1989 F150 I6 Ignition issues?
09-08-2008, 04:46 PM
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1989 F150 I6 Ignition issues?
Got this truck a few weeks ago from someone who had no idea about how engines work.
Replaced a few parts: plugs, wires, cap, rotor (all Motorcraft), reman distributor (bolt for cap broken off in the old one) and the IAC.
So, I've fixed the high idle and the MAJOR ignition breakup. Now, the idle is a bit rough after the truck warms up and it has a hesitation when at about 5%-10% throttle. Just enough to shake the truck slightly enough to be annoying. Most noticeable when cruising on the highway. Idle's at ~700rpms though. When accelerating at anything about 10%, it runs great and pulls great. No hesitation, no misfires or anything.
A few points:
Timing is a bit...odd. I was expecting a divot on the crank pulley, instead there is 1/4" wide machined notch taken out of the back. I guess that's the way its supposed to be, but when trying to set timing it seems horribly inaccurate. Is that the way its supposed to be?
Now here's the really odd part: I can't get it to time on the 1st spark plug. It runs great, but will not fire where the notch is. If I move to cylinder 3, it seems to be firing dead on. Is it possible someone put the wrong crank pulley on this truck?
EDIT: I should mention, when the truck is warming up, it idles nearly perfect. The idle and ignition breakup gets worse and worse as the engine heats up.
Replaced a few parts: plugs, wires, cap, rotor (all Motorcraft), reman distributor (bolt for cap broken off in the old one) and the IAC.
So, I've fixed the high idle and the MAJOR ignition breakup. Now, the idle is a bit rough after the truck warms up and it has a hesitation when at about 5%-10% throttle. Just enough to shake the truck slightly enough to be annoying. Most noticeable when cruising on the highway. Idle's at ~700rpms though. When accelerating at anything about 10%, it runs great and pulls great. No hesitation, no misfires or anything.
A few points:
Timing is a bit...odd. I was expecting a divot on the crank pulley, instead there is 1/4" wide machined notch taken out of the back. I guess that's the way its supposed to be, but when trying to set timing it seems horribly inaccurate. Is that the way its supposed to be?
Now here's the really odd part: I can't get it to time on the 1st spark plug. It runs great, but will not fire where the notch is. If I move to cylinder 3, it seems to be firing dead on. Is it possible someone put the wrong crank pulley on this truck?
EDIT: I should mention, when the truck is warming up, it idles nearly perfect. The idle and ignition breakup gets worse and worse as the engine heats up.
Last edited by N1XRR; 09-08-2008 at 04:58 PM.
09-08-2008, 09:36 PM
#2
On the scale mounted to the block there is a deep notch, that should be 10 degrees BTDC, where the timing should be set. The harmonic balancer should have a groove in it to align with the deep notch when setting the timing. You need to remove the spout connector near the distributor to set the timing or it will be off. Follow the directions on the underhood decal. After setting the timing you need to reset the computer because it stores a code for the spout if you don't.
09-09-2008, 09:04 AM
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On the scale mounted to the block there is a deep notch, that should be 10 degrees BTDC, where the timing should be set. The harmonic balancer should have a groove in it to align with the deep notch when setting the timing. You need to remove the spout connector near the distributor to set the timing or it will be off. Follow the directions on the underhood decal. After setting the timing you need to reset the computer because it stores a code for the spout if you don't.
I should have explained this earlier, that part I have already done. Pulled the SPOUT connector, attempted to set timing. I should probably take a picture of what I'm talking about tonight.
The crank pulley (harmonic balancer) doesn't have a notch or groove in it. On the back of it there is a chunk of metal taken out of it that looks like it came that way from the factory. That chunk is about 1/4" wide and 1/4" deep. I have looked all over the pulley, I don't see a groove anywhere.
