Spankrjs 1985 Spring Special CJ-7

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Biloxi
State
MS
More testing/parts swapping, still no dice.

Removed the "Team Rush" parts, i.e. Ford distributor cap, cap adapter, rotor, MSD coil, and Ford plug wires:

20200309_180005.jpg

Reinstalled the old parts off my green Scrambler, i.e. stock 258 cap, rotor, coil, plug wires:

20200309_175952.jpg

No change, which I figured, still have the issue. No performance change, either, Not saying the "Team Rush" upgrade is bad, but no benefit IMO.

Bought a new ICM, just for the hell of it, swapped it in, no change:

20200309_182345.jpg

The box says "Made in China", the ICM says "Made in Mexico" LOL. Regardless, no change.

It does come with a 5 year warranty:

20200309_182448.jpg

Another note in the box:

20200309_182456.jpg

So, several ICM's, complete ignition swaps, coil swaps, still have the issue. Resistance checks out on the coils, hot or cold, on all three I have swapped in. I will check the resistance of the "pick up coil" next, even though I have rarely if ever had problems out of these. I presume that they are an "all or nothing" failure, but you never know?

After the pick up coil check, I am running out of things to check, except internal carburetor stuff:

20200309_193005.jpg

Besides the very slight "stumble/surge" at cruising speed, the only other clue: When I hit 3,000 RPM while driving down the road, 2nd or 3rd gear, it gets "soft". The engine will rev past 3,000, but at 3,000 it kind of stops pulling for a few seconds, then slowly climbs to 4,000 RPM. Not an abrupt "stop", but it gets real lazy. Not driving, the vehicle will easily rev past 4,000 RPM, so I do not think it is a plugged exhaust issue. And, the "soft spot at 3,000 RPM" changes. Sometimes it is worse then others, sometimes it doesn't show up at all.

Switch gears real quick, I got my repaired passenger front seat belt back. I shipped it last Monday, they received it Wednesday, they shipped it out Saturday, I got it yesterday. So, quick service!!

Packed well:

20200309_190807.jpg

20200309_190828.jpg

Reinstalled it, works like it should.

The only "clues" it was repaired:

missing two rivets
they reassembled it with a screw
glued the one cover back on

20200309_191018.jpg

That's it for now!!
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Biloxi
State
MS
No rest for the weary, let's pull the carburetor back apart:

20200310_185758.jpg

I am still getting some fine sediment/rust particles in the float bowl. If rust, its coming from the frame mounted meal lines, or OEM sending unit, since the tank is plastic:

20200310_190002.jpg

I cleaned the float bowl out, and checked the float height, both wet and dry. Float was maybe 1.5mm low, so I raised it a hair. Pretty sure that is not enough to cause an issue?

Anyway, I couldn't leave well enough alone, and thought to myself, "Let's pull the jets out and make sure there isn't an obstruction down here".

I normally NEVER pull the jets when cleaning/rebuilding a Carter BBD, no real reason to, and the risk of damaging a jet is greater then the reward IMO.

And of course, one jet came out no problem:

20200310_194521.jpg

One stripped bigger then $hit:

20200310_194535 (2).jpg

What to do?

I hammered a T20 torque driver into the jet:

20200310_210845.jpg

And simply backed it out:

20200310_210918.jpg

20200310_210925 (2).jpg

This seemed to be the best solution. I didn't dream this up, found it on the Google. Less risky then trying to drill/tap/Eazy-Out the jet out.

Either way, lots of brass debris left behind to clean out:

20200310_211020.jpg

According to the internet, Edelbrock 1425 jets are a direct fit/size for the stock Non-Altitude Carter BBD jets, .092.

Will pick them up this afternoon and see.

That's it for now :wave:
 

jammer1

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Maple Hts.
State
Oh
You wouldn't by chance have the distributor weights sticking or rubbing on the distributor body. Reason thinking as centripetal force pulling the weights apart, if they were rubbing at a certain point (approx. 3,000 rpm) you would think the result would be momentarily retarding the timing, until the centripetal force over comes the rubbing (or sticking)?
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Biloxi
State
MS
You wouldn't by chance have the distributor weights sticking or rubbing on the distributor body. Reason thinking as centripetal force pulling the weights apart, if they were rubbing at a certain point (approx. 3,000 rpm) you would think the result would be momentarily retarding the timing, until the centripetal force over comes the rubbing (or sticking)?
Yeah, thought about that. I have to look and see in the manual, and check it myself with the gun while the vacuum advance is disconnected/4"&10" switch unplugged from the MCU, but I think the mechanical advance is all in before 3,000 RPM ?

