an injector but let me know what you guys have experienced in your past

I fill up on 91 or 93 (usually 93)

Mods: JB4 G5, down pipes, exhaust, BMS DCI, chargepipe+Bov

spain4065 · 05-13-2015, 08:21 AM

Spark plugs, how old are they? Might be time to change them out.

dm874 · 05-13-2015, 11:40 AM

The car has 82k and i'm not sure if the previous owner ever changed them.
Luckily my new set of 6 came in the mail yesterday

mike@x-ph.com · 05-13-2015, 12:06 PM

Quote:

Originally Posted by dm874

The car has 82k and i'm not sure if the previous owner ever changed them.
Luckily my new set of 6 came in the mail yesterday

Get them changed and let us know if you are still getting any misfires

ShocknAwe · 05-13-2015, 12:16 PM

borderline too much boost for octane (wouldn't even try it on 91) and betting your AITs are sky high as well.

dm874 · 05-13-2015, 01:34 PM

Quote:

Originally Posted by ShocknAwe

borderline too much boost for octane (wouldn't even try it on 91) and betting your AITs are sky high as well.

Can someone confirm this? what would be a safe max boost level with the mods I have?

Solo_M_Tech · 05-14-2015, 03:41 AM

I wouldn't run more than 16 psi without race gas, when using the stock intercooler. AIT's are probably too high and the engine is pulling timing due to engine pre-ignition. I leave mine on Map 5 and never have issues. I run Euro 98 (U.S. 93). Boost usually peaks at 16psi.

BEAR-AvHistory · 05-14-2015, 08:07 AM

You really need to make a log to see what is happening, all the rest is just guess work

dm874 · 08-20-2015, 06:51 AM

So I went to the dealer (took off all my mods) and had them look over my turbos before my car hit 82k (car had 81,940) and the dealer ended up replacing both turbos!!
So after I got the car back I immediately replaced my spark plugs and put my mods back on.

My car now boosts Waaaaay too high according to the jb4. When I go wot the boost on oil shows boost go from 0-16 steady and then 16-20 quickly (the needle can't go up any higher) on every map (1,2,5)...which is not normal..

I'm thinking it's my boost solenoids...

05-13-2015, 08:06 AM	#1
dm874 Lieutenant 84 Rep 501 Posts Drives: 15' M4 Join Date: Jul 2014 Location: Bucks County,PA iTrader: (0)	High Boost Misfire Help Update: Misfire fixed, now jb4 issue Hey guys, Recently I decided to play around a little with the user adjustments on map 6 on the JB4 and increased my peak boost to 17 psi. On the regular map 6 and 5 I was hitting 15-16 psi No problem, and No misfires. But with the increased boost to 17 psi I started to get a Misfire Only on cylinder 1 when I would do a WOT pull in 3rd gear (in the higher rpm range). Any ideas of what it could be? It's just on one cylinder. I am leaning towards it being an injector but let me know what you guys have experienced in your past I fill up on 91 or 93 (usually 93) Mods: JB4 G5, down pipes, exhaust, BMS DCI, chargepipe+Bov Last edited by dm874; 08-20-2015 at 06:51 AM..
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05-13-2015, 08:21 AM	#2
spain4065 First Lieutenant 18 Rep 303 Posts Drives: EM1 and 08 135i Join Date: Sep 2012 Location: DC/MD iTrader: (1)	Spark plugs, how old are they? Might be time to change them out.
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05-13-2015, 11:40 AM	#3
dm874 Lieutenant 84 Rep 501 Posts Drives: 15' M4 Join Date: Jul 2014 Location: Bucks County,PA iTrader: (0)	The car has 82k and i'm not sure if the previous owner ever changed them. Luckily my new set of 6 came in the mail yesterday
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05-13-2015, 12:16 PM	#5
ShocknAwe 1Addict 3237 Rep 7,897 Posts Drives: E82 Mutt, M57 Truck Join Date: Jul 2012 Location: Charleston iTrader: (22)	borderline too much boost for octane (wouldn't even try it on 91) and betting your AITs are sky high as well. __________________ 2010 135i 6MT Jet Black N54/3 FE82 Mutt \| BUILD THREAD \| GARAGE SALE
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05-14-2015, 03:41 AM	#7
Solo_M_Tech Brigadier General 1688 Rep 3,140 Posts Drives: 2014 M5 6MT Join Date: Nov 2013 Location: Massachusetts iTrader: (7) Garage List 2014 BMW M5 [0.00]	I wouldn't run more than 16 psi without race gas, when using the stock intercooler. AIT's are probably too high and the engine is pulling timing due to engine pre-ignition. I leave mine on Map 5 and never have issues. I run Euro 98 (U.S. 93). Boost usually peaks at 16psi. __________________ 2014 M5 6MT
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05-14-2015, 08:07 AM	#8
BEAR-AvHistory 2020 Z4 M40i - 2022 M4C Convt 3129 Rep 5,264 Posts Drives: 2020 Z4 M40i - 2022 M4C Convrt Join Date: Jun 2011 Location: Raleigh, NC - OIB, NC iTrader: (0) Garage List 1965 COBRA (FFR rep ... [8.57] 2023 Jeep Wrangler ... [9.50] 2009 Yamaha V-Star [0.00] Cars 2-BMW, 2-FORD, ... [0.00] 2023 Ford Expeditio ... [0.00] 2020 Z4 M40i [10.00] 2022 BMW M4C [7.25] 1998 FORD Ranger 4X4 [0.00]	You really need to make a log to see what is happening, all the rest is just guess work __________________ Kevin Dravit Gray, Black Leather, Moonlight Roof, Red Calipers 2022 M4C - 2020 Z4 M40i - 2023 FORD Expedition XLT Max 4X4 400BHP - 2009 V-Star - 1998 Ranger 4X4 5MT - 1965 Cobra (R) 5MT - 2023 Jeep Wrangler Sport S 6MT
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08-20-2015, 06:51 AM	#9
dm874 Lieutenant 84 Rep 501 Posts Drives: 15' M4 Join Date: Jul 2014 Location: Bucks County,PA iTrader: (0)	So I went to the dealer (took off all my mods) and had them look over my turbos before my car hit 82k (car had 81,940) and the dealer ended up replacing both turbos!! So after I got the car back I immediately replaced my spark plugs and put my mods back on. My car now boosts Waaaaay too high according to the jb4. When I go wot the boost on oil shows boost go from 0-16 steady and then 16-20 quickly (the needle can't go up any higher) on every map (1,2,5)...which is not normal.. I'm thinking it's my boost solenoids...
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