Re:Re:Re:2007 Ford Expedition 5.4L 3v Triton

OK folks this one has me stumped and I would appreciate any and all help you can give me.

I've got a 2007 Ford Expedition that is hung on the O2 and Catalytic drive cycle test, for the past 4 years! I've taken it to multiple Ford dealers, state certified emission shops, and "car experts" with no luck. Everyone wants to shotgun it and replace 8 x spark plugs, 8 x ignition coils, and 4 o2 sensors, the problem is I've changed all of those items twice already (all Motorcraft parts) and it hasn't fixed anything. Over the course of the four years I've also replaced one of the catalytic converters, PCM, mass airflow sensor, and cleaned the throttle body. Tested the compression which was within 5 psi across all cylinders and there are no exhaust gases in the coolant.

Now these drive cycle tests have never failed, they are always "incomplete". The only DTC is P1000 which is drive cycles not complete.

I've been working on it on and off myself but my mechanic skills are focused on the 1960's vehicles.

Here is a video of the O2 sensors, Short Term Fuel Trim and Long term Fuel trim as i drove around the neighborhood. Can anyone see anything wrong or suggest what i look at next?

I'm leaning more towards a problem with the enable of the drive cycle maybe a tps issue or a speed sensor issue or a problem between the instrument cluster and the pcm where the pcm isn't receiving the speed signal . I don't have any info in front of me right now I can get it tomorrow or someone else can post what the drive cycle criteria is for this vehicle but my bet is enable isn't being met rather than a problem with the monitored systems

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I don't think the engine computer is seeing enough crossing counts on S2S22 it is with a couple of exceptions completely flat lined. While the engine computer expects a downstream sensor to be more or less flat high or low it looks for a set number of crossing counts through the 0.5v level as the engine warms up,
Also the upstream O2 sensors are responding very differently from each other
I would monitor the O2 sensors and fuel trims at idle and drive it very rich and very lean by introducing propane then a vacuum laek and watch the response on all 4 sensors.

In these situations it is very important to look at service information and see what inputs are used for drive cycle monitors. temperature sensors and oxygen sensors are the usual suspects. How long does it take on a cold start for the vehicle to reach operating temp?

Having a hard time finding what it uses to determine if it's going to run a drive cycle the list I found in snapon scan tool is pictured. However in addition to that it probably uses tps ,speed and maybe more?

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Pic

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Andy.MacFadyen wrote: I don't think the engine computer is seeing enough crossing counts on S2S22 it is with a couple of exceptions completely flat lined. While the engine computer expects a downstream sensor to be more or less flat high or low it looks for a set number of crossing counts through the 0.5v level as the engine warms up,
Also the upstream O2 sensors are responding very differently from each other
I would monitor the O2 sensors and fuel trims at idle and drive it very rich and very lean by introducing propane then a vacuum laek and watch the response on all 4 sensors.

Thank you for the insight. If S2S22 and upstream sensors aren't acting correctly why wouldn't an error code be thrown? I've replaced all 4 sensors twice and driven the vehicle 500+ miles in the 4 years i've been working on this issue.

I and a "car guy" tried propane and a mechanic tried a smoke test and found no vacuum leaks.

Ben wrote: Pic

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THANK YOU!

I will add these to my monitors and do another drive video.

What were the results of the propane test? did all sensors go high including b2s2 or did it stay at .7ish? Did that video start at cold startup? I'm not sure if it expects to see cross counts to enable monitor ( I believe it expects to see it when it's being monitered not as a enable criteria) though I am not positive on that.

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Ben wrote: What were the results of the propane test? did all sensors go high including b2s2 or did it stay at .7ish? Did that video start at cold startup? I'm not sure if it expects to see cross counts to enable monitor ( I believe it expects to see it when it's being monitered not as a enable criteria) though I am not positive on that.

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The video I posted was not from a cold start.

I miss understood your propane test, I was referring to using unlit propane in the engine compartment to find a vacuum leak. For this post you want to see how the 02 sensors respond when a lit propane torch is applied to the o2 sensors? I can do that tonight along with timing how long it takes to reach operating temp that another member suggested.

How long should the torch be applied to the o2 sensor?

No not a lit torch applied to sensor. the propane test I was referring to is using a modified propane torch to allow more propane out unlit into the intake stream causing a rich condition, the fuel trims should go way negative and the oxygen sensors should go full rich them when you remove propane 02 sensors should dive lean and stay there for a short time while fuel trims stabilize

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John Curtis wrote: In these situations it is very important to look at service information and see what inputs are used for drive cycle monitors. temperature sensors and oxygen sensors are the usual suspects. How long does it take on a cold start for the vehicle to reach operating temp?

Starting with IAT 88 and ECT 90 it took 8 minutes for ECT to exceed 170 and 12 minutes for the temp gauge to reach half way (ECT 190) at idle.

Ben wrote: No not a lit torch applied to sensor. the propane test I was referring to is using a modified propane torch to allow more propane out unlit into the intake stream causing a rich condition, the fuel trims should go way negative and the oxygen sensors should go full rich them when you remove propane 02 sensors should dive lean and stay there for a short time while fuel trims stabilize

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From :20 to :35 I injected propane into the air box before the MAF.

I updated my Forscan and now the oscilloscope stopped working.

lv123 wrote: From :20 to :35 I injected propane into the air box before the MAF.

Something changed here. In your first video, the long term trims were less than 10% on both banks. Now long term on bank one is almost maxed - without propane added.

Was the engine running poorly before you added the propane? Does the engine run differently in Open Loop rather than Closed?

Does Forscan have Rear O2 Trim PIDs in the PCM data list?

I updated my Forscan and now the oscilloscope stopped working.

Really? :huh: Version 2.3.40? I haven't tried the oscilloscope since updating.

Thank you to everyone for your willingness to help. 

After so many years of this truck being a problem i've decided to just sell it and concentrate all my "mechanic hours" on my classic vehicles.