Timing

[ericmp]

I have a 96 F150 with a 300 L6. It keeps missing, so I turned the distributor and that just made it worse. Im ready to replace the spark plugs and wires, but first I need to know an easy way to find TDC of my #1 cylinder. I cant use the crank pully because it is off its mark. Secondly, sometimes when the truck is running, Ill push the clutch in and it will trigger the ignition and the starter will sqweel. Ill turn the truck off and restart it, and it wont do it no more. Is there a swith or something that would have gone bad? This is all new to me so any advice will be helpfull.

 

[conanski]

Pull #1 spark plug and rotate the motor by hand with a breaker bar on the crank, as the piston comes up to TDC on the compression stroke you will feel air being pushed out the plug hole of you put a finger over it. You can verify the piston is at exact TDC with a small piece of wire placed in the plug hole and touching the top of the piston, you will feel when it there by rocking the crank back and forth a little. The crank timing mark should also be at 0 at this point. After you replace the plugs and wires remember to remove the spout plug to set the base timing, if you don't it will be way off. Also sounds like you may have an ignition switch problem or some rubbing wires under the dash.

 

[Old_Paint]

I have a 96 F150 with a 300 L6. It keeps missing, so I turned the distributor and that just made it worse. Im ready to replace the spark plugs and wires, but first I need to know an easy way to find TDC of my #1 cylinder. I cant use the crank pully because it is off its mark. Secondly, sometimes when the truck is running, Ill push the clutch in and it will trigger the ignition and the starter will sqweel. Ill turn the truck off and restart it, and it wont do it no more. Is there a swith or something that would have gone bad? This is all new to me so any advice will be helpfull.

X2 on Paul's technique for finding TDC on #1. If you're changing the plugs anyway, pull 'em all. That'll make turning the engine over a lot easier.

There is no need to change the timing if you're just replacing ignition parts. Cap, Rotor, wires, and plugs can all be changed with a very minimal effect to timing. You shouldn't have to change it much at all. BUT, what you do need to do, is make sure that SPOUT connector is out like Paul said before you put the light on it. That eliminates the advance supplied by the EEC, and makes the engine rely purely on mechanical timing. That is the 10 degrees BTDC that nearly every Ford engine I've ever heard of wants for base timing.

You said something about the timing marks being "off"? Have you spun the harmonic balance? IF so, I'd be getting a new one real soon because you're talking about some pretty nasty damage to bearings if that balance is not where it should be. If it's "OFF" because SPOUT is still connected, though, that's a whole other story. If the balance has spun, it won't do any good to find TDC on #1 unless you intend to put your own timing marks on the balancer. I don't think that's going to be the best idea. A new balancer is not very expensive if that is indeed the problem. Or did you mean the marks have rubbed off? Ya gotta be careful doing this, but you can brighten up the outer edge of the balancer with some Scotchbrite while it's idling. Put it on the end of a stick, though, and don't stick your fingers up there. You may wind up drawing back a nub. It's probably safer to do it with the engine stopped and use a piece of sand paper to clean the timing marks. Once you clean the rust off, mark the 0 (TDC) mark and the 10 BTC marks with a white paint pen to make them easily visible with the timing light. Pull SPOUT, put the light on it, set it for 10, clamp it down, put SPOUT jumper back in. That's all you can do to the ignition on these systems.

Now, as for the starter picking up when you push the clutch in, that sounds like a contact is sticking in the ignition switch. Try this:

With the clutch out, engine off, turn the keyswitch to START, and slowly let it turn back to RUN, but don't let it snap back. With the tranny in neutral, push the clutch in and see if the starter picks up. If so, you'll need to replace the ignition switch in the column. Not a hard job at all, really. Try it several times to see if the switch is really sticking, though. If you manage to make it happen, then repeat the test, only let the key snap back to RUN as most people do by just letting go of the key. See if the starter engages when you press the clutch again.

The clutch switch is a pressure switch on your hydraulic clutch which is not activated until the clutch is fully depressed. The starter "squealing" when you push the clutch means the start signal was applied to the clutch switch before the pedal was pushed, and pretty much indicates the clutch switch is working just fine.