yesterday I removed the EGR and cleaned it and the manifold passage with FI cleaner and a 1/2" diameter wire brush- it fit perfectly into the manifold port. I squeezed the wire handle together with a pair of pliers to get it further into the port and pulled out even more nasty black crap. Blew it out with compressed air and did it 2 more times. looked pretty clear. Then I unhooked the battery to clear the code and took it for a ride. It ran great, no hesitation and no check engine light. Drove 10 miles to work this morning with no hes/no light, and 5 miles home when the light came back on. little hesitation now, but still runs good. temp went down a few degrees also. but the light did return. Did I miss something?

Wasn't looking forward to disassembling the manifold and components (first FI vehicle...!) to clean more thoroughly, and am not sure what I can spray or brush without causing any damage to sensors, etc. Can anyone help? Local shop couldn't. Or I should say wouldn't without me paying thru the nose...

I have some exp with engines (rebuilt a 79 Pontiac 400 with a mentor-no longer in touch with, unfortunately) and have the ability, just not the specific knowledge for this particular situation. I had a similar EGR problem on the Poncho that cleaning fixed the first time; never to return. Was hoping this would work also, but no such luck.

Someone also suggested replacing the '2 hoses', but I can only see one vacuum hose (has vacuum to it) and the metal tube that goes from the exhaust manifold to the EGR inlet (a little dirty inside, but not clogged). Could another sensor be bad and causing the 'Insufficient EGR data' code? Or am I just not cleaning all the carbon out properly?

Any help would be greatly appreciated!!!
~Rob
98 F150 2wd 4.6
It just turned 100k today.

 

The first step would be to get it scanned and see what code comes up. The most common EGR code is a P0401 which usually means the DPFE sensor is shot.

 

P0401 is the code that came up when Autozone scanned it. they told me it was a bad EGR valve. What is aDPFE sensor?

Thanks!
~Rob

 

Here's what I found on that sensor, but it was listed only as applying to the model years 86-94:
"Ford vehicles equipped with a Pressure Feedback EGR Sensor, (PFE) or a Differential Pressure Feedback EGR Sensor, (DPFE) may experience repeated occurrence of false EGR system codes and possible incorrect replacement of components due to limitations of the factory diagnostic procedures. While the Ford "H" manual does include reference to the EGR valve as a possible source of an EGR PFE Sensor code it does not address valves that "Hang" momentarily.

Our testing has found that contaminant build-up in the area of the EGR pintle shaft, or pintle seat may cause the valves on these applications to be slow in opening when the PCM commands additional vacuum be applied to the valve. Sensing that insufficient EGR is occurring the PCM commands for more vacuum to the EGR valve. When the valve does pop open the combination of valve inertia and vacuum build-up cause the valve to over travel. This creates the sensed excessive EGR condition that triggers the false code.

Drivers complaints usually include a bucking or trailer hitching condition during shifting or initial off-idle acceleration as part of the driveability complaint, which can be especially noticeable on manual transmission equipped vehicles. EGR valve replacement is the recommended service.

A similar false code may also occur if the metering orifice located in the intake below the EGR valve and DPFE sensor is restricted. This type of problem will not create a trailer hitching condition but loss of fuel economy will be noted. Cleaning the orifice will correct this condition. "

The last paragraph described my problem- fuel economy is suffering, but no bucking. I cleaned it, but was thinking that maybe there's more carbon inside that i can't see...

 

ok, found more info. will check the sensor tomorrow. thanks for pointing me in the right direction, Dave!
~Rob

 

Here's what I actually found:

Technical Tip: DPFE Testing

Application: 1993-2002 Ford, Lincoln, Mercury, Ford Truck with DPFE Sensor.

Symptom: DPFE Trouble Codes.

Theory: The DPFE sensor allows the PCM to check EGR flow. In the passage between the Exhaust Manifold and the base of the EGR valve, there is a restrictor. This restrictor causes the pressure to be higher on the Exhaust Manifold side than on the EGR valve side when the valve is open. The DPFE has two ports on it, one connected above the EGR restrictor and one below. The more EGR flow there is, the greater the pressure difference at the restrictor. This is how the PCM determines actual EGR flow and can adjust the EGR solenoid command accordingly.

The Test: There are two ways to check a DPFE. One is in the shop and the other is driving down the road. To do the in-shop test, hook a voltmeter to the DPFE signal wire, usually Brown/Green. Disconnect the hose attached to the DPFE on the port marked “ref” and hook a hand-vacuum-pump to the port. In case the sensor is too dirty to read, this port is the smaller of the two. Turn the key on and check the voltage. It should be right around 0.5v. Now, using the hand-vacuum-pump, apply 9hg of vacuum to the “ref” port. The voltage should change to at least 4v. Also, the DPFE should hold this vacuum. If it leaks down, stop testing and get a new sensor. If it passes the in-shop test, we need to monitor DPFE voltage while driving. Hook up your scanner and find EGR percentage or duty-cycle and DPFE voltage. At idle, EGR duty cycle should be 0%, and DPFE voltage should be 0.7v. Start your road-test and have somebody watch these two scanner readings. At a steady 60mph in overdrive, the scanner should show about 75% EGR duty-cycle and 1.1v DPFE volts. Slip your foot off the accelerator pedal, and the DPFE should show a momentary spike of about 2.4v and then drop down again.

The Fix: Obviously, if the DPFE sensor failed any of the in-shop tests, replace it. If it passed the in-shop tests but the readings you got on the road-test were incorrect, we need to check the EGR valve and passages. If the valve is okay, don’t forget about that restrictor in the passage between the Exhaust Manifold and EGR valve. This can be missing due to rotting away or knocked out during a previous passage cleaning attempt. Also, if you found a melted DPFE sensor or hose, check for a restricted exhaust system.

 

Ford came out with a message now that says that anytime we see a P0401 we arent even supposed to check anything but just replace the DPFE. Yes the problem is that common.
If you pick up a new one you'll be able to find it easier on your truck and it will only take a few minutes to replace.

 

I see the unit- easy replacement. Can I get the sensor at a retail store, or is it a dealer-only part?
Thanks,
~Rob

 

I'm not sure if aftermarket places sell them but I think I'd go with the genuine Ford part unless there is a major price difference.
Ford had updated them so hopefully they wont cause any more problems.

 

Dave,
I checked with Advance and they can order one, but it's $95. The local Ford dealer only wants $76. Found one on eBay starting at $20. I checked other web parts houses and found nothing...
Thanks again for your help,
~Rob

 

I'd be a little leery about buying one off ebay.....it might be an older not updated one.

 

I thought about that, but the pic is pretty clear- it's the updated plastic unit # F77Z 9J460 AB. The older metal unit on my truck is F48E 9J460 BB. I called a local Ford dealer to confirm the number before I bid. If I can get it cheap enough (still $20 right now) I'll give it a shot. it's only a 10-minute job, so if I lose $20 and 10 minutes I won't be upset. I've done waaaay worse! Thanks for the heads-up though!
~Rob

 

Oh, and Advance can order me one... Sorensen part number 779-11009. I looked at it on their site... according to their pic it's the older metal one! LOL

Can't trust anyone anymore!

~Rob

 

I just won the auction on eBay for the DPFE sensor #F77Z 9J460 AB for $20, so I'll be trying it out as soon as I get it.

Should I also replace the hoses that run down to the EGR tube? are they regular vacuum hoses, or should they be high temp silicone hoses?

I love this site!

 

They are high temp hoses and are usually ok. If they arent cracked or anything I wouldnt worry about it.