Egr issues

[MakinJeepsWeep!]

I have looked over the info already on here and I still feel its not quite what i have going on here. I have a 96 awd 5.0 X 270 some odd miles on it, has new (within 6 months) Fuel pump and filter, plugs wires, injectors 24lbs, mass air sensor, valve cover gaskets, pcv valve, 1" phenolic spacer, cold air intake i made, box was gone already when i got the truck, all intake gaskets, one vacuum line, thermostat, egr vacuum reg, egr valve position sensor, probably other things i forget ect ect and everything set with volt meter within specs with info off here as to what they should be and some books. I have a recurring code for egr flow excessive and some times insufficient but rarely. I have yet to check the voltages off the position, i did do some test and found some odd things. Now this has been happening for years and slowly getting worse, it did it at least twice when m father still owned it. Now it throws the code soon as you crank the truck witch it should not because the egr isnt in operation at idle. If you clear the code after cranking the light will not come back on until you **** the truck off and crank it back it up no matter how far or short you drive. The computer is still adjusting fuel mapping for the movement of the egr i found out with a test i did, i hooked up my old position sensor and just left it hanging out back there with the new one still on the egr so it would seal, while driving this way the truck would have a stumble idle rough or be fine depending on open road stop go ect but did not set off the light my assumption is that the computer was getting closed feedback so in turn when it tried to open egr it opened it wide open because it was always seeing closed and that caused the missing since it did not know it was actually open so it did not change fuel mapping for it. So that would say it is functioning and the computer is changing the fuel mapping when its all hooked up.

In summary : All is working in theory. Light only comes on when starting. If you clear code and drive it will not come back on drove 150 miles never shutting truck off no light, just let it idle at places. I am going crazy with this. Please help! I will do any test needed or give any info needed to fix this!

 

[CDW6212R]

That should be in the EGR control circuit, it sounds like the EGR is open at some point during the startup. What shape are those parts, the EGR and the control devices(not the PCM)? Have you removed and plugged the EGR vacuum hose to test it yet? That should disable the EGR momentarily, so no airflow then.

I would have likely changed all of them by now to narrow down the issue(I have the spare parts somewhere, they would have been free for my testing). I wouldn't have randomly replaced them all with new parts, test first before doing that.

 

[MakinJeepsWeep!]

i have indeed plugged the vacuum to the egr and still got the code for excessive flow. The position sensor was still plugged in. The sensor and vacuum regulator have been replaced the only thing not replaced is the egr as it seems to be functions i used my mouth but it holds vacuum an as hard as i can pull it only moves a tiny bit, and while running if i move it by hand idle slows and with more open it gets worse so i assume it seals since the truck does idle smooth when left alone.

 

[CDW6212R]

Have you cleaned the EGR valve, as it can get fouled and not seal fully, just like the IAC? It may be cracked open just a little and flowing enough to throw the code. I've never cleaned one, like the IAC is done commonly, but give it a look or change it if you can.

 

[MakinJeepsWeep!]

Yes i have, twice along with entire system, TB, Iac, 90, Upper and lower, egr.

 

[MakinJeepsWeep!]

Wait IAT? i have not cleaned the mass or the intake air temp sensor since last oil change. If that is waht you mean

 

[CDW6212R]

That's the hardest kind of problem, changing everything and it doesn't change it. It is often one of the same items already checked etc, my last issue like that was a coil pack failed(a new one). I'd go back through it slowly again, you have asked and done the right things already.

 

[CDW6212R]

Wait IAT?

That should have been IAC, the idle air control solenoid. Sorry, mistyped that, you clean that sometimes to help smooth the idle.

 

[MakinJeepsWeep!]

Okay, sounds like a plan. I have read that the egr plate that holds the bladder can warp with time and heat, its the only thing i havent changed just didnt know of the truth in it since it did not come off here.

 

[CDW6212R]

A lot of these parts are very old now, very reliable, but it's time to replace some just due to the age. I've collected quite a few NOS relays to replace them all in my one keeper. Stuff like that is old car normal issue stuff. My Mountaineer was running the battery down a few years ago, it turned out to be a faulty relay for the fog lights, they were on almost always until I noticed it.

