nayrb64

i searched and found tons of EGR posts, but nothing like my issue. I have experienced shuttering and loss of power. I get code 327 - and have been checking for issues. I removed the EGR valve to ensure it was still holding vacuum and to clean the carbon from the valve. Vacuum held with no issues. when I cleaned the valve with carb cleaner - the valve in the closed position would not hold the fluid. I would think if the valve closed, the valve upside down (threaded side up) you should be able to fill that 'cup' with fluid and nothing run out.... so if there fluid is bypassing the closed valve, I assume the gas will bypass the valve as well. Could that possibly be my culprit?

I hate throwing parts at a problem esp at 80 bucks for new EGR. What say y'all?

wde3477

Didn't see your model year, but suggest if you have the position sensor on top of the valve - chances are better than average that's your problem. If you choose to replace, be sure the color matches...

nayrb64

It's a 95 and the color is white

nayrb64

So, I used the following link to test the EGV position sensor and found all to be within the specs:
• Reference Voltage (5v at pins VREF and SIG RTN) 4.75
• EVP Sensor Resistance (< 5000 ohms at pins VREF and EVP) 3,557
• EVP Sensor Resistance (> 100 ohms at pins SIG RTN and EVP) 218.8

http://www.fullsizebronco.com/forum/...placement.html

I not exactly sure to test next. What I am still concerned about it the inability of the EGV valve to close 100%. As I stated earlier, with the valve off and upside down it will not hold fluid.

wde3477

Never paid much attention as to whether the valve sealed off, but I suppose that's a possibility.
1) Piece of crud in the valve seat or other binding / stem or seat damage that is not allowing the valve to drop fully, causing an erroneous position.
2) Problem with the vacuum control solenoid that supplies the vacuum to the valve, so the valve is not where the computer wants it to be when it wants it there (I had this problem - there's a little foam inlet air filter no more than 1/4-inch diameter at the bottom of the solenoid that supplies air through the solenoid to dump the vacuum and drop the valve. Mine was plugged solid. Tried cleaning it, broke the plastic tabs, ended up replacing the solenoid).
3) Thinking your model year has the differential pressure setup - some members report that the ports get plugged, and can be cleaned out with a pipe cleaner - sort of a fuzzy twist tie looking thing. Never have fooled with this, so have no idea what it looks like or where it even is.

You're on the right track - testing before replacing, rather than just shotgunning parts and dollars at the problem. Good luck, and keep us posted.

nayrb64

Found the issue! After testing everything 6 ways from Sunday - I finally pulled the PCM and the capacitors are bad.... Hello Digi-Key

vjsimone

Did you remove the EVP and check the resistance while pushing the plunger down all the way and back looking for dead spots in the resistance?

I you remove it to test, re-record the resistance measurements across the pins again.

Make a Block-Off gasket for the EGR to eliminate flow of gases to see if it make a difference.

vjsimone

"Replaced the caps - didn't check for the 5vdc at pin 48, but the truck has had no change. Runs like crap Also, I cannot get the KOEO Check Engine lights to give me code faults. This is becoming more and more frustrating"

Are you sure all of the existing Caps were 47uf?
What was the voltage rating on your replacement Caps?
Did you replace them in the correct polarity?

"5vdc at pin 48" You did have 4.75vdc at your EVP reference....

nayrb64

OK - Truck still runs like crap - no power - even got a new ECM for testing - same. Ran all vacuum lines. Found one broken today - replaced. NO change. Pulled plugs today -several are white tipped - as if too lean, so maybe I have been chasing my tail and it could be timing? Or issues internal to the distributor? all new rotor, caps, wires, plugs, TPS, coolant temp switch, fuel pressure at 45-50#, new throttle body gasket, the list goes on. I am at my wits end. I appreciate all thoughts on the matter.

vjsimone

See post #7....