I checked one of the old coils with a better multi meter at work today, and it shows the resistance being out of spec. The current coil that is on there showed the same readings on my multi meter that the one I rechecked with the other multi meter showed, hell might have two bad old coils, but what would be the odds? Will probably buy/test/install a new coil after I put the carburetor back on?

I have the carburetor almost all the way reassembled. Still need to adjust the metering rods/accelerator pump. I am "thinking" I had an issue here. Before I tore it down, the rods/pump were kind of binding, and they shouldn't be. I think I had the plastic accelerator pump on wrong, pulling the plunger at an angle, causing the metal rod that controls the metering rods to kind of stick. I am pretty sure this is the case because I remember trying to figure out how that plastic arm piece was going to shut/open the bowl vent correctly. Tonight, took my time, paid attention, everything is moving smooth, and the bowl vent flap is operating correctly.

Even if a coil is bad, I'm still blaming myself, something was not 100% correct with that carburetor since I rebuilt it on the front porch a few months ago. I remember the slight sticking then, it was doing the same thing when I readjusted the metering rods/accelerator pump a few weeks ago. Now, everything is smooth as silk. Unless one of the old jets had a bad spot grabbing one of the rods causing a stick, but I don't think so. I rechecked the metering rods tonight, no marks/gauges/bends/scratches, they were both straight and true.

Yeah, pretty sure I screwed something up. Won't be the first or last time. At least I hope I finally have it figured out :fingerscrossed:
 

walkerhoundvm

Just trying to stay upright
LIFETIME
CJ-8.com Member
City
Cave Creek
State
AZ
Yeah, pretty sure I screwed something up. Won't be the first or last time. At least I hope I finally have it figured out :fingerscrossed:
Every time I try some new, major work, I screw something up. Case in point, the knock sensors I replaced a couple weeks ago. I know it's going to happen and even budget time and money expecting it, but never know what it is I'm bound to screw up. On the plus side, each time I do it I learn how to do it faster and with fewer errors. You'll get this sorted out sooner or later!
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Biloxi
State
MS
Every time I try some new, major work, I screw something up. Case in point, the knock sensors I replaced a couple weeks ago. I know it's going to happen and even budget time and money expecting it, but never know what it is I'm bound to screw up. On the plus side, each time I do it I learn how to do it faster and with fewer errors. You'll get this sorted out sooner or later!
Yep, know what you mean. I just consider all of this "good practice" :thumbsup::cheers:
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Biloxi
State
MS
Just a few pictures.

These are the jets I purchased, exact match for stock, threaded right in, no problems:

20200311_195848.jpg

The Edelbrock 1425 is a .092 size, same as stock in this application:

20200311_200027.jpg

On these new jets, a "non abused/new" flat screwdriver fit in the slot good and tight:

20200311_200221.jpg

20200311_200232.jpg

On the old jets, the slots were too wide for a regular screwdriver. I had to take an old one, cut/grind the tip off, to make a big fat flat driver. Still didn't work.

One other issue from the last rebuild - I used the wrong "kit", maybe there was a difference in a gasket somewhere I didn't spot, who knows:

20200311_201727.jpg

I used this correct kit this time:

20200311_201734.jpg

Like I mentioned above, still pretty sure I did something wrong with the previous rebuild/adjustments. Everything went together much better this time, and moves nice and free.

Still need to do the two most critical adjustments: accelerator pump and metering rods

20200311_215748.jpg

Hopefully I got/get it right this time!!!!!!!!!
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Biloxi
State
MS
You wouldn't by chance have the distributor weights sticking or rubbing on the distributor body. Reason thinking as centripetal force pulling the weights apart, if they were rubbing at a certain point (approx. 3,000 rpm) you would think the result would be momentarily retarding the timing, until the centripetal force over comes the rubbing (or sticking)?
You were mostly correct :cheers::thumbsup::wave:
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Biloxi
State
MS
So, I adjusted the metering rods/accelerator pump on the carburetor, and reinstalled.

Two quick pictures showing the bowl vent flapper installed, hard to find pictures of how this goes:

20200313_163254.jpg

20200313_163300.jpg

Basically, the little spring holds the flap open at idle/light cruise, and the plastic rod on the accelerator pump pushes it shut during hard acceleration. The flap is open when the engine is off, allowing vapors to flow into the charcoal canister. It's an emissions thing.

So, put the carburetor back on, test drove, same problem. I must have readjusted the accelerator pump stroke/metering rods 20 times, did not matter what I did, same issue. So, I adjusted them one final time, back to factory specification.

