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Discussion Starter #1
Hi there,

I have attempted to replace the wiring loom on my 94 Fireblade, with a wiring loom from a 96 Fireblade. The only difference I could see in the whole loom was that the 96 model has a throttle position sensor and no fuel pump.

That said, the throttle position sensor wires go to 3 unused pins on the ecu, other than that the loom is identical. The fuel pump and cutoff relay on the old loom appear only to take a feed off the feed to the coils. Other than that the two looms are identical.

However the bike won't start. Does anyone know if there is something in the ECU that could be scuppering me, will I have to put the old loom back on?

Kind regards
Rob
 

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When you say doesn't start, what exactly do you mean? What happens when you turn the key? Lights? What happens when you hit the start button? Does the starter turn?
 

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Discussion Starter #3
There was nothing going to the coils. everything else worked wonderfully, but no spark. I can't work it out.
 

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Discussion Starter #5
The 94 one. I think the 96 ecu would give problems because the 94 Fireblade has no TPS and the all three wires of the TPS go straight into the ECU.
 

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Other subtle differences in the 96 harness and ignition mapping (I believe the TPS provided more of a 3D map) may be the issue. Have you tried taking all the safety switches out of play? Or putting the kill switch to OFF, maybe the newer harness has some things reversed from 94? Like puffin the side stand down and swing if it gets spark?? If it's a spark problem I would start with the ECU as well I guess. All the pins are in the proper place for the 96 harness connector into the 94 ECU? I can't see the TPS killing spark of its not connected, but maybe inside the 96 ECU there is a connection internally from the TPS wires to the module completing a circuit for spark that the 94 ECU can't make. Do you have the 96 ECU?

The coils aren't going to matter, I have 99 coils on my 93. So you can rule that out. Do you have the coil primary leads from the loom on the coils properly? The wire with the color tracer goes to the coil lead with the colored collar. Other than that I'm pretty much out of ideas. ECU's are a mystery.
 

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Discussion Starter #7
Thanks for your input, Yes, all the pins did match, though I did notice on the actual ecu itself, that there is a pin on all the connectors on the ECU, I suspect that it might generate an error code if an extra wire is sensed. I really hoped it would go on, but it seems that even in 96 engine management systems were quite complex.

I have had to replace the old harness, I am now using the newer one to repair the old one properly, I don't like seeing cheap connectors and electrical tape on a wiring loom. Admittedly not everyone is aware of loom tape and how to crimp a connector properly. Also the starter solenoid was welded to the loom and had to be separated.

I hope it still goes, I have not had a chance to try it again yet, it got too late last night.
 

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I completely agree with you Rob. I hate hack jobs with bad tape, no solder, and colorful twist connections. If you get it fired up with the rebuilt loom be sure to post a couple pics of the work done and a couple shots of the bike. And don't forget to update the thread with the final outcome. Good luck!!!!
 

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Not sure when the sense diode was incorporated into the ignition switch, but it sounds very much like that.
I thought about that, but looking at the wire diagrams I thought it was a pink wire out of the ignition switch to the ECU. The wire diagram-for the U.S. Models anyway-didn't show any pink wire. Just the one limited to the speed sensor. UK models on the other hand could have it:idunno:
 

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Discussion Starter #11
Hi,

Well the bikes back together and it runs again, I decided to butcher the new loom for the chunk of loom that was really nasty on mine, and I have managed to get rid of all the nasty connectors on the whole loom and either replaced them with motorsport waterproof connections, or the original connectors are back on with the help of some soldered an heat shrink wires.

I don't have any before pictures which is a shame, but here is what I have done compared to what was on the bike. So the pics I do have are one of the bike from it's good side, a couple of pictures of what came off, ugh, revolting, and a couple of what I have put back on all around the regulator rectifier and starter solenoid, I had to re build as it was just single wires hanging out of the rectifier. On the picture from above, the three alternator wires are securely crimped with proper crimps and insulated, through I have also would some loom tape around just to make sure no moisture can short between them. This is usually a 3 block connector but I was not able to track one down that could deal with ampage of more than 2 amps, which is annoying. There is also a disconnected plug, this is for the fuel pump which currently needs some new points and has never actually been connected but was always wired in. This bike has been somewhat butchered, but hopefully, new exhaust , second hand rear shock and repaired wiring loom later, it should start to be a nice bike I can rely on again.

I have finally found out that my main problem now is that the alternator has given up the ghost, with engine off, reads 12.6 V with engine running, it shows 12.5 V. Have tested for continuity through the three phases of the windings and there is no resistance between any of the windings and no resistance to earth from any of the windings. Unless anyone knows an obvious thing here, looks like I will have to bite the bullet as I just charge my bike up every other night at the moment so I can get to work.

Thanks for all your input yesterday.
 

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Well done Rob!!!! Glad you got her back together and running!!!! You can also check the stator while its running for AC voltage out of each leg. I think the magic number is like 50VAC from each yellow. It may be that aftermarket Chinese looking reg/rec that could be the culprit for the non charging issue. Also, in regards to to the stator 3 pin connector. If you're really after the factory look eBay sells them, as well as them being offered from Honda as a repair kit for older gold wings. They are abundant here in the states right from Honda. Here's a pic with the part #:



Again, great job getting her running and breathing new life into her veins (or wires):rotfl:

PS- The solenoid part of the harness, you're right what a HACK job! YUCK!!!!
 

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Discussion Starter #13
It is unfortunately my commute bike and basically the British winter and the salt that's put down on the roads had it's wicked way. Actually, the reg/rec is Electrex, a very reputable company over here. And funnily enough they are made not 10 miles from where I currently (no pun intended) live, it was replaced about 3 months ago. But I don't think it was the problem, I think the alternator went, and I have been in denial about it every since.

One last question, the alternator side of the bike, can I take that cover off without draining the oil? As I would like to have a look at it to see if there is anything obvious going on.
 
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