I am working on a 954 engine for a go-cart application. I have gone through the wiring at least 4 times and everything seems fine. The wiring diagram iseasy to follow until it reaches the blackbox ECU. All the components of the system check out fine....ignition switch, key switch, bank angle sensor, fuel relay, engine stop relay, etc....basically everything in the start sequence. I am getting a malfunction on the indicator. It stays lit and does not blink. 12v goes to the engine stop relay so there is no problems with the switches, fuzes, etc. I also show 12v to the fuel cutoff relay but the relay is not pulled in. It shows power to the coil of the fuel cutoff relay but the other wire goes to the ECU. Therefore, it is my assumption that the ECU is preventing the coil of the fuel cutoff relay to pull in.

What is preventing this??? I have heard that the key switch of the 954 has a zener diode in it to act as a Theft Deterrent Device. I ordered a key switch for a 954 and it did not solve the problem. I read where this diode is supposed to send 9.2v to the ECU by means of the pink wire labeled "fan". This is to act as a theft deterrent device to make it harder to steal the bike than just crossing the ignition wires. I am showing 12v out of the pink wire on the key switch instead of the alleged 9.2v that is supposed to be there. Does anyone know about this key switch or have any ideas on what else to check. I want to try everything before I breakdown and buy another ECU because I doubt that it is bad.

Thanks.

 

"It shows power to the coil of the fuel cutoff relay but the other wire goes to the ECU"

what happens if you ground the wire going to the ecu??

 

It pulls the coilwhich allows 12v to go to the pump but that is nota bandaid I want to pursue. Something in the ECU is not lettingtheBr/Bl wire ground out and pull the coil. Something isinterlocking it out and I do not know what it is.

 

it is not a bandaid if you are trying to figure out if the engine will run,if it does-then you can rule-out a ecm problem(atleast 90% posibility)
is the relay even good??have you tried jumping that??

 

I tested all the relays and they aregood. Do you know anything about this reduced voltage through the pink FAN wire to ECU?

 

i cant find any info on it,other than what you already know-i would rec searching through the 929 section
does the engine crank?

 

Alright, I have gone through everything AGAIN and it comes back to either the ECU or the theft device on the key switch. I need help!!! I can get the fuel pump to run when I ground out the Br/Bl wire. I can crank on the starter but there is no spark because, yet again, the ECU controls this. Any ideas on what is locking the ECU out?? I have covered everything on the wiring diagram as well as on the fuel pump system diagram on the start of chapter 5. Please help!! I am losing my mind on this one.

 

hang in there bro!!,
i would rec-double checking tip-sensor circuit(i am assuming it isfor fire prevention,in case of roll-over!)try jumping the circuit in a different setting then what you have it at now!!
if you have already done this-try talking to a dealership tech-explain that this is for a kart(dont threaten their business!)there has to be info that is not available to you
please keep posting,as i am very interested on the out-come

o8

edit-i have not seen or been able to find any info on a theft device system-IDK!!,a honda mc tech should know this!,the owners manual suggests that the key just has to fit into the cylinder-off you go!!!-sorry that i have not been able to help you more!
o8

 

I am hopefully going to have some time this week and this weekend to look into this furthur. I bought an ignition switch off ebay and it looks like some of the part numbers were filed off so I got taken on this. The 3rd wire that connects to the pink wire sends out 12v when tested but this will do that if the diode is fried. I plan to tear down the switch tomorrow to see what kind of diode, resistor, etc that might be in there. From reading a lot of forums, I am leaning toward that the ECU needs a certain voltage through the pink wire for it to work. I have 0-10v analog output on a piece of equipment I am going to borrow for a couple of days. Hopefully I can find the right voltage to trick the ECU.

Another guess on the problem not finding the answer is that these forums delete any entries that tell exactly how to override the theft device. I just hope I am heading down the right path to get this motor going. I will keep you posted.

 

So anyway, I still have the same problem. I bought a keyswitch off ebay and there was no diode/resistor, etc. It was a plain old keyswitch. I hope that the guy had it listed correctly when he said it was a 954. I also tried to vary voltage to the ECU through the pink wire by using a variable dc voltage supply. I could not get it to prime or anything. Does anyone have any ideas?