EGR Repair Laugh..(daily driver)

[Arnold]

I am doing a lot of work that requires a lot of use out of my 94 1 ton extended GM van.It is a 5.7
 The cel has never come on. This has run like a new vehicle since I bought it many years ago.  Plugs,wires,cap,rotor,filters every 50,000.

 I am driving on the highway the cel comes on. No change in performance.I come to a stop. It has NO power..almost stalls..then SURGES ahead.Next to impossible to keep running. Nice..in the line at the dump..and in the dump.
  I have someone working for me and am in the middle of NEEDING this truck NOW. Codes are a map sensor and a speed sensor. Off comes the dog house..I cannot figure out the best way to get the map off..the connectors to it look like..do not touch them to test it either.
 Maybe I better test this thing cold first
 I immediately see the egr METAL HOUSING moving in and out
making a pretty serious sucking/backfiring sound.It has rusted away from it's cast iron base. Needs an egr ya think No problem. The egr is from
about $150-$200 WTF :?: and needs to be ordered(gvw is above 8800) Noone within a good hour even has one. It is Thursday. No egr until at least Tues..IF anyone can get one from their supplier.

  Dumdeedum.. let's see if I can stick this one back together
  This should work..a piece of angle iron mounted in between some large washers through the engine lifting eye..and adjusted to a 90 deg angle
to the egr housing. Then just something to exert pressure on the egr housing to hold it together Time for some accurate machining..back to my old automotive machinist days. Sure..a piece of WOOD..2x2
That autta be about the right length. A screw in the end so it can't fall off.

 Cel off.No codes. Mileage dropped from 7 km/L to 6.5km/L. Low end torque which was really great does not appear to have suffered. Definite increase in horsepower.Must be running richer.Starts,runs just like new as usual. Sort of a little bit tricky to get the right amount of egr opening(the valve in the right amount) when the housing is too rotted..pieces missing..to get it back together the way it should be..and deadly accurate eye balling of the 2x2 wood piece length cut with my circular saw
 I dunno..might not pass emmissions unless I put a threaded rod and "adjust" the egr position properly :cry:

  That was a few months ago..I never even botherred to check on ordering one online cheaper

[wayne petty]

the egr valve for that app shows to be a Part Number: EGR120  Alternate Part Number: 34-365 at az.. under 40 bucks.? if this is a vacuum operated EGR valve.. if its one of the digital versions.. that would explain the massive price quoted..

Application:    Over 8500 Lbs GVW
Connector / Terminal Configuration:   No Connector
EGR (Exhaust Gas Recirculation) Valve Operation Type:   Vacuum Operated
Gaskets Included:   Yes
Installation Hardware Included:   Washer Kit


a few things...   that are not really well understood..

what EGR flow does inside the engine..

atmospheric oxygen percentage is around 21%..

so this is whats coming in thru the throttle body..

in order to reduce combustion temps below 2600F back in the early 70s egr was used to dilute the intake air charge with exhaust gasses that have already been burned.. what was not discussed is there is less oxygen in the burned gasses.. a properly running fuel injected engine puts out around 14% oxygen ...

so the egr flow reduces the need for fuel  as there is less oxygen to combust it..

with computerized fuel injection..   the EGR flow on most is taken as always working properly..

when the egr fails..  the oxygen percentage in the incoming air charge goes up...  this leans out the air fuel mixture.. but the trick is.. under smaller load percentages.. the fuel injection system runs off oxygen sensor feedback to control air fuel ratios.. so the missing egr flow is not really missed..
this is called closed loop.. where fuel is controlled by the computer.
but..  when you mash the throttle.. where you are calling for increased power.. the system falls into open loop.. for acceleration or power modes..

this reverts to preprogrammed fuel control numbers and the EGR flow is expected to be there..  when its not.. there is a lean mixture and it will ping like crazy as there is not enough fuel for the increased percentage of oxygen..

