1985 4 cylinder Base Model CJ-7

[spankrjs]

Worked on this one some more yesterday.

Would not accelerate, unless you were in the throttle hard, no Sol-Vac idle.

Decided to pull the carburetor and disassemble it:



This was a "rebuilt" carburetor I bought off eBay.

I have two filters on the fuel line, float bowl clean and full:



Accelerator pump works as it should, mostly.

When I pulled this carburetor apart, there was no check ball under the weight in the accelerator pump circuit. I added one from the spare parts/junk carburetor pile. Silver ball next to the brass weight:



I checked all of the other carburetor adjustable points, they were all spot on.

So, besides the missing check ball, no smoking gun found.

Checking the Sol-Vac unit:



The Sol-Vac that was installed was kind of iffy, swapped on another used one that seems to function 100%.

Reinstalled the carburetor, fired up the engine. The fast idle was spot on still (it has it's own adjustment screw that directly contacts the fast idle cam). The Sol-Vac idle speed was spot on, too.

The base idle speed was around 4-500 RPM. This is where I messed up. The FSM/supplemental book says to adjust the base idle speed with the Hex head screw that comes out the back of the Sol-Vac. This is incorrect. The hex screw is for adjusting the Sol-Vac idle.

So, with the base idle really low, the Sol-Vac would function. BUT, once I increased the base idle speed up via the Sol-Vac screw, it extends the Sol-Vac out too far to extend any meaningful amount when the Sol-Vac is called to engage.

Easy enough to readjust. The timing was still spot on, too.


Before I adjusted the base idle, the Sol-Vac would keep engaging increasing the idle speed. This makes sense, with such a low RPM, the MAP sensor thingy was sensing a load, and would kick up the RPM to compensate. The Sol-Vac would also engage while turning the wheel (PS pressure switch circuit functional).

So, I just need to go back and readjust the Sol-Vac idle speed, AND adjust the base idle speed with the adjustment screw that makes contact with the front of the Sol-Vac ram/arm.

Another interesting note - previously I could not adjust the idle mixture. It was consistently a bit rich. Two changes:

(1) I added the check ball to the accelerator pump circuit. Maybe excess fuel bleeding into the carburetor at idle without this ball, doubtful?

(2) I replaced some non-functioning relays, including the closed idle relay. Maybe this relay is needed to tell the ECU that the carburetor is at curb idle and to engage the mixture control solenoid. I think this fixed it.

Regardless, I installed the carburetor with the idle mixture screw out two full turns. It is easier to adjust this screw with the carburetor off the vehicle, since it faces the valve cover. Not a lot of room over there to fiddle with it. Anyway, hooked up the dwell meter to the correct diagnostic port connector, right at 30 where it is supposed to be!!



Besides the dwell meter reading, the idle exhaust smell was better.

So, thinking I had two issues, which are/will be repaired shortly:

1) Closed throttle relay bad, ECU could not engage mixture solenoid, rich idle mixture, now FIXED

2) Need to adjust the curb idle with the adjustment screw at the FRONT of the Sol-Vac (the one on the throttle arm) NOT the rear Hex screw (which is used to adjust the Sol-Vac idle). I will readjust these two idle speeds, should be good to go.

A bunch of ass scratching to figure it out, that's it for now

 

[Dave The Sparky]

It is still odd:

1) Ignition 12 volt power IN
2) Wire to choke OUT
3) Brown wire from alternator, which is part of the resistor wire circuit, so minor voltage key on, batt volt once engine running

No ground wire anywhere???

