I'm reinstalling my distributor on a 20 r engine.
What am I doing wrong????
( Engine turns over but won't ignite...occasional backfire )

A) Set Crank to TDCC at 12 o'clock
B) Confirmed TDCC via Cam Shaft Sprocket mark at 12 o'clock.
C) Inserted distributor into engine with rotor just before number one on distributor cap.

Engine will turn over but won't fire.
What am I doing incorrectly?

I cleaned the distributor cap. Check the wire sequence ( 1-3-4-2 ) half a dozen times. Confirmed connections on spark plug an on the distributor cap.

Nothing.

What needs to be done?

TIA.

 

Just thought of something I was once told to do.
What are your thoughts on this method...

A) Wait until dark.
B) Pull all the wires off the plugs.
C) Put new spark plugs into the now unconnected wires.
D) Place spark plugs atop metal valve cover to ground.
E) Turn over engine.
F) Look to see IF all four plugs spark and spark in correct firing order ( 1-3-4-2 ).

By this method, it can be confirmed that the electricity is getting to the plugs.
Then the wires, the rotor, the distributor cap, and the coil can be eliminated as potential problems.

 

What direction is it back firing? Out the carb or the tailpipe?

 

Tail pipe.
But only once or twice.

I've pulled the distributor about six times to reset it.
Checked the wires and their order the same.
Cleaned the distributor cap and rotor for clean connection.

The engine still won't fire up.

I'm baffled...

 

What are the points gapped at? Or did you replace them since last that it ran? Have you advanced the distributor or retarded it to see if it helps?

 

Two thoughts:

1) You can time an engine off the starter with a timing light if you have a helper to crank the engine for you.

2) Crank the engine backwards a bit so the timing mark lines up with the initial advance you want (say 8* btdc) and then stab the distributor straight-up so the rotor points right at #1. This is a much more accurate technique then putting the crank straight up and eyeballing the amount of advance at the distributor.

 

Aaron, WT, and All - Thank for the insights you have shared. I'll give those a try. My gut instinct says it's a "tooth" off on the distributor gear into the cam. But when I visually look at the placement, it is just before TDCC.

I'm wondering if the battery is weak and doesn't have enough cold cranking amps.
Maybe this and some other fault is contributing to the malfunction....

 

was good fam

 

If the engine cranks at an acceptable speed and spark events occur, then the battery should start the vehicle.

There is no such thing as "a tooth off" for a distributor, that is an old-wives tale that gets tossed around. The spark event occurs at the relative position of the rotor vs. the distributor cap. All the engine cares about is that when the engine is at the proper degree BTDC the rotor is pointing at #1 on the distributor cap. It doesn't matter where the rotor is in it's rotation, or where the distributor cap is, only that they are lined up in relation to each other.

If this is confusing, just think of it like this: if you reclocked the shaft by one tooth and then turned the distributor body by the same amount, nothing would change. Likewise if you reclocked the shaft by 90* and then moved all the spark plug wires around on the cap so they lined up with the rotor, nothing would change. See how it is all relative?

The only limiting factor on any distributor positioning is getting the vacuum pod and/or trigger or points wires out of the way.

 

Where are you located? Maybe a local guy could come give you a hand... if you are in the Portland OR area I'd be glad to drop by.

In this situation here is what I would do:

1) Verify spark at the plugs (pull a plug or use a spare plug and put lead back onto it then hold it to ground with a pair of pliers and crank the engine, see if you have spark)

2) If no spark; pull the wire coming off the coil and hold it near ground then use a flat blade screw driver to open and close the points (may have to turn the motor to get the points to close all the way). If you get a spark, it could be a bad cap, rotor, plug wires or even plugs. If not we we'll get to chasing down no spark...

3) If you get a spark pull the valve cover and turn the motor by hand over while watching the valves, when both intake and exhaust valves are close that is TDC, I also like to use a stiff piece of copper wire in the plug hole to use as a feeler for the piston, you should be able to feel the wire move up with the piston then pause then start to move back down. The pause is TDC.

Now that you are on TDC verify the balancer is also indicating TDC, then make note of where plug wire #1 (I like to hold my finger pointing at it) then take the dist. cap off, the rotor should be pointing back at your finger). If its not (by a fair but) you could be off a tooth on the gear, pull the dist out until the rotor stops turning (curved gears) then carefully move the rotor back towards the direction it was off while pushing the dist slightly back in until you feel it catch the next tooth, slide it in and it should line up closer.

