1978 FJ40 EGR--Related Question

[Solace in Solitude]

So, now that I have the emissions manual, I've started going thru all the emissions on my 40. While most of it is there, I still need to inspect/test everything to see what's working and what's not. First step is to replace all this old dried out vacuum tubing.

I can't locate anything EGR-related: no EGR Valve, no Cooler, no hoses, no brackets, etc...

Since I've registered my 40 as a 'Classic Vehicle', I don't have to pass smog and must keep my mileage under 5k miles per year.

I want to be sure that the smog equipment that is present works... And would like to restore any missing smog equipment, at some point... But, not right now.

My question: will the absence of the EGR equipment degrade the performance of my 2F engine, with stock Aisin carb?

Thanks!

 

[platypusREX]

Then show us a pic under the hood.
Should look like this.

 

[Solace in Solitude]

Then show us a pic under the hood.
Should look like this.

I pulled the Air Cleaner again and took this pic - the 3 disconnected hoses are disconnected from the air cleaner. The corrugated hose is from the Air Pump - it runs to the Air Cleaner.

It has min-truck power steering, so the PS pumpis in the foreground, on the left.

I left the Air Cleaner off, if more pics will help.

Thanks!

 

[platypusREX]

Look under you exhaust manifold and see if the EGR pipe is there or is it plugged. Same with the bakelite carb plate.

 

[Solace in Solitude]

Look under you exhaust manifold and see if the EGR pipe is there or is it plugged. Same with the bakelite carb plate.

Ok, I'm not sure what you mean by 'bakelite carb plate', unless it's the black ~5/8" plate under the carb - is that bakelite you are referring to?

The only plugs under the headers are freeze plugs and the drain plug - there are two pairs of threaded holes (that may or may not have had something mounted to them - one pair between exhaust 3 and 4 and the other pair behind exhaust 6 - you can see the exhaust 6 pair in this pic:

There are also a pair of threaded holes on the intake manifold (which is where I think your EGR Valve is sitting - you can see the holes here:

The carb is an Aisan - with an "8A25" date code - which matches my 01/78 FJ40 - here's a pic:

Again, I'm just trying to be sure that the absence of the EGR parts will not degrade performance - I'll add it all back later, if it won't.

Thanks for your help!

 

[N919HJ]

As long as it is blocked off and not causing a major vac leak it shouldn't hurt anything. As far as I know the EGR makes it run cleaner in cruise. My EGRVM has failed, so I blocked off the vac line to the EGRVM so the EGR is always closed. Runs fine, looking for a functional EGRVM

 

[Solace in Solitude]

As long as it is blocked off and not causing a major vac leak it shouldn't hurt anything. As far as I know the EGR makes it run cleaner in cruise. My EGRVM has failed, so I blocked off the EGR and it runs fine.

Where would it be blocked off? The only thing I can find that appears to be EGR-related is the curved tube on the bottom of this carb schematic - that runs from the carb to the EGR Valve - my carb has this tube and it has nothing connected to it - is this what you are saying should be blocked off?

Thanks!

 

[Solace in Solitude]

Look under you exhaust manifold and see if the EGR pipe is there or is it plugged. Same with the bakelite carb plate.

So, I'm guessing that since you have an exhaust manifold and I have exhaust headers, your manifold has an EGR-related port (that your EGR Cooler connects to) and my headers does not. As I said in post #5, above, there is no 'open' or 'blocked' port under my headers.

 

[N919HJ]

The tube coming off the carb is the insulator but my 79 doesn't have one. It changed in 79. I would think it would be hooked up to some sort of fresh air for cooling but don't really know. In the above pic the tube coming off the EGR to the right goes to the intake manifold just below the carb. If there is no EGR or tube, something should be blocking off the hole in the intake manifold. The curved tube on the bottom goes to the exhaust manifold. When I get home I can take a picture of mine for you to compare.

 

[N919HJ]

So, I'm guessing that since you have an exhaust manifold and I have exhaust headers, your manifold has an EGR-related port (that your EGR Cooler connects to) and my headers does not. As I said in post #5, above, there is no 'open' or 'blocked' port under my headers.

Yes, sorry didn't realize you had a header. But your intake is stock right?

 

[Solace in Solitude]

Yes, sorry didn't realize you had a header. But your intake is stock right?

Sorry - the 'header' reply was directed at platypusREX...

As far as I know, the intake is stock...

The tube coming off the carb is the insulator but my 79 doesn't have one. It changed in 79. I would think it would be hooked up to some sort of fresh air for cooling but don't really know. In the above pic the tube coming off the EGR to the right goes to the intake manifold just below the carb. If there is no EGR or tube, something should be blocking off the hole in the intake manifold. The curved tube on the bottom goes to the exhaust manifold. When I get home I can take a picture of mine for you to compare.

Since the tube ("insulator"?) is wide open and facing the front, it is, in essence, 'open to fresh air' - right?

Are you saying, the EGR (when present) actually connects to the intake manifold?

Perhaps a picture will help...

Thanks!

 

[Fast Eddy]

A "smog-legal" header would have a port from which exhaust gasses, which are much lower in oxygen, can be drawn through the Exhaust Gas Recirculation (EGR) system. The exhaust gasses are cooled in the EGR cooler, then passed into the carb base. It replaces some of the fresh air in the mix with non-reactive gas from the exhaust, which lowers the oxides of nitrogen (NOX) level in the overall exhaust gas.

