XFI with XIM, #1 showing 120 degrees on cranking...

eclipse5302 · #1 (**permalink**) 08-22-2010, 06:50 PM

Hey all, I'm new here but not new to tuning. I've been working primarily with HP Tuners and EFILive, but have recently gotten into XFI. Working on tuning a twin-turbo big-block Ford, but running into some issues.

This is an XFI with XIM, IPU-MSD crank trigger, modified factory cam pickup (also IPU / 2-wire). GM LS1 coils.

Crank pickup set at 50 deg BTDC, cam pickup set at 75 degrees BTDC (#1). Car won't start. Will sometimes backfire, has strong spark and the injectors are firing (can smell fuel).

Settings in XFI have been checked. I should be getting 35 degrees during cranking, however the balancer shows 120 degrees (steady - doesn't move around). I've got proper cam/crank lights on both boxes, and I've checked and double-checked everything I can think of...but can't seem to find the problem.

Any thoughts?

TurboNova · #2 (**permalink**) 08-22-2010, 08:05 PM

Have you looked inside the xim? Are the dip switches set correctly? Is the status light lit up on the xim? I am assuming that the cam and crank are wired to the xim? Is the coil firing order wired correctly?

eclipse5302 · #3 (**permalink**) 08-22-2010, 08:23 PM

The DIP switches were wrong initially and I wasn't getting any spark. Once 1-4 were turned off, then I would get spark.

The STATUS light on the XIM is on/flashing, and it turns off when I unplug the CAN cable.

CAM and CRANK are wired to the IPU inputs on the XIM, the discrete inputs are looped.

I've checked the coil firing order wiring again, and it's wired per the firing order for the engine (CYL - EST output --> 1-A, 5-B, 4-C, 2-D, 6-E, 3-F, 7-G, 8-H)

eclipse5302 · #4 (**permalink**) 08-22-2010, 08:35 PM

Correction: Apparently the timing is all over the place when cranking...not steady as originally thought. Continuing to crank more than a few seconds shows something interesting:

Using a timing light on cylinder #1 during cranking, it looks like it will spark ONCE per revolution (at 120 degrees) for 3 or 4 revolutions, then the fifth time it will spark TWICE in a row (numerous degree points), then back to once per revolution at 120 degrees for 3 or 4 revolutions, then twice...and on.

I'm certain I'm missing something obvious here...

TurboNova · #5 (**permalink**) 08-23-2010, 09:24 AM

The dip switches are set for sequential fire and not wastespark? Which coils are you running? The truck coils with the finned heat sync will not work, the dwell is not right and they will hit max duty cycle and fire random.

The status light should be on and steady, it is hooked into the XFI can and has the terminator plugs at both the XFI and xim ends? The dip switches are set for can and not standalone?

XFI has the crank connector looped?

eclipse5302 · #6 (**permalink**) 08-23-2010, 11:56 PM

Yes to all of the questions asked - they are car coils (no fins).

Figured it out though. Turns out that running the cam and crank pickup wires together, parallel along one side of the engine was causing the noise. I had suspected a noise issue, but with each pickup being shielded and the shields being properly grounded, I guess I ruled it out (too soon). Extending and then moving the cam sensor wire to the other side of the motor fixed it - timing is now exactly what it should be and it doesn't move. The engine started, however it's pretty fat right now. The fun begins...

I imagine that if the pickup wires were twisted (in addition to the shielding) this wouldn't have been such a problem.