I have a new "rebuilt" carburetor on the shelf, decided to take a look at it. Two things:

1) It didn't even have the bowl vent flap inside
2) The accelerator pump shaft was 3/4" from the top of the carburetor body, NOT 1/2" like it should be.

So, beware of "rebuilt" carburetors from the big outfits, good chance the settings/adjustments are not correct. Would be a good idea to check all this stuff before installing one.

So, somewhat confident I do not have a carburetor problem, I started looking at ignition stuff, again.

The MSD coil was bad, and the coil that was installed was not checking out right either. So, bought a new coil, checked it:

20200313_190749.jpg

The MSD was reading too low, the one listed as "old" was the one that was installed, it was reading too high. The new NAPA coil was just right.

And installed:

20200313_191928.jpg

And still, did not fix the issue.

And so, time to check timing stuff, again. A few weeks ago, the base timing was set 100% correct. Checked it again, it was way retarded, not even showing up on the crank pulley!! How does that happen? Well, time to figure it out.

And I should have known to do this at the start, since I have had to do this before.

Time to map the mechanical and vacuum advance curves, see what is going on.

To start with, I made a little chart telling me what the dashes on the timing scale are:

20200315_095708.jpg

The number on the left is the "dash" spot, i.e. "2" is the second line on the scale. The circled number next to it tells me where I am at. So, dash "2" is TDC. You can't see all the numbers on the timing scale, but you can see the dashes. Since I am working alone, it easy for me to just write down which line I am at, as opposed to trying to figure out exactly what the advance degree is. Remember, you are holding the throttle steady at a specified RPM, looking at a tachometer, holding a timing gun, while the engine is running. It is easy for me to just to look down, say "dash 3", figure it out later. At this point, pure data collection.

The factory service manual shows the mechanical advance and vacuum advance curves on little diagrams. They are small and hard to read. So, I remake them on 8.5"x 11" graph paper. I also make smaller "data collection tables" that I fill in while I am under the hood. After I fill out the little table, I can graph the results later on.

One table/graph for mechanical advance:

20200315_095803.jpg

On the left, advance position. Along the bottom, RPM.

Data collection table for mechanical advance:

20200315_095731.jpg

And a set for the vacuum advance:

20200315_095817.jpg

To the left, advance position. Along the bottom, inches of vacuum fed to vacuum advance module on distributor.

And data collection table for vacuum advance curve:

20200315_095718.jpg

So, I made my tables, time to get the data. Then, I can graph it, see where I am at. All this may not be necessary, but I kind of like it, and it shows you exactly what is happening. This is useful for finding problems, and potentially improving performance.
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Biloxi
State
MS
I start with mapping the mechanical advance curve. To do this, two things must be done:

1) Disconnect and plug the vacuum line that feeds the vacuum advance module on the distributor

20200315_102933.jpg

2) Unplug the 4"/10" switch from the MCU harness (you MUST do this, or the computer will still be messing with the timing)

20200315_102941.jpg

So, the MCU and vacuum is out of the timing picture. The only advance in play now is pure mechanical/centrifugal.

Got the under hood tachometer/timing light hooked up, and got some data:

20200315_102952.jpg

And you can already see the problem. I am only getting 8 degrees mechanical advance. It hits 8, will not go any higher.

And since I like to draw pictures, here it is graphically, the blue line on my chart:

20200315_103012.jpg

It stops well short of the 15 it should get to. It hits 8, flat lines.

So, time to pull the distributor apart.

Note the #1 on the distributor cap corresponds with the #1 spark plug wire:

20200315_124323.jpg

I pulled all the spark plugs to make it easier to turn engine over with a socket/ratchet on the crank bolt. Engine at TDC, rotor position:

20200315_125622.jpg

Just because the rotor is pointing at #1 on the cap does NOT mean you are at TDC. You can be 180 degrees out!!!!

Verify at the crank, this is TDC:

20200315_125654.jpg

20200315_125703.jpg

Kind of a side tangent, all the plugs looked the same, but they all had some deposit build ups, not sure if this was from the crap additives I put in the gas tank. Besides deposits, all a nice color:

20200315_124350.jpg

BUT, #2 concerns me, the gap is closed. Maybe I damaged it putting it in, dropped it on the floor, OR the piston hit it, or something got in #2 cylinder, piece of carbon? Who knows. I will pull the new plug back out after a few hours, see if it gets damaged.

