Hey all. I saw a lot of great responses from people in here, so I hope I came to the right place! Many other forums I have visited don't have a clue...
I have owned an engine from every Ford motor family, but this is my first 302. It is a 1982 and runs the EEC III system, not EEC IV, so my tester doesn't even fit the test port...
The motor uses the CFI system (central fuel injection) with the throttle body and two injectors. (looks like a modified 2V carb)
When I am driving, the motor feels like someone is pulling an emergency brake handle at random. When at speed, I pop into neutral, and there is no problem. At idle, the engine doesn't run very smooth, and applying a/c makes things even worse (magnifies the symptoms).
What does this sound like? It feels to me like an intermittent exhaust restriction or something... Could a plugged egr feel that way?
Just for more info, the cats are long gone... What can I look into? I am hoping someone else has had this problem and found a fix. I can't afford to give the dealer $100 just to plug into a code reader, then to have to pay for their parts and labour for something like a $5 dollar part!Thanks for any help!
Mark

 

have you tried a good tune up? do you have the duraspark distributor with vac. advance? if so check the vacuum advane see if its working? probaly first thing to do is new fuel filter. may this will get you in the right direction. DW

 

It could be the EGR valve. I've experienced similar symtoms that you describe. It was intermitent too. My truck has EEC-III, but carbureted. The vacuum to the EGR valve is controlled by a solenoid. So it's on/off control. I'm sure it was never intended to work so poorly, but the on/off control of the solenoid is what I believe causes it to surge. The other problem is even when the EGR vacuum is disabled, the plug and seat on the valve must be leaking through because I can still hear it go 'thwup' every once in a while at idle.

 

I am not sure which Duraspark it is... What is a good way to release fuel pressure from the test valve so I can change the fuel filter? This is where I want to start at... I have to first 'find' the fuel filter! LOL
Then, I will check the EGR valve operation and for plugged ports...
Mark

 

well if you have an inertia switch disable it, if not then pull the fuse or relay for your fuel pump, then crank the engine till it runs the gas out of the system this will relive most of the pressure. Good Luck! DW

 

Take the gas cap off and relieve the pressure at the fuel line near the TB.

 

Fuel filter is now changed. I disconnected the inertia switch and turned the engine over. It wouldn't fire, so I proceeded to change filters. I emptied the old filter and found gas that was colored black, and that was from the 'filtered' side of the filter! Anyway, while I was at things I installed a new cap and rotor. Wires are new. I found the pcv hose to be all cracked up, so I replaced that as well. Pcv valve seems to be working fine.
Now for the EGR... Horsepuller, I am in a place where emission testing is non-existant. What can I do to disconnect all of this crap? I also have the air pump still installed and running with the belt... Should I chunk this as well? If I am gonna pull all the emissions stuff off, I may as well do it right! I am still getting the surging. If I put the trans in 1st and hold the throttle steady, I can really feel it! In drive and coasting shows it the most, still... If I toss the EGR valve, won't I need a spacer of some sort to replace it under the TB?
Mark

 

Hey, as a side note, is it possible that the EGR is stuck open? That would explain the rough idle, wouldn't it? The book explains that in a test you supply vaccuum to the egr and you should hear the engine run rough, meaning the egr is working properly...
Mark

 

About the EGR valve: Yes, I think they do leak through. Especially given the pressure differential between the intake and exhaust. I used a little hand operated vacuum pump to operate the EGR valve and it replicated the problem. The I tee'd a vacuum gauge into to EGR solenoid vacuum line. Every time the vacuum gauge indicated the solenoid was open, I could see the drop in RPM and rough running. My temporary fix was to disable the vacuum to the solenoid. The EGR valve is only about a year old, since it was replaced at the time of engine rebuild. So I'm going to try and remove and clean the valve seat first, before I replace it. After that I might try putting a blind plate under it and drilling a small oriface hole in it to keep it from slugging the intake with EGR gas.

Now about disabling the rest of your emissions equipment: I say don't do it. At least get some more info from the guys here on the board before you start gutting it. The reason I say that is because the EEC engines with either EFI or Feedback carb's depend on that stuff to provide information to the computer. Example: If you remove the air pump, the exhaust gas oxygen sensor tells the computer the mixture is too rich. So then the computer sets the EFI to it's leanest setting. That's just a hypothetical 'what if', but you can see where I'm going with it. It's the same with the EGR valve. There's a position switch on the actuator that tells the computer what position the EGR valve is in, which in turn relays that info the the computer.

It would be nice to have a listing of all the "if-then" statements and subroutines the little computer goes through from the input it gets from the engine sensors to make it's calculations. Then it would be easier to predict what would happen when you alter or disable the electronic engine controls. That kind of stuff must be long gone though. If you think about it, these little microprocessors were pretty remarkable for their time. At which point, the IBM personal computer was not yet even available until 1983.

EEC-III will have a Dura Spark III ignition module and distributor. The module will have a brown grommet and the distributor has no vacuum or mechanical advance. The ignition is timed by a Crankshaft Position Sensor.

 

Yes, right after I posted, I gave thought to the computer and the feedback it needs, so needless to say, I will just fix what is there... I have to check to see if everything is intact, like the O2 sensor, since the cats were removed, who knows what else could have been taken... The car seems to smell like it is running rich, so I am suspecting something like that... I am going to look into things a little more today... I already noticed that there are two little pieces of pipe tied into the exhaust, about 3/4 inch diameter, and one cas been capped off... Not sure what that is yet... see what I can come up with. thanks for the help!
Mark