95 ford trowing a 334 egr position sensor. should I buy a egr valve?

 

Not until you test the system to see if the valve is bad. Get a Haynes manual and go through the EGR system checks to pinpoint the problem.

 

check all your vac lines...i had the same thing and it was just a melted vac line. Email me before you buy any parts for it.

 

You didnt get 'insufficient flow' also?

You need to check this at the solenoid (sol pack near the coil)

look for proper activation of the sol when hot, idling and blipping the throttle.

then test if in fact vacuum is presented at the EGR, if so, test the EGR to hold vacuum, if so then test the EGP similar to a TPS to look for glitches.

 

Like they said check your vacuum lines and if that doesn't work try the EGR postion sensor. It's fairly inexpensive and easy to change out. I wouldn't buy a new EGR valve yet, they're kinda a pricey at the cost of $75.00

 

i have been getting insuffisent Egr flow code. can you explain a little more in depth on how to check the solinoids and sensor and anything else i should check?

 

ok, that code is telling. It indicates that the output of the EVP did not match what was expected from the use of the solenoid/EGR, i.e. the ECM was saying 'I need some EGR please' and turned on the solenoid, but the EVP whose sole purpose is to grade the effort did not indicate such.

there is a set of 2-3 solenoids (I forget without a truck in front of me) right next to the ign coil on top of the motor, to the right of the intake runners/plenum.

Trace the vacuum line from the EGR to determine which one you want. This is a good time to see if it is rotten. back probe the 2 wire plug with a tester to see that yes indeed as you increase throttle off idle the solenoid does in fact change (I forget whether the ECM supplies voltage or ground - Im not near the shop or manuals right now) as you release the throttle the solenoid should go dead.

If you get the proper electrical signals all that means is that the ECM and/or its connections to those wires are intact and nothing more.

Problem is, the connections are not sealed like GM does - they corrode, pull the plug and using a tiny nail file clean the metal contact surfaces. This is perhaps 3/4s of the 'EGR valve problems' you will find on ford vehciles of any type using this system.

now, pull the vacuum line from the egr and hook to a vacuum gauge. At idle, no vacuum should be seen. Increase throttle and you should see vacuum, let go of throttle and it should disappear.

If you get this result then it proves the solenoid is working properly and that the wires are making contact with the terminals.

Next, apply a vacuum pump with gauge (avail for $40ish from autozone etc) to the EGR itself and test to see if in fact it can hold vacuum.

If it can, then this means the system works to this point - the EGR can in fact be acted upon by the ECM.

Next, backprobe the EVP and look for a varying voltage from the EGP as you apply vacuum via hand tool to the EGR. if you do see it, then it proves that the ECM is getting SOME feedback.

But note, at this point the EGR can still be sticking internally intermittently and the EVP output might be going out of range.

Here is where a few moments on the SBDS system will tell you if the EVP output matches the expected inputs.

Recently, in my own trucks case, my testing showed that the solenoid connections were corroded. I cleaned them, and replaced the solenoid anyways. Later, at intermittent times, I still got insufficient flow. Removal and inspection showed that the EGR was also sticking from time to time, feeling flush, I chose to replace the EGR and EVP. These parts are all avail at any advance/autozone and the sum should be <$100 which may or maynot be excessive to you.

* I might have given the EVP as EGP in another post - this is a typo

 

^ Right on. The computer varies ground to the EVR solonoid, and the solonoid should have a constant 12V with the engine on at the red wire.