 

[MakinJeepsWeep!]

Thought i should add, the truck does run great! Throttle response is spot on runs up from idle to 5200-500 steady with out any major swings in lag or pick up.

 

[MakinJeepsWeep!]

i had something like that happen to me in my 5.0 swapped ranger, the relay for the comp went bad. so it be crank tune run good after things settled down shut it off next start over and over and over the relay was for the memory so every time we killed the truck it was like unhooking the power.

 

[MakinJeepsWeep!]

I thank you for the help i hope i can go back through and spot something i missed the first time. or just break down and get a new egr.

 

[CDW6212R]

I know the feelings, I have so many old Fords that I can't keep up with the little things which they all need. I keep 3-4 running and try to manage the batteries of all of them, working on something occasionally. Now in Winter it's easier to just stop and plan for later, get a nice day etc. Here it's snowy today, with some sun tomorrow.

 

[XploderPhil]

I have looked over the info already on here and I still feel its not quite what i have going on here. I have a 96 awd 5.0 X 270 some odd miles on it, has new (within 6 months) Fuel pump and filter, plugs wires, injectors 24lbs, mass air sensor, valve

I see that you have changed injectors and maf, so I'm taking that you have a custom tune or chip? If so something may be corrupted.
What code are you setting? Is that code in memory? Can the code be reproduced with KOER (engine running) test?

 

[MakinJeepsWeep!]

Its winter here too, I am sure not like yours but in south Texas below 60 is winter to me and it was 26 this morning. I have three and my mother inlaws Chevy and right now they all need ball joints really.

 

[MakinJeepsWeep!]

xploderphil: the code is the P0402 excessive egr flow. I do not have a custom tune or anything on the truck, with the bigger injectors alone you dont really have to get a tune as i went from the stock 19lbs four hole to 24lbs 6 hole so you get a finer spray pattern for better burn wich helps even the gap to some small extent but to deal with the extra fuel a adjustable fuel pressure regulator and a mass that if i remember correctly came off a cobra witch came with the 24lbs in it. I also have extremely low ohm wires and hotter plugs to make sure the fuel gets busted off. The phenolic spacer helps as well because it increased the vacuum so it upped what air it can effeciantly suck in. I played a game of tip for tap to keep a fairly even keel overall. Most of all though the eecv computers are pretty good for moddifying they will take alot of change and adjust for it.
Oh and yes the code is there every time it gets cranked also the code was there a few times when it was bone stock, i was hoping cleaning and fresh gaskets all over would remedy the issue while i was in there putting in a few goodies.

 

[Gary Crist]

Don't those trucks have a back pressure sensor?

 

[MakinJeepsWeep!]

Not that i am aware of. I thought that was kind of the job of the DPFE that this truck does not have since it has the sonic/internal egr system.

 

[MakinJeepsWeep!]

Update, while thinking and doing more looking around I think i may have figured out the problem. I ohm'd out the old sensor sense it was clearly not the issue. I realized it (Duh) is basically a resistor or a potentiometer. After that i verified that the egr itself was working correctly. Clean, opens closes freely, I pushed on the back inside where the position sensor goes an where the vacuum happens to check that it was indeed fully seating. While doing that i noticed that there was a dot or pip on the center for the rod from the sensor to rest. I had read other articles stating that you may have to shorten the rod from the sensor to get it to read correctly do to variables involved. So I took and shortened the rod by the amount the pip stuck up off of the plate in the egr going with the thought of most of the time a aftermarket part(the egr) wouldn't have that pip and if you are buying a egr your probably getting that sensor as well and that difference is what was causing to see it "leaking". Now its only been 35 miles and a couple start up but the o2s seem to acting better and the truck seems to be happier. I will update when i get more miles on the truck weather or not the light comes on or not!!! Thank you all tremendously for the help and information.

I would not tell anyone to do this unless it is the absolute last resort and you have checked again and again that it is mechanically functioning as it should along with all other parts/items in the operation of the egr!