20200315_124410.jpg
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Biloxi
State
MS
With the distributor still bolted to the engine, I used two screw drivers to pry off the trigger wheel:

20200315_130122.jpg

The wheel has a little roll pin that holds it tight, be careful NOT to lose it!!!

20200315_130139.jpg

With the engine still clamped down, and at TDC, I took a measurement from the block to the vacuum advance nipple. That way, when I reinstall the distributor, I can put it back exactly how it was:

20200315_130446.jpg

Distributor out, I pulled the pick up coil out of it, just two screws; then the vacuum advance, again two screws:

20200315_131124.jpg

Now we see the belly of the beast, the centrifugal advance mechanism:

20200315_131131.jpg

Lots of engine oil, old grease, grime in there, so cleaned it out:

20200315_134249.jpg

Nothing obviously broken or binding. Do take note of how I marked the arm/one of the weights. Also note which spring goes where. There is a "stiff" and "loose" spring. The "13R" slot is engaged to the stop. There is an "18R" slot on the other side. I have heard you can spin this part around, get more mechanical advance. I am not worried about that at this time.

Went this far, let pull the whole thing apart. I marked the shaft/gear before driving the roll pin out:

20200315_134957.jpg

And this is when it went bad. I though you pulled/pried on the top of the plastic retainers that keep the mechanical advance weights on. WRONG. Pry the whole weight up, the busing/retainer will come off with the weights. Too late now, I broke them.

20200315_142225.jpg

All is not lost. The round/tube bushing part is still good, I just need new retainers. Well, it just so happens that carburetor linkage clips will work in a pinch:

20200315_142850.jpg

The plastic bushings/retainers are NOT a tight fit. They are a little loose to allow the weights to move freely. While this "Redneck Ray" trick might work in a pinch, I gutted an old junk distributor for these plastic retainer parts. I do not know where you can buy these bushings/retainers at?

I pulled the pick up coil apart, too, for cleaning. NOTE - spring washer, flat washer, "E-Clip":

20200315_144103.jpg
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Biloxi
State
MS
I cleaned the pick up coil assembly, made sure it moves freely, and reassembled it:

20200315_144308.jpg

Since I am "blessed" with a bunch of junk parts, I pulled another old 258 distributor apart to get the plastic mechanical advance weight bushings. Note the different marks on the advance notches, and the springs:

20200315_165959.jpg

This was another "Motorcraft" distributor, i think it came from a YJ. The weights were the same, but the springs were lighter then the ones that came out of my CJ-7.

I ended up using my weights, the YJ plastic weight retainer.bushings, AND the YJ springs:

20200315_171822.jpg

Another source of springs I read about from the internet. I bought these along time ago for my green Scrambler never used them, still have not used them:

20200315_171830.jpg

OK, all this is fine and dandy, but what was the problem? Well, with the original advance springs installed, I could not get the mechanical advance to fully actuate. I would have to pry the weights with a screw driver to overcome the spring tension. There is no way the distributor could ever spin fast enough to overcome the original springs tension. As far as I know, this is the original distributor to this Jeep. It is stamped "Motorcraft", has the original parts tag? Did the CA emissions model have tighter springs installed to hold total mechanical advance to 8 degrees? Maybe? But, I have not found a "CA emissions specific advance curve" to prove this?

Even with just the tight spring installed, this is as far I could force the advance to open:

20200315_172358.jpg

So, I took a gamble, used the lighter springs I found in the junk distributor:

20200315_173225.jpg

Then bolted on the vacuum advance:

20200315_173631.jpg

Then installed the pick up coil, then the trigger wheel and roll pin:

20200315_174947.jpg

Not sure if it is necessary, but I quickly polished the surface of the trigger wheel with some emery cloth:

20200315_174953.jpg

Don't forget the new distributor base gasket (or use a cereal box to make one like Jersey Jeep did in Michigan on his Overlander!!!)

20200315_175115.jpg
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Biloxi
State
MS
I cleaned the block where the distributor goes. it was very oily/messy here, and the old gasket was dried up, so maybe I fixed my "mystery driver side engine oil leak":

20200315_175214.jpg

Reinstalled the distributor, clamped it down, reset it to the original measurement:

20200315_180854.jpg

It was getting late, so I installed 6 new plugs, hooked everything up, and went to start it up.

It immediately fired up, no issue. Backed it out the garage, took a test drive, no more problem. Fixed.

NOW, I am still going to recheck/reset the base timing, AND map out my mechanical and advance curves. Just to see where I am at.

I will say this - this thing has never drove so well. Instant throttle response, no surge/dead spots, catches third gear in the yard!!

