302 timing chain check
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From: northwest Georgia
302 timing chain check
I have an '85 f150 with an EFI 302 that has been having trouble running. The only way i can describe the sound when trying to start it is that it sounds like the battery it low on charge. if you hold the gas all the way down, after about 10 seconds of rotating, the engine starts but smokes bad and wont stay running unless you hold the gas. i think the timing chain might be stretched but i dont know for sure. i've adjusted the timing over and over. i can get it running good for a little bit but then it just goes back to smoking and dying. is there and way to see if the chain is stretched or broken without removing the cover? sorry for the long post and thanks for any help.
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From: south louisiana
Remove the distributor cap. Put a breaker bar and 15/16" socket on the crank damper bolt (center of the front pulley). Rotate the crank with the breaker bar (back and forth) and see how far it moves before the distributor rotor moves. I don't know what the spec is on this before replacing the timing set, but if you can rotate the crank more than about 1/8 turn, I'd replace the set. 1/4 turn is one whole turn in the firing order. Two complete turns of the crank in each cycle of the firing order.
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From: northwest Georgia
4-5 degrees is enough to indicate a bad chain? the only reason i singled out the timing chain is because i've heard they are pretty bad about going out since they are plastic. you think i'm even on the right track? would low compression do what i described?
Hotshot
Joined: May 2003
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From: south louisiana
Originally Posted by reecem13
4-5 degrees is enough to indicate a bad chain? the only reason i singled out the timing chain is because i've heard they are pretty bad about going out since they are plastic.
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Postmaster
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Don't be fooled it can flood out trust me.........
start checking things
pull the vacuum line off the fuel pressure reg and see if it has fuel in it.
pull the fuel pump fuse and see if it runs any better...might only run good for a few seconds and then die, so if it does get a fuel pressure gauge on it while it's running and see
start checking things
pull the vacuum line off the fuel pressure reg and see if it has fuel in it.
pull the fuel pump fuse and see if it runs any better...might only run good for a few seconds and then die, so if it does get a fuel pressure gauge on it while it's running and see
Last edited by HemiEater; Jul 12, 2007 at 04:57 PM.
More Turbo
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From: Sweden
Timing chain is REALLY likely if it hasn't been changed.
Check the vac "coffee can" canister behind the starting battery for corrosion.
Check the hard plastic vac lines going over the passenger side. The heat there (esp if there's a manifold leak) causes them to harden and crack.
The timing chain is a major job but necessary. The water pump, alternator, smog pump, air conditioner/power steering brackets all have to come off. You don't have to open up the AC system thank god. Notes: You MUST have a Ford harmonic balance puller (borrow from AutoZone) to pull the HB, a normal gear puller will only rip it apart. Be prepared to have a water pump bolt break off in the engine, it happens a lot so have an EZ-out or Dremel grinder or whatever you think you might need on hand. Always replace your water pump bolts in this process. Consider replacing your water pump at this time. Replace the timing cams and chain even if one of them doesn't look worn.
Check the vac "coffee can" canister behind the starting battery for corrosion.
Check the hard plastic vac lines going over the passenger side. The heat there (esp if there's a manifold leak) causes them to harden and crack.
The timing chain is a major job but necessary. The water pump, alternator, smog pump, air conditioner/power steering brackets all have to come off. You don't have to open up the AC system thank god. Notes: You MUST have a Ford harmonic balance puller (borrow from AutoZone) to pull the HB, a normal gear puller will only rip it apart. Be prepared to have a water pump bolt break off in the engine, it happens a lot so have an EZ-out or Dremel grinder or whatever you think you might need on hand. Always replace your water pump bolts in this process. Consider replacing your water pump at this time. Replace the timing cams and chain even if one of them doesn't look worn.
Postmaster
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so if my truck start to act like it's flooding out ...blowing smoke, hard starting, have to hold it to the floor to keep it running....I should just replace the timming chain and gears...??????????
don't check anything just replace the chain......
don't check anything just replace the chain......
Postmaster
Joined: Jun 2005
Posts: 2,656
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Originally Posted by reecem13
i can get it running good for a little bit but then it just goes back to smoking and dying.
don't sound like a chain to me...........The fact that it will run good for a while makes me wonder.
I have had chains slip before and when they did the motor runs like chit and thats it.....
Senior User
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From: willamette valley ore
The easiest way to check for a stretched timing chain is to get it running, if possible, and put a timing light on it. If the timing marks waver back and forth or are erratic then you have a chain that is history. Steve
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From: northwest Georgia
havent got a chance to work on as all my free time goes to restoring a bronco. if it is the chain, it wont be as hard for me as all the emissions equipment is gone. it was removed by the previous owner. i'm going to get a timing light and try that since it sounds like the easiest way except the fact that the only way the truck stays running is if the gas is held down.