Running lean?
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Running lean?
So I finally got my EGR valve fixed on my 98 Explorer. What a nightmare. Everything was rusted, none of it wanted to come off. Ended up rigging the EGR feed tube to the EGR valve, but hey, it works!
Now heres my problem. I'd been driving the truck for almost 2 months with the bad EGR valve. I was getting absolutely ***** gas mileage and a horrible idle once the truck warmed up. Now that it's fixed, within 45 minutes of driving it after I fixed it, I got a CEL. Scanned it this morning, and I believe the codes were P0141 and P0151. They were in sequence like that, I could be wrong on the numbers. But they were both lean codes for bank 1/2.
Here's my question, and I really hope I don't sound like a complete idiot
but...
It is possible that during those couple months that the truck had the bad EGR, and it was running extremely rich, that the computer got "used" to running that rich, therefore it not thinks it's running lean because it's fixed and working the way it's supposed to?
I understand I could have possibly burn'd up a cat, but I'm completely lost right now.
Now heres my problem. I'd been driving the truck for almost 2 months with the bad EGR valve. I was getting absolutely ***** gas mileage and a horrible idle once the truck warmed up. Now that it's fixed, within 45 minutes of driving it after I fixed it, I got a CEL. Scanned it this morning, and I believe the codes were P0141 and P0151. They were in sequence like that, I could be wrong on the numbers. But they were both lean codes for bank 1/2.
Here's my question, and I really hope I don't sound like a complete idiot
but...It is possible that during those couple months that the truck had the bad EGR, and it was running extremely rich, that the computer got "used" to running that rich, therefore it not thinks it's running lean because it's fixed and working the way it's supposed to?
I understand I could have possibly burn'd up a cat, but I'm completely lost right now.
Logistics Pro
Joined: Jun 2009
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From: Cedar Rapids, IA
Per the factory service manual:
Diagnostic Trouble Codes (DTCs) P0135 P0141, P0155 and P0161 indicate a short to ground, open, or short to VPWR in the HO2S heater circuit.
DTC P0141 = HO2S HTR-12
Possible causes:
-- Shorts to VPWR in harness or HO2S.
-- Water in connectors.
-- Cut or pulled wires.
-- Disconnected wiring.
-- Open VPWR circuit.
-- Open GND circuit.
-- Low battery voltage.
-- Corrosion or poor mating terminals.
-- Damaged HO2S heater.
-- Damaged PCM.
Diagnostic Trouble Code (DTC) P0151 is set when the HO2S generates a negative voltage.
DTC P1051 = HO2S-21
Possible causes:
-- Contaminated HO2S (water, fuel, etc.).
-- Crossed HO2S signal/signal return wiring.
Double check the codes your vehicle is reporting since you didn't seem totally convinced the codes you listed are correct. Since the two codes you mentioned are not very common AND do not point to the same O2 sensor, I doubt that the problem is the O2 sensor itself.
-Rod
Diagnostic Trouble Codes (DTCs) P0135 P0141, P0155 and P0161 indicate a short to ground, open, or short to VPWR in the HO2S heater circuit.
DTC P0141 = HO2S HTR-12
Possible causes:
-- Shorts to VPWR in harness or HO2S.
-- Water in connectors.
-- Cut or pulled wires.
-- Disconnected wiring.
-- Open VPWR circuit.
-- Open GND circuit.
-- Low battery voltage.
-- Corrosion or poor mating terminals.
-- Damaged HO2S heater.
-- Damaged PCM.
Diagnostic Trouble Code (DTC) P0151 is set when the HO2S generates a negative voltage.
DTC P1051 = HO2S-21
Possible causes:
-- Contaminated HO2S (water, fuel, etc.).
-- Crossed HO2S signal/signal return wiring.
Double check the codes your vehicle is reporting since you didn't seem totally convinced the codes you listed are correct. Since the two codes you mentioned are not very common AND do not point to the same O2 sensor, I doubt that the problem is the O2 sensor itself.
-Rod
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Yeah those are definitely not the right codes. I can't remember them for the life of me. I clear the CEL and it comes back on within like 2 days, same codes. I just cleared it too. I wanna say it was P0171 and P0174? Not 100% But they indicate system is too lean
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When it throws a left and right bank lean code at the same time it is usually not the O2 sensors but a vacuum leak somewhere. You need to find the leak by spraying carb cleaner or propane at anyplace on the intake after the MAF that can leak while the engine is idling. Any change in RPMs will indicate when you have found the leak. Happy hunting.
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Logistics Pro
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From: Cedar Rapids, IA
Yep, and the V6 engines have a couple of known common vacuum leak sources. Certainly don't assume these are the only locations, but intake manifold gaskets and PCV elbow are a couple of common points to leak.
-Rod
-Rod
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When fixing the EGR valve, I was un-able to get off the original nut from the old EGR valve. I had to cut the EGR tube, and I used a compression fitting coupler to go from the EGR tube to the new EGR valve. I was unable to completely tighten it up, because the bracket that goes from the EGR to the side of the motor that holds the dip stick in place, it pulls the bracket short of being able to completely tighten it up, and put the bolt back into place on that bracket. I've got it tight enough to hold the dip stick bracket in place, and have that bolt just hand threaded into the side of the motor.
There is a very very small exhaust leak now, coming from I'm assuming that compression fitting, because I don't have it completely tightened down. Could that possibly be making the lean code(s) come up?
Reason I asked if it were the o2's is because when I drove the car with live diagnostics on the computer, it was showing "0" for the o2 sensors. I'm not entirely sure what type of regular numbers are supposed to be shown there. But it was zero any you looked at it. I don't recall if it was just one "0" or if it was something like "0.0"?
There is a very very small exhaust leak now, coming from I'm assuming that compression fitting, because I don't have it completely tightened down. Could that possibly be making the lean code(s) come up?
Reason I asked if it were the o2's is because when I drove the car with live diagnostics on the computer, it was showing "0" for the o2 sensors. I'm not entirely sure what type of regular numbers are supposed to be shown there. But it was zero any you looked at it. I don't recall if it was just one "0" or if it was something like "0.0"?
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From: Cedar Rapids, IA
What was the parameter name you were looking at for the O2 sensors? There are some that may be an indication of "lean" or "rich" and maybe your software reports that as a '0'
or '1' depending on if it's lean or rich. There is probably also an "HO2S voltage" which should be anywhere from 0-1 Vdc, and when the voltage for the Sensor 1 sensors should toggle quite rapidly from something less than 0.49 V to something greater than 0.49 V. If the software is displaying '0' and '1' for 'lean' and 'rich' I would expect that parameter to change everytime the voltage changed greater than or less than 0.49 V as well.
And, yes, and exhaust leak could cause lean codes as well as cause the PCM to attempt to compensate for the lean condition by increasing the injector pulse width.
-Rod
or '1' depending on if it's lean or rich. There is probably also an "HO2S voltage" which should be anywhere from 0-1 Vdc, and when the voltage for the Sensor 1 sensors should toggle quite rapidly from something less than 0.49 V to something greater than 0.49 V. If the software is displaying '0' and '1' for 'lean' and 'rich' I would expect that parameter to change everytime the voltage changed greater than or less than 0.49 V as well.
And, yes, and exhaust leak could cause lean codes as well as cause the PCM to attempt to compensate for the lean condition by increasing the injector pulse width.
-Rod
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