My Dads truck is 1989 F150 with a 5.0L and has a problem with an EGR code. Ive put a vacuum pump on the EGR valve and the engine wants to die, so it is opening. I also removed it and checked to make sure it is closing. Which it is. How would I determine if it is the solenoid thing or the position sensor?
KOEO
81 Air Diverter selonoid fault
82 same?
CM
31 EVAP control below minimum voltage
KOER
33 EGR Valve Fault.
44 Thermactor air system fault
52 Power steering pressure switch open
The EVAP and Thermactor codes are because those systems are just *gone*. The only thing left of EVAP is the charcoal canister and that looks like someone took a hammer to it. I also discovered the air solenoids were not hooked to anything, so I disconnected them to prevent a vacuum leak.

 

bumpety bump

 

First of all make sure you still have a vacuum source going to the EGR solenoid after you disconnected the two A.I.R solenoids.

Service Code 33 in Key On Engine Running indicates that the EVP sensor input did not change after the EVR solenoid was instructed by the processor to open the EGR valve. Because a Code 84 was not received in the Key On Engine Off Self-Test, it is known that the EVR solenoid functions electrically. It is also known that the EVP sensor is in the expected closed valve range because Code 32 and 34 were not received in either Key On Engine Off or Key On Engine Running Tests.

Possible causes:
Vacuum hose leaks
Obstructed vacuum hose
Obstructed EVR solenoid filter
Damaged EVR solenoid.
Damaged EVP sensor.
Damaged EGR valve

You could try grounding the Dark Green wire at the EGR solenoid with the engine running and see if the the engine wants to die.

 

Besides leaking hoses also check to see if any caps on the tree are dry-rotted and also see if the vac output is strong at the reservoir (black coffee can on top of pass side fender skirt).

 

So basically, its a vacuum problem. Where is the solenoid filter? I could put a gauge on the vacuum line going to the valve. If I trigger self test, how much vacuum should I expect to see if it is operating correctly? I may just remove all the brittle plastic lines and run some hose since I only need to connect to the egr. So I could go engine -> can -> solenoid -> egr... Then plug the air solenoids back in.

 

The filter is inside the EVR solenoid, image below.



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I went and ran vacuum hose to the various items and got rid of that brittle plastic tree. Still same EGR code.

 

Did you ground the green wire and see if the EGR valve opens?

 

Well, I discovered I hooked the hoses to the can backwards, so it was getting very little vacuum. I switched them around. I did just now ground the green wire and the engine is responding. I shut it off then re-did the test and 33 came back.

 

If the engine ran bad while you grounded the green wire and you are still getting the 33 then I would say you have a bad EVP sensor.

 

That is the one on top of the egr?

 

Yes it is.