5.8 new headers help
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5.8 new headers help
Hi everyone I'm new and I have a hopefully minor problem. I have a 95 f250 5.8. I put new headers and a flowmaster exhaust on it. It sounds great but now it runs a little rough, if you push the pedal down hard it romps but at low rpm it shudders a bit. The smog pump lines that went to the old headers are not connected anymore. I plugged the vacuum line (pink) to the smog thing on the top of the motor. It ran great before the exhaust upgrade. The only thing I can think is now there is so much more flow it's throwing the o2 sensor off? Is that possible? It has new plugs wires cap and rotor already. No cel on.
FTE Legend
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Where is the O2 sensor installed now? What plugs and wires did you install? You could just have a crossfire problem with the new wires, it is very important to keep wires for plugs 4-5 and 7-8 separated.
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I did the plugs a few moths ago , motor craft I think, I'm pretty sure it's all right, it idles rough now, like up and down a bit. The new headers didn't have a hook up for the smog pump. The o2 sensor is in front of the cat as it was before. I replaced it, but I have the original, could that be it? It's a "flowmonster" cat. I have all the original stuff though
Lead Driver
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The headers themselves are not the issue, although it's certainly possible that something else that you replaced/messed with is causing a problem.
Did you break any vacuum lines by accident? A broken vac line to the map sensor will cause issues.
Unplug the o2 sensor and see if that helps as well.
Did you break any vacuum lines by accident? A broken vac line to the map sensor will cause issues.
Unplug the o2 sensor and see if that helps as well.
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I'll check the map sensor out when I get home, if I unplug the o2 sensor won't it go into open loop /limp mode? I'll try it and see. The smog pump not being hooked up won't cause an issue? It was dumping a lot of air into the exhaust , doesn't that influence the o2 reading? Could the headers be messing with the spark, the passenger side is really close to three of the plug wires
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All the vac lines are good, I went back to the stock o2 sensor, maybe a little better? It's still doing it. I tried unplugging the o2 sensor but it definitely ran worse. Help!
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This may sound silly, but check that every plug wire is fully locked on the plugs.
I had a buddy that put long tubes on his 351 and several days later he complained of a similar problem.
Checked for codes, nothing. I asked him did he fully put the plugs wires on until they were locked and he said he thought so. I went through and found 3 that were just slipped on.
After that, no more problems.
I had a buddy that put long tubes on his 351 and several days later he complained of a similar problem.
Checked for codes, nothing. I asked him did he fully put the plugs wires on until they were locked and he said he thought so. I went through and found 3 that were just slipped on.
After that, no more problems.
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Could an exhaust leak at the header cause this? The passenger side header had fitting issues. I don't think it's leaking but I just test drove it and felt a hiccup associated with a weird like puff sound almost. This happened at wide open throttle hard acceleration. It is idling up and down , uhh-uuhh uhh-uuhh. Any help is appreciated!!!
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The passenger side header is really close to the plugs, the flange is actually touching the wires on the three plugs it crosses. I know that the stainless headers hold a lot of heat, could this be the problem? Could excess heat directly at the plug cause a misfire? It does seem a little better right at startup from cold
FTE Legend
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From: Ottawa, Ontario
Are you absolutely sure you have the plug wires routed correctly? If you are new to Fords you may have them all wrong. You can rule out the exhaust upgrades as a cause of your problems, and as long as there are no leaks in the exhaust system upstream of the O2 sensor the disconnected air injection system won't matter either.
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What "smog thing" did you plug the vacuum line for: the EGR valve? The tube from the air pump is/was downstream of the O2 sensor so that has noting to do with the problem. Did you trace the four wires on each bank back to the distributor to verify you didn't mix them up?