351 Runs Bad!!!!!
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Freshman User
Joined: Jun 2002
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From: Salmon Arm Canada
351 Runs Bad!!!!!
I have this Ford remanufactured 351W in my 88 F-250 4x4 EFI 5-speed and its running really bad ill try to explain. At low rpm it sounds like it wants to die but does not then when you hammer down it hesitates then starts backfiring and poping really loud when it reaches higher rpm. When you are starting off it sometimes takes alot of right foot to get it moving feels like as soon as you put weight on the engine it just dies. When you power shift it pops really bad and starts shaking and i dont know where to start looking for the problem since it just started doing this. Just throw ideas at me and tell me what you think it is and ill start looking myself ill tell you all when i figure it out what is wrong with the thing. Thanks
Senior User
Joined: Aug 2001
Posts: 321
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From: Queen Creek, AZ
351 Runs Bad!!!!!
Sounds almost like the timing's off, but if it was running fine before then that's not it. However, it could be that a plug wire has been installed incorrectly, if you've have them off recently.
Now, I'm goin' for ignition. Sounds like the ignition module could be goin' out, or the coil isn't firing correctly, or the cap/rotor are corroded, or a plug wire's not installed correctly, etc.
Being EFI, pull the engine codes. They'll probably say something about O2 sensors being out of range, but that's probably not the cause, but rather a symptom. Look for codes mentioning ignition failures or fuel system problems.
A vacuum leak is a possiblity, and definately worth checking out, but I think it's electrical/ignition.
Oh, also check that your battery is good. It sounds wierd, but I've seen stranger things. Also check for physical damage to your spark plugs/plug wires. If the truck will run long enough for you to do this, run the truck at night with lights off in the dark and look for a light show, either from the plug wires or the coil, and check for a bad ground wire.
Sounds like a lot, good luck.
Later,
Ben
Now, I'm goin' for ignition. Sounds like the ignition module could be goin' out, or the coil isn't firing correctly, or the cap/rotor are corroded, or a plug wire's not installed correctly, etc.
Being EFI, pull the engine codes. They'll probably say something about O2 sensors being out of range, but that's probably not the cause, but rather a symptom. Look for codes mentioning ignition failures or fuel system problems.
A vacuum leak is a possiblity, and definately worth checking out, but I think it's electrical/ignition.
Oh, also check that your battery is good. It sounds wierd, but I've seen stranger things. Also check for physical damage to your spark plugs/plug wires. If the truck will run long enough for you to do this, run the truck at night with lights off in the dark and look for a light show, either from the plug wires or the coil, and check for a bad ground wire.
Sounds like a lot, good luck.
Later,
Ben
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Freshman User
Joined: Jun 2002
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From: Salmon Arm Canada
351 Runs Bad!!!!!
One thing I just remembered awhile ago my fuel pump on my frame rail died for some reason it was getting no power so I hot wired it off the nearest power source that came on with the key the truck ran fine up untill now do you think that may have something to do with my problem??? I will check for vacume leaks and all my ignition. The battery is pretty beat and sometimes it smokes pretty bad time to get a new one I guess.
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Joined: Aug 2001
Posts: 321
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From: Queen Creek, AZ
351 Runs Bad!!!!!
Umm, yeah. If your battery is smoking, it's probably a safe bet that it's time to replace it. Generally, batteries do not smoke.
As for hot-wiring the fuel pump, it's possible that you may have damaged it if the "hot" source you're using is over- or under-loading the pump. If it's over-loading it, then it's probably just a pump that's damaged. If it's under-loading it, then it would've blown a fuse for that circuit by now, I'd think. If not, it's possible that you've damaged that particular electrical ciruit.
In my humble opinion, replace the battery because it needs replaced anyway, and spend the half-hour it takes to properly troubleshoot the fuel-pump's original electrical problem and repair it. If you've directly "hot-wired" the pump, then you've by-passed certain safety features, like an enertia cut-off switch, which could potentially save your life or that of another in an accident.
Just my humble opinion. In any case, doing both of those two things I just mentioned will probably have your truck running fine again.
As for hot-wiring the fuel pump, it's possible that you may have damaged it if the "hot" source you're using is over- or under-loading the pump. If it's over-loading it, then it's probably just a pump that's damaged. If it's under-loading it, then it would've blown a fuse for that circuit by now, I'd think. If not, it's possible that you've damaged that particular electrical ciruit.
In my humble opinion, replace the battery because it needs replaced anyway, and spend the half-hour it takes to properly troubleshoot the fuel-pump's original electrical problem and repair it. If you've directly "hot-wired" the pump, then you've by-passed certain safety features, like an enertia cut-off switch, which could potentially save your life or that of another in an accident.
Just my humble opinion. In any case, doing both of those two things I just mentioned will probably have your truck running fine again.
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Freshman User
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From: Salmon Arm Canada
351 Runs Bad!!!!!
Ill give it a try soon the only reason I hot wired the pump was just to get the thing home but it ran fine for awhile so I put it off always seems like I have a millin things to do well ill tell you what happens when ive tried all that.