4) Now that you are sure you are getting spark and the timing is set to TDC it should fire up. If it still won't fire try slowly turning the dist by hand while someone cranks it one way then the other and it should start. Then just turn the dist until it sounds good then you can set the timing by timing light (a dial back light helps a lot) If it just back fires a lot and won't even try to run the dist could be 180* out.

5) If it still doesn't fire verify you are getting fuel. Pull the air cleaner off and look down the carb while cycling the linkage, you should see (and hear) a big shot of fuel getting squirted into the carb. If you aren't getting fuel you could try running it on carb cleaner, starter fluid, or pouring gas down the carb.

That is a pretty good start...


Good luck, don't give up!

Ryland

 

Aaron, WT, 3sp...Everyone here at Toyotaminis:

WOW!

The replies and sharing of knowledge is EXACTLY why I come here and post: to ask, to learn, experience, and to do!
MANY, many thanks to all!


Okay, I got the engine to run,

I took a little bit of knowledge from everyone ala Stone Soup and actually did it all by myself. FIRST time I ever did it all with just me and the knowledge coveted.
( and thank you for the words of encouragement. I was going to throw in the towel and call for assistance. A local shop said he would reset the timing for $220 if I towed the truck in )

Here's what I did.

A) I checked the battery and brought it to an auto parts store to recharge. It was giving off 12 volts but not enough Cold Cranking Amps (cca). So I got a battery from my other truck, charged it, and placed it into the the truck I'm working on and posting about.

B) The engine turned over strong but would not ignite. So I pulled the number four wire and put a spark plug into it. I put the wire near the windshield and grounded it to the body where I could have a clear view. ( remember, it's just me; no one to turn the ignition ...). I saw the spark, so I know rotor, distributor, plugs were okay.

C) It had to be timing. reset engine to TDCC compression and retarded it back to 8* as was posted. Still nothing, no ignition. I checked the rotor position. It looked okay, but it wasn't firing, so I suspected it was the positioning of the distributor and rotor..

I did this at least six times. I removed and adjusted the distributor tooth by tooth. As I was doing this, it seemed futile. It seemed to me that by moving the entire distributor and cap was the equivalent of pulling the distributor out and putting it back in by one more tooth. But I didn't know what else to do.

D) Finally, after all the attempts, the engine turned over and ran!

I didn't recognize the sound of the motor. I guess when I adjusted the valves, it made a difference...

But the engine turned over, and the truck moved for the first time in months!

THANK YOU ALL for the assistance and guidance! You all taught me with little bits of knowledge, and it all added up. I'm grateful!

E) I'm still not sure it is timed correctly. I put a timing light on it and moved the distributor. The timing mark when from one end of the spectrum to the other. So I'm not sure if the timing is off and that's why I hear the engine making new sounds. Or maybe it was all the adjustments... plus I'm told change the oil twice after a blown headcasket to get any residual water out of the engine....

I'm not sure. I'll do the timing later and post what I'm attempting to do.

Right now tonight I'm just savoring my personal victory! Back in 1986 I had to pay my mechanic $1000 to fix a blown headgasket on my other Toyota truck.

So to do it all myself was a trying, frustrating learning process that has made me better on something I thought I could never do.

Thank you all!

 

Great feeling isn't it. Congrats on getting it running!

 

Feels like a great accomplishment when youre able to it on your own. Congrats bro

 

In your response to point E; if you can adjust the full sweep of the marks your distributor is close enough. I prefer tuning off a vacuum gauge, setting your car to factory specs doesn't take into account the age/condition of the engine, quality of the fuel, or any other variable really.

 

Correct. Reread the second paragraph of my second post for the explanation.

You are loosening the hold-down bolt too much and moving the distributor too far. You only want to loosen the hold-down bolt to the point where you need to push the distributor with some force to move it, otherwise it will bounce around as the engine runs. Very slight movements of the distributor are key here, like a fraction of an inch.

This is a good idea if you are recurving the distributor, but a BAD idea if you have a stock distributor in a stock motor, especially an older distributor with possibly worn out advance springs. Tuning for max vacuum at idle will almost always result in a motor that pings badly unless you recurve the distributor to limit the total advance and the speed at which the advance tips in.

 

I was going to recommend checking full mechanical advance but decided that was jumping ahead.

I have tuned many old cars from the 50's,60's, and 70's and never had an issue of over advancing a car from tuning off a vacuum gauge. That also kind of segues into the old hot rod adage of advance it until it pings then back off...

 

Advance till it pings then back off till it shuts up. Then grab the vacuum gauge to set the idle mixture. This ain't rocket surgery.