Hello YotaTech! It is good to be back behind the wheel of an old Toyota truck. I recently purchased a 1980 Toyota Pickup from the original owner!


This truck ran absolutely flawlessly for the first month of ownership. Like 3 hour drives twice in 1 weekend, no problem. I even drove it to work every day for 3 weeks straight. Scary good! Last week the truck developed an intermittent slight stumble at about 1500 RPM and a loud backfire when decelerating from highway speeds. The backfire seemed to get slightly worse over the following few days until it gave one load backfire and the distributor seized causing this:


After cleaning out all of the debris, I pulled a camshaft gear and distributor off a 1983 Celica with 22RE. Since the distributor plugs between the 20R and 22RE are different, I pulled the pickup coil out of the old seized distributor and put it in the 22RE distributor and re-gapped to about 0.012”. I also replaced the cap and rotor with a new one for 20R.

After getting the timing set to 8° BTDC, the truck will act like it wants to fire up, but just won’t run. Another weird symptom is the coil and igniter assembly gets really hot when the key is in the “run” position.

Here is what I’ve tried:
- Moving the plug wires across from each other (ensuring timing isn’t 180° out)
- Making sure the truck has spark (it does, although it seems weak)
- Checked plug gap. All good.
- Checked coil resistance (checks good)
- Put a new coil in it anyways. Still won’t run.
- Hard wired the coil to the battery (eliminating the ballast resistor) Still won’t run.
- Checked ignition switch was working for other components with switched power.
- Moving the distributor forward a tooth (truck won’t even try to run)
- Moving the distributor back a tooth (truck won’t even try to run)
- Putting gas in the carb to rule out a fuel issue
- Triple checked timing with timing light
- Checked pickup coil resistance (checks good per repair manual)
- Checked voltage at coil <- this is where I think my issue lies.

The voltage at the coil seems low, 10 volts on 1 side and 2 volts on the other. My next step is to bench test the igniter per the repair manual and replace it if necessary. I’ve heard that the bench tests are often inconclusive. I don’t want to throw parts at it in case I’m missing something obvious, which is why I’m coming to the experts!

Thanks in advance for your help!

 

did you stab the distributor in @ TDC ? plug # 1 ... sounds like your out 180*

 

I'm not positive since it's been a long time since I've had a 22RE, but I think timing on a 22RE is controlled by the computer. The 22R probably has a different pickup and an advance system in the distributor.

Edit, I re-read your post and I see you swapped in the original pickup. I still don't think you will have and advance system in the 22RE distributor. Let us know what you find out. Dead end threads suck.

Nice looking truck!

 

Thanks for the replies. I’m ordering a distributor specifically for 20R. Should be here tomorrow night. We will see what happens.

 

Something that might be worth trying before getting the new distributor would be checking all the engine grounds. I could see that causing weak spark. Swapping the entire ignition system from the Celica over could also be a good diagnostic. I am wondering if the pickup coil in the 20R distributor got really hot and shorted out when the distributor seized and somehow partially cooked the ignition module. I think 22RE engines still had a mechanical and vacuum advance system before Toyota switched to TCCS in '85, but my suggestion won't work if the Celica has the ECU controlled ignition like aztoyman suggested. I would personally want to make sure everything else is in order before installing the new distributor to not risk something cooking the new pickup coil.

 

Thanks for the reply! Grounds were something that I also checked quickly. I’ll go through all of them again.

I believe you are correct about the pre ‘85 distributors. I do not see any difference between the 20R distributor and the 22RE one.

That does make a lot of sense. The igniter does get hot even if I have it disconnected from the pickup coil. This indicates something may be shorted inside. After I bench test the igniter, I will swap back to the 22RE pickup coil and see if anything changes before installing the new distributor.

 

Alright, I was able to fix the problem! I went about finding tdc a different way: I used a screwdriver down number 1 spark plug and spun the engine over by hand until the screwdriver just started to move downward. I pulled the valve cover and verified the timing mark was at the 12:00 position. The distributor was off a tooth or two.

Lessons learned:
1. Early 22RE distributors will work in 20R.
2. Always set tdc with the screwdriver method. Don’t rely solely on crank pulley marks and timing light.

 

TDC (Top Dead Center) of #1 cylinder on the compression stroke, NOT the exhaust stroke. Kinda important.