2f cylinders one and two are not helping... (1 Viewer)

[Cruiser_GT]

I want to make sure I've run all the traps before pulling the valve cover off...

My engine has been missing after sitting for a period. I've replaced the contacts in the distrib (stock on the 78fj 40), plugs, and wires. Re-set the timing and still the engine misses.

I revisited each plug to ensure I had solid connections when I noticed that disconnecting one and two plugs had no affect on how the engine ran. I even connected the tac and vacuum gage and saw no change. I'm getting spark through the wire.

Checked the compression... not a problem.

 

[cruiser88]

I want to make sure I've run all the traps before pulling the valve cover off...

My engine has been missing after sitting for a period. I've replaced the contacts in the distrib (stock on the 78fj 40), plugs, and wires. Re-set the timing and still the engine misses.

I revisited each plug to ensure I had solid connections when I noticed that disconnecting one and two plugs had no affect on how the engine ran. I even connected the tac and vacuum gage and saw no change. I'm getting spark through the wire.

Checked the compression... not a problem.

pull the cover off

 

[Poser]

Swap another spark plug lead to the dead holes....try another plug.

 

[grant5127]

Checked the compression... not a problem.

what are the #s

 

[Cruiser_GT]

Switched plugs out... no affect.

Changed wires from known good cylinders... no affect.

But, I found that 3 is not helping either. So 1-3 are not getting anything done. Just going through the motions.

 

[Cruiser_GT]

what are the #s

Just shy of 150 lbs. Right on spec. Right?

 

[grant5127]

being the firing order is 153624... you say 132 is dead.. that's every other one... sure the cap and rotor are good? quality of spark is up to snuff? wires installed in the correct order??

 

[Cruiser_GT]

being the firing order is 153624... you say 132 is dead.. that's every other one... sure the cap and rotor are good? quality of spark is up to snuff? wires installed in the correct order??

I'm with you. Adding the 3rd cylinder changes the whole picture (especially when the firing order is considered). The cap and rotor were replaced in my efforts to tune everything in the first place I am assuming that they are okay. I also replaced the coil... the only item that has not been replaced is the igniter (I'd rather not pay the big bucks to replace him... until I am sure that is the problem).

Any ideas on measuring the quality of the spark? I held the wire to the block and it looked good. One bit me ... felt like it was pretty good quality I'm not sure how I could check it in a more quantitative way.

Any ideas? I will double check the contacts on the rotor and the cap just to make sure.

grand5127 - I suppose that I should note before someone else does that we have now determined that I'm "hitting on every other cylinder." LOL

That explains a lot.

 

[Cruiser_GT]

Could this (missing on every other cylinder) be a symptom of a bad ignitor?

 

[65swb45]

Based on your scenario, I would recommend temporarily swapping in a loaned dizzy AND coil [non-ignitor type] from an earlier cruiser to see what happens. It's a little work, but not nearly as much as pulling a cylinder head.

Best

Mark A.

 

[cruiser88]

Could this (missing on every other cylinder) be a symptom of a bad ignitor?

igniters usually work or not work

 

[Cruiser_GT]

igniters usually work or not work

cruiser88 - Got it. I don't want to assume anything at this point. The Haynes manual has a digram that allows me to bypass the igniter with a .22 mfd condenser. Now all I need is a source of a .22 mfd condenser.

Mark - I hear you. The problem is finding a dizzy to swap. Thanks.

gt

 

[grant5127]

Hey,, Bama.. what is the condition of your dizzy?? does it have side to side movement of the shaft... are the lobes in good condition??

 

[Cruiser_GT]

Hey,, Bama.. what is the condition of your dizzy?? does it have side to side movement of the shaft... are the lobes in good condition??

Just pulled it out and took a peak. It looks good. No slop anywhere to be found.

One other item I'd like to remove as a possibility in this whole mess. The FSM and Haynes manuals call for a dwell angle of 39-43 degrees. My reading is right at 30 degrees.

 

[cruiser88]

Just pulled it out and took a peak. It looks good. No slop anywhere to be found.

