my nephew has a 88 F250, 300/C6 410 gears. the previous owner put a jasper long block in it 10k miles ago, with all new tanks, lines and injection parts due to vandelism, involving gas tank additives that blew the motor.
it now is starting to act up. every now and then it will sputter, like an ignition miss,and the cel comes on. i pulled the codes, and got an egr code. put in new egr controler and valve, but still get the cel and egr code. if i take it out and romp on it, the cel goes out, but if you let it sit for 5 min, or drive it easy(like he does) the cel stays on. is there possibly a passage somewhere in the egr circuit that is plugged? i know nothing about these newer cars, everything i have is from the 60''s and early 70's, or is diesel

 

O.k., I'll try and give you a hand here....

Let's see......I'm kinda' thinking you're not getting enough vacuum to the EGR valve to open or hold it open......."it now is starting to act up. every now and then it will sputter, like an ignition miss,and the cel comes on. i pulled the codes, and got an egr code. put in new egr controler and valve, but still get the cel and egr code. if i take it out and romp on it, the cel goes out, but if you let it sit for 5 min, or drive it easy(like he does) the cel stays on."
Have you checked to see if your new EGR Valve will hold vacuum with VERY LITTLE bleed off ???

Can you give us the code number it's throwing ??? That'd be a good start.

Have you done the obligitory check for vacuum leaks on all hoses (especially the PCV valve hose to vacuum tree) ?? That hose is probably the most overlooked source of a vacuum leak under your hood. Use a couple of small hose clamps on each end.

Also, check to make sure your vacuum tree is snug and not leaking air.

Double and triple check the vacuum line(s) that go from the "coffee can" (vacuum reservoir) to the EGR control solenoid. A worn or pinched line behind the valve cover is VERY HARD to find. If there is a leak in that/those hoses you won't have enough vacuum to open the EGR valve and you'll get a CEL w/EGR code.

Have you checked the throttle body to upper plenum gasket ??
Visual inspection won't do here, I'd just replace it .....the gaskets are cheap and easy to replace.
Just for the fact of knowing it's been done....get a spray can of throttle body cleaner and give the TB a good cleaning as well as the Idle Air Control.
It may help.
Have you tried spraying starting fluid (be careful when doing this one) around the Upper to Lower intake manifold gasket and notice any RPM change ??

A couple of "other" places to check...

Check the Fuel Pump Relay (at least switch it with one that you know works) they've been known to get water in them and cause problems.

Check the Tank Selector Switch (if you have dual tanks).....mine went bad and caused stuttering and really bad missing before it gave up the ghost.

And, of course,........ check the wiring harness connectors for the fuel pump(s) and make sure everything is grounded well.

Get back to us and let us know what you found !!!!

Bob

 

guess i missed a few things there. the throttle body was cleaned about 3 months ago when all this started . new gaskets were also put on, and the whole top end was checked for vacuum leaks by me. i did not check the pcv, but he said he did. i will have to check that. guess it is time to break out the service manual and trace all the vacuum lines. the fuel pump and filter was just changed, and it did not help with the miss, but it did make it run again.

 

Also, don't forget to check the Fuel Pressure Regulator.

cjsteak (Chris) just went through lot's of checks and fixes in this post "300 Has Shaky Idle".
Lot's of good info there to look at even though he has a newer truck.

Here's the link.
https://www.ford-trucks.com/forums/s...d.php?t=376287

Still waiting on the code(s) it's throwing and if it's with KOEO and or KOER.........

Bob

 

When my engine was throwing codes about EGR and EVP the coffee can on the passenger inner wheel well was cracked. It is a vacuum reservoir and must be airtight.

 

ok bob, he just came over and i pulled the scanner out again. koeo gives 111, all systems good. koer gives me code 31, egr valve position or exhaust pressure transducer sensor voltage low. there was 1 vacuum line to the heater control broken, but fixing it did nothing . i ckecked all the big lines, and did not like some of them,(dryrot) next week he is going to bring it over again for the day, and we are going to replace all the vacuum lines, but i don't think this will fix the egr problem. any ideas??

 

but i don't think this will fix the egr problem.
Don't be so sure about that.

Vacuum opens the EGR valve. The sensor on the end of the valve tells the PCM (computer that's throwing the code)...via variable resistance in ohms... how far open the EGR valve is. If the EGR Valve can't open because of a lack of vacuum or a vacuum leak, the sensor will be telling the PCM (computer) that the EGR valve isn't or hasn't opened properly and the PCM will throw a CEL.

I'd say there's a vacuum leak, probably where the EGR sensor bolts up to the EGR valve based on this:
if i take it out and romp on it, the cel goes out, but if you let it sit for 5 min, or drive it easy(like he does) the cel stays on.-----and the fact that you get the 31 code when the engine is running.

My truck is a 94 and when I replaced the EGR valve and sensor I HAD to use some sealant in addition to the sealing ring that came with the EGR sensor.
See if you can beg, borrow, or bribe someone to let you use a hand held vacuum pump---the kind with the little guage on it---and hook it up to the EGR valve and apply 5-6 in-Hg of vacuum to the valve.-----This is right out of the Haynes Repair Manual----Vacuum should not drop more than 1 in-Hg in 30 seconds.

