Reduce emissions without ERG?

[StockFJ401975]

I'm rebuilding a 2F engine for a 1975 FJ40. No emissions controls required in Washington state. Planning to install SOR Hi TECH headers and NOT hook-up all the original ERG controls. Can I get the vacuum advance distributor to function without the rest of the ERG? I'm looking for a simple but honest effort to reduce emissions. Please advise.

 

[65swb45]

75 did not come with a vacuum advance dizzy, so you'll have to clarify that. Carb wasn't ported for it either.

A properly rebuilt, properly tuned engine should produce good tailpipe emissions without AI or EGR systems. Make sure your carb is set up properly to run without external vacuum signals [which will now be incomplete] to ensure proper break in of the new engine. Then reset and rejet as needed until you hit best emissions profile.

Easier said than done, unless you own an engine exhaust analizer and a box full of jets.

Best

Mark A.

 

[Pin_Head]

The EGR reduces nitrogen oxides (NOx) which is the stuff that makes the air brown in the LA basin by reducing the combustion temperature. This system has no significant effect on performance, since it shuts off when you put the pedal to the metal, but it does decrease cruising fuel economy by a couple %. On the mid 70s 2F, the EGR was used in combination with a vacuum retard of the spark that also served to reduce NOx. The engine will run fine with or without it. Your call.

 

[StockFJ401975]

Isn't this a vacuum advance distributor?

This is my 1/25-12/75 California carb.

Aren't they ported for each other? How do I set up this carb to run without external vacuum signals?

 

[Pin_Head]

It is a vacuum retard distributor because vacuum will cause the points plate to rotate CW. Don't take my word for it; pop the cap, pull a vacuum on the line and look for yourself. The carb does have an appropriate port for a vacuum advance, but if you want one you will need to buy a new distributor. The vacuum signals on your '75 were originally controlled by a vacuum switching valve under command of the emission computer.

 

[StockFJ401975]

Is the following correct? Vacuum retard distributors make no meaningful difference in emissions, and if I want to get a vacuum advance distributor to put in its place, it needs a different type of vacuum signal. Vac retard is hooked in downstream of the throttle valve (under command of the emission computer) where it sees vacuum at LOW throttle and idle.
Vac. advance distributors connect to a vacuum port located directly on the carb, so they see vacuum at HIGH throttle, when lots of air is going into the motor.
Is the Vac. advance-to-carb link as simple as connecting a vacuum hose from one to another with no other go-between?

 

[Pin_Head]

Is the following correct? Vacuum retard distributors make no meaningful difference in emissions, and if I want to get a vacuum advance distributor to put in its place, it needs a different type of vacuum signal. Vac retard is hooked in downstream of the throttle valve (under command of the emission computer) where it sees vacuum at LOW throttle and idle.
Vac. advance distributors connect to a vacuum port located directly on the carb, so they see vacuum at HIGH throttle, when lots of air is going into the motor.
Is the Vac. advance-to-carb link as simple as connecting a vacuum hose from one to another with no other go-between?

No.

Vac retard distributors are used to lower NOx and they are controlled by the computer, not a vacuum port under the throttle plate. The stock carb has the proper vacuum port to run a vacuum advance if you had a vacuum advance distributor. You just connect this port to the distributor advance.

 

[StockFJ401975]

I'm getting a better handle on this puzzle. Perhaps most importantly, I realized that my '75 carb isn't Cal specific, and that it has the vacuum port just over the idle mixture adjusting screw.

The Power valve control and the Choke breaker/throttle positioner ports get connected to the two manifold vacuum ports, and the AUX Accel pump port gets plugged-off from the entire system? And finally, the idle fuel cut off solenoid wire gets connected to the voltage regulator? (Please bear with me, where is the voltage regulator located?)
That's all the basic connections necessary for the carb?

 

[FJ40Jim]

The ICS remains connected to the stock power wire. It is not controlled by computer on your '75 truck.

 

[Pin_Head]

Why not leave all that stuff the way Toyota intended it? It works independently of the EGR.

The power valve needs vacuum to shut off. It is controlled by the computer. If you don't want to let the computer manage it, then connect it to manifold vacuum, but I am not convinced that it will ever see vacuum low enough to open.

The choke breaker needs manifold vacuum.

I am not familiar with the AAP. I guess that manifold vacuum would support its function.

The solenoid should have its own black wire with yellow stripe. This is the same circuit that feeds the voltage regulator.

The VR is typically mounted on the firewall near the steering column.


If your aim is to increase performance and fuel economy, you will spend a lot of money and end up disappointed.

 

[Downey]

Pin-head, a few days ago I saw the post regarding Nardek Pty Ltd in Australia having Vacuum Advance units, supposedly to fit the 1975-80 Distributor. Do you imagine those would fit the USA 1974-77 Vacuum Retard Distributors?? Seems like that could be a home run in this case??

 

[Pin_Head]

I wouldn't be surprised if they fit. Somebody needs to try it. You just don't want to give away trade secrets like that because you could have a winner there.

 

[StockFJ401975]

Thank you for all of your help and advice.