Distributor/timing help

Maintenance/Repairs
1

Folks, I legitimately need help. I may have bitten off more than I can chew by myself.

I put in a new distributor in my truck not knowing all the ins and outs. Now im paying for it.
I have a 1993 Ford f-250 with the 5.8l 351W with electronic fuel injection.

So, I have gotten to where the truck will run and have narrowed the wires down to one of two spots.
Spot 1: Runs, but idles poorly. Unless im actively rotating the distributor to accelerate or retard the idle it can’t decide where it wants to idle.

Spot 2: idles fine, runs rough as heck. It can idle at one set RPM, but the motor bounces like a man eating demon.

I have a timing light, and im positive one of those two spots are where the wires belong. (Note: I already replaced spark plugs and all the spark plug wires so im not worried about that) However I think I put the distributor in wrong and or I may a wire or two out of place.

2

Did you install the distributor with #1 cylinder @ TDC?

And did you install the distributor so the rotor would point to the tower for #1 cylinder on the distributor cap when it dropped down?

Tester

3

I didn’t. I learned that here a little bit ago. Ill have to pull the #1 spark plug and manually move it there then try again.

However, once that is set and my idle/timing is set, if it still have issue then its for sure the wires being slightly out of order right?

4

This is the firing order for your engine.

Tester

1 Like
5

And you need to pull the base time connector to adjust the timing with a timing light. If left connected the timing will wander several degrees as you move the distributor.

6

So I tried pulling the #1 cylinder spark plug out, and reinserting the distributor to where it sits at the #1 plug. Now I can’t get it to start as I had it earlier.

Mind you I put that cylinder at its highest point. Is it possible thats reversed? Does that cylinder need to be at the bottom?

7

The piston must be on the compression stoke in the #1 cylinder.

Tester

8

So the piston should be on its way up then? Or sitting at the bottom as of its about to come back up?

9

When the crankshaft harmonic balancer indicator lines up with the block ZERO indicator piston #1 will be at TDC but it’s up to you to determine if it’s at the top of compression or exhaust.

10

Remove the spark plug. Place your thumb over the spark plug hole while someone turns the engine over by hand.

When you feel pressure on your thumb, the piston is coming up on the compression stroke. Turn the engine until the timing mark on the damper pulley is at zero degrees.

That’s TDC at #1 cylinder.

Tester

11

So Ive tried all of that, and the specs say 10 degrees before top dead center. Tried putting it there and haven’t been able to start it since earlier today. Got that lined up and the distributor rotor lines up with the #1 spark plug and nothing.

Can’t for the life of me figure it out why or what I did earlier to get it right.

If you had to guess, how much would it cost to turn it over to a pro?

Also its stuck in garage atm so i may have to get it towed…

12

10 degrees BTC is the static timing while the engine is idling.

If the timing mark is pointing at zero degrees, try inserting the distributor into the engine so the rotor points to where the #1 plug tower on the distributor cap.

If the distributor won’t drop in, look at the bottom of the distributor shaft and you’ll see a hex shaped hole. That hex shaped hole drives the oil pump drive rod.

You may have to reach down the distributor hole with a 5/16" socket on an extension to slightly turn the oil pump drive rod. Tape the socket to the extension so it doesn’t fall off into the engine.

With #1 cylinder at TDC, the distributor will drop in where the rotor points to where #1 spark plug tower is, and the distributor shaft will engage the oil pump drive rod.

Tester

13

So i got it to turn over again. BUT it bottoms out, itll idle smooth at 900rpm and then just dump to 500 and hold, granted I don’t let it run like that for very long. Any idea?

14

If the timing is retarded the engine will idle slower, even so slow that it might stall. At a cold start the computer attempts to push the idle speed up to well past 1,000 but if the timing is retarded it won’t get that high. You must get the timing set to the factory spec and then work from there on the idle speed.