2004 sportster le di CRAZY INJECTOR PROBLEM

[calebdavis96]

I have puzzled more than one mechanic with this, so I am hoping that someone can help me here.
I have an 04 sportster di that I picked up and replaced the motor. It turns over fine, has spark, but no start. I narrowed it down to fuel injectors not firing because there is no pulse signal; but if I put a little gas in the cylinders, it starts and then the injectors kick on and it will run from then on but will not start up again if shut off. Also, I added a new fuel pump. Thanks so much, ready to have this thing in the water!

 

[snikwad003]

Total guess here, metal shavings on crank trigger? That caused some weird issues on my car once.

 

[Dr Honda]

Yep... a weak signal from the trigger can do it. (look for filings on the pick up and magnet)


But... have you verified the air pressure?? If your air pump is weak... you may not have enough pressure at cracking speed to push that fuel out.

 

[calebdavis96]

So would that be the sensor on the front of the magneto cover? And I believe the air pressure is good because when I pull the injector rail off, a good amount of air blows out. Thanks for the replies guys, trying to get this boat right on a college budget would be impossible without forums.

 

[calebdavis96]

So would that be the sensor on the front of the magneto cover? And I believe the air pressure is good because when I pull the injector rail off, a good amount of air blows out. Thanks for the replies guys, trying to get this boat right on a college budget would be impossible without forums.

 

[Andy4k6]

Could be a connection issue on the starter motor, sounds odd but I have seen it on a van in the past. The bad connection causes spikes in the power to the ecu and it doesn't inject. It can only be seen with an oscilloscope but can cause all kinds of impossible to find issues.

Andy

 

[calebdavis96]

Thanks for the replies, but I embarrassed to admit that it was the fuel pump fuse. Even though the fuel pump was working before, as soon as I swapped the fuse it cranked right up. So for future reference, swap out all fuses first

 

[Coastiejoe]

Thanks for the replies, but I embarrassed to admit that it was the fuel pump fuse. Even though the fuel pump was working before, as soon as I swapped the fuse it cranked right up. So for future reference, swap out all fuses first

So the fuse was bad. BUT,, it was good if you put fuel in the cylinders???
I would think it was a good fuse with a bad connection and once it stared it got enough amps to get a good connection...

 

[calebdavis96]

So the fuse was bad. BUT,, it was good if you put fuel in the cylinders???
I would think it was a good fuse with a bad connection and once it stared it got enough amps to get a good connection...

Absolutely. It was a very odd fuse that said 32v so I replaced it with a regular 15 amp and it is good to go

 

[calebdavis96]

Yep... a weak signal from the trigger can do it. (look for filings on the pick up and magnet)


But... have you verified the air pressure?? If your air pump is weak... you may not have enough pressure at cracking speed to push that fuel out.

Sorry to revive the thread, but how much pressure should I get at the air pump? I started having the problem again intermittently. Thanks