timing or tfi?
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Elder User
Joined: Dec 2003
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From: shelocta, pa
timing or tfi?
I'm starting to work on them truck again since it is warm out. It's a 93 f 150 auto 2wd. It won't start and it ran fine till i drove it, turned it off came out the next day and won't start.
I do have spark and the fuel pumps come on. so I guess there is fuel. it had a miss once in a while so i changed cap rotor plugs and wires and it ran afterwards. The next day it wouldn't start. So i'm wanting to check the timing, but i have 2 sets of marks. on towards the top right(drivers) side and one on the passenger side that has some marks with a hole in it. Which one should i use? or just crank it till number one is in compression and see where the rotor points?
I do have spark and the fuel pumps come on. so I guess there is fuel. it had a miss once in a while so i changed cap rotor plugs and wires and it ran afterwards. The next day it wouldn't start. So i'm wanting to check the timing, but i have 2 sets of marks. on towards the top right(drivers) side and one on the passenger side that has some marks with a hole in it. Which one should i use? or just crank it till number one is in compression and see where the rotor points?
Elder User
Joined: Feb 2004
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From: San Luis Obispo, CA
A '68 240 I am working on actually has two marks on the harmonic balancer and two scales on the timing cover. I was looking at it (on the bench) today, and when one mark is on its TDC, so is the other. It seems that Ford wanted to make timing easier and planned ahead so that if an accessory got in the way on one side, the mechanic could use the timing light on the other. I have seen the hole you describe on later models - I think it is for a dealer tool for checking timing.
All the same, if the distributor is tightened down, it should not move (without help) in between when the engine last ran and now. I have had a running engine jump cam timing, but keep running. Upon shut-down, the engine would not run. I hope this is not your problem, but your engine probably does have the infamous fiber timing gear on the cam - there are numerous threads about this.
If you are getting spark at the right time, I'd look deeper on the fuel system side of the situation. Sorry I can't help you much with the EFI.
All the same, if the distributor is tightened down, it should not move (without help) in between when the engine last ran and now. I have had a running engine jump cam timing, but keep running. Upon shut-down, the engine would not run. I hope this is not your problem, but your engine probably does have the infamous fiber timing gear on the cam - there are numerous threads about this.
If you are getting spark at the right time, I'd look deeper on the fuel system side of the situation. Sorry I can't help you much with the EFI.
Elder User
Joined: Feb 2004
Posts: 909
Likes: 9
From: San Luis Obispo, CA
If your distributor timing has moved from being close to TDC and in the retarded direction, you might suspect the cam gears. They are more likely to jump timing than the distributor gears because the fiber gear is the weak link, especially at high mileage. You can be certain your cam timing is OK by removing the rocker cover and observing the rockers on #1 and #6 cylinders. They share the same TDC, which is the one on your timing mark. Take out all the plugs to make it easy to turn the engine by hand. When the timing is right, the "overlap" should be "split" at TDC. Just rock the crank back and forth, say 1/8 turn each side of TDC. On one of the two cylinders, you should see the intake & exhaust valves open & close. Right at (or very near) TDC, they are both barely open (this is the overlap). Other than in special cases, most cams are installed with this overlap occurring near TDC, hence the name "split overlap". If your cam timing has slipped, then this event will occur later. It is common for timing chains to jump one or more teeth, but I would expect this to be more rare in the case of timing gears. If the valves do not move at all when the crank turns, then you have a bad fiber cam gear. Even worse, you may have some bent valves. This is the worst case, so I hope that this has not happened to you.
Elder User
Joined: Feb 2004
Posts: 909
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From: San Luis Obispo, CA
I hope somebody will confirm this, but I think that the 300 is an interference motor.
I would not pull the valve cover unless you find that the distributor timing is retarded, even though the distributor is still clamped down. You will need a timing light to check this, while cranking the engine. In the old days you could use a 12-volt bulb across the points, but . . .
Bottom line: check the timing.
I would not pull the valve cover unless you find that the distributor timing is retarded, even though the distributor is still clamped down. You will need a timing light to check this, while cranking the engine. In the old days you could use a 12-volt bulb across the points, but . . .
Bottom line: check the timing.
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Elder User
Joined: Dec 2003
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From: shelocta, pa
i figured i would have heard it connect piston to valves. I'll post more when I find out what's what. I have to be in cleaveland most of next week.
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