Catless and CEL...?

StangATX

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Hello guys!

I have a quick question for y'all (I know, I know, Again! :D).

I'm having some trouble with my car (As usual lol). I have a lose of power when flooring it. It's not jerking or anything but I stinks pretty bad and I can see my fuel gauge going down. I don't have any CEL but I'm pretty sure my Cats are going bad right now. I'd like to cut my cats and put a pipe instead. The problem is that each cat have an O2 sensor in it. I'm not looking at removing the O2 sensor before the cat (From my understanding I need it for my fuel mixture). But, I'm looking to remove the cats temporally to see if that'll clear my doubt to know if they're shot or not. Our car have 4 O2 sensors. 2 before the cats and 1 on each cat. I'm pretty sure if I remove my cats the CEL will go off. How would I bypass that CEL without welding a bung on the test pipe? I don't have emission test in my county and this is just temporally. I'm not looking at leaving it this way forever but just for a few month while I save some money to buy new ones. It's my DD car and it pisses me off that I literally have no freaking power or CEL to show Ford the cats are shots.

Thanks for your help and advice!

StangATX.

 
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StangATX

StangATX

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Alrighty, I found a way to get rid off the CEL. However, Before I proceed to get my cats out I'd like to know if anyone recommend trying something else? I'm still kinda surprise for 74K miles my cats are shots... I pretty much have all the symptoms of a bad catalytic converter. Bad smell, loss of power (only when cold kinda...), really bad mpg, (except rough idle)
 

stang17

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I recently went through something similar. I purchased the car new from the dealer with a whipple supercharger wrapped into the financing.

I always had piss poor gas mileage in the 7-9mpg range, which I attributed to my short stop and go commute to work.

At about 7,600 miles, I started to get an occasional misfire followed by a strong sulfur smell. Next few hundred miles it became much more common and my city mpg started to tank at about 4-6 mpg.

Turned out the dealer never gapped the NGK spark plugs at time of the Whipple install and left them at 0.044 when they should have been gapped at 0.028.

I never got a CEL to stay on, but my cats were toast. Once you get the sulfur smell, that is a sign of a failing converter.

I went ahead and installed new plugs and a set of kooks 1 7/8 headers with their standard high flow cats (not the green cats).

I have driven approximately 100 miles since the swap and have been averaging 16.1 mpg city without any change in driving habits. The CEL never came on with the new high flow cats either. Car now has just a tick over 8,000 miles on it.

Keep in mind, the driver side cat is incorporated into the exhaust manifold, making it uber expensive. I priced a set online for OEM cats and is was approximately $980. Therefore, if you need to replace the stocks cats at some point in time, you may be better off getting a nice set of aftermarket headers with high flow cats for a few hundred dollars more.

As far as testing to see if the CATs are bad without a CEL, you can use a exhaust back pressure tester to confirm. Testers can be found online for a reasonable price.

https://www.autozone.com/test-scan-...ust-back-pressure-tester-and-gauge/347232_0_0
 
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StangATX

StangATX

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I recently went through something similar. I purchased the car new from the dealer with a whipple supercharger wrapped into the financing.

I always had piss poor gas mileage in the 7-9mpg range, which I attributed to my short stop and go commute to work.

At about 7,600 miles, I started to get an occasional misfire followed by a strong sulfur smell. Next few hundred miles it became much more common and my city mpg started to tank at about 4-6 mpg.

Turned out the dealer never gapped the NGK spark plugs at time of the Whipple install and left them at 0.044 when they should have been gapped at 0.028.

I never got a CEL to stay on, but my cats were toast. Once you get the sulfur smell, that is a sign of a failing converter.

I went ahead and installed new plugs and a set of kooks 1 7/8 headers with their standard high flow cats (not the green cats).

I have driven approximately 100 miles since the swap and have been averaging 16.1 mpg city without any change in driving habits. The CEL never came on with the new high flow cats either. Car now has just a tick over 8,000 miles on it.

Keep in mind, the driver side cat is incorporated into the exhaust manifold, making it uber expensive. I priced a set online for OEM cats and is was approximately $980. Therefore, if you need to replace the stocks cats at some point in time, you may be better off getting a nice set of aftermarket headers with high flow cats for a few hundred dollars more.

As far as testing to see if the CATs are bad without a CEL, you can use a exhaust back pressure tester to confirm. Testers can be found online for a reasonable price.

https://www.autozone.com/test-scan-...ust-back-pressure-tester-and-gauge/347232_0_0

Thanks for your tips! I removed 2 spark plugs out of 6 quickly before to go to work. What do you think about it? (They have 78K).

Also, I heard it could be my upstream O2 sensors. Could it be possible even without a CEL? The car runs great when cold but when it warms up it's a total sloth lol. I heard on some cars they could disconnect their O2 sensors to test. Let's say I unplug my upstream O2 sensors. Does that mean whenever my car warms up I shouldn't have the problem anymore or the car would run even richer?

Thanks!
StangATX.
IMG_20180316_174442.jpg
 

mc68386

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Thanks for your tips! I removed 2 spark plugs out of 6 quickly before to go to work. What do you think about it? (They have 78K).

Also, I heard it could be my upstream O2 sensors. Could it be possible even without a CEL? The car runs great when cold but when it warms up it's a total sloth lol. I heard on some cars they could disconnect their O2 sensors to test. Let's say I unplug my upstream O2 sensors. Does that mean whenever my car warms up I shouldn't have the problem anymore or the car would run even richer?

Thanks!
StangATX.
Just off the top of my head, those gaps look pretty big. Do you have a gap tool to check them? If not, they're free to maybe a $ at the auto parts store.
 


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StangATX

StangATX

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Just off the top of my head, those gaps look pretty big. Do you have a gap tool to check them? If not, they're free to maybe a $ at the auto parts store.
That's what I was thinking as well. However, I don't have any miss-fire or anything... I heard I can't gap iridium/platinum plugs so I never really looked into a tool for it.
 
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StangATX

StangATX

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Alrighty, Tomorrow I'm gonna change my spark plugs. I was looking at getting Iridium. I found those Denso 4719 Twin Tip (Iridium). It seems that they come with a .040 gap. However, I looked at the Motorcraft SP-520 and it looks like they come with a .050 gap. I checked on the manual and it says the V6 (and V8) plugs needs to be between .049 and .053. The odd things is that the Denso 4719 are recommended for my engine at Autozone and Rock Auto... Should I just go ahead and leave them at .040 or should I just get my regular Motorcraft SP-520?

Thanks again guys for your help!
Capture.JPG
 

 
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