ScionFred

iTrader: (1)

Boomslang followed AEM's new crank and cam wiring instructions but still added resistors between the + FIC input and - signals. I wonder if that's the problem? I'm guessing that most of the people running the resistor mod are wired the old way.

coryjames

so how do they have it wired cause the resistor used to go between the neg and pos if its just a one wire tap what did they do

Rob_DESCENDANT

hey guys...just wanted to give an update on the harness issues...

after reviewing the boomslang wiring diagram & our original DESCENDANT patch harness diagram we have found differences. Once I made the changes to the boomslang harness I was able to eleminate all check engine lights, stalling issues & irregular tach signal.

I will be talking to Rustin at Boomslang Monday & figuring out how we go about working out the problem.

coryjames

i have a boomslang harness wonder if you guys got a bad batch cause i dont have the problem what wires were crossed?

ScionFred

iTrader: (1)

They intercept the + crank and + cam wires from the oem harness. tap the - wires and add resistors between the + and - wires to reduce the signal voltage sent to the FIC. On the FIC output side, they just run the + crank and cam wires to the ECU.

According to Boomslang they have always wired Scions this way instead of AEM's older wiring instructions to intercept the - wires. They say they will call me as soon as they have a fix.

It's odd that every XB2 owner I know of who wired their own FIC followed AEM's old instructions and none of them seem to have any problems. I'm sure that all the TC guys also used AEM's old instructions. I hope they get this fixed soon.

ScionFred

iTrader: (1)

Great news! Thanks Rob.

Rob_DESCENDANT

solution coming soon brother...

coryjames

whats the fix and i wonder why mmines not affected

Rob_DESCENDANT

The fix for us was cutting open the boomslang harness & using a different diagram to wire up the FIC. Not sure why yours would be different unless you are maybe running a earlier model of fireware or something but all 6 boomslang units I have here have shown the same check engine light problems & tach problems. After preforming the modifications to the boomslang harness we have had no issues with the car we tested it on.

ScionFred

iTrader: (1)

I got my harness back today. Boomslang changed the - crank from tap to intercept and left the - cam tapped. I just tested it and the car started fine, idled fine but died about 200 yards out of the driveway. P0335 cranksaft position sensor "A" circuit malfunction. I pulled the freeze frame data and the most notable exception is that the rpm was 0 at 27mph.

FAIL #2

Also, this is a minor gripe but for $500 I wish they had included some of the aux FIC wiring. Originally all it had was UEGO input and user switch input. They used the user switch input wire to rewire the crank gnd so now all I have is the UEGO lead. I'd like to have the user switch input for dual map switching, +12V out for water/meth trigger and aux A and B in case I ever need them. I can add them but IMO they should be included.

crush02342002

iTrader: (2)

^^ amen brotha, preach it.

ScionFred

iTrader: (1)

At this point, I'd be happy to go without the extra $1 worth of wiring just to have it work at all. It's not all Boomslang's fault though. They wired the harness exactly the way AEM recommends. It's just not working with AEM's ____ty crank and cam signal handling and AEM has done nothing to rectify the single biggest problem with their FIC. Aside from user ignorance, the single most frequent FIC problem I see is with the FIC screwing up the crk and cam signals.

ScionFred

iTrader: (1)

I finally got around to checking more than the crk and cam sensor wiring on the Boomslang harness. They tapped the FIC +12V off the secondary O2 heater circuit. According to Toyota the ECM controls this circuit based on engine coolant temp and load. This would explain why the engine died everytime it saw high load. The FIC was losing power. This probably explains the crk and cam signal problems also. OBD2 freezeframe data for the P0335 shows 0 rpm with the engine running. The FIC lost pwr and the ECU lost it's crk signal.

The original Boomslang harness included the second ECM connector (A36) and tapped FIC pwr from it. I have the second revision harness with only the B33 connector. The only other XB2 I know of that isn't having problems has the original design harness with B33 and A36 ECM connectors and a reliable 12v pwr source for the FIC.

