Egr Vacuum Modulator Valve

[daves]

Can anyone tell me what the difference is between a blue cap and red cap EGR Vacuum Modulator Valve.

There has been disscussions on the value or not of having the ERG valve operational, what is the informed opinion on this matter.

Dave

[chrisandhiace]

Dont know about blue or red caps but I have disconnected mine by pulling the vac tube from the valve and plugging that tube.

Read people say more power when disconnected. Couldn't say for sure about the power...done 0-60 time with and without egr and I can't tell the difference.

I did start getting upto 1 mpg more..but that may have been due to the time of year I disconnected it..........(vehicle hiace supercustom 2.8 deisel)

[daves]

Chris

Which tube do you block off ?

Is it the tube at the bottom of the EGR vale or the tube from the top of the EGR valve to the EGR modulator

Thanks

Dave

[chrisandhiace]

Dave,

Think things are a bit different depending on vehicle.......anyway on mine there is a flying saucer looking thing.......the exhaust goes to this/below this before entering the intake........you could consider it a diaphram operated plunger type affair activated by vacuum.......it blocks or allows exhaust to enter the air intake depending on operating conditions.

When there is no vaccum to it, the valve is closed so no exhaust enters the intake. Also the vacuum is prevented from reaching the valve until the engine is at a certain operating temp.

If you can get hold of a vacuum pump and attatch to the 'saucers' spigot, you will hear the valve open and close.....on mine there is only one hose to this.

The correct tube may be lower on the unit on yours...its near the top of the 'saucer' on mine

I pulled the hose and plugged the hose with a watering valve from B&Q...though a ball bearing or anything that plugs the tube without getting sucked in is OK.

Left the spigot on the egr unplugged as advised by someone, in case any pressure needs to escape.

Don't pull any wires or the electronic control unit won't get the info that the valve is closed and you will run on a bad mixture.

Some other people may just make a blanking plate for the manifold......if you trawl the townace sites you should find some pics/articles on disconnection.

The examples I saw on the townace sites are a little different to my egr set up so may be closer to yours...(you don't say which vehicle)...

Either way....once you get the thing disconnected you may or may not notice the difference...if you notice an improvement I would guess it would be very marginal....it would be interesting to read your observations on how it changes your vehicles performance..........

[chrisandhiace]

Sorry, forgot to mention...the reason you need to plug the vac tube....if you don't the engine stops violently when switched off...so do plug it..

Just been looking at some pics...if you have a tube near the top of the egr valve assembly.....well this will be the one that lifts the valve internals up to allow exhaust to the inlet....

[daves]

Chris

The vehicle is a 1990 previa with 21000 miles on the clock.

From your description it will be the tube from the modulator valve to the EGR valve which would lift the valve to allow exhaust to vent into the inlet manifold.

Thanks

Dave

[USApreviaOWNER]

I would not recommend bypassing the EGR system. You will notice little difference in power but your tailpipe emissions will go up (we have to pass emissions tests annually in New York State) and your ECU will get confused. The resultant confusion by the ECU will negate any power gains as it tries to cope with anomalous tail pipe readings.