Hey there, almost certain my 3B is running too lean, and it’s HORRIBLE on mountain roads. Anyways I just want to make sure this is the screw before I mess anything up, thank you!
3B Fuel Adjustment Screw Location? (1 Viewer)
- Thread starter theglobb
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Hey there, almost certain my 3B is running too lean, and it’s HORRIBLE on mountain roads. Anyways I just want to make sure this is the screw before I mess anything up, thank you!
That is the Wide Open Throttle Max Fuel Screw.. often just called the "fuel screw". Wind it out (towards firewall) to increase the fuel delivery at Wide Open Throttle. Go half a turn at a time max and if you've got a turbo - you really want to be watching your EGTs.. you're looking for a tiny bit of smoke under heavy load. If your "mountain roads" are high altitude you might well have an improvement, but unfortunately when you drop back down to sea-level you might be blowing lots of smoke.
- Thread starter
- #3
Thank you! Runs much better here at elevation now while on vacation, I don’t have a turbo so I should be good with just a water temp gauge. Appreciate the help!
So am I right in thinking you can adjust this screw when you go up in elevation with a 3B with no turbo?
- Thread starter
- #5
Usually, you would adjust it to give it less fuel to keep the EGTs down and the black smoke from rolling out, at elevation. In my case I was just running really really lean at sea level and didn’t know, once I turned it up at elevation I started having a tiny bit of smoke come out on hard acceleration, which is what I believe you want to look for. Not too much, not too little. Back down at sea level there is practically no smoke anymore, but more power too. Just play with it and find the right balace.
I have a lot of black smoke coming out when I rev mine up, at sea level. Doesn't need to be at load, even at idle. I'm trying to figure out the possible causes and fixes.
- Thread starter
- #7
Turn the screw away from the firewall, in half turns. Eventually, it'll let up and lean out a bit. Should be the fix
I wouldn't depend on the temp gauge to determine your EGT's. Not necessarily related. A pyro is the only positve way to monitor your exhaust temps. Especially without a turbo to cool the cylinders. I have always suspected hgih EGT's as being the major culprit for cracked pre-cups.
- Thread starter
- #9
Most definitely! I had a water temp gauge so I kinda go off that but the OEM temp gauge will not correctly show ur EGTs
When you're tired of no power, give me a holler as we have a turbocharger kit that will solve those issues(shameless plug, just bored sitting around today,lol)!
- Thread starter
- #11
Hey, no shame in that lol. I’m already tired, just gotta get the funds together. I’ll hit you up in a year or two lol
If you can, definitely install a pyrometer as soon as possible... Adjusting the fuel on a 3B with no turbo can cause blown head gaskets, cracked pre-cups, or even cracked heads without much warning. Water temp gauge will not give you any clue to how hot your cylinders are. Since you don't have a turbo, you can drill and tap the probe right into the exhaust manifold and run the lead into the cab. These engines are getting more and more expensive to rebuild so a few bucks and an afternoon are worth it...
- Thread starter
- #13
Really? Wow, I had only heard it was necessary to get a pyro with Turbo'd 3B's. Thank you for telling me!
@theglobb if you leave the fuel screw alone, then you should be fine, but really a pyro is the best way of knowing what is going on with these engines...
While you should not see any issues driving around at sea level, when you go to altitude and/or push long hills you are essentially adding more fuel and therefore can create higher egts that can harm older pre-cups, head gaskets, or even the heads itself. I used to live at 10,000 feet and speak from experience...
IIRC Toyota tuned these for sea level and to run a little hotter than most would like. I know a lot of people that ran stock fuel settings and added a pyro and we're shocked that the numbers they were getting.
While you should not see any issues driving around at sea level, when you go to altitude and/or push long hills you are essentially adding more fuel and therefore can create higher egts that can harm older pre-cups, head gaskets, or even the heads itself. I used to live at 10,000 feet and speak from experience...
IIRC Toyota tuned these for sea level and to run a little hotter than most would like. I know a lot of people that ran stock fuel settings and added a pyro and we're shocked that the numbers they were getting.
John in Utah
SILVER Star
Plus all the POs that turned the fuel up trying to get any bit of power out of the little NA motors. I put a pryo on shortly before adding a turbo and was shocked at the temp I could reach (and had been sustaining unknowingly for years).
It’s plenty quick now with @gerg’s turbo kit and fuel turned down from what it was
