amdoming5

Can someone with a car that passes smog please check something for me? Once the car is warm, pull the vacuum line from the EGR and either by hearing or connecting a vacuum guage, check to see if there is vacuum at that line that increases as you rev the car at the throttle body. Ready below for why I need this.
Thanks.

The car ('87 5.0 GT) runs great...but won't pass smog! The EGR solenoid (EVR), mounted to the back of the passenger shock tower, will not open so it won't pass the smog check. It burns clean and passes every portion of the exam except the EVR function ("no signal, or vacuum to the EGR").

I bought the motorsport mass air conversion kit so it has the 24 lb injectors, 70 mm mass air and cobra computer. Once the car is warm, the EVR is supposed to open proportionally with the rpms. It has a 12 volt wire from the battery and a green wire which goes to the computer. The computer opens and closes the circuit (grounds it) as needed to open and close the EVR. I've checked for 12v to the EVR and traced the continuity of the green wire back to the computer. I checked the ground to the computer, replaced the 3 main relays, replaced the EGR, replaced the EVR three times, coolant temp sensor, air charge temp sensor and cleaned the "salt and pepper" units that clip to the back of the intake, checked the vacuum lines, replaced the computer, etc. I ran the scanner and it came up with a few codes. None really seamed related to my problem, but there were two that I took care of from the mass air conversion. One is the vehicle speed sensor loop and the other was related to the fuel pump relay. I'll have to run it again and make sure those cleared. I don't know what I could be missing, but if you have any ideas I would appreciate it. I just think I've done everything possible and am wondering if the EVR is supposed to open while the car is in neutral (being tested at the smog station).

mjr46

vaccum won't increase as you rev it in nuetral because load is an important factor that figures into the egr operation which is calculated by the map sensor in the sd car and by the maf in a maf car which you have converted........the SMOG station if they are trying to fail your car based on the test criteria they are using to judge operation of the egr are wrong and don't understand description and operation of that system on the 5.0....at idle there should be vaccum on the supply line and if you run a koer test then in the test you will notice the selonoid will be commanded on briefly by the ecm and you should see a quick rise and then fall on your vaccum gauge onve selonoid closes again......it does not operate proportionally the way you are testing it, now out on a test drive you will see it open and close if you tee in a vaccum gauge to the egr supply line as you accel and decel cause load will be factored into the equation now.....no vaccum should be supplied to map sensor when maf conversion is done....run a koer test and if no egr codes come back system is operational and the smog people need to pull out a description and operation manual and realize they are improperly testing the system in accordance with the way ford designed it

Joel5.0

If you run a simple KOER self test and no codes show up, specifically code 33...... the EVR is doing its job. Like MJ mentioned, load needs to be present in the system (NSS detecting system in-gear, MPH reading from VSS over 6 MPH, TPS @ part-throttle position) for the EEC to run the EGR strategy. The only way they can verify the EVR, is by running a KOER with the EGR valve line disconnected, and the vacuum gauge monitoring the vacuum at the line for the short period of time the self test will activate the EGR valve......

amdoming5

Well, I'm glad there are smarter people out there than me. There is definitely vacuum to the EVR, but as you're saying won't pass it on to the EGR unless there is load. I did not think to tee into and run a longer line into the car to monitor while driving. I'll run a koer test to double check.
Thanks guys, I've spent hours and hours and too much money replacing parts that probably were working fine. I should have asked first, but I thought I could figure it out. Last time I went "around the block" to warm up the car for testing, I got pulled over for expired tags. The guy must have though I was going to run on him since he did not pull me over until the second car arrived. The car may be ugly but she means a whole lot to me!

mjr46

you don't even need to drive it around the block!!,. .....tee a vaccum line in on the egr valve and run a koer test, and watching the vaccum gauge when test commands egr / evr operation...the needle on the gauge should move up a little then drop back to 0 in. hg..if it does what I stated = system operational and fine and no codes as joel5.0 stated exist for egr

amdoming5

I converted to mass air probably 10 years ago and never bothered doing all the other, what I thought to be "small" things. Due to not passing smog, I got a code scanner and fixed the fuel pump code and VSS code. I thought that I was closing the VSS circuit for the newer computer since I did not have a VSS. I disconnected the vacuum to the MAP as well. I'll run the koer test first before heading around the block. The code scanner manual says all koeo codes must be cleared before doing keor...is this true? I have one koer code still hanging I think. I'll have to look back and see what codes were pulled and run it again to make sure I cleared the ones I thought I cleared.

Joel5.0

Nope......

amdoming5

Thanks again.