Disabling the EGR valve
Originally, I suggested blocking off the EGR valve to improve power and increase gas mileage then I changed my mind and enabled it. Well, after about 3/4 of a tank of gas - it's disabled again. It just hurts performance and all around driveability too much to enable it! Disabled, it provides about a 5% increase in both hp and gas mileage from what I can tell. The engine runs better and has better acceleration without the egr.
The EGR (exhaust gas recirculation) valve's job is to introduce exhaust back into the intake manifold to reduce emissions at the expense of power and gas mileage. The previous link does a good job of describing its operation.
This seems to be utterly stupid especially because exhaust gases are added after the fuel/air mixture is determined. It seems to be defeating the purpose of a proper air/fuel mixture!
Now, my goal is to increase fuel efficiency so that I use less gas - consequently reducing the pollution to the atomosphere. So far with all the mods (including this one), I've increased my highway mileage dramatically and increased the engine's power!
The EGR valve at the back of the engine.
The EGR valve is located at the back of the throttle body. It has a pipe that runs from the exhaust manifold over the head next to the firewall to the EGR valve. Ideally, you would like to disconnect and block off that pipe but you'll find that it is seized and rusted in place. A big nightmare to get it off. The alternative is to block off the EGR to throttle body passage - that's a lot easier. Just takes an easily made blocking plate made out of a piece of sheetmetal you have lying around. I've been told that a 351c mechanical fuel pump block off plate is the exact same size and shape and will work if you can't make your own EGR blocking plate.
The exhaust pipe from manifold to EGR valve
Gasket on top, sheet metal blocking plate on bottom
There's two bolts (10 mm head) that hold the EGR valve onto the throttle body. The top bolt is easy to get to but the bottom is very awkward. Disconnect the throttle body position connector from the driver's side of the EGR valve to give yourself room. I used a box end 10 mm wrench to unscrew the bottom bolt.
Undo two bolts and slip in new gasket and blocking plate
I purchased a new EGR valve gasket for $4.00 and used it as a template for making a blocking plate. Put the new gasket against the throttle body and the blocking plate on the EGR side. Bolted it all together. Took less than an hour! The engine runs quieter and smoother. I have a little more power and will find out if the gas mileage improves with the next tank of gas.
Some Final Words
Aaron K. sent me an email with some good questions, here's my response:
- The 351c mechanical fuel pump block off plate is mentioned for those that don't have the tools or skills to make their own EGR blocking plate
- You can't remove the EGR components otherwise the ECU will think something has failed - we are fooling the EGR system here.
- It's pretty much impossible to remove the pipe from the exhaust manifold to the EGR valve - it will be rusted solid in the exhaust manifold
- After every modification that affects the fuel/air mixture like this one - you must reset the ECU by removing the negative terminal of the battery. Wait 5 min, reconnect and then over the next 15 miles of driving (idling won't work!), the ECU will relearn the new air/fuel mapping.
- You don't have to turn the key to the on position when resetting the ECU. Just disconnect the negative terminal as outline previously.
Tips and Tricks
If you have some tips and tricks that squeeze a little more power out of your 2.3L Ford and you want to share them, contact me at:
