Electronic Vacuum Regulator (EVR) testing
 

I have a 92 Ford f150 with a 351w and am getting error 327 off of the KOEO test using the mil and a jumper wire per Chiltons

the EGR test passes ( i used a vaccum tube to and my mouth to apply vaccum pressure to egr and the engine did drop RPMs)

I dont seem to be getting vaccum so I moved on to the EVR for testing

I searched and searched here and could not find detailed testing for the EVR

I did find a post (HELP - EVR / EGR Problems ?) that said the resistance should be:

My 1990 Mitchell manual give the following resistances for the EVR solenoid:
4.9 and 5.8 under 8500 GVW - 20-45 ohms
7.5L 100-135 ohms
All others 30-70 ohms

the resistance was 35 ohms (within tolerances)

So I removed the part and tried to apply vaccum to input and test for vaccum at output - none detected

Then I got adventurous and applied 12 volts to the device from a 12v power supply and then it passes the vaccum to the output

seeming to function normal? - I am not sure?

So i put it back in and start engine and test for voltage at the terminals i get 14 volts on both terminals (same as battery voltage for my meter)

I am thinking that there should be some voltage drop when the system is active?

questions:
What should the voltage be and at what engine condition / speed / load?

How can I test to see if the circuit is open on the ground / ECU side?
(which it seems to be)

Is my test valid?

Thanks you guys
The Info here has helped me a great deal since I got my truck a couple of years ago !
I dont think I would have finished my long block install last year without you :-) !

All your tests are right on, so it doesn't sound like the EVR is the problem. Check the EVP - the sensor on top of the EGR valve - that is what the code is for. Check the signal voltage from that and check the reference voltage. If you have a Chilton manual, then those tests should be in there as well. It could also be a break in the vacuum system between the EVR and the EGR valve.

I did start with the EVP test per the book and it passed at that time.

When I did the vacuum test I disconnected the rubber connector from the EVR and plugged the vacuum side of the rubber connector and connected a short length of tubing and an inline connector right to the rubber EVR vacuum connector opposite the green line to EGR and created vacuum “straw in a milkshake style” put my tongue on the end and waited a minute to see if it held pressure testing both the EGR and the vacuum line at the same time. Good to go from there I thought.

Since I posted I did find a leak in the vacuum system it was near the air bypass valve, close the manifold…. Melted, and collapsed on the back side where you could not see it (of course). That brought up my vacuum pressure some since they share a common vacuum supply line. Then I disconnected the battery for ten min and reset the system. The 327 MIL code came back after it warmed up.

I have the old EVP (I replaced with a new OEM during the rebuild) I’ll test it and swap them just for kicks. It is easy enough.
…………………………………………………………………………………………………………………………………… …….
Well that did it!

On retest the EVP failed the diagnostics.
However the Old Part is in fine working order and my problems are gone

Darned intermittent failures!!!!!!

Thanks so much

Jeff

(you guys ROCK!)