04 Mastiff-No spark, changed Cam sensor May be Bad EHC- Advice Needed

[Escobar]

Hi guys, I could use a little help trying to trouble shoot my bike. Took it out a couple days ago and the other day I wanted to go for a ride, It just wouldn't fire. I originally thought it was cam sensor that wasn't allowing the Thunderheart to recieve a signal because the red light on the module wasn't blinking. I changed the sendor out and still it wouldn't fire. started to look deeper and checked the coil and then the EHC.

At the primary side of the coil i don't have voltage on either side and when checking the resistance it appears to be fine as it reads 3 ohms across both sided with key off, and 14.9 K Ohms at the secondary or end of the plug wires.

Started looking into the EHC and when checking the voltage i get 12.65V from the Battery but only about 9V to the Thunder heart, 0 V to the Coil and my headlight won't even turn on (10V). Does anyone know if the 12V should be distributed throughout the entire electrical system or the voltage drop im seeing from the EHC is normal.

Is there anything else I could do that would help me determin what is wrong this this Mutt. I leaning heard towards the EHC but don't understand why it would just crap out on my like that.

Thanks!

 

[Escobar]

I forgot to mentionthat when i turn the key on, the yellow "Main Power" light on the EHG comes on but when trying to crank the bike it turns off while its turning over. When I let go of the start button it comes right back on. I measured the battery voltage while cranking it and noticed it dropped to about 7VDC for a sec but is this the reason the light goes off or is that normal during a start up. I never really payed attention.

 

[mobsta]

which ehc do you have?what color?

 

[Escobar]

It's Black with all the connectins shown above.

BDM PN: BD4030-04

 

[mobsta]

that looks like the original,i have an 04 mastiff,i change mine a couple years ago,its kind yellow with a pigtail coming off of it.could very well be your ehc,before mine went south i had no high beam,some days no start,then start then no start,you said you already changed the cam sensor right?check all your connections also thats just my:zz2cents:

 

[Escobar]

Yeah I already changed the Cam Sensor, I searched around the site and found a thread where "PureDistruction" was having the same symptoms. his issue was the cam sensor which made perfect sence so i didn't bother troubleshooting it further. After changing the sensor and it not working, i revisited the thread and checked the coil which ended up not having power to it leading me to the EHC.

 

[DRBarnhart]

It could be the EHC but I'd check your battery first...

Dennis

 

[Escobar]

Hi Barnhart,

it's a new battery, however I just it from Autozone instead of BD or HD, it has the same amount of cold cranking amps but I've been wondering if this was the problem aswell. How do you propose I check it, the local autoparts store?

I read your posting on a couple of the other threads and you mention that if there wasn't any voltage ar the primary side of the coil then the EHC could be the issue as well.

 

[DRBarnhart]

it's a new battery,... How do you propose I check it, the local autoparts store?

You can get it checked anywhere that can do a load test to it. The auto parts store would be one place that should be able to help you out. You did charge it up BEFORE you tried to use it right?

I read your posting on a couple of the other threads and you mention that if there wasn't any voltage ar the primary side of the coil then the EHC could be the issue as well.

That's true. For your model year the power to the coil came directly from the EHC separately from the power to the ignition module.

Dennis

 

[Escobar]

Correct, I did charge it over night and installed it the next afternoon. that's when i noticed the thunderheart module wasn't blinking when i press the start button. That led me to the Cam sensor.

Any thoughts on the voltage drop im seeing when i press the start button. I'm noticing the power light on the EHC turning off when its cranking, I'm wondering if the EHC is shutting itself off due to the drop and not powering up the coil or the thunderheart. But then gain, with only the key on shouldn't there be power to both sides of the coil regardless?

Not to mention, my headlight doesn't even turn on now when i switch the key on. I bypassed it and powered it directly form the battery just to check the light was still working; it was.

 

[DRBarnhart]

Any thoughts on the voltage drop im seeing when i press the start button. I'm noticing the power light on the EHC turning off when its cranking, I'm wondering if the EHC is shutting itself off due to the drop and not powering up the coil or the thunderheart.

Sounds logical to me.

But then gain, with only the key on shouldn't there be power to both sides of the coil regardless?

With the key on and the "RUN" button pushed you should have 12V on the red wire of the coil. I'd disconnect it to check from that wire to a good ground.

Not to mention, my headlight doesn't even turn on now when i switch the key on. I bypassed it and powered it directly form the battery just to check the light was still working; it was.

Hmm, you're right, the headlight should be on when you turn the key on. The EHC is powering the bike like it should. Any chance you knocked a connector loose when you installed the new battery?

Dennis

 

[Escobar]

Sounds logical to me.

With the key on and the "RUN" button pushed you should have 12V on the red wire of the coil. I'd disconnect it to check from that wire to a good ground.

Dennis

I may have forgotten to pres the run button, I'll go check that again.

Hmm, you're right, the headlight should be on when you turn the key on. The EHC is powering the bike like it should. Any chance you knocked a connector loose when you installed the new battery?

Dennis

No, I've already gone through pretty much the entire thing, I'll give it a once over again just to be sure.

 

[DRBarnhart]

Another quick thought about the headlight...

I don't know if the '04 EHC will switch beams automatically if one is burned out so make sure you try both low and high beam just in case.

Dennis

 

[mobsta]

that ehc part # is the old one

 

[Escobar]

Sounds logical to me.

With the key on and the "RUN" button pushed you should have 12V on the red wire of the coil. I'd disconnect it to check from that wire to a good ground.

Dennis

Alright, I double checked again and yes it was in run when i was checking the primary side coil voltage, still 0 VDC.

I also double checked the voltage coming going to the Thunderheart again, now it's at 10V but still nothing when trying to start.

Do you know if when you start your bike, does that yellow "power" light on the EHC turn OFF while its cranking up?

 

[Escobar]

that ehc part # is the old one

It lookin like I'll be needing a new one; I'd just like to be sure it's the problem before I order it. Any idea how much they run?

 

[mobsta]

i have a newer ehc but i can check the lightbfor you,if you need a ehc you might check with jake and get the wire plus kit,does away with the ehc

 

[mobsta]

just checked,on my ehc the yellow light is on with key on and stays on when cranking

 

[mobsta]

i paid $560 bucks and it was hard to get.i thought i just saw someone on here say the factory was out of stock,i could be wrong,good luck and if were me i would get the wire plus.

 

[Escobar]

just checked,on my ehc the yellow light is on with key on and stays on when cranking

well then perhaps mine is bad after all.