One other item I'd like to remove as a possibility in this whole mess. The FSM and Haynes manuals call for a dwell angle of 39-43 degrees. My reading is right at 30 degrees.

hmm.yep dwell is just as important as gap

 

[Cruiser_GT]

hmm.yep dwell is just as important as gap

I didn't figure they were kidding around

Do you know how the dwell is set? I assumed that the gap for the points should be used on the pickup (.018). I also test opening and closing a bit and had no major impact on my dwell reading. I suppose my meter (combo tach and dwell) is not getting it done.

gt

 

[Cruiser_GT]

cruiser88 - Got it. I don't want to assume anything at this point. The Haynes manual has a digram that allows me to bypass the igniter with a .22 mfd condenser. Now all I need is a source of a .22 mfd condenser.

Mark - I hear you. The problem is finding a dizzy to swap. Thanks.

gt

On the '78 dizzy, the points are replaced with a signal generator (pick-up). And, the .22 uf condensor bypass of the igniter will not work.

As per thread searches... and SOR part nomenclature.

Still no luck in determining how to set dwell angle for a dizzy equiped with the signal generator.

BTW - Poser mentions on several threads that dwell settings to spec were not that important... at least not a low rpms... so I'm not putting a lot of hope in this correcting my problem.

Any knowledge anyone has about the signal generator equiped dizzy would be greatly appreciated.


gt

EDIT: I'm ordering an igniter (Napa $180 USD).

https://forum.ih8mud.com/showthread.php?t=118614&highlight=signal+generator

Other factors pusing me in this direction... Signal Generator has been replace, plugs replaced, plug wires replaced, coil replaced... only the igniter is original (partly because I agree that either it works or doesn't... but the above thread makes me believe that it can operate out of spec and cause troubleshooting problems). Either way, I'd rather replace it in my garage rather that on the trails.

Lastly, I've had this LC a very long time and know a lot of details about it. I recall checking spark by holding the plug wire to the block and getting a very strong POP. That POP has now been reduced to more of a click. So my hypothesis is that the quality of the fire is now what id should be... we'll soon see.

 

[grant5127]

I thought you stated "contact points"??? on signal generated options the air gap is adjusted...distance between signal rotor and pickup coil projection..... 0.008" if any of the components are rusty? that has a effect on the performance.. the pickup coil can be tested with a OHM meter for resistance......

 

[Cruiser_GT]

I thought you stated "contact points"??? on signal generated options the air gap is adjusted...distance between signal rotor and pickup coil projection..... 0.008" if any of the components are rusty? that has a effect on the performance.. the pickup coil can be tested with a OHM meter for resistance......

grant5127 - I'm challenged in many ways here... first, I don't know crap and second (partly attributed to the first challenge point) I'm not a great communicator.

Thanks for the projection (is this the correct term? rather than gap?) value. I have been searching for that number for days.

Do you know the specs on the resistance value of the igniter? Or a thread where I might find some details. I found .5-.7 ohm as spec for the fj60, but nothing for the 40.

thanks much for the help.

gt

 

[FJ40Jim]

grant5127 - I'm challenged in many ways here... first, I don't know crap and second (partly attributed to the first challenge point) I'm not a great communicator.

Thanks for the projection (is this the correct term? rather than gap?) value. I have been searching for that number for days.

Do you know the specs on the resistance value of the igniter? Or a thread where I might find some details. I found .5-.7 ohm as spec for the fj60, but nothing for the 40.

thanks much for the help.

gt

The air gap is .008-.016".
Anywhere in that range is fine. The signal generator is a go/ no-go type of thing. It either generates a timing pulse or not. It cannot cause a weak spark, but it could cause an intemittent spark.

The resistance value for the ignitor is roughly the same for all 78-87.

The ignitor will not consistently fire one cylinder, but not another. It will either shut down for good, or misfire erratically. The ignitor doesn't know if it is hitting #1 or #4 or whatever. It just makes a spark after it hears the trigger from the dissy.

The dwell is built into the ignitor, and it is variable w/ RPM.

HTH.