I need to get a copy of where the spark plug wires go on the distributor cap for a F150 4.9L 1990 model. Someone changed my distributor cap and I believe two are on the wrong posts. Can I find this diagram on the internet or will I need to purchase a repair book?
You should be able to find it, but you should also buy a Haynes manual - $12 from most parts stores. I don't like Chilton's manuals, but it will have the "firing order" that you're looking for. Your cap should AT LEAST have a "1" molded into it to ID the #1 post.
Hi Steve, OK here goes ---- set number one clinder on the compression stroke ( OK I know it is hard to tell, pull the plug and look in the plug hole and you can see when both valves are closed and the piston is up )if you are correct the timing mark should be pretty close to lining up with some mark on the timing plate. Set the timing mark on the damper, the scribed line not the notch, to line up with the zero timing mark on the timing cover plate. No! not the one that is cast into the cover and is visable from the right side of the engine. The correct timing mark is on a plate held on with the timing cover bolts at the left side of the engine at about the 9 oclock position. Naturaly you can't see the plate very well from above. Slide under the truck and you can see the plate. Set the damper mark at zero. Pull the distributor cap and see where the rotor is pointing. That will be the number one for THAT distributor. NUmber one can be anywhere as long as the firing order is followed in wiring the cap, if the dist has been removed and relaced ,the rotor might not line up with the 1 cast in the cap. There are 3 different places shown in the motor books for number one. To the right and to the left of the cap hold down screw located at about 7 O'clock, are two of the positions shown. There is another shown as 2 spaces to the left of the hold down screw, I think that might be the one that has the one cast into the dist cap. You can pull the distributor and set number one anywhere you like, as long as the timing mark on the crank damper is at zero on the timing scale when you do it and after you finish.
The firing order is as follows ------- When viewed from the drivers side Number one is located to the right of the cap hold down screw in this example. GOING CLOCK WISE STARTING WITH ONE. 1-5-3-6-2-4
The engine cylinders are numbered from the front to the back as 1-2-3-4-5-6
NOTE+++++ IF SOME HAS HAS SET THE DISTRIBUTOR USING THE INCORECT MARKS ( THE CAST ONES )AND THE DISTRIBUTOR HAS NEVER BEEN REMOVED THE TRUCK WILL STILL RUN AND HAVE NO GET UP AND GO BUT IT WILL START WHEN HELL FREEZES OVER AS IT WILL BE VERRRRRRRRRRY RETARDED.
An easy quick check is that the firing order is 1,5,3,6,2,4. If the wires don't follow this order, something is definitely wrong. If they do follow that order, you probably are OK, because otherwise they all would be off (unless routed backward) and it likely would not run at all--seems to me anyway.
INLINE SIX POWER! '95 F150 XL
300 Cubic Inches of Low RPM Truck Torque! And twin-I-beams too!
"Drive a stick young man! There'll be time for automatics when you're old and unable."