Hey fellas, I have an '08 Mastiff Limited not EFI. I'm having a major issue which I believe is an ignition problem but can't positively confirm. It sounds similar to some other posts here. I had just gotten the bike from the shop (East Coast Superbikes) a former Big Dog authorized warranty shop. They rejetted and cleaned the carb and installed new tire. Previous owner had it improperly jetted because of a mis-diagnosed gas cap vent issue. Bike was popping like crazy on decel and would sometimes stall at idle or low speed. After re-jetting the bike mint! No popping on decel, more power. That lasted 4 days then the popping came back, but not as bad. On the fifth day it shut down on the highway, I would throttle it a bit and eventually it would backfire huge and run again. That happened 3 times on way to work. On way home happened few more times but once it kept me on side of road for 10 minutes before it would restart. Pulled the plugs and they looked pretty tired so I changed them. Got my inline spark tester so I could try riding until it failed again and I could positively diagnose ignition issue. Every time it died as soon as I got it on the bike would fire right up. However the last time it would only run with the spark tester ON! So I had to ride it home with the tester on. Get it home and of course it fires up immediately like a champ with it off. I'm thinking ignition module or coil. Although I guess it could be a cam sensor... But how could I reliably test any of them with it being so intermittent and not staying dead long enough to troubleshoot? Any advice or experience would be hugely appreciated!!! P.S. if I installed a dyna 2000i or Crane hi-4 or Daytona Twin Tec ignition system would that eliminate the cam sensor? If so that would address all 3 possible parts. From the reviews it seems Dyna or DTT is the best choice.. Opinions? Thank you in advance - Jay
Possible intermittent ignition problem. Help appreciated
- Thread starter Araris
- Start date
Also to add to the above... When I test drove it the second day I warmed the bike up for 3-4 minutes then I made it 3 blocks before it died, that's when it would only run with the inline spark tester on. I never ride the bike cold, ever, if I don't have 5 minutes to warm up then I take the truck. So the bike is always warm/hot but it isn't happening exclusively at highways speed on long trips.
KaptinAmerika
Guru
Your bike has a crank sensor not a cam sensor.
Pull it, front left side of motor, make sure there is no debris on it
Might be going bad on you
Pull it, front left side of motor, make sure there is no debris on it
Might be going bad on you
Nukeranger
Nukeranger
Just a thought but are you sure your Gas Tank venting issue isn't back again?
Yea, I'm a dummy... It's a crank sensor, I'm going to pull it today and take a look if I get a chance. And with the gas cap vent issue... That problem is burned into my brain lol... Everytime the bike died I cracked the gas cap and when I was rolling it didnt effect whether the bike ran. Before I got the new cap as soon as I cracked it open the bike would liven back up. Also when I was stuck on side of the road I cracked the cap and heard no vacuum release at all. Do you guys happen to know if the aftermarket ignition systems Eliminate the crank position sensor? And any recommendations if I have to go that way? I'm just hoping this isnt the dreaded EHC meltdown here, I might have to send it to Wild Steed Worx to be tested. I appreciate the help guys, thank you!
nothing will completely get rid of either cam or crank sensor, the ignition will always need some way of referencing when to fire.
Dan22644
Member
Yup. I would just replace the crank sensor, it's only $55 or so, just to rule it out if nothing else. There's no real way to test those components on a bench, the intermittent problem could be caused by heat or vibration only seen while riding.
I just fixed an intermittent ignition shutdown while riding by replacing the crank sensor. Bike would just suddenly shutdown while riding, but would restart by just hitting the start button.
Do you have to hit the run button then start to get it started again? If so then it's something else, possible key switch problem, wiring, or maybe even EHC...
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KaptinAmerika
Guru
CRANK SENSOR TEST
Disconnect the plug wires and unplug the
crank sensor. Set the DMM to measure AC
volts and measure across both pins of the
plug. While cranking the engine, you should
see AC voltage greater than 1 Volt. If no
voltage registers, replace the crank sensor.
Disconnect the plug wires and unplug the
crank sensor. Set the DMM to measure AC
volts and measure across both pins of the
plug. While cranking the engine, you should
see AC voltage greater than 1 Volt. If no
voltage registers, replace the crank sensor.
Dan22644
Member
And if you have an intermittent problem the test will show that it's good, but you still need to replace it....
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KaptinAmerika
Guru
I have successfully pin pointed bad crank sensors by applying heat, with a heat gun, as well as tapping with a screwdriver handle simultaneously and ruled them out the same way. Doesn't always work but its better to troubleshoot to death than randomly throw parts at a problem.
I might add that I do the same thing with EHCs
Juz Sayin
I might add that I do the same thing with EHCs
Juz Sayin
Dan22644
Member
That's the only problem
if it passes the test you haven't really ruled it out. On a five year old bike with ignition problems, I wouldn't consider it money down the drain to have a new sensor even if it doesn't solve the problem. Besides, there's only one sensor Not trying to pick a fight or anything, just giving alternative possibilities and passing along my experience from a similar problem I had this summer.
It would be good to know what the lights on the EHC and ignition module look like when it dies. Might help rule out the crank sensor without testing or replacement....
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The gas cap was from BDMPP, Im still friends with the precious owner and when I told him about the problem he remembered he had ordered a spare when the same problem happened to him. Although every now and then it happens with this new cap. When the recent problem happened I tried cracking the cap and there was no vacuum loss hissing sound. I even left the cap semi-open to see if the bike would still die and it did. Last night when I got home from work I pulled the crank sensor and there was 2 small pieces of metal on it. One was an extremely tiny ball of metal, the other resembled a micro Allen key perfectly. (Which has worried me further, hopefully I didn't spin a bearing or worse) I removed the pieces and cleaned the sensor. I took the coil cover off and ran the bike while wiggling the wires and tapping on the coil, I also jiggled the key to see if the switch was maybe going. I also tapped on the crank sensor and bike didnt miss a beat. I didn't have my meter on me to ohm out the sensor, I'll do that tomorrow. I took the bike out after and was able to put 25-30 miles on it with out it dying. I drove on the highway doing 60,70, and 80 for prolonged periods of time, and I did stop and go driving sometimes getting way into it and it didnt die. You guys think that metal could cause enough interference with the sensor to cause that? I plan on changing out the crank sensor either way, can't hurt to have a spare if its good, the guy at East Coast Superbikes said to drop my sensor off on Tuesday to see if he can match it up with a Harley sensor for now. I'm hoping it at least lasts me to the end of the season, when I plan to do a wires plus kit and dyna ignition (might even do the ignition this week) to get rid of this crap electrical. Apparently I might be doing a lower end rebuild as well lol. If that's the case I'll be doing a cam, and have the heads machined. I'm sure I'll be getting some advice from you fellas when that time comes, I'm glad I found this site. Oh and Dan, I found a thread on here that shows what all the lights mean on the EHC, Im gonna print it out and keep it on me to match up to it if the bike does for any substantial amount of time although on my bike it's hard to see all the lights on it where they tucked the EHC. But that's the problem the bike doesn't die long enough for me to even get the inline spark tester in, or even look at the ignition module lights with it not starting. Thank you so much guys for all the help! -J