........

when you reinstall a new egr valve.. please TEE in a vacuum gauge and toss it on the windshield under the wipers so you can see it from the drivers seat...   there should be no vacuum applied at idle.. but as soon as you take off.. you should start seeing egr flow above about 5 mph..

this shows the EGR solenoid is properly functioning..

now... did anybody notice that washers are included...

most EGR valves today are universal.. and you might miss the nice stainless washers that come with them..  hmm..

please use the included chart to match the original EGR valve stamping number to the proper sized opening washer and install it...

if you don't install a proper sized washer.. you will either have TOO MUCH EGR flow for the amount of opening.. or NOT enough egr flow and drivability will suffer... as will fuel mileage.. if it pings.. engine life will suffer.. please use a tie wrap and a zip lock back to store the washers and instructions..  use a  sharpie or engraving tool to transfer the original EGR number to the replacement egr valve..

you might have to do some fine tuning by going up or down a size..  usually they have a good idea of what size to use.. sometimes . they just screw up..

i found a replacement EGR valve.. where the location for the washer.. was NOT in the egr flow.. that drove me crazy for a while..  as the engine would stall when the EGR would open.

i ended up making a steel plate with slots so i could get it out easily.. and drilled increasing sized holes in it until i got the engine to not only run properly without stalling or pinging.. but got it to pass smog here in california..

[rooster]

Any picture's of whats rusted away?

[Arnold]

the egr valve for that app shows to be a Part Number: EGR120  Alternate Part Number: 34-365 at az.. under 40 bucks.? if this is a vacuum operated EGR valve.. if its one of the digital versions.. that would explain the massive price quoted..

Application:    Over 8500 Lbs GVW
Connector / Terminal Configuration:   No Connector
EGR (Exhaust Gas Recirculation) Valve Operation Type:   Vacuum Operated
Gaskets Included:   Yes
Installation Hardware Included:   Washer Kit


a few things...   that are not really well understood..

what EGR flow does inside the engine..

atmospheric oxygen percentage is around 21%..

so this is whats coming in thru the throttle body..

in order to reduce combustion temps below 2600F back in the early 70s egr was used to dilute the intake air charge with exhaust gasses that have already been burned.. what was not discussed is there is less oxygen in the burned gasses.. a properly running fuel injected engine puts out around 14% oxygen ...

so the egr flow reduces the need for fuel  as there is less oxygen to combust it..

with computerized fuel injection..   the EGR flow on most is taken as always working properly..

when the egr fails..  the oxygen percentage in the incoming air charge goes up...  this leans out the air fuel mixture.. but the trick is.. under smaller load percentages.. the fuel injection system runs off oxygen sensor feedback to control air fuel ratios.. so the missing egr flow is not really missed..
this is called closed loop.. where fuel is controlled by the computer.
but..  when you mash the throttle.. where you are calling for increased power.. the system falls into open loop.. for acceleration or power modes..

this reverts to preprogrammed fuel control numbers and the EGR flow is expected to be there..  when its not.. there is a lean mixture and it will ping like crazy as there is not enough fuel for the increased percentage of oxygen..

........

when you reinstall a new egr valve.. please TEE in a vacuum gauge and toss it on the windshield under the wipers so you can see it from the drivers seat...   there should be no vacuum applied at idle.. but as soon as you take off.. you should start seeing egr flow above about 5 mph..

this shows the EGR solenoid is properly functioning..

now... did anybody notice that washers are included...

most EGR valves today are universal.. and you might miss the nice stainless washers that come with them..  hmm..

please use the included chart to match the original EGR valve stamping number to the proper sized opening washer and install it...

if you don't install a proper sized washer.. you will either have TOO MUCH EGR flow for the amount of opening.. or NOT enough egr flow and drivability will suffer... as will fuel mileage.. if it pings.. engine life will suffer.. please use a tie wrap and a zip lock back to store the washers and instructions..  use a  sharpie or engraving tool to transfer the original EGR number to the replacement egr valve..

you might have to do some fine tuning by going up or down a size..  usually they have a good idea of what size to use.. sometimes . they just screw up..

i found a replacement EGR valve.. where the location for the washer.. was NOT in the egr flow.. that drove me crazy for a while..  as the engine would stall when the EGR would open.

i ended up making a steel plate with slots so i could get it out easily.. and drilled increasing sized holes in it until i got the engine to not only run properly without stalling or pinging.. but got it to pass smog here in california..

