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Discussion Starter · #1 ·
Big project - got an F4i engine from a guy, complete with wiring and computer. Putting it in a kart. I jumpered the clutch switch, kickstand switch, bank angle sensor, engine stop switch, and it will crank but no start. When I turn the key, the Engine Stop relay energizes and sends out power. The Fuel Pump relay won't click, but it's energized by the ECU. The FI/MIL light comes on steady, but doesn't blink at all, even with the diag plug jumpered. I compared this to my 900RR, but it's not even close, due to the EFI. Any advice would be appreciated. Also, any place to send an ECU to get it tested? I have two supposed "good" ECUs, both do the same thing. I need to see if I've wired it wrong, or bad ECUs. Would be glad to pay $$ for help. Any advice would be appreciated, thanks.
 

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I would check out all the relays and connections for the side stand, clutch, fuel cut-off, engine stop switch, etc. before I blamed the expensive ECU. Even with all those high-tech engine management items, you still have to resort to the old-school standard. Is there spark? Pulling a plug will tell you if you have spark and fuel. When you have spark, then move on to fuel. I don't understand that the fuel pump is energized but not pumping. The Haynes manual for my old CBR describes how to test the pump and relay separately, and all the other relays. Plus it has a good wiring diagram.
 

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The bank angle sensor;3 pin flat plug,jump the 2 outside wires togeather.There might be a anti-theft circut so you will need the key switch or the appropriate resistor in the lead wire. Also it may need the instrument panel to function,not sure on the F4i.

Hope this helps.
 

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GSXR750DJ said:
The bank angle sensor;3 pin flat plug,jump the 2 outside wires togeather.There might be a anti-theft circut so you will need the key switch or the appropriate resistor in the lead wire. Also it may need the instrument panel to function,not sure on the F4i.

Hope this helps.

Ding, ding, ding...many of these bikes look for a specific resistance through the ignition switch or instrument panel to start. Honda's in particular are also notorious about letting the motor turn over but not spark when the stop/run switch on the handlebar is off.

Also, as NW mentioned, have you pulled a plug to test for spark? are the plugs getting wet from the injectors firing (or can you see them spraying)?

Finally, what do you mean the fuel pump relay won't click when energized? Have you bench tested the relay to see if both sides are functioning properly?

Larry
 

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Discussion Starter · #6 ·
Thanks for the help!

I have jumpered the BA sensor jumpered as recommended. I jumpered the engine stop switch, the sidestand switch, the clutch switch and when the ignition is on, the Engine Stop relay is energized, sending +12 to the coils and injectors and ECU. The Fuel relay has +12 on one side, but isn't energized by the ECU on the brown wire, looking for a Gnd there from the ECU. My wiring diagram (Haynes) doesn't show an anti-theft ckt. There's two plugs for 3-wire O2 sensors, which I don't have connected, but I figure the ECU would throw a code for that. The ECU sends a steady Gnd out to the FI light on the blue/white wire, but it's a steady signal, no blinking. It's a 2002 motor, and a 2002 harness, and the harness has plugs for O2 sensors, is that for CA ? Thanks for all the help.
 

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In your first post you say "when I turn the key", does that mean you are using a Honda ignition switch for a 2002 F4i?

If not, I am going to guess, and this is only a guess, that this is your problem. Some manufacturers have a built in security circuit where the ECU looks for a specific resistance from the ignition switch (basically so it can't be "hot-wired"). Unfortunately, if it exists and what value it is looking for are usually not published or included in wiring diagrams.

I suggest either getting your hands on an oem ignition switch or seeing if you can have somebody test theirs with an ohm meter to see if you need to add a resistor to one of the circuits.

Of course, you could always temporarily jumper the fuel pump relay wiring to see if it will start...

Larry
 
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