1997 Expo Running Lean?
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1997 Expo Running Lean?
I got the error codes pulled at AutoZone and they say that cylinder bank one is running lean and two is also running lean. It is my wifes truck so I just got notice that the light has been on for over a month and that it has started running a little rough. Anyone know where I can start looking for a culprit?
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Everyone, repeat after me, 1,... 2,... 3,... PCV Elbow.
Generally, when we see banks 1 and 2 lean on a vehicle of this age, we assume it is the PCV elbow located on the cam cover (which side and front or back I can't remember becuase I don't have one of these engines). It's plasic, becomes brittle, cracks, and becomes a vacuum leak.
To get more technical, the PCM (Powertain Control Module) determines the mass of air flowing into the engine via the MAF (Mass Air Flow) sensor and commands the fuel injectors to place a proportionate amount (Mass) of fuel into the intake stream. This amount of fuel is insufficient because of the extra unmetered (measured) air coming from the vacuum leak. This 'lean' condition is picked up by the O2 sensors and is reported via the CEL (Check Engine Light) also known as the SES Service Enging Soon, or MIL Malfunction Indicator Lamp.
Generally, when we see banks 1 and 2 lean on a vehicle of this age, we assume it is the PCV elbow located on the cam cover (which side and front or back I can't remember becuase I don't have one of these engines). It's plasic, becomes brittle, cracks, and becomes a vacuum leak.
To get more technical, the PCM (Powertain Control Module) determines the mass of air flowing into the engine via the MAF (Mass Air Flow) sensor and commands the fuel injectors to place a proportionate amount (Mass) of fuel into the intake stream. This amount of fuel is insufficient because of the extra unmetered (measured) air coming from the vacuum leak. This 'lean' condition is picked up by the O2 sensors and is reported via the CEL (Check Engine Light) also known as the SES Service Enging Soon, or MIL Malfunction Indicator Lamp.
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OK, I found it on the driver's side, mid cam cover, and it is not cracked or even brittle. Neither is the upper mount that goes into the throttle body, or the long plastic tubes that connect the two. I can only see a couple other vacume lines going into the intake, mostly from the exaust and none seem to be too messed up. Is there some way for me to check the vacume system as a whole for a leak? I know from running my old two srtoke bikes that lean is not good, so I need to try and fix this ASAP as the wife ain't going to stop driving the truck just because the little yellow light on the dash is on.
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Joined: Oct 2004
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From: North Alabama
The pcv valve & related hose is in the passenger side valve cover. Look directly behind the oil filler hole, going toward the firewall. You should see it. Here's a picture of exactly where it is. In this picture, it's the shiny silver piece. I have since replaced it with a Motorcraft pcv valve, & I suggest yu do the same. The pcv is only about $6 at the Ford dealer.
The hose in the driver side valve cover is the crankcase ventilation hose.
Once you have replaced the pcv hose, also clean the MAF sensor. Use ONLY CRC electronic cleaner (nothing else). Give the MAF sensor wires a good spraying, but don't touch them with any objects.
The hose in the driver side valve cover is the crankcase ventilation hose.
Once you have replaced the pcv hose, also clean the MAF sensor. Use ONLY CRC electronic cleaner (nothing else). Give the MAF sensor wires a good spraying, but don't touch them with any objects.
Last edited by wavinwayne; Apr 21, 2006 at 07:20 AM.
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From: North Alabama
One thing I forgot to mention; If you buy a non-Motorcraft pcv, you will not get the rubber grommet that the pcv fits into. The grommet needs to be replaced, & if you buy a Motorcraft pcv, it will come with a new grommet.
Lastly, when you remove the existing pcv valve, take the 90° "elbow" off of it. The new Motorcraft pcv valve will not come with this "elbow" piece, & I don't know if it an be ordered seperatley. Just pull it off the old pcv valve, & push it onto the new pcv valve.
Lastly, when you remove the existing pcv valve, take the 90° "elbow" off of it. The new Motorcraft pcv valve will not come with this "elbow" piece, & I don't know if it an be ordered seperatley. Just pull it off the old pcv valve, & push it onto the new pcv valve.
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