EGR Issues?
 

2000 E250, 5.4 motor, 287,447 miles currently

So am sorta chasing a Lean Bank 1 & 2 DTC that takes quite a while to set a code after its cleared. Along with replacing a few very old vacuum hoses I'll be changing plugs (just over 52K on the existing) and thought to clean the throttle body at the same time.

Here's what the back side of the TB as first removed:

https://cimg1.ibsrv.net/gimg/www.for...09a592909b.jpg
Front side, as first removed:



This is the intake fitting the TB bolts to, the EGR valve connecting just behind the opening shown here:

https://cimg6.ibsrv.net/gimg/www.for...b4dd8bda23.jpg

TB front & back sides as first removed:

https://cimg4.ibsrv.net/gimg/www.for...fdc4358dcf.jpghttps://cimg3.ibsrv.net/gimg/www.for...6a3777b63d.jpg

Not the best image resolution-wise as its almost impossible getting a good camera angle. Anyway that "goop" shown is similar to what was on the back side of the TB. Its not a huge hassle to replace the EGR but I'd remove 90 degree "adapter" for a thorough cleaning if that's recommended.

The TB has been thoroughly cleaned by now.

Any help or ideas would be greatly appreciated.

TIA:-X22

That type of build-up is usually the result of a cracked intake or leaking intake valves.

I was afraid it was something like this---with that mileage it wouldn't surprise me at all. Just curious---would this be a combo of oil and fuel or more of one than the other?

Not raw fuel, more like oil and/or exhaust.

How about a worn valve guide , guides ````

When was the throttle body cleaned less than 100K ago ```

Two decades of blow-by would significantly contribute to that as well.
Consider a catch can on the PCV.

I'm guessing somewhere around 87K miles ago---but that was nothing more than a superficial scrubbing of the outer side, the one without the build up as now shown. There were 203K miles on the van at that time, quite possibly this already existing albeit not quite as pronounced.

Can you expand on the catch can idea Sam?

I'm seriously considering replacing the intake with a new Ford part----or going one step further and replace the entire engine with new intake too. This van is already outfitted and well suited for my business so that's a strong consideration. I'd go with a Ford reman'd engine.

I'll bet that engine is sound ~ other than some ware ~ if there's no chain clatter ```

A catch can is a container between the PCV and throttle body.
It is designed to "catch" the oil vapor and other moisture coming out of the crankcase before it enters the intake flow without restricting the crankcase ventilation.
It works essentially on the same principle as a water trap on an air compressor. It must also be emptied periodically.
There are many available online at the typical racer products sites.

That's possible and I've not noticed any chain clatter but if this is valves or guides worn out I'm not sure how much money and time I'm willing to spend to let it limp along for a while longer. I'd like to keep this van running as its been outfitted to help my business, would hate to lose its service without careful thought as to what I should do keeping the body/frame alive for a long while yet.

Never knew of such a device Sam--sounds like a good idea. Thanks for that explanation. :-X22 Would adding one of these require any sort of check valve too?

I'll cruise Jeg's a they're local to me--been buying from them since the middle 60's in fact. :)

That would be the PCV valve.

p0171 and 174 are a result of unmetered air entering the engine, ( not measured by the MAF), so you may have a vacuum leak or a bad maf, Ford are notorious for maf failures.
lean at idle (high FTs) and low (under plus 10) FTs at part throttle are almost always vacuum leaks