dfi gen7 code 66 HELP! lots of info in post

[ed hess]

1st of this is not in a buick so the msd numbers wont be the same as used here.

dif gen7 with the latest upgrades to the ecm.

code 66 Ignition output driver over
current
Driver current exceeds 2.5 Amps MIL set, shut ignition off

in an attempt to resolve this

tried:

2 msd digital 6 boxes

1 msd 6a box

ran a complete new wire for the blue est circuit from the dfi box to the msd white wire.

msd boxes are installed exactly as per msd instruction.

msd box is mounted on pass side floor using rearmost seat mounts ( seat no longer there). msd box used to be under hood and we moved it inside. same failure occured with borrowed know good proven 6a box mounted inside.

dfi box is mounted in pass front corner to A pillar bar of cage.

2 coils swaped, terminal is mounted vertically and grounded properly

the only thing remaining on the cirucit is the factory tach.

of course the next thing to try is disconnect the tach.
skeptical at this point if this will resolve the problem

failure occurs most often in a burnout. burnouts hit 8k.

havent datalogged burnout or 12v+ duing a run but last night at the 1-2 shift at 8k rpm (this is the shift point for the combination, not a typo) it shut off.

past failures during a burnout we didnt attempt to make a pass, last nite i did.

when it fails you simply clear the code and fires right back up.

on rarer less frequent occasion will have had it shutoff at idle. most often without a code occuring. only 1 time did it code from idle.

so far accell hasnt been able to help.

so anyone here had any expereince chasing down a code 66?

even the remotest idea or possibility would be greatly appreciated.

thanks in advance
ed

 

[norbs]

Disconnect the tach, its worth a try. You made a typo it overcurrents at .25 amps not 2.5 amps. The tach could have issues at 8000 rpm. , but if the tach output is through the msd box it shouldn't matter, but try it anway

 

[Craig Smith]

Actually the latest version of Gen 7 firmware allows 2.5 amps of driver current on the ignition output. Not a typo.

The output driver is hurt. At some point something got a hold of it. Not sure what but it certainly seems to me that the driver has been compromised. It is also possible that another component in the current detection circuitry in the Gen 7 has developed a problem. Even a cold solder joint could do this. It should be an easy thing to check out for them, there are only a few parts in that circuit and all sorts of stuff to load test it.

 

[ed hess]

Actually the latest version of Gen 7 firmware allows 2.5 amps of driver current on the ignition output. Not a typo.

The output driver is hurt. At some point something got a hold of it. Not sure what but it certainly seems to me that the driver has been compromised. It is also possible that another component in the current detection circuitry in the Gen 7 has developed a problem. Even a cold solder joint could do this. It should be an easy thing to check out for them, there are only a few parts in that circuit and all sorts of stuff to load test it.

craig

thanks for the input.

I am going to try a known good borrowed box as well as disconncet the tach( move tach to tach output on msd box).

craig, are you the same craig that used to work at accel dfi?

ed

 

[Craig Smith]

That's me.

Where is the tach connected right now?

 

[ed hess]

That's me.

Where is the tach connected right now?

the tach is still on the est circuit, same as it was on oem setup.

ed

 

[ed hess]

the tach is still on the est circuit, same as it was on oem setup.

ed

nope not anymore... tach is now on msd box tach output.

going to run it on borrowed gen7 box tomorrow.

ed

 

[ed hess]

craig hope you see this.

went to track with borrowed ecm. same thing happened.

we now have 2 datalogs showing the shutdown.

1 is during a burnout.

2nd is during a 60ft.

both of them show 12v ignition dropping to from 13.1 to 12.4 and then shutdown.

alternator was swapped out earlier.

I'm being told battery needs to be changed out.

at what point does the dfi say voltage is to low for all drivers to compensate and have enough for their respective circuits.

burnout shutdown occured at 8710 rpm

60ft shutdown occured at 6600 rpm.

for the 60ft we had disabled the gen7 rev limiter and used a 8600 chip inn the msd box. to rule out the rev limiter as the cause.

at what point does the dfi say voltage is to low for all drivers to compensate and have enough for their respective circuits???

ed

 

[Craig Smith]

So you have shotgunned every single part in the circuit and it STILL does it???

What are the firmware versions of the ECMs you have, and what are the latest upgrade dates?

I don't think it's a voltage problem. Driver circuit current actually decreases as ignition voltage decreases because the ignition box runs off of ignition voltage.

There is something specific I am wondering about but I will not post it here right now. Please tell me the firmware versions and revision dates from the serial number sticker on the back and we will proceed from there.

 

[ed hess]

yes each and every part has been swapped out and yes it still does it.

both ecm's are version 5.1

ecm used this past sunday revision date: 10-26-05

other ecm revision date: 2-13-06

fwiw the ecm with 10-26-05 revision date I just sold to the guy i borrowed it from.

ed

 

[ed hess]

looks like i may have gotten lucky.

just for grins i hooked my msd tester up figureing to let the existing 6al box run on the tester at 8k rpm for awhile.

hooked it up, turned the dial and only a split second of spark. I notice the tester would keep going thru its text boot up procedure. 2x checked my connections.

seemed like something was shutting it down and then allowing it to restart.

for the heck of it i disconnected the wire that goes from my flaming river shutdown switch no fr1013 to the white wire on the msd ( the other side of this switch goes to ground).
the dial was still on when i unplugged the shutdown switch.
and darn if the msd tested began making spark instantly and continuosly.

left it on at 8k rpm while i called flaming river. got off phone reconnected shutdown switch wire and it kept working. seems like i got lucky at the right time and found a intermittant failure on the EST circuit (white wire).

so installed a new shutdown switch and going to the track thursday nite to see if we can put up a number to take the title of worlds fastest syclone.

btw, fwiw the truck will be in the november issue of gm high tech magazine.

if you dont hear back from me, in this thread...safe to assume this was the cause.

ed

 

[Craig Smith]

Well, it's good to hear that the problem is likely solved. Solidly grounding the points wire on the MSD box would definitely do it.

Good luck at the track. May I suggest that if you need a hard shutdown switch like this, rather than grounding the input of the MSD box to kill it you use a switch that opens the input to prevent triggering the box. No chance of damaging anything this way.

 

[PHANTASM]

had the same code in my mustang and sent it back to accel.

said the driver was burnt out in the box. pretty common when some one hooks up the trigger wire wrong for the coil.

you must hook up the WHITE WIRE form the aftermarket cd box. most are this color.

tech at accel looked up the diagramfor what ignition i was using and faxed it to me.
turbo people(job spetter) are also good to ask that question to.