Could it be a clogged catalytic convertor?

Tiny
BRANDONLEE
  • MEMBER
  • 2001 FORD EXPLORER
  • 130,000 MILES
I have a 2001 Ford Explorer Sport with about 130k miles. About three months ago it started running very sluggish and at times even backfires. I ran the codes on it after the check engine light came on and got P0102, P0172, and P0175. Basically the engine is running rich on both banks and it's sensing a MAF low sensor fault. I have changed the MAF, all spark plugs, and the idle air control valve. It's killing my gas mileage and causing terrible acceleration. Please can anyone help me out here - I'm stumped. Could it be a clogged catalytic convertor?
Sunday, July 29th, 2012 AT 2:37 PM

11 Replies

Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
Anything is possible lets rule the cat out take it to a exhaust shop and have them do a back pressure test. Also have you checked the fuel pressure yet?Do you have a scan tool that reads live engine data?
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Sunday, July 29th, 2012 AT 3:06 PM
Tiny
BRANDONLEE
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  • 6 POSTS
Thanks for the prompt reply Saturntech. I do believe that my dad's reader can give me live engine stats. Let me run a test on it and I'll post the results. As for the back pressure test - I should be able to take it in for a reading sometime this week. I had seen where a small hose near the oil fill cap has caused some owners headaches but mine is fine with no cracks or splitting. What stumps me is the low MAF sensor reading - especially since its new.
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Sunday, July 29th, 2012 AT 3:17 PM
Tiny
SATURNTECH9
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You could have a wire issue a terminal issue or a computer issue causing the low maf reading its not always the component causing the code. So see if you can read the maf reading on the scan tool.
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Sunday, July 29th, 2012 AT 3:25 PM
Tiny
BRANDONLEE
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  • 6 POSTS
Okay here's the live engine data from about ten minutes ago. I ran a complete set so there is a lot of data.

FUELSYS1 CL
FUELSYS2 N/A
ETC (DEGREES CELSIUS) 60
SHRTFT1% -18.8
LONGFT1% -22.7
SHRTFT2% -23.4
LONGFT2% -21.1
RPM 760
VSS 0
SPARKADV 16
IAT (DEGREES CELSIUS) 43
MAF (G/S) 9.24
TP% 20.4
O2S B1SI2 - B252 G
O2B1S1(V) 0.835
SHRTFTB1S1(%) -23.4
O2B132(V) 0.750
O2B251(V) 0.841
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Sunday, July 29th, 2012 AT 4:04 PM
Tiny
SATURNTECH9
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Lets start with what I posted let me know what you find.
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Sunday, July 29th, 2012 AT 8:33 PM
Tiny
BRANDONLEE
  • MEMBER
  • 6 POSTS
I'll take a close look at the MAF and surrounding area/hoses and get back with you. Thanks for helping me out on this!
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Sunday, July 29th, 2012 AT 11:32 PM
Tiny
SATURNTECH9
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Your welcome thats what were here for keep me posted.
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Sunday, July 29th, 2012 AT 11:36 PM
Tiny
BRANDONLEE
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On your post above - these tests can be performed with the scan tool I used to get the live data? I've been on duty the last few days and will get to look more into the MAF tomorrow when I get off.
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Tuesday, July 31st, 2012 AT 11:21 PM
Tiny
SATURNTECH9
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Alright keep me posted.
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Tuesday, July 31st, 2012 AT 11:35 PM
Tiny
BRANDONLEE
  • MEMBER
  • 6 POSTS
Okay here's an update on this issue. I finally got a few days off from work yesterday and today and got a chance to do some investigative work. I checked the tube that supplies air to the throttle body and it was in good shape. Grabbed a can of ether and did the poor man's vacuum leak test but that too didn't indicate any leaks. My uncle (GM mastertech) came in from AL on vacation and ran a live test to watch the voltages to the MAF both at idle and under load. At idle we were getting 11 g/s and ran her up to about 2500 - 3000 rpm. Guess what? The reading didn't move a bit! Turns out the MAF was bad. All other readings read good including o2 sensors. I have since installed a new MAF and it seems to be running much better. I'll post back in a week after putting a few more miles on it.
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Sunday, August 12th, 2012 AT 8:16 PM
Tiny
SATURNTECH9
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Alright good find glad to here you found the bad sensor. Please keep me posted.
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Sunday, August 12th, 2012 AT 8:29 PM

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