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EGR system diagram for 1999 SVT

B

bigbear1963

New CEG'er
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Feb 14, 2015
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Howell Township, New Jersey
I recently purchased a 99 SVT #6787, and I am going through the mechanics, trying to undo some of the "mods". One discovery I made, while replacing the EGR valve this past weekend was an open air/vacuum lead on the manifold to EGR valve pipe. I am attaching a pic, even though it is very cramped back there. Any ideas where that lead should be connected? There is another twin lead nearby, also open, that leads somewhere in the engine. Does anyone know of a diagram of the EGR system which could shed light on this mystery?
 

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That is an extremely terrible picture but i'm betting it is the DPFE. which should have 2 of those nipples next to each other. The have hose that runs to the egr tube on both lines.
 
that looks like an egr port on the egr pipe. As noted there should be two hoses of different size, both about 2 to 3 inches in length. These connect to the DPFE sensor.
 
(D)elta (P)ressure (F)eedback (E)xhaust...................it measures the pressure drop as the EGR opens to the intake manifold and tells PCM how far it has opened. The hoses can accidentally be mixed up and problems then. The exhaust stack they are attached to has a washer welded internally with a calibrated hole and one tap is before the washer to get full exhaust back pressure and the other tap is AFTER the hole. It measures the effect of the drop as the washer restricts the pressure from filling the second compartment as quick, thereby making it easier to tell a difference when EGR opens. The PCM measures the back pressure before washer and relates it to the lower pressure after to determine how far EGR is open.
 
amc49 said:
(D)elta (P)ressure (F)eedback (E)xhaust...................it measures the pressure drop as the EGR opens to the intake manifold and tells PCM how far it has opened. The hoses can accidentally be mixed up and problems then. The exhaust stack they are attached to has a washer welded internally with a calibrated hole and one tap is before the washer to get full exhaust back pressure and the other tap is AFTER the hole. It measures the effect of the drop as the washer restricts the pressure from filling the second compartment as quick, thereby making it easier to tell a difference when EGR opens. The PCM measures the back pressure before washer and relates it to the lower pressure after to determine how far EGR is open.
Click to expand...

Hmm.. look at that, You learn something new everyday.. i have idea how it worked but wasn't 100% thanks AMC
 
Same part with 50 names.

If only one hose like around '94 it becomes a PFE instead of DPFE. Operates the same but more stone age as it didn't have the separate hose to direct back pressure as a relativity point. The later design is more accurate.

The V-6 EGR is well known for carbon plugging to not work.
 
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amc49 Thanks again! This p/n F77E-9J460-AB (as shown), does have dual hose connection. My next obvious question, being that this was destroyed, and no hoses were present, which hose goes where? Parts arriving Friday: I picked the replacement part up, including hoses from eBay. Any help would be greatly appreciated.Thanks again,
 

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The ports are two different sizes. Just need to match them up.

I wonder how people are melting their sensors like this. Granted I had it happen also, but that was with a 3L turbo running very lean in 90+ degree weather with near 100% humidity.
 
BrApple Thanks again for the info. To be honest with you, this SVT project is amazing to me, also. There are a lot of "mods" on with this vehicle I am discovering, that are just plain "stupid" So, probably trying to race this car was one of them. The guy I bought this from told me the the splines in the differential may be bad, but when I drove it a few feet it was obvious to me that it was just bad bearings. There is some leakage with the power steering hoses, because it's blowing out the power steering fluid, and there is a power (torque) problem, which I hope can be partially resolved with the EGR working properly. There are quite a few holes to be plugged. I do have my work cut out for me, being that I am not a certified mechanic, I very well may be on my way to becoming one, with this car! Thanks for your help, and sorry I got off topic here.
 
Man I go off topic every 37 seconds................

The DPFE as long as it has a sealed case is simply a dead end tube pair that bounces any pressure backwards when it hits the dead ends. No real flow in or out of either chamber, just slight pulsation. When that plastic gets old though, it cracks, and then the crack allows flow to come out of it. The no flow condition doesn't get that hot but with flow leak comes the heated gases and they then melt the plastic.

Don't know where DPFE mounted on the v-6 but if close then that melting would be worse. On Focus cars they had the unit up on firewall using like 8 inch hoses, then dropped it down to using simple short 2 inch rubber hose stubs from the pressure feed pipe and that relocation makes the DPFEs die super quick because being super close also means they are much more exposed to the water normally in all exhaust. I remoted my DPFE from on top of the standpipe to higher up on the air intake tube and 3 FOOT each long hoses from it down back of engine drooping in front of firewall to create a water trap low spot and then the DPFE problems common to them mounted OEM style (death in 30K miles) disappeared. Been several years now (after replacing 3 in short order) using the same one and no codes, the system apparently doesn't care much about added volume, only that the pressure change does occur. All because Ford wanted to save a few inches of hose. They're getting really bad about shortchanging things like that all over cars to create new opportunities for selling work.

IIRC the DPFE marked with 'hi' for high pressure and 'ref' for reference signal. The hi is the exhaust before the washer orifice and the ref is the actively changing signal after the washer. Somebody correct me if that is wrong. For sure the hoses need to be right there.
 
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amc49 Thank you very much! This is not off-topic in the slightest, because this is exactly the info I need to know to make an informed installation! I was considering trimming the hoses, as a matter of fact. Now I know not to.

On the Contour V6, the DPFE is mounted below the EGR valve directly behind the throttle linkage. It is a tight spot, but I will reinstall at that location for now, and see what happens. The replacement hoses I have measure 11.5 inches, and I will not trim them, and I will try to create a similar style water trap using zip-ties, if possible.

I do have a question regarding attaching the hoses: Should I simply push the hoses onto the connections for the DPFE, and the other side? Or, should I use a clamp, zip-tie, or sealant to hold them in place? I'm leaning towards no clamps, but what have you done with your Focus? My shop manual shows no clamps, and makes no mention of them, either.
 

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Try nothing but at one corner I had to put a clamp because of hose that was not quite the right size..............it came off after say 6 months and clamping stopped that. The norm is none.

If there are issues further down exhaust pipe then blowing hose off on a regular basis is evidence of it. Too much back pressure, say a clogged cat.
 
Thanks again, amc49. Actually, yesterday the larger of the two hoses (the one that does not connect to the manifold-to-EGR tube), blew off while I was driving, so I replaced it today, and used "Jubilee" hose clamps on both ends. I had an idea of zip-tying the two hoses together to prevent one, or the other from getting lost. They're not expensive, but annoying to install. naturally I thought of doing that while I was working on something else, later during the day.
 
Maybe yes and maybe no. At least one of the DPFE stubs is an in between size that if not using the exact OEM hose is hard to find a tight fitting hose for at parts stores, it almost slips on and comes off with only normal running back pressure. BTDT. As well, some of the DPFE parts out there have a slight angle to the stubs to make injection molding easier to pop the parts out, they can shed the hose easier for that. No barbs on them to hold hose on, that would probably be enough but cheaper to engineer the part without them.

I've had to clamp them and running after that for many years with no issues at all. If you got say a cat issue you will be popping a code for it. Or engine won't run right due to extreme back pressure. So, there will be other indicators there.
 
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