I just checked my FIC logs and lo and behold, the battery voltage drops to zero after the O2 sensor warms up. Gotta test and confirm it but I think we have a fix.

paul_dezod

Keep us all posted

ScionFred

iTrader: (1)

Okay, I finally got around to testing my theory and it is now proven. The 2nd rev. Boomslang harness does not, will not and can not work with the FIC pwr tapped off the #2 O2 heater circuit. The #2 O2 sensor heater circuit is controlled by the ECU and the ECU does cycle it on and off. This is the cause of all the problems. IMO there is no suitable circuit on the B33 connector to tap FIC pwr from.

There are several good locations on A36 and 3 ign switched fuse locations in the main fuse panel next to the ECU. I tapped off the 7.5A 'IG2 No. 2' fuse. The other ign sw fuse locations are 'EFI No.1' and 'EFI No.2'. I've yet to see a low-profile mini ATM fuse tap so I made my own using a standard mini ATM fuse. It fits but sticks up a little however there is plenty of room under the cover for it.

Now I just have one new problem. Misfire codes. I'm still working on this and will post back on it.

*UPDATE* The ign switched fuses are not useable for FIC pwr. Tapping EFI #1 or IG2 #2 yields misfires. Tapping EFI #2 yields a P0031 for primary O2 htr circuit low. I spoke with Cory about this and he had similar problems when tapping a 2-step off any of these 3 fuses.

*Update* The misfire codes were coincidental to the FIC pwr tap location. EFI No.1 is the same circuit that provides pwr to the ECU through 1(a) and 2(a) on A36. Tapping FIC pwr off this 10A circuit works great.

tainoxl

Hey scion fred use this to tap for power;
28(a)IGSW , Black wire , Ignition Switch on A36 connector

tainoxl

These are the pinouts for the fic your harness should either be taping or intercepting.

Harness connectors are B33(b) and A36(a)


Terminal No(Symbol) , Wiring Color , Description
105(b) N04 , LG , Injector 4
106(b) N03, G , Injector 3
107(b) N02 , Y , Injector 2
108(b) N01 , V , Injector 1

122(b)NE+ , W , crankshaft position sensor
121(b)NE- , B , crankshaft position sensor

99(b) G2+ , R , camshaft position sensor
98(b) G2- , G , camshaft position sensor

118(b)VG , V , Maf sensor
116(b)E2G , B , Maf sensor

112(b)A1A+ , B , Air Fuel Sensor(primary 02)

115(b)VTA , LG , TPS sensor

44(b)E02 , W-B , GND(pwr)
46(b)E04 , W-B , GND(pwr)
86(b)E03 , W-B , GND(Sig)
28(a)IGSW , B , Ignition Switch[table]

ScionFred

iTrader: (1)

Thanks! Now if I only knew how many amps the FIC really draws. According to AEM's manual, it can draw up to 7.7A before tripping the overload circuitry but I'm sure the normal draw is much less. 28a looks like a great tap except that it's one of the low-current circuits (7.5A fuse, 22ga wire, small pin). After all I've been thru with this, i want to be 100% sure that the FIC always has a steady, adequate power supply.

Boomslang originally tapped FIC pwr from 1a (A36, 10A fuse, 18ga wire, large pin) and that seems to work but I traced it back to the EFI No. 1 fuse. When I tapped that fuse I got misfire codes but even when tapped off the battery, the engine still misfires (just no codes yet?). I may just install a relay taking +12V from the battery and trigger the relay with 28a. It's probably overkill but at least I'll never have to worry about the FIC causing problems due to inadequate power.

tainoxl

? I have been runing my fic hardwired to this pinout location with no issues. So have others I assure you no issues with powering the fic from there.

ScionFred

iTrader: (1)

Okay, you're right. AEM says that the FIC only draws ~2A so 28(b) should be fine as long as you don't use the FIC's 12V output or if you do, it's only for a relay. I may use it or I may use 1 or 2(b) which appear to be the main power supply circuits for the ECU. I might even use a battery powered relay switched by 28(b) so I could power up to 6A off the FIC output (UEGO, etc.)

Unfortunately I haven't done anything for the past few days because of work and lousy weather.

Thanks again for the very useful suggestion.