[GreenTX7.3Ex]

2000 Excursion 7.3 auto

Truck was running great and had an issue with rough idle and stall out while I was sitting in a drive through.
The truck runs great until it hits OT or just after, then it begins to miss and eventually die. If I unplug the EBP the truck will run, but very rough and with no power. After a few hours of cooldown she will run perfect again.

I have replaced IPR and CPS (MC Brand), cleaned and checked terminals for ICP and EBP for 5v reference signal and found all to be good. BAFX tool shows that I have 15% IPR and 600PSI idle, 36PSI EBP. No codes besides those related to unplugging the sensors, but no CEL preceded the issue either.

 

[Greg687]

Where did you get your Motorcraft sensors from?

 

[GreenTX7.3Ex]

Where did you get your Motorcraft sensors from?

Orielly auto, specifically to avoid Amazon fakes

 

[RT]

36 psi EBP is excessive at idle. MAP and EBP should be pretty close to atmospheric at idle and then EBP will be a few psi higher than MAP when driving. 36 psi indicates either your EBPV is stuck on or you have an exhaust restriction.


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[GreenTX7.3Ex]

Update- Issue is truck runs poorly when operating temp is reached. It will die entirely unless I unplug the EBP sensor. EBP is now reading 51 plugged in engine on and 43.5 unplugged, engine on or off. almost like it sees 43.5 as a baseline. I have checked the wires to EBP and they are good. 5v reference and ground are good. sensor shows a difference of around 7.5-8psi when plugged in. Is my cheap BAFX scanner giving me bad info? Does the PCM really think there is that much backpressure? Unsure if I am chasing the right issue or not.

EBP is MC brand and tube is brand new. New MC brand IPR when this issue started. ICP reads 600psi idle which seems correct. IPR duty cycle reads 14.8% idle. Visually confirmed EBPV is open and it is unplugged for the moment.

 

[RT]

Check your exhaust system. Do you have a catalytic converter? I'm still trying to piece together which models came with them and which didn't. I'm pretty sure the excursions did have one. When they get clogged, it will wipe out your performance. I did a timing chain on a 5.4 Expedition once and found on the test drive that it was an absolute dog. After hours of diagnostics, it turns out both his converters melted when he was running around with the broken timing chain tensioners. Absolute exhaust restriction. Couldn't hardly get it to move.

 

[bugman]

Check your exhaust system. Do you have a catalytic converter? I'm still trying to piece together which models came with them and which didn't. I'm pretty sure the excursions did have one. When they get clogged, it will wipe out your performance. I did a timing chain on a 5.4 Expedition once and found on the test drive that it was an absolute dog. After hours of diagnostics, it turns out both his converters melted when he was running around with the broken timing chain tensioners. Absolute exhaust restriction. Couldn't hardly get it to move.

RT,

Here is a thread that I have saved on catalytic converters and our trucks. Smoky's post has which ones did and what ones didn't.

Where is the Catalytic converter at on the 7.3L?

FWIW... My 02'6spd 275 per valve cover sticker. brother in-laws 02' auto 250 valve cover sticker. Later Tim

www.thedieselstop.com

 

[klhansen]

EBP is now reading 51 plugged in engine on and 43.5 unplugged, engine on or off.

That tells me that you may have a short between VREF and EBP signal in your wiring harness. I would check your wiring to see what's going on.

Alternatively, you may have the wrong units - kPa, versus psi. The EBP signal at zero volts corresponds to 41.25 kPa (or 6 psi) and 51 kPa is 7.4 psi. Atmospheric pressure is 14.7 psi, so with EBP plugged in and key on, you should be reading ~101 kPa.

 

[GreenTX7.3Ex]

That tells me that you may have a short between VREF and EBP signal in your wiring harness. I would check your wiring to see what's going on.

Alternatively, you may have the wrong units - kPa, versus psi. The EBP signal at zero volts corresponds to 41.25 kPa (or 6 psi) and 51 kPa is 7.4 psi. Atmospheric pressure is 14.7 psi, so with EBP plugged in and key on, you should be reading ~101 kPa.

I have just finished ohming out everything from pigtail to engine harness, and from pigtail to PCM connector as well. Wires are good. the kPa thing is interesting though... that might be it.

 

[GreenTX7.3Ex]

Check your exhaust system. Do you have a catalytic converter? I'm still trying to piece together which models came with them and which didn't. I'm pretty sure the excursions did have one. When they get clogged, it will wipe out your performance. I did a timing chain on a 5.4 Expedition once and found on the test drive that it was an absolute dog. After hours of diagnostics, it turns out both his converters melted when he was running around with the broken timing chain tensioners. Absolute exhaust restriction. Couldn't hardly get it to move.

no cat on the early 7.3 superduties, but the OBS did have them. I actually straight piped it about a month ago. If klhansen is correct, then i dont have an EBP issue at all, just a running at OT issue. Which sucks for me but makes a lot of sense

 

[klhansen]

When you check the wiring, did you check for shorts between circuits? Unplug the main engine harness connector and probe the three terminals at the EBP sensor connector. If you don't get an open circuit between any of the pairs, then you have a short between circuits.
There have been instances of a bad EBP sensor causing issues as well, but i think you said you replaced that. But there have been counterfeit MC parts out there. Did you buy it from a Ford dealer?

 

[GreenTX7.3Ex]

When you check the wiring, did you check for shorts between circuits? Unplug the main engine harness connector and probe the three terminals at the EBP sensor connector. If you don't get an open circuit between any of the pairs, then you have a short between circuits.
There have been instances of a bad EBP sensor causing issues as well, but i think you said you replaced that. But there have been counterfeit MC parts out there. Did you buy it from a Ford dealer?

Yes, I did that. I actually checked it from the sensor to the engine harness plug, and from the sensor all the way to the PCM plug. Good connection the whole way, no bleed through across the three pins. And yeah, I got the EBP from a reputable source. I've gotten several fake motorcraft parts before, and I always check the packaging before I open them to make sure it looks right. As of this morning, it doesn't run at all, and now I'm getting an IDM code in the PCM. At least I'm finally getting something else to go on. But I don't have the tool to read that kind of stuff, so it's going to a shop in the morning. I trust them and they should have it diagnosed pretty quickly. I'll make sure to get back on here and post what was actually going wrong with it.

 

[TwiceStroked]

Check your exhaust system. Do you have a catalytic converter? I'm still trying to piece together which models came with them and which didn't. I'm pretty sure the excursions did have one. When they get clogged, it will wipe out your performance. I did a timing chain on a 5.4 Expedition once and found on the test drive that it was an absolute dog. After hours of diagnostics, it turns out both his converters melted when he was running around with the broken timing chain tensioners. Absolute exhaust restriction. Couldn't hardly get it to move.

My '01 Exc is Non-Catalyst since new 9/2000

 

[LurkerX]

2000 Excursion 7.3 auto

36PSI EBP.

When you replaced the tube, did you clean the carbon out of the old sensor, or is this a new sensor.... tell us more about the EBP sensor.

I have NEVER cleaned one of these sensors without ruining it (and I have tried cleaning more than a few).
However, I've never had an engine not run due to EBP readings being off the chart.

EDIT:
NM. I re-read and see MC (MotorCraft).
The missing could back up suspect IDM diagnosis.
Pull IDM and shake it. Could be full of water. Has happened to me several times.
If you replace the IDM, I highly suggest 140v mod.