In a nutshell, that's the test for vacuum leakage in the EGR valve/sensor assembly.

924X2150 suggested you check the "coffee can" vacuum reservoir.
Pretty damned good advice.......re-read his post carefully.........it may save you some time and money....maybe lot's of both.

If the EGR valve isn't leaking, then you need to see if there is vacuum getting to the EGR valve then trace the hose(s) from the EGR valve all the way back to the vacuum tree on the Upper Plenum and check for leaks.


Replace those dry rotted hoses, check the EGR Valve for vacuum leaks/ no vacuum AND the "coffee can" and let us know how it went.


Bob

 

ok,good advice. he did a vacuum pump bleed down test on the valve before he got out of school last week and said it held 10 inches for the 5 min it was on it. i did a quick look at the coffee can, and it looked ok, but when i change the lines next week i will look closer at it. the charcol cannister under the battery is the one with the worst lines, especially the ones going to the top of the throttle body, they are so dry rot i can't see how it runs at all. it never ceases to amaze me how someone can spend $2500 for a replacement motor, but are too cheap to replace $5 worth of vacuum lines or a 25 cent gasket. when he got it it ran like crap. i figured the throttle body needed a cleaning, and pulled it to clean . it had the old, crusty, pieces missing gasket still in there, but it was a new tb.

 

so is it fixed now? did any one mention the vacume control valve on the fire wall, to see if it is bleeding engine vacume to egr. onother thing isnt it the o2 that reads if egr is working? oh and one more thing did you run a coat hanger through the small metal lines leading to the tranducer (egr pos sensor) you know the ones that go to the egr tube that clog with carbon alllllllll the time

 

Well..........??????

 

he didn't show up yesterday so i called this morning to see when he is coming over to do it up, and my sister told me he went to puerto rico for the week, and will not be home till tomorrow night.
the o2 sensor is new, but i did not snake the lines. i will do that when i do the lines.

 

well, the mystery gets deeper still. i changed all 40 foot or so of the 4 different size vacuume lines, and no difference. unpluged the vacuume line from the fpr, no difference. changed the pcv and line and hose clamped them, no difference. the "coffee can" holds 20 inches of vacuume.20 inches going to the fpr. any tap i hit, i get 20 inches, EXCEPT to the egr valve. nothing i do will change it, 0 vaccume to the egr. but if i introduce a vacuume leak, it idles up and purrs like a kitten, no miss or stutter at all. and if i have all lines hooked up to their proper taps except for the egr valve, and introduce vacuume to the egr valve ,the motor dies instantly.
btw, the cel code is still 31, and if i clear codes, it will come back within 30 seconds.i did not take it for a ride after changing the lines, but he called and said the cel did not go out or flicker,even when he stood on it ,so there is definatly something wrong. he is going to take it to a friends station that is a state emitions repair facility to see if they can figure it out on their off hours.

 

A couple of things......

An EGR valve closes on Wide Open Throttle and our PCM's may be programmed to ignore the EGR under that operating condition.
That'd explain why the CEL went out when you took it out and romped on it (as you said in one of your earlier posts).
I'm kinda' puzzled here though.....does the CEL come on while the truck is idling or driving it around ???
The CEL shouldn't come on (as far as the 31 code is concerned) if the truck is started without touching the throttle and allowed to idle .

Second...... just by chance, is there a round disk looking thing in the vacuum line that supplies vacuum to the EGR Control Solenoid (it'd be somewhere in the vacuum line between the coffee cannister and the EGR Control Solenoid)???

If so, that's probably a one way vacuum valve and its most likely installed the wrong way blocking vacuum to the EGR Control Solenoid and thus the EGR Valve.

One last thing.....when you replaced the EGR Control Solenoid, did you make sure the voltages and wiring were o.k. at the connector ???

I think I'm as stumped as you are on this one.
If the emissions guys' figure it out before us, PLEASE let everyone here know what it was and how it was corrected.

Keep us updated,

Bob

 

i definatly will keep you posted bob. there is nothing in the canister to valve line. the cel light is on full time now, i cleared codes and it came back on in less than 30 seconds at idle. i get absolutly nothing to the egr valve, no matter what the rpm is, so i am thinking the new controller is defective, but this is all new to me. i am a diesel mechanic, and except for my 99 crown vic,all my other toys are diesel or points and carbed, so i can figure them out.

 

One comment I noticed, "The engine dies when I apply vacuum to the EGR"..that is good, the EGR diaphragm is OK.

The EGR opens and closes as the "EVR" asks it to. The EVR is controlled by the Computer, the computer simply grounds a pin on the EVR solenoid, and the solenoid action causes vacuum to be applied to the EGR via a hose, and the computer makes decisions based on what the "EVP" sensor is doing. The EVP is on the side of the EGR valve, it is a variable resistor that changes value as the EGR opens and closes.

Either the EVR or EVP wiring may be suspect.

The EVR will not hold vacuum, it is designed to bleed vacuum off so the EGR can close quickly, when asked to.

Check your brake booster lines or brake booster for vacuum leaks also, the brakes are a big customer of vacuum pressure.