Engine performance after removing catalytic converters
07-24-2016, 06:05 AM
#1
Engine performance after removing catalytic converters
95 F150 4.9
Truck would not run (idled fine no power putting the pedal to the metal). I determined the catalytic converters were bad. I gutted the first one by cutting a flap in it, welded that shut. Replaced second one with straight pipe.
It ran great for the first week after I took out the cats. Now the truck is hesitating, stumbling, stuttering, sputtering when accelerating. Runs normally when I get it up to speed around town at 30 - 45 mph but runs rough over 55 on the highway.
It's getting worse. Did I mess something up by taking out the cats?
From what I understand this model has one O2 sensor before the first cat. There is also a pipe after the first cat that leads to the EGR.
I am pretty darn sure I have a fuel delivery issue. Still idles great. Oil is clean and plenty of coolant with no leak issues. Put in new plugs one month ago. I just bought new plug wires and a cap and rotor which I'll install soon. I was also told to clean the throttle plate. Good idea yes?
I am very amateur-- but learning all the time. I am also very poor. Zero money for mechanic. This is my daily driver and I'm worried sick. Any helpful comments are much appreciated.
Truck would not run (idled fine no power putting the pedal to the metal). I determined the catalytic converters were bad. I gutted the first one by cutting a flap in it, welded that shut. Replaced second one with straight pipe.
It ran great for the first week after I took out the cats. Now the truck is hesitating, stumbling, stuttering, sputtering when accelerating. Runs normally when I get it up to speed around town at 30 - 45 mph but runs rough over 55 on the highway.
It's getting worse. Did I mess something up by taking out the cats?
From what I understand this model has one O2 sensor before the first cat. There is also a pipe after the first cat that leads to the EGR.
I am pretty darn sure I have a fuel delivery issue. Still idles great. Oil is clean and plenty of coolant with no leak issues. Put in new plugs one month ago. I just bought new plug wires and a cap and rotor which I'll install soon. I was also told to clean the throttle plate. Good idea yes?
I am very amateur-- but learning all the time. I am also very poor. Zero money for mechanic. This is my daily driver and I'm worried sick. Any helpful comments are much appreciated.
07-24-2016, 10:04 AM
#2
Senior Member
if the cats were an issue and clogged....then something made them clog. that does not really happen on its own with a honeycomb style cat. with age they can stop catalysing, but clogging is very rare. so you are likely correct that you have a fueling issue.
need to pull codes, check fuel pressure...autozone, advance, etc can pull codes and loan tools..start with basics before throwing parts at it, especially if you are low on cash.
need to pull codes, check fuel pressure...autozone, advance, etc can pull codes and loan tools..start with basics before throwing parts at it, especially if you are low on cash.
07-24-2016, 05:12 PM
#3
The pipe between the 2 cats isn't EGR - it's fresh air from the air pump. That won't affect your performance.
If your cats really were plugged, it's pretty likely that your 02 sensor could be covered in the same crap which would give a false reading.
A fuel pressure gauge and checking your codes are the first 2 things to look into.
If your cats really were plugged, it's pretty likely that your 02 sensor could be covered in the same crap which would give a false reading.
A fuel pressure gauge and checking your codes are the first 2 things to look into.
07-24-2016, 09:11 PM
#5
Appreciate the replies. I'll post again during the week when I get time to work on the truck in the evenings around the job schedule. I like to update posts in the hope that some one else might be able to learn from it.
The following 2 users liked this post by madmarchie:
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