Rich Mix Problem Solved!
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Postmaster
Joined: Jun 2004
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From: Pleasant Hill, MO
Rich Mix Problem Solved!
No replies are really needed, but maybe I'll help someone here. In my 1994 F-150 5.8L, my gas mileage lowered substantially, and it felt like I lost a little power. The exhaust was coming out smelling horrible and a little dark.
I pulled some codes and the code that pertained to this problem was the 173. (Obviously 1994's have OBD I) It was something about a hego sensor dectecting rich exhaust. DUH! anyway...
I replaced the hego sensor thinking it may have been coated with too much carbon to get an accurate read, therefore adding more gas. Not the problem. I did some reading here on FTE and decided to take a swing at the Fuel Pressure Regulator. BINGO.
So, maybe someone else has been having this problem. My gas mileage has increased a few MPG, the gas smells normal, and I've noticed a good bit of HP returned to normal.
Ryan
I pulled some codes and the code that pertained to this problem was the 173. (Obviously 1994's have OBD I) It was something about a hego sensor dectecting rich exhaust. DUH! anyway...
I replaced the hego sensor thinking it may have been coated with too much carbon to get an accurate read, therefore adding more gas. Not the problem. I did some reading here on FTE and decided to take a swing at the Fuel Pressure Regulator. BINGO.
So, maybe someone else has been having this problem. My gas mileage has increased a few MPG, the gas smells normal, and I've noticed a good bit of HP returned to normal.
Ryan
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Joined: Sep 2002
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From: Langhorne, PA
Ok, I won't reply. But I'll add that I had the same problem and it stopped after a new HEGO, I pulled the original HEGO out of the pipe at 166,000 miles. I wasn't sure if it was the vac leak I fixed, or the HEGO, that stopped the nasty tailpipe odor.
Is your truck running a little hotter now that its leaned out a bit,????...my engine temp went up.
I'm wondering, what color was the tip of everyone's HEGO sensor(the working end) after it was removed from the exhaust??? I have been worried about a coolant leak, and wasn't happy to see a grayish, almost white HEGO come out of my truck.
Is your truck running a little hotter now that its leaned out a bit,????...my engine temp went up.
I'm wondering, what color was the tip of everyone's HEGO sensor(the working end) after it was removed from the exhaust??? I have been worried about a coolant leak, and wasn't happy to see a grayish, almost white HEGO come out of my truck.
Postmaster
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From: B/CS, Texas!!
Mine was black, very dark when I pulled it out. It was the OEM one, still said FORD on it...lol!
I had an issue with the regulator as well. One thing that gets me though, is that when any HEGO code comes on, most people want to replace it thinking its 'bad' when in fact, its just doing its job of reporting an incorrect mixture.
I had an issue with the regulator as well. One thing that gets me though, is that when any HEGO code comes on, most people want to replace it thinking its 'bad' when in fact, its just doing its job of reporting an incorrect mixture.
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From: Langhorne, PA
Mine says Ford also, I never had a HEGO related code, I thought it was just time to try a new one. almost 14 yrs old and 167,000 miles on it. Now you have me worried, based on the fact my HEGO tip was white.
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From: West Mansfield, Ohio
My 95 F-150 with a 351 just kicked over 210K and its still got the original O2 sensor and dont have a check engine light on or any codes at all, and I'm getting 14.5 MPG. Think I should replace it anyways? The truck runs amazingly well even with all those miles.
Last edited by handyman43358; May 8, 2005 at 12:35 PM.
Postmaster
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From: B/CS, Texas!!
Exhaust smoke is black when running rich.
handyman, I would replace it. Even though there isn't any CEL, an old 02 sensor takes longer to switch.
924x, maybe some fuel additive could've caused the sensor's tip to turn white....im just taking a guess here.
handyman, I would replace it. Even though there isn't any CEL, an old 02 sensor takes longer to switch.
924x, maybe some fuel additive could've caused the sensor's tip to turn white....im just taking a guess here.
Last edited by MemOrex; May 8, 2005 at 06:44 PM.
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Posting Guru
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From: Langhorne, PA
I "Seafoamed" my intake manifold recently, I may have done that before the O2 sensor change, but I'm not sure. I haven't been using any other additives and always run 87 octane.
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From: Pleasant Hill, MO
my hego sensor was pitch black from the black exhaust. I replaced it first, believing it was the problem. Turns out, it was doing it's job and telling me it was too rich. So, there ya go, I didn't think it through.
Ryan
Ryan
