EGR valve-'85 C10 Question

[jhngardner367]

I have a 1985 C-10 ,305 engine.
I'm wondering what effect it would have on the running/drivability,if I remove the EGR valve,and block off the manifold with a plate .

[KevinD85]

I deleted it on my truck but I bought a different intake.
runs good for me just a little cold blooded.

[jhngardner367]

Did it make any difference in how hot the engine gets ,as far as gauge temp?

[KevinD85]

didn't seem to. I moved my temp sensor from the head to the intake due to putting headers on as well.

[SkinnyG]

You may have to reduce some vacuum advance if you find the truck pings now that EGR is disconnected. I fabricated a simple sheet metal slotted stop to ensure I only had 12° of vacuum advance (14° if you run EGR).

You may have to add some fuel by opening up the APT in the carb (assuming you're running a Rochester), since there will be more "real" ail getting into the engine during cruise, vs. a portion of inert exhaust filling.

I deleted the EGR in my truck (no provision for it in the Edelbrock manifold I'm running), but due to the nature of the engine, the ignition and carb were doctored quite a bit.

[jhngardner367]

The carb is not the stock one. It came off an earlier engine(77-79 Chevy),and has a hand choke.
I had disconnected the EGR vacuum line,a couple of years ago,and now it's showing signs of EGR valve failure. (stalling when dropped to idle,rough idle,etc),so I want to remove it,and put a plate over the mounting area.

[jhngardner367]

I removed the egr valve,and made a plate.
I also checked the EGR valve,and it works fine,but most of the thermal/vacuum switches were pulled off,before I got the truck.
Found both gaskets were leaking,so I installed the block-off plate,and ,other than having to adjust the idle speed,and mixture screws(1/4 turn out), it runs great,with no temp rise,and I actually picked up about 3 MPG !

[sgr60]

It seems that the EGR valve on my '84 is actually broken off (sorry for the crappy iphone pic) - can I just clamp off the inlet where it broke? I'm not sure when this happened, or what effect it's had on the motor. I don't mind not having the EGR - I was actually going to remove it anyway - I just want to make sure the performance of the engine doesn't suffer like this. Can it be run as is?



**Note - that screw in the vacuum line that you can see is not my handywork... I think that might have gone to the AIR system that is also already removed...

[jhngardner367]

You need to make a block off plate,if you aren't going to replace the valve.
Leaving it open will cause many problems. Use 1/4" steel.
Use the old gasket,(or a new one) to mark out the plate,and the 2 bolt holes,then use the new gasket,and after cleaning the manifold,bolt it down.
You may have to reset the curb idle mixture,as did I.

[sgr60]

Originally Posted by jhngardner367

You need to make a block off plate,if you aren't going to replace the valve.
Leaving it open will cause many problems. Use 1/4" steel.
Use the old gasket,(or a new one) to mark out the plate,and the 2 bolt holes,then use the new gasket,and after cleaning the manifold,bolt it down.
You may have to reset the curb idle mixture,as did I.

Thanks - appreciate the help. Can I run it until I get the plate made and new gasket, or no?

[jhngardner367]

NO! Don't run it until you block it off! The engine will run extremely lean,and can cause damage !

[sgr60]

Gotcha - thanks!

[jhngardner367]

Anytime,my friend !

[sgr60]

I've got another question on this. I went to look at my carb to adjust the idle fuel mixture, and the screws aren't visible. I now see a note on the sticker next to the vacuum diagram that the screws are preset from the factory and are not adjustable.

Has anyone run into this? Is there a way around it I'm not seeing?

[jhngardner367]

They are preset,as stated. There are metal caps over them,that will have to be removed,to adjust them.
However,if it runs ok,then leave them alone.