Jump to content
SittyDown

04 Rubicon 500 intermittent spark...

Recommended Posts

Hey all, I’ve got an 04 Rubicon 500 with intermittent spark. I’ve been running in circles because of it being intermittent, but now that I put some time into watching the spark (and verifying fuel and compression) I’m fairly confident that’s my issue. I’ve been using the service manual download and the ignition pulse generator assembly is failing the test. Everything else checks out (Connections, fuses, ignition coil, ECM) so I’m going to order one Monday. Has anyone changed one? I know it’s inside the alternator cover beside the stator...but the manual says you have to remove the swing arm to access it. I have the air box removed, and it looks like there may be room without removing swing arm?

Share this post


Link to post
Share on other sites
 

The stator area is a btch to access. If you have the tools, I'd say remove the swing arm. Inspect the seals and bearings while you have it apart 

  • Like 1

Share this post


Link to post
Share on other sites
 
 

I had an intermittent spark issue on mine after I put it together. It was a brand new harness from Honda and before it ever ran 'good' the ignition coil wire to the back of the coil broke inside the sheething. Couldn't see it but could create the miss wiggling it. Found it with a DVOM. 

 

Anyway, just a suggestion. I know I'm late to the game and you said you found the issue back at the stator...but thought I'd throw that learning out there. I also had an issue with that sire to the pickup sensor that the spade connector was loose and had to be tightened down. Previous owner claimed it was Honda, found out later it was a knock off. 

  • Like 2

Share this post


Link to post
Share on other sites
 

Great info there, going to try to replace the pulse generator tonight and report back tomorrow. Thanks for the reply I appreciate it!

Share this post


Link to post
Share on other sites
 

Got the cover and stator assembly removed...it is possible to do it without removing the swing arm, but you have to remove the starter and hold the reduction gears clear of the cover to wiggle it around and remove it! I was surprised when I ran into oil behind that cover (started to get worried, but did some reading and found out that’s the way it is supposed to operate) but won’t be able to put it back together until I can get a new seal, and a new o ring for the cover. Probably should have planned ahead a little better, but here I am. 😂

 

Is it ok to use Ultra Black for the grommet where the wiring passes through that cover, or does it need to be Honda Bond? The ignition pulse generator screws had red loctite on them, so I’ll go back with that as well. Thanks again!

 

Also, it may just be me, but the old pulse generator looks a little swollen, and the magnetic part looks pretty worn.

D3F516CA-548D-4C30-A9D8-37D4E0FD3439.jpeg

23105307-40CF-417C-B131-682CBBC9FFC2.jpeg

CF85CA2F-BB6D-46D9-8A2E-D8A65CFB9E98.jpeg

DE7BC502-D2BB-402B-8A07-7BE6C16E5C71.jpeg

  • Like 1

Share this post


Link to post
Share on other sites
 

Good job accessing without removing the swing arm. I think any oil resistant sealant will work fine on that wire grommet 

  • Like 2

Share this post


Link to post
Share on other sites
 

you might check for rodent damage, looks like there have been some damage. very well could explain the spark  issue your having, the one thing you don't want, is them chewing on the electrical system. 

image.jpg

image.jpg

  • Like 1

Share this post


Link to post
Share on other sites
 
13 hours ago, Tim-ANC said:

Good job accessing without removing the swing arm. I think any oil resistant sealant will work fine on that wire grommet 

Thank you!

 

12 hours ago, _Wilson_™ said:

you might check for rodent damage, looks like there have been some damage. very well could explain the spark  issue your having, the one thing you don't want, is them chewing on the electrical system. 

image.jpg

image.jpg

I have looked this thing over a bunch and have been surprised to find all the connections clean and dry, and not a single chewed wire on the machine! Like you, I see signs that mice have been around, but I’ll be damned if I’ve seen one or any damage they’ve done. Pretty much exactly like my deer season this year 😂

  • Like 1

Share this post


Link to post
Share on other sites
 

good deal, just toss out some moth balls around the shop, or area where the bike is stored, that help keep those critters away, works good on snakes as well. 

  • Like 1

Share this post


Link to post
Share on other sites
 
 
 

Welllllll...back to the ol’ drawing board I reckon! I got the Rubicon put back together (new ignition pulse generator, checked wires while I was in there, new seal, new rubber o rings, Ultra Black where the grommet passes through the stator cover) and I am still having the same issue. Intermittent spark, machine will not start on starting fluid, have verified fuel to the carb and compression. I have had this machine running two separate times riding it through the neighborhood (great power), so I hope nothing too bad is wrong! I was sure that the ignition pulse generator was failing the test, but apparently I wasn’t testing properly. I am going to take a video and post it in a bit, so everyone can see this spark issue...stay tuned, and thanks in advance for reading!