There is a ground or the relays coil wouldn't work you need to stop thinking of this as a conventional relay setup.
I haven't got the wiring diagrams for your year Jeep so i am maybe theorising a bit but there has to be a ground (a weak one) on that resistance wire when the alternator is not spinning. Its the same ground that would cause an alternator check light to come on if the CJ had one and is simply being used to make the relay coil switch in this instance.
The alternator also needs that brown resistance wire with 12volts on it to get it to start producing electric at a sensible speed in the first place and i bet the relay coil hasn't enough power draw to do that so they kept the resistance wire in.
If you want to prove me wrong or right and have a small ammeter to hand then check and see if there is a slight current draw on that resistance wire when the ignition is on that goes off once the alternator is fired up.
The resistance wire is just producing (hopefully) a small amount of heat with the ignition switched on but will stop doing so when the alternator is charging.

The switch that works off the oil pressure to run the choke on a 4.2 is far easier to understand and get your head around, why they didn't copy that system for the 4 Cyl i have no idea...

 

[ag4ever]

All DC power circuits have a positive reference voltage and a negative reference voltage. Power at one side, ground at the other. If you tap into that wire, you are tapping into a + and - at the same time. Kinda like how a CJ’s turn signal grounds through a positive power feed to a ground. Hard to understand at times.

It also depends on which side of the circuit load the tap is located. On the negative reference side, voltage will be low. On the positive reference side, voltage will be high.

 

[spankrjs]

Adjusted the idle speed(s) correctly, Sol-Vac functional again, mostly.

Should have read the instructions under the hood LOL:



Sol-Vac idle sped adjusted with this screw, which contact the Sol-Vac arm:



Curb idle speed adjusted at the other end of the Sol-Vac, brass hex head, basically manually extending/retracting the Sol-Vac arm:



Choke working, fast idle working, Sol-Vac idle working (on a hot restart the engine will idle up at the Sol-Vac idle speed of approximately 900RPM, after approximately 30-45 seconds, Sol-Vac disengages and the engine drops to curb idle of approximately 750RPM).

But, the power steering pressure switch is now bad:



When this switch works, turning the wheel at idle speed causes the Sol-Vac to engage to idle up engine and prevent it from bogging. If I jump the switch, the Sol-Vac engages, so all parts of this circuit work except for the pressure switch, which is made into the PS pressure hose. It is not really needed, but still kind of cool.

I am going to call this one complete. It is now a running/driving Jeep, way better then the condition it arrived in. It could still use some more maintenance work, but the next owner can handle that.

Put it away, until it moves back out of here.



That's it for now

 

[Jeep Addict]

Load it up and pull it with you blue Rubicon truck. Or better yet someone buy that sweet Jeep now that it’s been spankrjs certified!

 

[spankrjs]

Drove this one around the block one last time this morning in the 30 degree weather, loaded up all the extra parts:





I had to fix the trailer yesterday (one bad valve stem, one rotten deck board):



Tommy and his nephew MackDaddy Mason admiring all my handiwork LOL:



And just like that, it was gone:





It was a fun and interesting project. First time messing with an AMC 4 cylinder engine/feedback system. A good, solid little Jeep, runs and drives great, hope it goes to a good home.

That's it for now

 

[Jeep Addict]

Hats of to Spanky RayRay on this one! After some Jeep shuffling today I ended up driving the 4 banger home for about an hour and a half on the interstate and it didn’t miss a beat. It led the way for my nephew who is 16 to follow me pulling another CJ.
This Jeep may only have a 4cyl but the 4:10 gears and recent spankrjs lovin’ makes it seem faster and more responsive than my 6 cylinders. It shifts through all 5 gears really quick and smooth. I wasn’t easy on it either. I had no problem holding it at 70-75 the whole way. And the gas mileage was fantastic too.

 

[mhinchliffe]

Heck yeah, let that dog eat at 75!

 

[spankrjs]

Back in the saddle again!! Poor Jeep has been sitting for over a year! Fresh battery, bit of gas down the carb, fired right up and is still running pretty damn good!



Who is that handsome man LOL



Moved this one from the JeepAddict satellite facility back to home base. Drove it across Baton Rouge, drove fine on the interstate at 70mph still.



Even though it is just a 4 cylinder, the stock tire size and 4.10 gears really make it quite peppy!!

Hope it doesn't sit up this long again!!