79 f100 trouble
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From: fort bragg nc
79 f100 trouble
ok i have a 79 f100 it back fires and hesitates when you accelerate on the throttle in 2nd , 3rd, and 4th and sometimes first im going insane trying to get it working right what could be the problem i had it timed and tuned up
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From: THIS IS SPARTA!, ...Mo.
Why does everyone assume something is out of time when they have a running issue??!! Sorry, this is one of my biggest pet peeves. It's RARELY EVER THE TIMING!!! If it's back firing and running poorly, there's a chance the cam shaft has a flat lobe on it. Take the valve covers off and check for a really loose rocker arm. If you adjust it and the back fire goes away, plan on putting a new cam in it in the future.
Of course this is just a guess since you didn't even tell us what engine it has or a brief history on the truck. How long has it been doing this? Has it steadily gotten worse and worse? Does it do it more when cold than hot? More hot than cold? Have you done a tune up recently? All good stuff to know here.
Of course this is just a guess since you didn't even tell us what engine it has or a brief history on the truck. How long has it been doing this? Has it steadily gotten worse and worse? Does it do it more when cold than hot? More hot than cold? Have you done a tune up recently? All good stuff to know here.
Fleet Owner
Joined: Dec 2009
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From: NorCal
What TROUBLESHOOTING have you actually done prior to fishing in this forum for possible answers?
We're all here to help but we all have an expectation that you put some effort/thought into figuring it out prior to posting a thread.
We're all here to help but we all have an expectation that you put some effort/thought into figuring it out prior to posting a thread.
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From: fort bragg nc
sorry im kinda new to this the motor is a 289 hi pro from a 65 mustang i got the 9inch rear end 2wd 4sp manual new cap, rotor, plugs, wires holley 4bbl 650cfm with eletric choke eddle brock 14 in air filter. it just started doing after new cap and rotor and wires i havent replaced the igniton coil yet. it acts like its starving for fuel then back fires threw carb then goes it only happens when i hammer on the gas or going up hill it feels like its lacking power. it idles smooth works great when i slowy accelerate its been quite cool here in fort bragg nc starting to warm up i got the truck this year from a guy
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From: townsend DE
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Joined: Jan 2011
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From: THIS IS SPARTA!, ...Mo.
There was a 289 that used a different cam with a different firing order. (ask me how I know) Make sure the firing order is correct for your engine. Then take all the plugs out and re-gap them. If you used Champion plugs, throw them away and buy Autolites. Tell us how it goes. I'm sure we all didn't mean to come off as abrasive, but there's some things that need to be put in the post so we know a little about what's going on.
Nothing makes me more crazy than a customer coming in to the shop and saying, "My car's not running right. What's wrong with it?"
Nothing makes me more crazy than a customer coming in to the shop and saying, "My car's not running right. What's wrong with it?"
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Fleet Owner
Joined: Dec 2009
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From: NorCal
First of all, thanks for the additional information. That helps a TON.
With that said, I dug up a recent issue of Mustangs Monthly which contains a troubleshooting guide to at least provide some possible leads. Here it is verbatim from the article:
Engine Misfires
With that said, I dug up a recent issue of Mustangs Monthly which contains a troubleshooting guide to at least provide some possible leads. Here it is verbatim from the article:
Engine Misfires
- Faulty spark plug or spark plug fouling
- Ignition wire insulation breakdown and crossfire
- Weak battery
- Improper point gap
- Weak distributor ground (check breaker point ground strap). Cracked distributor cap or rotor
- Faulty ignition coil
- Poor distributor rotor continuity
- Wet ignition system
- Intermittent short in property or secondary ignition wiring
- Blow head gasket btwn cylinders
- Fuel mixture extremely lean (Ding!?)
- Ignition timing too far advanced (pinging/pre-ignition)
- Ignition timing too late (runs like a slug and the exhaust is loud)
- Improper centrifugal advance curve
- Aggressive vacuum advance curve (comes on too fast)
- Point bounce
- Faulty ignition coil
- Defective ignition wires
- Throttle linkage improperly adjusted (not opening all the way)
- Secondaries not opening on four-barrel carb.
