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

[Cruiser_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.

FJ40Jim - With the dwell built into the igniter, that explains why my changing the air gap on the signal generator is not having any effect. FSM says the dwell should be much higher than the 30 degrees that I'm reading (at idle speed). Another reason to replace the igniter.

The signal generator is fairly new so I don't suspect a problem there.

What is difficult in determining the precise problem (besides the fact that I can't find my butt with both hands) is that it appears that 4, 5, and 6 are running fine. The miss is somehow associated with 1, 2, and 3 (since removing those plug wires does not effect in any way the miss). This leads me to think that I have a very specific problem rather than a random problem (erratic behavior). This makes me believe that the issue is not with the igniter... but, I've ordered the part and will replace it Monday or Tuesday of next week.

I'll know more then...

thanks.

 

[FJ40Jim]

FJ40Jim - With the dwell built into the igniter, that explains why my changing the air gap on the signal generator is not having any effect. FSM says the dwell should be much higher than the 30 degrees that I'm reading (at idle speed). Another reason to replace the igniter.

The FSM does not specify a dwell reading for the ignitor, because there is not one. It would be the same as specifying a point gap.

The variable dwell is low at idle, as you've noticed, then increases at higher speeds to keep from overheating the coil at low speeds.

 

[Fuzzy Logic]

Points/Dwell:::: Dwell Angle: The dwell angle is the number of degrees of rotation of the cam/distributor during which the points are closed. During each rotation of the cam/distributor, the points must open and close once for each cylinder. The points must stay closed long enough to allow the coil primary current to reach an acceptable value, and open long enough to discharge and produce a spark.

 

[FJ40Jim]

updated for electronic

Updated to reflect coil operation w/ solid state ignitor:

ignitor/Dwell:::: Dwell Angle: The dwell angle is the number of degrees of rotation of the cam/distributor during which the ignitor is on. During each rotation of the cam/distributor, the ignitor must apply and break power to the coil once for each cylinder. The ignitor must stay on long enough to allow the coil primary current to reach an acceptable value, and open circuit long enough to discharge and produce a spark.

 

[FJ-40Original]

I read until my eyes hurt and still I see nothing about cylinder compression.... Where are the values for the cyl's? OOOOOhh I see, 150, that's good.

I am still thinking that you have a valve issue...



FE

 

[chajazz]

good point the valve are closeing but are they opening. good point. could be flatted cam. that would suck.

 

[Cruiser_GT]

The FSM does not specify a dwell reading for the ignitor, because there is not one. It would be the same as specifying a point gap.

The variable dwell is low at idle, as you've noticed, then increases at higher speeds to keep from overheating the coil at low speeds.

FJ40Jim - Got it. A simple comment in the FSM saying that the dwell angle is applicable only in the points/condensor configuration. The igniter/points and igniter/signal generator configurations do not have an adjustable dwell. This may be intuitively obvious to everyone here, but it was not to me

Thanks for clearing this up for me and I'm sure others as well.

gt

 

[Cruiser_GT]

I read until my eyes hurt and still I see nothing about cylinder compression.... Where are the values for the cyl's? OOOOOhh I see, 150, that's good.

I am still thinking that you have a valve issue...



FE

FJ-40Original - I only checked cylinder #1. The engine was rebuilt about 35k miles ago. I didn't update all the ignition system when that work was done... that's why I've been biased toward electrical more so than an electrical problem.

That's not to say it is not a valve problem. I'm just set on understanding the ignition and ensuring it is right prior to opening the valve covers. I noticed symtoms similar to mine on another thread that turned out to be a valve problem. Stay tuned...

 

[grant5127]

FJ-40Original - I only checked cylinder #1.

Some of your post on this thread have been misleading as HELL!!

 

[FJ-40Original]

Do us all a favor and OPEN THE DAMN V/C! Twist all the pushrods with your fingers and see if they are bent.

If the engine was rebuilt, that's fine. There are idiots out there that still rebuild engines... It could be internal.... Mechanic error not your fault type thing..

It could be than you had bad fuel in the tank when you last ran it and that fuel glued the valves shut or open... And has bent some push rods. It happened on my Falcon twice! I had to drain my fuel tank and clean it and out to get it to stop bending pushrods, I went through 2 sets and now I have a mismatched set but they're not bent )


FE

 

[Cruiser_GT]

grant - Missleading as HELL.??? I gave the value of 150. Does that sound like I got a reading for more than one cylinder? I suppose they could have all had the same value... but, unlikely.

If you or anyone else can give me a good reason that I need to check the compression on all six cylinders, then I'm all over it.

gt

 

[cruiser88]

grant - Missleading as HELL.??? I gave the value of 150. Does that sound like I got a reading for more than one cylinder? I suppose they could have all had the same value... but, unlikely.

If you or anyone else can give me a good reason that I need to check the compression on all six cylinders, then I'm all over it.

gt

yes check all 6

 

[stumpy]

If you or anyone else can give me a good reason that I need to check the compression on all six cylinders, then I'm all over it.

well, they arent connected to eachother in the block, are they? they can behave very differently.

you might even find a dead valve or two. that wont affect readings in all the other cylinders.

i blew the head gasket in my F block many years ago. had 150 on 4 of 6, 110 or so on 2 of 6. the gasket blew between cylinders 5/6. 1-4 were great!


you might be suprised.

 

[sepr2]

Consistency is the key to a happy/healthy engine...

 

[FJ-40Original]

The reason to check is because I SAID SO!
And it's the smart thing to do.

 

[Cruiser_GT]

The reason to check is because I SAID SO!
And it's the smart thing to do.

Sorry folks, I've been away. Also, I didn't fully understand that I was told to get compression readings for ALL cylinders...

The igniter was replaced. 1-3 cylinders are still not helping me out. So, here are the compression values for each cylinder:

#1 - 150
#2 - 155
#3 - 155
#4 - 150
#5 - 150
#6 - 150

Pulled the valve covers off as requested. The gaps all appear to be off, but nothing jumps out at me as a problem. Here's a pic for what it's worth...

 

[cruiser88]

those #s are fine

 

[grant5127]

The gaps all appear to be off.

appear to be off??... but you don't know for sure?? but I'll go along with you.... now what??

 

[Buckwheat]

The ass-end of the engine is firing but not the front end? The good compression readings do not eliminate valve adjustment being slightly tight, or a major vacuum leak - like a crack in the intake. I had a misfire when cold that stopped after warm-up that I cured by lashing the valves correctly but your problem sounds like you aren't getting fuel.

 

[Cruiser_GT]

appear to be off??... but you don't know for sure?? but I'll go along with you.... now what??

grant - I'm checking the gaps now. Of the ones that I checked previously, all were tighter than spec... at that point I had not checked every gap. Hence, my hedge.

I think the next step is to adjust the valves... since I'm there and they need it.

After that... figure out why I'm not getting gas to the cylinder.