FJ62 de-smog question... (2 Viewers)

[orion]

Quick question - Can all the vacuum solenoids on the drivers fender be removed after a de-smog?

Backstory: Bought an already de-smogged 62 with engine issues, and I'm swapping in a new(er) 3FE...and cleaning up under the hood at the same time. I was hoping to eliminate the extra solenoids and wiring associated with them.

Wasn't sure if I would encounter any codes or a CEL by eliminating them.

I did search, and didn't find anything specifically addressing this. Thanks in advance.

- Brian

 

[OSS]

Highly unlikely.
Unplug them and see what happens.
Most likely nothing good.

 

[cruisermatt]

Ditch em. They are dead weight without the associated smog components on the motor. No other function will be affected.

 

[orion]

^^^ I figured as much - Thanks.

I try to avoid changing too much at one time, in case I have an issue that needs troubleshooting...but I figured these were OK to delete w/o consequence.

I've driven this truck maybe 1000ft total (and with a knocking motor). It might have issues I'm not aware of, and I don't want to add to my to-do list by taking stuff off w/o knowing the result!

- Brian

 

[Kleatus]

You will get a CEL (code 71 to be exact) if you remove the EGR, but only on a Cali-emissions spec FJ62. (Cali trucks have an EGR temperature sensor on the EGR valve).
One VSV is for EGR, one for air injection, and the other for the fuel pressure regulator.

 

[pappy]

There are three VSVs on the fender. My opinion is you can remove two of the three. The third is not for an emissions device, but goes to the fuel pressure regulator. You can simplify the routing by moving the VSV between the vacuum source and the regulator. See pic.

 

[Dynosoar]

One of the VSV's controls fuel pressure. You need this and the truck wont run correctly without it.

Dyno

 

[cruisermatt]

Well dang. That might explain a few issues I’ve been having.

 

[orion]

Grest info...thanks @pappy and @Dynosoar...!

- Brian

 

[red66toy]

There are three VSVs on the fender. My opinion is you can remove two of the three. The third is not for an emissions device, but goes to the fuel pressure regulator. You can simplify the routing by moving the VSV between the vacuum source and the regulator. See pic.

View attachment 1686976

Dang that is clean on many levels. Slick way to mount the VSV.

 

[lechnito]

Whoa, I removed that VSV when I desmogged almost 10k miles ago and I can't say that I've noticed any obvious consequences. Having said that though, my expectations for performance are pretty low on this old tractor.

@pappy - How did you route the electrical plug to be so close to the fuel pressure regulator? The old plug on my rig is wrapped up in the wiring harness attached to the fender and I'm intimidated by unwrapping the thing. Can I buy matching male/female plugs and make an extension cable?

Also, that's an unbelievably clean engine. Amazing!

 

[Prairie Swamp]

There are three VSVs on the fender. My opinion is you can remove two of the three. The third is not for an emissions device, but goes to the fuel pressure regulator. You can simplify the routing by moving the VSV between the vacuum source and the regulator. See pic.

Genius. I've got that lonely VSV mounted in original location with the vacuum lines going to it. Very awkward looking and in the way in what is an otherwise wide open area. Thanks for the tip!

 

[orion]

^^^ Yeah, I'll be stealing that idea for this 62. Looks like it should have been there from the factory.

And since this thread has some good info in it, I'll add the specific function of this VSV relating to fuel pressure.

Found posted by 'pappy', in this thread:
88 FJ62 Pressure regulator????

Function of the fuel pressure regulator and the vacuum switching valve.

"Fuel Pressure Control. The ECU sends signals to the fuel pressure regulator VSV to increase fuel pressure based on intake air temperature, coolant temperature and starting signal. By this system, engine restartability is maintained when the engine is hot. When restarting a hot engine, the ECU increases the fuel pressure above the normal level to reduce the fuel tendency to percolate. This helps restarting and also maintains the engine idle stability. The controlled fuel pressure is 21.2lb/in2."

"Operation. When the coolant temperature switch is ON (above 221*F) or higher, if the engine is cranked, the ECU turns on the VSV. As the VSV goes on, atmospheric air is introduced into the diagram [sic] chamber of the pressure regulator and the valve closes the passage. The fuel pressure becomes higher than the fuel pressure under normal driving condition by the amount of the intake manifold vacuum only. Even after the engine is started, the VSV remains on for several seconds."


- Brian

 

[Prairie Swamp]

Thanks for the additional info. I like to know how things work even when they are working properly.

 

[pappy]

^^^ Yeah, I'll be stealing that idea for this 62. Looks like it should have been there from the factory.

And since this thread has some good info in it, I'll add the specific function of this VSV relating to fuel pressure.

Found posted by 'pappy', in this thread:
88 FJ62 Pressure regulator????

Function of the fuel pressure regulator and the vacuum switching valve.

"Fuel Pressure Control. The ECU sends signals to the fuel pressure regulator VSV to increase fuel pressure based on intake air temperature, coolant temperature and starting signal. By this system, engine restartability is maintained when the engine is hot. When restarting a hot engine, the ECU increases the fuel pressure above the normal level to reduce the fuel tendency to percolate. This helps restarting and also maintains the engine idle stability. The controlled fuel pressure is 21.2lb/in2."

"Operation. When the coolant temperature switch is ON (above 221*F) or higher, if the engine is cranked, the ECU turns on the VSV. As the VSV goes on, atmospheric air is introduced into the diagram [sic] chamber of the pressure regulator and the valve closes the passage. The fuel pressure becomes higher than the fuel pressure under normal driving condition by the amount of the intake manifold vacuum only. Even after the engine is started, the VSV remains on for several seconds."


- Brian

Taking this another level. That came from the attached document.

 

[Prairie Swamp]

Printed and in a binder. Thanks!

 

[Prairie Swamp]

Wow lots of good info in there.

 

[pappy]

Thanks for the additional info. I like to know how things work even when they are working properly.

I think you said it. I also like to know how things work.

 

[OSS]

Toyota never mounts VSVs to the engine- ever. Maybe a heat or vibration thing.

 

[pappy]

Toyota never mounts VSVs to the engine- ever. Maybe a heat or vibration thing.

They mounted two on the 22RE.​