Which FIC for 2008 Scion XB?

[fred_ pohl]

I'm having crank sensor problems with my 30-1910 FIC/6. I'm using a Boomslang harness which came wired per AEM's latest instructions with the crk magi- and cam magi- tapped and with 2.2k resistors installed between the crk and cam input leads. I tried intercepting the crk magi- and that didn't help. I also tried using no resistors and 4.7k resistors.

I know that AEM hasn't validated the FIC for my car yet but is it possible that the 30-1911 might work better with my sensors? Any other suggestions?

The car is completely undriveable with the FIC installed due to the crk sensor issues (P0335) but runs great with the bypass harness installed. The FIC has all maps zeroed except for the MAF map which I programmed for zero voltage changes. TPS and rpm were calibrated. The engine will start, idle, rev but can't be driven more than a few hundred yards before the P0335 comes on and the engine stalls, revs up and down, AFR goes 10:1 rich and I have to coast back home.

[Elevationtc]

There has been sucsess with using the fic-6 on a xb2 platform

Sounds like you have a problem with your harness or your fic! Have you checked any scion xb forums to check and see what others are doing? There are companys like decendant world racing that make kits usuing the fic!

Maybe you should contact them and see what your doing wrong!

Good luck and let us know how it turns out!

[fred_ pohl]

The problem seems to be with the Boomslang harness. Dezod, Descendant, myself and others have not been able to get any 1910 FIC/6 to work with the Boomslang harness. Dezod has tried 4 FICs and I've tried 2. The only exception is Cory James who still gets an occasional P0335. Descendant claims to have found a wiring fix for the harness but won't share it. For all I know, they may be simply tapping the +crk signal and bypassing the FIC's ignition timing control. This works but is far less than ideal for a boosted application.

The Boomslang harness is correctly wired per AEM's latest wiring diagram and works great with the bypass harness. The 1910 FIC simply doesn't work with the Boomslang harness and no one has been able to figure out why yet. I really don't know what Dezod, Boomslang, myself and others are doing wrong by following AEM's recommended wiring diagrams.

Thanks for replying.

[Elevationtc]

Can you suply me with the scion xb pinout?

And if there doing that they will loose timing control. Set me up with the pinout. Ill check things over. Ive made tons of harness's including one for a standalone in a scion!

[fred_ pohl]

Can you suply me with the scion xb pinout?

And if there doing that they will loose timing control. Set me up with the pinout. Ill check things over. Ive made tons of harness's including one for a standalone in a scion!

I need to correct some things I said previously. I just spoke with Rustin at Boomslang again and Cory isn't the only XB2 using their harness and 1910 FIC successfully. He said there were a few more that either hadn't reported problems or only had intermittent P0335 codes. Also, Cory corrected me about his P0335, he only got it once and has no issues with his harness. OTOH, Dezod tested four 1910 FICs, several harnesses and had the same problems that I've had. Descendant tested 6 Boomslang harnesses and none of them worked for them with the 1910 FIC.

In my case, I have two 1910 FICs, one new, one used. The new one doesn't work at all and the used one works a little but throws P0016 and P0012 codes, revs up and down at times, stalls and hesitates badly in open loop. I also have a 1911 FIC (courtesy of Boomslang) that doesn't seem to have the crk sensor issues but has cam sensor issues (P0340) instead. At this point my best guess is that the crk and/or cam sensors on the XB2 are right at the limits of the 1910 FIC. This might explain why it works for some and not for others. If the problems were in the harness wiring, why would the harness work 100% with some FICs or with the FIC bypassed?

If you want to take a look, I'd appreciate it. You might find something that Boomslang and Dezod are missing.

[fred_ pohl]

Update: The 30-1911 FIC/6 works like a charm with my 08 XB but only with the cam magi/mago disconnected. I disconnected the cam magi wires and re-wired them as harness pass-thru. So the 1910 doesn't work with my crk sensor and the 1911 doesn't work with my cam sensor. Looks like what I need is a modified 1910 with the 1911 crank sensor electronics.

Update #2: The ECU wouldn't go into open loop on acceleration with the 1910 (z104, z107) or the 1911 (z107). The afrs just went crazy lean and the engine bogged down badly. So I flashed the 1911 to z110 tonight, tested it and the ecu went into open loop when it should and with the expected ~11:1 afrs. I'd be very happy about that but it also threw a P0335 and I couldn't even drive it home without pulling over to remove the FIC and install the bypass harness. AEM has assured me that the slave firmware only affects fuel so wtf is going on here? Apparently I need a modified 1910 and new firmware to make this work. Again, the Boomslang harness works flawlessly with the bypass harness and all the problems appear to be caused by the FIC/6.

HELP!!!

[fred_ pohl]

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 pwr source for the FIC.

Sorry AEM. The fact that the engine ran fine with the FIC bypassed lead me to blame the FIC and I didn't check all of Boomslang's wiring until now.

Edit: Just wanted to add that my FIC logs confirm the loss of battery voltage. Apparently the FIC can operate on 5v from a PC connection but not very well and only at light loads. With no PC connected to the FIC, it shut down completely when the 12v pwr was lost and the car was undriveable.