Bulldog misfire

Energy One

RossDog

New Member
Hi all just new to this forum and hoping someone may know what this problem is:
Have a 2007 Bulldog EFI.
When i start the bike it runs rough, like a misfire. Checked plugs and replaced. The misfire comes and goes. Like electrical...checked compression and its ok on both pots. Im guessing it could have a bad coil or spark plug wires.

I also have an Ironhorse Chopper. They use a Iginitor that works the coils. Usually when the bike misfires or runs on 1 cylinder its most likely the ignition.

i have a shop manual on the bigdog but it doesn't give any ideas as to why the bike misfires on the front pot. The misfire comes in and out(both riding and on idle). i took the aircleaner off and you can see flames in the throttle body when it misfires. Any ideas.
 

BigDogBro1

Made in the USA
Welcome, Do an introduction to the forum members and get more responses.

In the meantime...It could be many things.

Start by searching the forum for more information.
EHC dielectric grease, clean out old and re-lube connector pins
Swap the horn relay with the power relay under left side cover.
Coil pack or plug wire or wire END in boot
Did you do a EFI RESET if you disconnected the battery cables? Can cause bike run idle rough.
Battery small wire good crimps and connections
Crank sensor
Loose or bad grounded voltage regulator
Loose connector wires
Bad battery...Bad battery...Bad battery
 
Last edited:

Jwooky

Well-Known Member
Chased down a mis that would only happen when hot for months. turned out to be plug wires. Cheap and easy to eliminate. Wish my buddy Tom(groundpounder) would have recommended to me.
 

Brew

Troop Supporter
Welcome from Washington State, hope you enjoy the site. Hope you get it figured out soon...:cheers:
 

BadDawg Bill

Well-Known Member
I would say plug wires. They get hot and break inside which then the spark has to jump and this creates a misfire. Other than that it could be your coil.
 

RossDog

New Member
Thanks again guys, just rode it today again. Bike misfires constantly from cold start to hot it doesn't matter. Changed plugs, checked coil and spark plug wires all good. The bike looses cylinder 1. It comes and goes like pulling the spark plug wire in and out. It drops the cylinder and the aircleaner (spiked) coughs. I looked at the plug and it seems dry like no fuel?? i had the injectors checked and they are fine. could it be electrical?
 

BadDawg Bill

Well-Known Member
Thanks again guys, just rode it today again. Bike misfires constantly from cold start to hot it doesn't matter. Changed plugs, checked coil and spark plug wires all good. The bike looses cylinder 1. It comes and goes like pulling the spark plug wire in and out. It drops the cylinder and the aircleaner (spiked) coughs. I looked at the plug and it seems dry like no fuel?? i had the injectors checked and they are fine. could it be electrical?
It could be the coil. You can get another one on Ebay cheap... Check the wires on and going to the coil to see if there is a bare spot and they are tight. You might also want to check the intake manifold gaskets you could have a leak in the #1 side.
 

BigDogBro1

Made in the USA
Buy New plug wires and install them.

You could try swapping the injectors with each other and see if the misfire problem follows over to the rear cylinder.

There really isn't a great fuel filter on the 2007 EFI Bulldog that will keep the injectors safe from debris in the fuel line. Although it does have a screen filter in the tank on the fuel pump that filter won't catch tiny particles that can plug an injector nozzle.
 
Last edited:

RossDog

New Member
Update, replaced EFI controller, crank sensor, coil, i have no spark the the number 1 pot.
There is 3 wires to the coil, red power, blue rear and the yellow front. the power wire works on ignition, the the rear wire tests ok and pulses. The Yellow has no power coming from the EFI controller. Its new. so my question is what gives the coil power, what powers up the yellow wire? the blue wire (rear pot) powers up but not the front yellow wire!
I thought maybe the crank angle sensor did it but its also new....any ideas?
 

Jwooky

Well-Known Member
Wow, you have thrown some expensive parts at it. Might want to step back and work on the diagnostics.

The chain is, crank sensor is an input into the VFI module. The VFI provides the signal to coil, coil fires plug.

If you have a new VFI, which is the source of the ignition signal, (confirm at pin 29 on VFI), and then you have no pulse at the wire to the coil, then there has to be an issue with that circuit.
 
Last edited:

BigDogBro1

Made in the USA
Both F&R coil firing signal wires operate the same way and if one (yellow) won't fire then trace back that wire thru all connectors to the SOURCE (ECM). Check ECM pins and connector end as well.

Make sure the voltage regulator is tight to the frame for GROUND and that it has external STAR washers on the two mounting bolts. The star washers go between the VR and the frame to make a good ground contact. We had a 4000 RPM miss because of this that took two years for find when we noticed the front chin spoiler was about ready to fall off. Tightened everything up with new star washers and all was good...no more misfire.
 
Last edited:

Sven

Well-Known Member
Update, replaced EFI controller, crank sensor, coil, i have no spark the the number 1 pot.
Replace old coil or ohm both coils so they match readouts. New or old is bad?

The Yellow has no power coming from the EFI controller.
Bent pin; broken off pin; female going into pin is I start at the female end [w/ohm meter] and work up to the next yellow junction to where? Switch? Coil? Wire harness? New box has zip out of pin/yellow I crank engine and have safety wire touching the female crimp inside the connector. This way the whole bike is wired up and I now check power at [back of female] prong; upon cranking engine over.

so my question is what gives the coil power, what powers up the yellow wire?
This is short and sweet are the steps:
1. Crank sensor makes AC.
2. The AC makes a square wave.
3. The crank idles and this is a long wave the crank comes around 360.
4. The low sweep past the magnet makes low voltage.
5. I'm going to make me some advance curves I use the word 'threshold.'
6. Past 2,000 rpm, I'm past a threshold of 2k = a voltage number put out.
7. This is now input all this time is for the processor to convert v to binary.
8. This is the language of the black box so the next key word is 'trigger.'
9. The fuck who's talking about 'Oh, Wilber' a horse hop along who?
10. The next word is 'discharge' all other voltages and hold this ign curve.
11. The next threshold is to trigger the next 360 degree is the next ign c.
12. The final threshold is to now set full ign curve via the crank speed.
13. I bring in the vacuum advancer or VOES off a harley, this now does it vac style. I gave you the backup/fail-safe/limp/check eng light; the VOES takesayshit say.
__________________________________________________
14. Now play wit me ass; go head. How do I find out if my processor is sequential or for the lack of I forgot the correct term of it, the last or the... turned obsolete is the multi-fire ignition.
15. This is now down to my yellow wire and if I fire with the other coil wire, then I am multi-fire. If I have my own, I forget the processing language, the parts inside, but I need my own room and my only connection is on/off is the threshold against the other spark it gets complex.
16. Which means I have an output side internally going to ground? Then I'd have a code, my intermittent is sure not part of a motherboard taking a shit. It's still wire in and wire out are the inputs and outputs inside that mboard.
17. But that is here nor there. I have to believe my yellow is going to light a bulb out of yellow prong I send in a thin safety wire into the back of the connector, ground the bulb to the frame and turn the key on; crank engine... home he does not need an ohm meter he be on the side of the road knowing his processor's in's and out's is brainwash use is withishit.
18. Basic computer diagnostics is know your square wave before throwing parts at it... neck time... you hang out the wallet for WATT???
 
Top