Ignition woes

[deejay1272]

When I was servicing my distributor and setting my timing tonight, I managed to royally screw things up and now no matter what I do, I can't get the car to start.

While I was turning my crankshaft (dizzy was removed at the time) I did take a few very small turns counterclockwise before noticing in the FSM that I'm not supposed to do that. Does this mean that my cam shaft is all out of sequence?

[takza]

Search on TDC....you need to find it.

[Petros]

Usually not, if your timing belt is loose it could cause it to skip a tooth. Pull the front cover and check your cam timing (little hole on sprocket lines up with the point when crank is at TDC). Make sure you get the dist back in correctly, the rotor has to point at number 1 cyl terminal when all the way in easy to get it a tooth off because of the dist gear helix.

you should be fine. Good luck

[Petros]

delete double post

[deejay1272]

Search on TDC....you need to find it.

I found it all right. I can remove cyl #1 plug and confirm that I see the top of the cylinder when the crankshaft points to 0 degrees (TDC). After I confirm that cyl #1 is at TDC, I install the dizzy with the pin and the marker in alignment (shown here http://www.tercel4wd.com/forums/viewtop ... f=7&t=5216) and attempt to start.

It turns over, but doesn't start!

Petros - Thanks for the additional information. will pull the front timing belt cover and check that my cam timing is correct. I don't think I'll have time, but if I do, I'll swap the timing belt while I'm in there. BTW - what is the bolt size at the crank shaft? I've been turning the engine over by hand and it's pretty annoying.

[Petros]

changing the belt is a lot more work, might consider the front seal while you are there.

I think the bolt is 19 mm (3/4" works).

[deejay1272]

After attempting to start my engine with the position of the crank shaft and/or the rotor totally wrong (I tried several different orientations before giving up for the night), do you think I could have harmed any equipment? (Occasionally I heard some odd noises or if the car would start, it ran extremely roughly).

[Highlander]

It sounds like you've got the ignition timing 180* out of phase from the cam timing- easy way to find out- firing order is 1342, swap 1 and 4 then 3 and 2 at the dizzy cap, if it runs well, that's it. Remember that the cam is running at 1/2 the crank speed, so it turns once every two rotations of the crank. You shouldn't have done any damage, since its a clearance engine.

[Petros]

Not likely, the spark would just fire when there was not conditions for combustion in the cylinder. Even if valve timing was off from skipped belt, they clear the pistons when fully down.

No worries, you just have to double check all your settings. It is not as easy to get the distributor in correctly as you might think, there is not any leeway, it must go in with the gear in the correct position.

[deejay1272]

Remember that the cam is running at 1/2 the crank speed, so it turns once every two rotations of the crank.

I think I just mentally discovered my problem. I was rotating the crank until cylinder 1 was TDC, but I probably didn't realize that I needed to rotate the crank shaft one additional time to ensure that I was in the compression stroke, not the exhaust stroke. (Just my luck that every time I found TDC, I happened to be on an exhaust stroke!). I really should have taken a moment to think about the FSM saying that if you cover the port, you should feel pressure as the #1 cylinder approaches TDC - indicating that it's a-fixin' to light the fire!

Well, since I've become so intimately familiar with my ignition system during this whole debacle, I think I'll go ahead and get new plugs and a new cap 'n rotor since I found significant wear on my contact points. My wires look new (haven't tested resistance), so I'll probably leave those alone.

[splatterdog]

There are 2 TDC's. You need the compression stroke TDC to install a distributor.

Stick a finger in #1 spark plug hole and have a helper just bump the starter till you get a whoosh out around your finger. Next line up TDC on the front cover. Now it's time to drop the distributor.

Test your plug wires with water in a spray bottle. Hose em down. If you can persuade the spark to come out, you need wires. Personally, unless I knew they were newer, I would do them with the rest of the tune up. A wire set is pretty cheap on these.

[deejay1272]

Last night I hooked everything up, started the motor and took 'er for a spin to see how she performs. At low load, it performs quite well, but at full throttle (esp when I can feel the Weber secondaries kick in), I'm getting a bog condition with low power.

Here's what I'm running right now as a reminder:

Weber 32/36 carb, vac advance hooked up to the gas filter. The other two vac ports on vac advance are plugged. Both Weber ports (EGR and vacuum advance) are plugged.

Timing: 13 deg BTDC with vac advance hooked up, but when I remove vac advance and plug the line, the timing retards way beyond 5 deg BTDC (to somewhere near 10 to 15 deg after TDC).


Could this low power/bog condition at full/medium full throttle be a vacuum leak or something that I haven't considered?

[Highlander]

First off, set the timing at 10* BTDC WITHOUT the vacuum hooked up (but plugged-vacuum side that is). I, personally wouldn't plug the other two ports on the dizzy, as it might keep the vacuum advance from advancing all of the way (maybe only plug one so that it can vent). The weber 32/36 is a little large for our 1500s, so with the throttle opened fully, the car is overcarbureted, try modulating the throttle a little instead of mashing it- try for the best response by using your foot. Another consideration, what elevation are you at, and is the carb set up for that elevation? Webers can be very sensitive to base mixture.

[Petros]

it looks to me like the timing is the problem. Better fix that before you do damage to your valves, get it set to 10 deg BTDC with vac lines off and plugged, idle at 800 rpm, like HIghlander says. Than see what you have.

Portland is about at sea level, so I doubt that is the issue, but the carb still could be too rich for the 3ac.

[4wdchico]

I would time it per the previous instructions. Also, if the advance diaphragm that is closest to dist body is still good, having both nipples on it plugged off you could have a situation where pressure is building in it when the other advance actuates and cranks in some advance. Since you will most likely never need to use the unused diaphragm again you could just leave both nipples open to the atmosphere. Or, if you want to go overboard, tiny vac system air filters are fairly common in older carbed cars in junk yards.