1994 Lincoln Town Car EGR Question

This is going to be an easy one for someone more familiar with this system than me so hopefully someone has a quick answer for me. I haven't worked on these older Fords. I also don't have an OBD1 scan tool so all I can do right now is retrieve flash codes.

1994 Lincoln Town Car Signature, 4.6L, 56K original miles. Customer complaint: "Sometimes it runs real bad...please change plugs/wires." Uh huh, OK. I retrieved codes 181,189 lean condition. Great, I thought. An easy one...I smoked the intake and found a couple leaks.

I found smoke coming from the vacuum line to the EGR valve, along with a cracked/broken EGR tube between the exhaust manifold and the EGR valve. So, needs a new EGR tube for sure.

I found that smoke was making it's way through the EGR solenoid to the EGR valve. I noticed this when I removed the vacuum line from the EGR valve to check the EGR valve. The EGR valve is good as I checked it with a vacuum pump. I also got smoke out of the broken EGR tube when I opened the EGR valve so I have good flow. When I looked closer at the EGR solenoid, which sits right above the EGR valve on the back of the engine, on the passenger side, I found the valve open all the time, even with the connector unplugged. I assumed this should be a normally closed valve yet I have smoke making it's way through it from the intake to the EGR valve. So, I assumed I found my issue and ordered a new solenoid and EGR tube.

However, when I got the new solenoid out of the box (straight from the local Ford dealer) I also found it to be open all the time. Am I missing something here? Shouldn't this solenoid be normally closed, not allowing vacuum to the EGR valve, until the PCM opens it for EGR flow?

So, searching for 94 town car on the Internet didn't pull up much but searching for F150 sure did. I did some reading about the solenoid valve and found that it's some kind of "dithering" valve or something meaning it won't be fully closed.

I tried connecting it to 12v to see what happens and it didn't do anything. I left it connected for about 10 seconds and the wire began to get hot. I ohm checked it and it's shorted.

Does anyone know if a shorted EGR solenoid will fry the computer driver on this model? I haven't connected it back to the car since attempting to bench test it but now I'm wondering about my computer. The new one shows about 30ohms which is what the info in my Vantage Pro says it should be.

If someone here can explain this valve better to me than the other forums I found info on, I'm all ears. The shorted coil inside is likely a separate issue. Not sure how that happened. I doubt it could be caused by me putting 12v on it from the battery.

Yeah, I don't think you bench testing it with a battery was the problem. I'm not surprised that the solenoid is normally open? I've seen other EGR systems of that vintage operate the same way.

The only way you're gonna know if the computer survived is to run its output. Will your scanner run the KOEO or KOER Self-Test? That should activate the solenoid output for you (briefly). Get a test light installed in place of the solenoid to give you as visual indication.

Yeah, I started second guessing myself....Is this really the solenoid or something else and did I fry whatever it is by bench testing it? But it is the solenoid and there's no way for me to have, even inadvertently, shorted the coil inside so it's not something I could have done. I do have power getting to one side of the connector so it didn't blow the fuse.

I don't have an OBD1 scan tool at all. All my tools are OBDII only. I ordered a little Bosch 1300 from eBay but it won't be here til later this week.

BUT...As I'm typing this, and now that you mention that, I think I recall the flash code retrieval method (jumper wire in the diag port) doing a KEOR test as I remember the idle jumping up for a while before displaying the codes which is what I've seen Fords do during KOER test on newer models. So, I just went out, connected my test light to the solenoid connector, jumped the diag port and started it up. After about 20 seconds or so on came the test light! Dim at first and got brighter until it went out. ECM working perfectly!

That wasn't the exact answer but gave me just the clue I needed. Thank you! Now I know it doesn't need a computer!

This Ford EGR solenoid is still a mystery to me in how it works and how to test it but I have a new Motorcraft solenoid so it should be trustworthy for now. Turns out I needed the new solenoid but not for the reason I initially suspected. Sometimes it's better to be lucky than good, I guess.

Side note....don't use a BWD EGR tube. They don't fit. (Yeah, shocker, I know.) Waiting for the dealer part on that.

On my 1993 Lincoln Town car with the 4.9 it was not the EGR valve but clogged EGR channels, which I was told is a very common problem on those cars. Have you reamed the carbon out the EGR channels?

As I indicated above, I don't have a flow problem. I have a lean code. Smoke test revealed good flow through the EGR valve so there is no need to ream out the channels.

Oh. Sorry. I need to read more carefully.