timming chain

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Dec 31, 2003 | 10:48 AM

Bronco86

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From: Gonzales

timming chain

i am having a prob with acceleration, truck runs great till i try to pass someone or give it alot of gas. can this be a symptom of too much slack in my timming chain? skipping wile under heavy load...if not what could it be?

Dec 31, 2003 | 12:31 PM

dbuck50

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could be that or something else. Measure the slack in degrees by turning the crank with a breaker bar to TDC and then slowly turn it back the other way and watch the rotor to see when it moves. you can see from the timing marks how many degrees of slack you have. Anything 5 degrees or over is a lot and needs to be replaced...I think it won't jump until a tooth until you have 7 or 8 degrees of slack at least. You would notice a difference if you replaced it if it has 5 degrees or more.

Jan 1, 2004 | 11:19 AM

siphor84

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From: Colorado

You mention missing under heavy load...

There is a deal with the placement of the PCV return line going straight into the 8th cylinder. This causes misses, after fixing this problem a lot of people have reported the miss goes away. Read this post and move the PCV return line to the top of the vac tree. Only takes but a few minutes, and you never know, it may be your problem.

https://www.ford-trucks.com/forums/s...threadid=15232

Jan 1, 2004 | 03:34 PM

1994f150truck

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Engine misfires under load is a also a classic symptom of ignition problems. Look at the plug wires, dist cap, plugs, coil, etc. A timing chain would olnly need skip a tooth or two before the engine ran very poorly, and then it would run like this all the time, regardless of load. It would also give lower vaccum at idle that you would be able to see with a gauge. Ignition timing would also be way off because the dist. is driven by the camshaft. There are ways of confirming a cam out of time without having to tear down the front of the engine.

Jan 2, 2004 | 11:52 AM

Bronco86

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From: Gonzales

good point 94. it isn't like it is simply missing it is like hitting the gas, letting off, hitting gas, letting off, and on and on and on untill you stop trying to accelerate, kinda like running out of gas. but my fuel pressure is good and i have a fresh filter, the tps seems to be reading good (i may not have read it corectly) but it seemed to be good. i am lost WTF do i do now?

Jan 2, 2004 | 12:19 PM

siphor84

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From: Colorado

Is your air intake clean, and the butterfly valves moving smoothly? I'd also check for vaccum leaks. 1994 is right, a loose timing chain would cause problems at all engine speeds. I have a really loose chain in my bronco, it gives me crappy gas milage and bad idle, but doesnt cause any significant problems.

Last edited by siphor84; Jan 2, 2004 at 12:24 PM.