1991 3F-E De-Smog Performed

[spdwaver]

So, would doing the bb's and looping the two vacuum hoses without disabling the smog pump screw something up?... I just wonder if this would be like doing "half an oil change"?

Maybe that's a bad analogy, but in my admittedly under-educated "mechanic brain", it seems to me that one of the biggest benefits I'd get from doing this mod would be the fact that I'm NOT pumping hot exhaust gas into my air intake... tweaking the vacuum hoses is just something I'd do in order to trick the truck into running right without that evil smog pump feeding it poison.

Am I missing something?
(entirely possible - vacuum hoses and such are like Chinese algebra to me!)


?

I am not so sure that not disabling the smog pump will cause an issue; some keep the pump running while simply looping and plugging the lines. I ran it this way for a couple days until I bought the replacement belt.

 

[ashooter]

So spdwaver1, how's your truck doing? You've been running it with this mod since last September, right?

It's so easy, I want to try it... but it almost seems like one of those "if it ain't broke, fix it 'til it is" kinda things.

 

[Jonny Wagner]

I've been running mine with BB's and shorter belt since September. I have never got any better mpg's, but did notice better acceleration. I have never had any problems or codes. Seems like it worked good to me.

 

[spdwaver]

So spdwaver1, how's your truck doing? You've been running it with this mod since last September, right?

It's so easy, I want to try it... but it almost seems like one of those "if it ain't broke, fix it 'til it is" kinda things.

Well, I would say "that truck is great", but I can't. You see, the de-smog procedure does not work well against a nice kiss on the rear wheel by a Honda travelling at ~35MPH. I wish I could say otherwise, but that would be dishonest.

But, when it was operational, the mod gave me a little more power; climbing hills, take-off and maintaining highway speed were all improved. The only thing that the mod could not do was to provide me enough power to get me out of the way of a motorist who did not notice a red light or my vehicle.

The mod is really easy, and the only items you really need to buy are the belt and a few BB's. The belt, as mentioned earlier, can be purchased at Napa. I would say that the gas mileage was not improved enough to pay for the belt, but the slight increase in power made up for that.

The best 3F-E in my opinion is the 1FZ.

 

[blzrfn]

The best 3F-E in my opinion is the 1FZ.

Traitor!

 

[spdwaver]

Traitor!

Sorry, too hard to resist.

 

[Eicca]

I'm not sure the belt part really needs to be done... that air just ends up back in the intake anyway, and it doesn't look like it mixes with anything on the way.

I'm going to play around with this desmog setup and see if I notice anything different affected by the air pump setup.

 

[spdwaver]

I'm not sure the belt part really needs to be done... that air just ends up back in the intake anyway, and it doesn't look like it mixes with anything on the way.

I'm going to play around with this desmog setup and see if I notice anything different affected by the air pump setup.

If anything, it's just one less thing for the motor to have to turn, for what it's worth.

 

[Eicca]

If anything, it's just one less thing for the motor to have to turn, for what it's worth.

True, although it spins freely by hand, so I wonder if any load is taken off at all really...

 

[spdwaver]

True, although it spins freely by hand, so I wonder if any load is taken off at all really...

My thoughts as well, but so long as your mind is convinced, it makes the $25 worth it and makes virtually more power.

 

[ashooter]

Well, I just did the bb/loop thing without messing with the smog pump. On the 15 minute test run, up to about 70mph, I didn't really notice any difference one way or the other in how the truck runs. MAYBE a little more pep, but not really worth mentioning - probably wishful thinking more than reality. Exhaust might smell a little "cleaner", but almost imperceptible since I wasn't really thinking about sniffing the exhaust before I stuck the bb's in there.

I'll probably leave it like this until my next fill-up, just to see if there's any change in fuel consumption.

Even if there's no hugely obvious gain, is there any downside to this mod?

 

[spdwaver]

Well, I just did the bb/loop thing without messing with the smog pump. On the 15 minute test run, up to about 70mph, I didn't really notice any difference one way or the other in how the truck runs. MAYBE a little more pep, but not really worth mentioning - probably wishful thinking more than reality. Exhaust might smell a little "cleaner", but almost imperceptible since I wasn't really thinking about sniffing the exhaust before I stuck the bb's in there.

I'll probably leave it like this until my next fill-up, just to see if there's any change in fuel consumption.

Even if there's no hugely obvious gain, is there any downside to this mod?

I believe that the success largely depends upon how well tuned your engine is, such as the throttle body, plugs, wires, distributor cap, air intake and AFM - these all will play a part.

I have never been told nor have seen that the is a downside to this mod, so long as it is removed prior to your next smog check.

 

[SUMMIT CRUISERS]

I believe the mod. shows the power gain in the hot summer. By shutting off the EGR system your intake temps drop making your vehicle run better like it does in cooler temps. During the winter, it appears my fuel mileage has slightly dropped. I'm thinking here that the cooler intake temps may contribute to a "Richer" fuel mixture. Just my thoughts.

 

[ashooter]

Luckily I live 300+ miles from the nearest place where emissions are checked.

Should I plug up or disconnect the smog pump hoses, or does shutting off the EGR keep the pump from actually pumping the "smog" back into the intake air?

...I'm one of those cautious types that doesn't really want to run the alternator on only one belt, and I don't think the smog pump pulley eats enough power to make a difference that I'll notice.

 

[ashooter]

Update - I've driven about 300 miles after doing the bb's (no change to smog pump). No noticeable change to gas mileage, maybe a little better acceleration, but almost imperceptible.

One thing that may be unrelated - I have noticed a slight "chirpy" sounding squeal coming from either the smog pump or the alternator. I just replaced the alternator a couple of weeks ago with a rebuilt OEM I got from cruiserdan... Is there any reason why doing this bb thing would make the smog pump sound funny???

 

[Eicca]

I just undid my desmog for vacuum leak testing and noticed zero results, including no loss of power...

 

[lordbater]

I did this a few months ago, went from 8.5mpg to 14.9.

Does anyone have the proper belt info for this? Not the one listed in the original mod, but the 'proper' one? I like the redundancy of having a second belt on the alternator, the mod calls for a belt that does not hit that pulley..

Andrew

 

[ashooter]

Update:

I went on a 400+ mile round-trip last weekend and mileage one way was about 18 mpg, but was mostly downhill and with a 20-30 mph tailwind for most of the trip. Mileage coming back, mostly uphill with a 20-30 mph crosswind or headwind and the AC on about half the trip was 14.5 mpg. DEFINITELY an improvement!

For the last couple of years, the best mpg I've gotten was about 14.5 - no AC, downhill, tailwind, etc all working in my favor.

Again, I didn't mess with the smog pump, but only did the vacuum hose mod.

 

[savageX]

hey i got a fj80 and i was wondering what are the benefits of this mod..?

 

[spdwaver]

hey i got a fj80 and i was wondering what are the benefits of this mod..?

Look at the post above you, for starters. My personal experience with this was that I gained more power to the wheels which aided in going up hills.

The difference is not very significant, but I would do it again (if I had the privilege of owning one still ).