Share this post


Link to post
Share on other sites
 
1 hour ago, SittyDown said:

Welllllll...back to the ol’ drawing board I reckon! I got the Rubicon put back together (new ignition pulse generator, checked wires while I was in there, new seal, new rubber o rings, Ultra Black where the grommet passes through the stator cover) and I am still having the same issue. Intermittent spark, machine will not start on starting fluid, have verified fuel to the carb and compression. I have had this machine running two separate times riding it through the neighborhood (great power), so I hope nothing too bad is wrong! I was sure that the ignition pulse generator was failing the test, but apparently I wasn’t testing properly. I am going to take a video and post it in a bit, so everyone can see this spark issue...stay tuned, and thanks in advance for reading!

well..i got to the party late, but..better late than never !. your first mistake was not checking all the timing marks BEFORE you tore the motor apart !!!. i say this, because if you had checked the timing marks FIRST ?, then it would point you in the right direction on where to dig in so to speak ?. lack of spark could be a few things, i will list them, then you take it from there. first, spark plug, did you try checking spark with a new spark plug ?, second, did you ohm out the stator before you started removing parts ?. third, once timing marks were checked, was all of them where they needed to be ?. i ask this, because this leads to number four, was the timing mark on the flywheel in the correct spot through the sight hole ?,  if it was not ?, then did you check the wooddruf key on the flywheel to see if it sheered ?, you can not find this out until you pop the flywheel off. this list should keep you busy for awhile..lol.

  • Like 2

Share this post


Link to post
Share on other sites
 

Hey all, I wasn’t convinced that my spark tester was giving me proper results, so I decided to do it the old fashioned way. I tried to attach a video but didn’t have any luck. I know you can’t tell much from a pic, but the spark is steady and looks just like the pic every time.

 

I took off the valve inspection cover, and the valves are moving. 
 

Anybody have any good ideas? My experience is in automotive/truck repair.

AC5CC931-3CA9-4CD9-A7EA-CB40A0A71632.png

Share this post


Link to post
Share on other sites
 
22 hours ago, shadetree said:

well..i got to the party late, but..better late than never !. your first mistake was not checking all the timing marks BEFORE you tore the motor apart !!!. i say this, because if you had checked the timing marks FIRST ?, then it would point you in the right direction on where to dig in so to speak ?. lack of spark could be a few things, i will list them, then you take it from there. first, spark plug, did you try checking spark with a new spark plug ?, second, did you ohm out the stator before you started removing parts ?. third, once timing marks were checked, was all of them where they needed to be ?. i ask this, because this leads to number four, was the timing mark on the flywheel in the correct spot through the sight hole ?,  if it was not ?, then did you check the wooddruf key on the flywheel to see if it sheered ?, you can not find this out until you pop the flywheel off. this list should keep you busy for awhile..lol.

Thanks for the reply I missed it! Yes the spark plug is a new NGK iridium.

Share this post


Link to post
Share on other sites
 

Well I’ve got an update and it isn’t the greatest news...30psi compression. I should have verified compression properly in the first place. @shadetree I shoulda followed your advice more closely.

 

I got the gas tank cleaned out, and the carb rebuilt, and it did need both those things but of course that isn’t why it won’t start!


I’ve been reading in the manual and about to dig in to start checking a few things...if I am reading and understanding right I need to do the following:

 

1.) Remove sight plug and get timing mark aligned and cylinder on compression stroke.

2.) Check rocker arms and valve clearance (.006 and .009)

3.) Make sure valves and rockers move properly

 

I’m sure there are some things I am missing and I wish I had listened to @shadetree so I could have checked the flywheel key while I was in there, hindsight’s 20/20!! 
 

Any other recommendations? Will I be able to see the timing chain to check it once the whole valve cover is off?

 

Thanks again for all the help and taking time to read this!

Share this post


Link to post
Share on other sites
 
13 hours ago, SittyDown said:

. @shadetree I shoulda followed your advice more closely.

 

 

 

Eh, we've all said that at one point or another.

 

 

  • Like 3

Share this post


Link to post
Share on other sites
 

I think I would adjust the valves and then retest the compression , be sure to hold the throttle wide open when spinning it over with a good battery  , if  it got the same reading I would try the test again with another gauge as the gauge could be faulty , then if it were still the same reading , I would dump some oil into the cylinder and do a wet test , if the compression goes up with oil then it is the rings , if it doesn't go up any  then it could be in the valves or head gasket 

  • Like 2

Share this post


Link to post
Share on other sites
 

@Fishfiles I will try that, thank you!

 

I should also add that I had this machine running and riding around. I was trying to see if it would fit in the bed of my Avalanche, and it was running good the whole time. The second time I backed it down the ramps it was sitting there idling for a minute or so then just died without sputtering or making any disturbing noises. I’ll post back here with results.

 

Side note: I am going to have to remove the brackets and drain gutters that hold the factory bed covers on the Avalanche in order for the Rubicon to fit 😂

Share this post


Link to post
Share on other sites
 

Something seems strange , it was running good enough to pull it's self up ramps into the truck , it was not smoking I take it ,  then just dies and now has 30 psi compression --- I think I would check my timing marks , it may have jumped a tooth  or a  valve stuck 

  • Like 1

Share this post


Link to post
Share on other sites
 

100% agreed! It ran really great through all gears! No smoke whatsoever, and I know the guy I got it from...no issues for years. I will read up on the timing marks...I’m not clear on how to view the mark on the cam when you get to TDC, or if that is even possible without removing another cover?

Share this post


Link to post
Share on other sites
 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...