This all assumes that the engine is running fast enough that the choked-down air won't cause it to stumble or stall, like it will do at idle if you pull vacuum on the EGR valve.

In an fj60 2f the EGR feeds into the intake manifold. On a '76-'78 it feeds into the carb base plate.

 

[N919HJ]

From what Fast Eddy says, if you don't have an EGR, that tube coming off the carb insulator should be blocked off or it is causing a major vac leak. I guess the 79 is more like the fj60. If you still want a pic let me know. I didn't realize that tube coming off the carb was for the EGR on a 76-78.

 

[Solace in Solitude]

A "smog-legal" header would have a port from which exhaust gasses, which are much lower in oxygen, can be drawn through the Exhaust Gas Recirculation (EGR) system. The exhaust gasses are cooled in the EGR cooler, then passed into the carb base. It replaces some of the fresh air in the mix with non-reactive gas from the exhaust, which lowers the oxides of nitrogen (NOX) level in the overall exhaust gas.

This all assumes that the engine is running fast enough that the choked-down air won't cause it to stumble or stall, like it will do at idle if you pull vacuum on the EGR valve.

In an fj60 2f the EGR feeds into the intake manifold. On a '76-'78 it feeds into the carb base plate.

So, in my '78 FJ40, if the EGR were present, it would pull from the exhaust header (if an EGR port were present), cool it in the EGR Cooler, feed the cooled gasses to the EGR Valve and pass it on to the carb base plate, thru the large, silver tube at the bottom of this SOR picture...

I my 40's case, the headers have no apparent EGR port (I'll look again, but haven't found any sort of 'open' or 'blocked' port), no EGR Cooler, no EGR Valve and nothing connected to the large, silver tube on the carb base plate - e.g. this tube is wide open.

So, back to my original question... should the absence of EGR-related parts and the large, silver tube "carb base plate tube" wide open degrade the performance (e.g. carb efficiency and mpg)?

Sorry for all the dumb questions, but with no carb/emissions experience, even the Emissions Manual schematics are difficult to follow.

Thanks for your help!

 

[Solace in Solitude]

From what Fast Eddy says, if you don't have an EGR, that tube coming off the carb insulator should be blocked off or it is causing a major vac leak. I guess the 79 is more like the fj60. If you still want a pic let me know. I didn't realize that tube coming off the carb was for the EGR on a 76-78.

...and I had tested/checked all over for a vacuum leak and found none - little did I know that this carb insulator tube could be construed as a 'vacuum leak" - I'm learning!

So, do we have a consensus that I should block input to the large, silver carb insulator tube?

Maybe if I can correct this and replace the bent idle mixture adjusting screw (sggoat is sending me one - thanks Gary!), I can actually lean the carb down...

Please confirm the blue statement, above.

Thanks for your help!

 

[Pin_Head]

The EGR port enters the carb above the throttle plate, so it does not cause a vacuum leak at idle. It will only cause a vacuum lead at high speed when the throttle plate is open. It needs to be plugged.

 

[Solace in Solitude]

The EGR port enters the carb above the throttle plate, so it does not cause a vacuum leak at idle. It will only cause a vacuum lead at high speed when the throttle plate is open. It needs to be plugged.

Thank you Pin_Head!

...and thanks to everyone else!

 

[N919HJ]

Pin_head knows his stuff. I would like to here how much better it ran with that pipe blocked off. Mine ran like crap from about 1500 rpm to 2200 rpm because the bad egrvm was making the egr open up at the wrong time.

 

[Solace in Solitude]

Pin_head knows his stuff. I would like to here how much better it ran with that pipe blocked off. Mine ran like crap from about 1500 rpm to 2200 rpm because the bad egrvm was making the egr open up at the wrong time.

I haven't had it out of the garage yet - but it was much easier to start it cold - it usually takes full choke and three attempts (key turns) - today, it started first attempt, with 1/4" of choke. I don't know if this is related to blocking the EGR port on the carb or not...

I'm going out into the desert tomorrow - about 1.5 hrs each way, on pavement, and a couple of hours off road - I'll report back when I return.

What do you mean,"...ran like crap..."? Ran rough... sucked gas... ???

Thanks!

 

[Racer65]

So, now that I have the emissions manual, I've started going thru all the emissions on my 40. While most of it is there, I still need to inspect/test everything to see what's working and what's not. First step is to replace all this old dried out vacuum tubing.

I can't locate anything EGR-related: no EGR Valve, no Cooler, no hoses, no brackets, etc...
Thanks!

I remember many years ago when I paid a visit to CCOT, one of the master mechanics told me to always replace the EGR Inlet Gasket whenever I get a chance, as he's seen many Cruisers with an exhaust leak there, causing exhaust noise upon acceleration. Well, that chance finally came this week when I needed to replace the brake master cylinder and booster. With the master cylinder and booster out of the way, there is clear path to the EGR pipe.

Look carefully at the Spector diagram. #46 is what I'm talking about. Here's an Ebay photo of the actual thing. It's a bizarre looking piece. After taking it off, I found the gasket (#45) to be broken, and the pipe itself to be broken at the inlet connection. Needless to say, you can no longer buy #46. It's out of production, so there are two choices: Find a used one, or get the old one welded. I'm going with the latter.

The gasket is also a bit hard to find. For a '79-'80, Part #25628-61050 works. I believe the same part works for prior years as well (all other part #s are no longer available).