The lighter springs are the cause for this. BUT, I need to see how the mechanical advance is actually working versus stock.

I would not advise just swapping to lighter springs until you see what the stock set up is doing.

For now on, this will be the first thing I check when tuning a Jeep - map the advance curve!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Biloxi
State
MS
So, took it out the garage last night, drove it to the gas station and back, about 20 minute drive. Drove like a dream - hard acceleration, slow acceleration, deceleration, cruising, performed flawlessly. Good get up and go, no "surge", absolutely perfect.

Unplugged the computer and the vacuum advance, this is my mechanical curve information.

The table below, note the second table in BLUE, this is with the new advance springs:

20200316_193136.jpg

And graphically; the current curve is RED, the original spring curve is BLUE:

20200316_193146.jpg

I now have a gradual upward mechanical advance curve until it hits the stop at 16 degrees advance. I "think" the little "plateau" at 12 degrees is a data collection error on my part. Regardless, good gradual upward advance, a little sooner then specified, but should be OK.

With the computer and the vacuum advance line disconnected still, I hooked up my vacuum pump to the distributors vacuum advance and fed some vacuum to it.

Data on the table below:

20200316_193156.jpg

You can see the nice gradual rise until 10". At 10", it reads "can't see". Basically, at 10" of vacuum, I can no longer clearly see how far it is advancing because I can no longer clearly see the timing scale on the engine due to the serpentine belt. But, as I kept applying more vacuum, I could tell by my "ear" that it is steadily advancing. The FSM is NOT clear, it says to "increase speed past idle" while testing this. I idled the engine up to 800 RPM to test. At 800 RPM, no mechanical advance is coming on line, this is pure vacuum advance.

And graphically, in RED:

20200316_193204.jpg

Nice, steady, upward trajectory, maybe a bit close to the "too soon edge of acceptable", but should be fine.

So, nice mechanical and vacuum advance. And, with the computer plugged in, everything is fine and dandy.

Until.

Couldn't leave well enough alone, so I reset the static timing to the "9 degrees advance, +/1 two degrees @1600 RPM".

My notes below:

20200316_193245.jpg

Basically, runs like crap with the timing retarded, like the under hood sticker calls for.

Ran better when I just randomly advanced the timing some more.

Runs best with where it was at after the distributor was reinstalled.


For now, I am leaving it where it is.

BUT, I still think something is not right with the MCU.

Lets say, static 12 degree advance at 1600 RPM, no computer or vacuum. You take out the mechanical advance that comes in at 1600 RPM, which is 12 degrees from my chart below, you are at 0 total timing at 800 RPM, 2 degrees retarded at bast idle speed of 650!!!

Now, I would think the computer should be compensating, and it is, but not enough IMO. The only thing saving me at idle is the full manifold vacuum applied to the vacuum advance, raising the total timing at idle from negative two, add 26 degrees from the vacuum advance, I'm at 24 degrees total advance before the computer does anything. It's OK like this, BUT much better with more initial advance.

I need to somehow find out exactly where my timing is at idle, with everything hooked up. It is past the scale right now I am pretty sure, BUT it runs perfectly. Starts up so easy it is not funny. Turns right off, no run on, accelerates and cruises perfectly. But, the only way to get it to run this good, is to have way more initial advance then what the FSM/under hood sticker calls for????????
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Biloxi
State
MS
I am not an "expert" on how the MCU works, but I know that it controls the timing via the ICM. Not sure how, I guess the MCU can regulate the spark duration signal sent to the distributo/coil, which can then delay/advance the spark timing/duration?

A few random pictures from the 1985 FSM, not really "meat and potatoes" information, just kind of relaying the obvious:

20200316_233553.jpg 20200316_233942.jpg 20200316_234026.jpg 20200316_234142.jpg 20200316_234212.jpg 20200316_234249.jpg 20200316_234537.jpg 20200316_234544.jpg 20200316_235514.jpg 20200316_235720.jpg

I would "assume" the three biggest inputs to the MCU, in regards to timing changes, would come via the "tach wire", the 4"/10" vacuum switch assembly, and the knock sensor?

Besides the "AMC scan tool" scan I did the other day, I need to look into these systems/diagnostics charts. The scan tool kept telling me I had an issue with "the high altitude circuit", which is not connected on this vehicle. I "presumed" it was a faulty reading due to corrosion on the diagnostic connector port, BUT maybe the scan tool was letting me know I have an issue with the electronic side of the spark/timing system?

It runs great now, but I do not think it is "right"?
 
Top