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Starting Issues - No spark, no firing

Old 08-25-2018, 09:00 PM
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Join Date: Aug 2018
Location: Seattle/Portland, USA
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Lightbulb Starting Issues - No spark, no firing

Hi all! New to the forum, been lurking for about a year.

I have an F4i (F4 with a 2002 F4i swap), that is not firing injectors or sparking.

The bike has not been running for a month. Started when I rolled out and cranked but did not start due to no priming. Took it in and traced the issue to the yellow service connector on the left side harness, the fuel pump ground was fried inside.

The connector looks like this, with the same wire fried (this pic is pulled from a RR forum, same connector though). Spliced this into a separate ground on the same connector - fuel pump primed now.

Cranked it again and no start. Turned off the bike and turned it back on, but this time more issues. No headlights, no taillights, no turn signals, no priming. The only thing running was dash, so I traced it down to the ignition kill switch. Swapped for another and everything comes back on.

However, the bike doesn't spark, nor does the injectors fire. It's still getting strong priming and the entire fuel system is pressurized. I've tested only a few things - I haven't picked up a peak voltage adapter yet, but I've determined BAS, and most of the other items for safety (kickstand, clutch, neutral switches) are good.

I've read the codes off of the ECM - reset and ran everything but its a solid light (no blinks), so that only lands an ECU issue.

Before I buy another ECU, is there any other chance something is wrong that I've missed? I am hesitant on buying an ECU for this as the cheapest I've found is $400usd. Also, if anyone is in the Portland OR area, I'd appreciate it if i could test my ECU with their bike. There doesn't seem to be any other active owners of CBR F4i's around here...

Old 08-28-2018, 10:42 AM
tentacleslap's Avatar
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Join Date: Oct 2013
Location: Calgary, Canada
Posts: 485

Ouch. I'm not an expert on electrical diagnosis, but it sounds like you've taken a systematic approach. One thing I would add is that before putting a fresh ECU on it, you'll want to do a careful inspection of any of the wires that are on the same common ground. That kind of heat can cause embrittlement and other continuity problems. A probe will be your friend. Make sure the ground-to-frame contacts are clean and tight. A $400 part hurts, but not as much as two $400 parts

Also, it goes without saying that the fuses are good, right? I'd bet you've popped a few to get this far

Good luck and good diligence
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