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[mrmagloo]

On my '06 SEUC I've had problems with a hard start and backfire if I don't hit the start button immediately after flipping the kill switch to on.  If I do it quick, it starts just fine, but if I let the fuel pump fully prime, it starts real hard, backfires and it seems clearly very rich. I tried some injector cleaner, and that didn't help. I also tried cutting the start up fuel on the power commander, and that helped a little maybe. I'm also been trying to chase a ping in between 20% and 40% throttle in between 2,000 and 3,000 rpm, and backing off the timing a couple of degrees and  richening it up about 10% didn't solve it. I did notice while changing the plugs, the rear cylinder is running rich, but the front is perfect.  As such, I'm starting to think I've got a bad injector.

In researching this, I saw that there was a change mid-year from the 8 degree to 25 degree injectors, that solved some erratic issues, and I'm wondering if anyone knows how to ID what you have? Also, if I find I have the 8 deg and I switch to the 25 deg, will I have to get another tune? Or won't that matter much?

Any insight would be appreciated.

[grc]

M1185 is the service bulletin related to the change to the injectors.  See attachment.


Jerry

[tazmun]

M1185 is the service bulletin related to the change to the injectors.  See attachment.


Jerry

Looks like they changed the 88 cu/in to the 103cu/in, nothing new on the 103!

[mrmagloo]

M1185 is the service bulletin related to the change to the injectors.  See attachment.


Jerry

Thanks Jerry - turns out that I do have the 25 degree injectors, so I must have one that's not quite sealing correctly.

[lonewolf55]

Some of the older PC's took the power from the fuel pump circuit. That's why it starts before the pump shuts off. Check with Dynojet or Fuelmoto because I think there is a fix.

[mrmagloo]

Some of the older PC's took the power from the fuel pump circuit. That's why it starts before the pump shuts off. Check with Dynojet or Fuelmoto because I think there is a fix.

I believe one of the past firmware updates dealt with this. I'm updated to the latest, so I believe this takes the PCIII out of the equation, I think?

BTW - I think a stock Harley will start before the fuel pump stops the prime, no?  I know I can start my Deuce quickly too, but then again that has a PCIII too. However, that starts perfectly.

[Midnight Rider]

Can you just unplug the PCIII and take it out of the loop?  That would at least let you know for sure if it's the PC and is simple to do.

[mrmagloo]

Can you just unplug the PCIII and take it out of the loop?  That would at least let you know for sure if it's the PC and is simple to do.

Hey, that's a good idea!  When I saw the rear plug indicating rich, in my mind I eliminated the PCIII, but what could it hurt?  I'll give it a whirl.

[mrmagloo]

Some of the older PC's took the power from the fuel pump circuit. That's why it starts before the pump shuts off. Check with Dynojet or Fuelmoto because I think there is a fix.

As an update, I did talk to the Dynojet folks and they don't know about a fix, but did offer a bandaid of sorts.

He said that I can take that 9 volt adaptor, cut the battery connecter off, and simply wire that to the switch power of the bike at 12v.  He says this is a common issue with a percentage of bikes in that when the fuel pump stops, the power to the PCIII is cut-off and the PCIII has to wait to start up again to tell the injectors to act.

Now, this doesn't make much sense to me as I'm certain I'm getting too much fuel when this happens, so I would think that the bike turning over without fuel would cause just the opposite condition than what I'm experiencing. 

Also, while it is cured almost 95% by a quick start, this will occur frequently if I wait a second, but still while the fuel pump is running, so I dunno.

Frustrating as hell.  The bike seems to start fine no matter what if I bypass the PCIII.

[Midnight Rider]

As an update, I did talk to the Dynojet folks and they don't know about a fix, but did offer a bandaid of sorts.

He said that I can take that 9 volt adaptor, cut the battery connecter off, and simply wire that to the switch power of the bike at 12v.  He says this is a common issue with a percentage of bikes in that when the fuel pump stops, the power to the PCIII is cut-off and the PCIII has to wait to start up again to tell the injectors to act.

Now, this doesn't make much sense to me as I'm certain I'm getting too much fuel when this happens, so I would think that the bike turning over without fuel would cause just the opposite condition than what I'm experiencing. 

Also, while it is cured almost 95% by a quick start, this will occur frequently if I wait a second, but still while the fuel pump is running, so I dunno.

Frustrating as hell.  The bike seems to start fine no matter what if I bypass the PCIII.

So by that I assume you've determined that it's definitely the PC and not an injector issue?

[mrmagloo]

So by that I assume you've determined that it's definitely the PC and not an injector issue?

That's all I can think of. If the bike starts fine bypassing the PCIII, whether I quick start, or wait 2, 5, or 10 seconds, and Dynojet says they recognize this as a common issue, I can't see the logic of buying new injectors at this point?

[sadunbar]

That's all I can think of. If the bike starts fine bypassing the PCIII, whether I quick start, or wait 2, 5, or 10 seconds, and Dynojet says they recognize this as a common issue, I can't see the logic of buying new injectors at this point?

It's a reasonable conclusion...