 Thanks Wayne..some  more great info

[Arnold]

Any picture's of whats rusted away?

  Sorry..can't get a pic. This is just a common looking V8 GM EGR valve from the 70's to the 90's. Stamped metal housing that holds the diaphragm of course..attached to a cast iron base that bolts to the intake.
Right where the stamped housing is attached to the base there are either
3 or 4..much smaller parts of the housing..almost like legs which attach to the base. There is really nothing left on the base of this valve where the housing USED to be attached. The stamped housing is completely rusted away RIGHT THERE where it used to attach. Some of the housing is missing due to rust.That is what made it tricky to stuff it back together I sortta had to guess just how far..or how close to set the egr valve. ONLY the spring pressure and the pressure of my 2x2 pressing against the housing is what keeps this thing on and together.
  I have not ever seen one of these rust away before.
  20 y/o work van in the salt capital of the world..these things happen

[Arnold]

Any picture's of whats rusted away?

  Sorry..can't get a pic. This is just a common looking V8 GM EGR valve from the 70's to the 90's. Stamped metal housing that holds the diaphragm of course..attached to a cast iron base that bolts to the intake.
Right where the stamped housing is attached to the base there are either
3 or 4..much smaller parts of the housing..almost like legs which attach to the base. There is really nothing left on the base of this valve where the housing USED to be attached. The stamped housing is completely rusted away RIGHT THERE where it used to attach. Some of the housing is missing due to rust.That is what made it tricky to stuff it back together I sortta had to guess just how far..or how close to set the egr valve. ONLY the spring pressure and the pressure of my 2x2 pressing against the housing is what keeps this thing on and together.
  I have not ever seen one of these rust away before.
  20 y/o work van in the salt capital of the world..these things happen

   What a dumb * idea that I came up with..(fixing it NOT properly)  :oops:  
   I COULD have ordered the right valve..for about $60 shipped..AND put it in..
   Did I..(get around to it :?: NOooo...)
    I just drove it a STUPID amount..from July to Nov Sure..slogging through a TON of fuel in a beat up 20 y/o work van..with a bad egr setup..just a plugging stuff up as I drove

    AFTER my "repair" the mileage did drop about 10%..In order to conserve some cash..I dropped my speed down to 50mph..that put the mileage back up to where it was..albeit I was driving it a fair bit slower..

    The other day it quit..idled..but would not take ANY throttle..(fine WHEN it got rolling..)

    With 1/2 a tank of fuel..in went the Seafoam..2 cans..plus a bottle of GM cleaner(aggressive stuff).
    WOW was thing thing now carbonned up.The carbon/smoke
blew out of this thing..fouling the plugs..MAYBE the convertor too..


   Bought the new valve..plugs,etc..THEY go in BEFORE I can drive it

   Live and learn..yep..guys burn out motors when egrs go bad..

[wayne petty]

dome a favor..

take an old broom stick. or dowel..   kinda sharpen the end  so you can plug it into the round hole for the intake side of the EGR mounting pad...

then have somebody start the engine.. let all that carbon built up in the EGR tube FLY OUT... rev it a few times..

i have used  various bristle brushes. coat hangers.. chunks of speedometer cable cores.. parking brake cable cores.. to wind thru the passages to clean them out.
then i blow them out again... i sometimes spray carb cleaner into the intake passage to assist in clearing it out with the engine running and my hand holding the throttle open to prevent stalling..

face mask please.. so it does not blow carbon into your eyes..

hint... if your car or truck looses power as soon as you do this..

shut down.   pull the forward oxygen sensors..   take a leaf blower or shop vacuum and blow into the tail pipes as you pound on the front of the cat housing..  you can get dust out of the engine that blocks the front of the cat.. that if you have not melted it.. can be blown out..

[Arnold]

Thanks very much Wayne
I have had no time to look at this thing :cry: .

I was in  the garage that does some of my work..they had an 05 Ford Diesel Van..E350..needed an egr heater(diesel).The mech.doing the work says it is about a day and half labour The heaters are $800 Total bills are from about $1500-2200 depending on if they can fix the heater.

Great! idea about blowing out cats btw