View Full Version : Boomslang fi/c harness fix for auto xb
built 08 xb 08-05-2010, 08:11 PM :flame: The fix for this harness is the same as the tC using a 2.2k resistor between the cam and crank sensor. It cleared up my problem and the only check engine light I have now is from my secondary O2 sensor. The resistor mod fixes a lot from misfires to cold starts. I talked to boomslang and the problem supposedly started with Descendant Racing. Boomslang says they sent Rob 2 harnesses to test, but Rob didn't test the harnesses and Boomslang started to mass produce this harness not knowing that there were bugs to be fixed. So if there is anyone to blame for the auto xB2 crank and cam CEL, it is Descendant Racing. Next time, Rob, when someone gives you something to test, please test it properly and don't lie and say that it works properly because it causes a lot of problems. :flame: Shame on Descendant :icon_nono:
FromTheOld 08-05-2010, 08:17 PM English Translation:
:flame: The fix for this harness is the same as the tC using a 2.2k resistor between the cam and crank sensor. It cleared up my problem and the only check engine light I have now is from my secondary O2 sensor. The resistor mod fixes a lot from misfires to cold starts. I talked to boomslang and the problem supposedly started with Descendant Racing. Boomslang says they sent Rob 2 harnesses to test, but Rob didn't test the harnesses and Boomslang started to mass produce this harness not knowing that there were bugs to be fixed. So if there is anyone to blame for the auto xB2 crank and cam CEL, it is Descendant Racing. Next time, Rob, when someone gives you something to test, please test it properly and don't lie and say that it works properly because it causes a lot of problems. :flame: Shame on Descendant :icon_nono:
built 08 xb 08-05-2010, 08:34 PM English Translation:
:flame: The fix for this harness is the same as the tC using a 2.2k resistor between the cam and crank sensor. It cleared up my problem and the only check engine light I have now is from my secondary O2 sensor. The resistor mod fixes a lot from misfires to cold starts. I talked to boomslang and the problem supposedly started with Descendant Racing. Boomslang says they sent Rob 2 harnesses to test, but Rob didn't test the harnesses and Boomslang started to mass produce this harness not knowing that there were bugs to be fixed. So if there is anyone to blame for the auto xB2 crank and cam CEL, it is Descendant Racing. Next time, Rob, when someone gives you something to test, please test it properly and don't lie and say that it works properly because it causes a lot of problems. :flame: Shame on Descendant :icon_nono:
ok microsoft spell check
FromTheOld 08-05-2010, 11:54 PM ok microsoft spell check
It was a lot more than spell check :)
I was just doing everyone a favor...
paul_dezod 08-11-2010, 05:42 PM I offered to test the 5 speed editions of the harness on our shop xB, but Rustin said he already had a tester.
Instead, we went with the APR unit, which turned out to be a blessing...
http://www.dezod.com/pd-allan.cfm
ScionFred 08-13-2010, 09:42 AM When you say "using a 2.2k resistor between the cam and crank sensor", where exactly do you mean? My Boomslang harness came with 2.2k resistors installed between crk magi +/- and cam magi +/- "the same as the tC" resistor fix. I couldn't rev past 5000 rpm due to the misfiring. Did you install extra resistors in addition to Boomslang's or what?
I even tried using POTs and an oscilloscope to try to find the correct parallel resistance value but ended up bypassing the cam sensor intercept completely to get rid of the misfires.
built 08 xb 08-13-2010, 10:43 PM When you say "using a 2.2k resistor between the cam and crank sensor", where exactly do you mean? My Boomslang harness came with 2.2k resistors installed between crk magi +/- and cam magi +/- "the same as the tC" resistor fix. I couldn't rev past 5000 rpm due to the misfiring. Did you install extra resistors in addition to Boomslang's or what?
I even tried using POTs and an oscilloscope to try to find the correct parallel resistance value but ended up bypassing the cam sensor intercept completely to get rid of the misfires.
well I put my resistors between the crk magi +/- and cam magi +/- wires .But i bought one of the first boomslang harness and mine did not come installed with the 2.2 k rersistors
ScionFred 08-14-2010, 12:28 AM well I put my resistors between the crk magi +/- and cam magi +/- wires .But i bought one of the first boomslang harness and mine did not come installed with the 2.2 k rersistors
The first Boomslang harnesses used both ECU connectors. I have one of the first 2nd gen harnesses that uses only one ECU connector and requires a fuse box tap to supply the FIC with +12V. Mine came with resistors installed near the ECU connectors. I believe Cory James has the very first gen 1 harness and IIRC his had resistors installed by Boomslang. Rustin told me that he's been installing 2.2K resistors on every Scion harness for years. Did Rustin confirm that your harness doesn't have resistors installed? Have you ever checked resistance across those circuits to confirm it? Which harness do you have? Gen 1 or 2?
Sorry for all the questions but I spent months trouble-shooting my harness and FIC and never found any combination of resistance that worked 100%. In the end I had to bypass the cam intercept to get rid of the misfires. I'm glad you found a solution that works for your car.
Rob_DESCENDANT 08-15-2010, 01:15 PM After a month of R&D between WORLD & AEM we found the solution to be tuning related. Although it was frustrating we've now got the pnp harness's to working fine on the Auto xB's & tC's we've done with our DESCENDANT Turbo Kit. AEM claims its all firmware...and will tell you 1.04 firmware works best without issues.
Turbocharging a 2011 as we speak...car drives no problems.
ScionFred 08-18-2010, 10:04 AM After a month of R&D between WORLD & AEM we found the solution to be tuning related. Although it was frustrating we've now got the pnp harness's to working fine on the Auto xB's & tC's we've done with our DESCENDANT Turbo Kit. AEM claims its all firmware...and will tell you 1.04 firmware works best without issues.
Turbocharging a 2011 as we speak...car drives no problems.
I wish my FIC misfire problems were "tune" related. That would have been a very easy fix. I tried 1.04, 1.07 and 1.10 firmware, FIC tuning, potentiometer controlled variable parallel resistance (signal/noise reduction) on both crk and cam magi and even used an oscilloscope to troubleshoot the problem. Bypassing the unnecessary cam intercept solved the problem for me. Never got a CEL for crk/cam timing mismatch even when delaying the crk signal by up to 10 degrees.
I'm glad that whatever you're doing is working for your customers.
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