Tuning after EGR hackjob delete (26 Viewers)

[YukonCruisers]

Starting on a refurb of a 40, the PO has "deleted" the EGR.

Is there a good thread on tuning post delete?

I don't want to get into a debate about reconnecting everything, I know if left alone EGR is fine, I don't think I have all the bits now, so am looking to just tune it up.

Truck itself is in amazing condition, April '75, no bubbling at the rear fenders, rockers in good original condition, no rust through on the floor pans etc. I already did the rear sill to 2x2 replacement, swapped out a broken rear leaf. I have to change the clutch master and will swap in a disk brake axle up front.

 

[bhsdriller]

I didn't do anything to mine just go through a lean drop setup on it and has been fine
Adjust timing with it as well if needed

 

[YukonCruisers]

Ah, maybe it needs a good carb clean or rebuild then. will spray in some cleaners and pump some seafoam through,

thx

 

[bhsdriller]

Also make sure everything is plugged that needs to be and no vac leaks

 

[DesertFJ40]

Screw the egr emissions crap.

To get your Fj40 running good:


Adjust the valves of the engine

Set your timing. The book tells you to set the bb at the "7 degree pointer mark." I push mine a bit more and set it at the edge of the window as I'm advancing it. So I think thats like 10mmHg

Get a vaccum advance distributor and hook that up. There's people here that will tell you "you need a special ported carb" to connect it. If you don't have a ported carb (like me and don't want to spend a lot of money to have someone do it for you), you can connect it to manifold vaccum. Theres an old article about a race car driver and he goes into the "science". Anyway, manifold vaccum was the best in his experience. Ive had good experience as well, zero issue. Others will say you're going against the "Toyota gods".

If you can, also get an earlier style carb. Suposedly the 1974 one is the best one. But any of the double barrel carbs from the early 70s are good. They got mechaniccal secondaries instead of vacuum acuated ones.

If you get an early carb, take off all that vaccum egr stuff off. Choke breaker, I forget what else. It's not needed.

you might need to get slightly larger carb jets depending on your elevation. Today's gas sucks and the original jets are ussualy too lean for today's gas. The only way to get around this is to use ethenol free gas. Then the carb works as it should. It's an easy fix to do if you decide to change out the jets

Set your idle screw either by ear or vaccum gauge. You can connect to the highest vaccum port and change your idle and see at what point you get the highest reading. If you do it by ear, turn the screw in so it sounds like it's about to die. Then back it off until it runs good. Then keep backing it off until it start to run rough in the other direction. I think it starts to "pop" and you won't notice any further increase I rpm once you reach a certain point. Zero in on the adjustment until it runs as smooth as you can possibly get.


Don't forget to cap off any unused vaccum ports as well. There should be one at your distributor, and a few around the carb, and any that were ocne connected to you egr

That should be it :]

 

[charliemeyer007]

I like straight mechanical advance, let the rpm of the engine determine the advance. +1 for setting the timing just going out the window in the summer - try that in the winter and it will kick back and eat the starter, maybe more if you aren't lucky.

 

[dmaddox]

My first thought to ask was....how is it running now? What are the symptoms, behaviors, etc? To be able to understand what direction to go.

 

[YukonCruisers]

Thanks folks, I will start to dig into it soon.

@dmaddox - current syptoms are very hard starting , despite fuel in the bowl and good spark. Occasionally responds well to a quick start vapour. Once running idle is a littl high, but fine. Stays started once running. When I first got it, the tank barfed so old fuel through the carb, so it may jest need a good cleaning there or a rebuild.

@charliemeyer007 ; @DesertFJ40 - I haven't checked the timing and advance as yet, but I think in order I will do the timing, clean the carb, maybe rebuild the carb. Altitude is a little high here in Whitehorse at 2200'.

Appreciate the suggestions folks, I was mainly concerned that something tied to the EGR pull was the issue, sounds more like a good tuneup and good to go, thx

 

[dmaddox]

EGR/desmogging may only create vacuum leaks. I agree with you here, @YukonCruisers - get the carb cleaned/sorted and the idle circuit blown out so you can confirm a clean jet during idle. Then go after timing. Valves could likely use an adjustment, but that wouldn't cause these issues, just improve power/efficiency as you know. The vacuum leaks/egr removal - after you get a good idle, even if a tad high, spritz around the base of the carb and around the manifolds to see if vacuum sucks in the cleaner (and the rpm will change) - and then address the vacuum leak. After that, will be easy to dial in timing (assuming the carb is squared away). Good luck.

 

[65swb45]

Get a vacuum gauge and get baseline measurements before and after each step you take. It’s actually quite rewarding to see numerical improvements.

Compression test
Adjust valves
Second compression test
Set timing
Lean drop carb

 

[Pighead]

Set your timing. The book tells you to set the bb at the "7 degree pointer mark." I push mine a bit more and set it at the edge of the window as I'm advancing it. So I think thats like 10mmHg

Get a vaccum advance distributor and hook that up. There's people here that will tell you "you need a special ported carb" to connect it. If you don't have a ported carb (like me and don't want to spend a lot of money to have someone do it for you), you can connect it to manifold vaccum. Theres an old article about a race car driver and he goes into the "science". Anyway, manifold vaccum was the best in his experience. Ive had good experience as well, zero issue. Others will say you're going against the "Toyota gods".

You're saying, then, that manifold vacuum is as good as ported vacuum for your vacuum advance distributor? I'm afraid I'm going to have to disagree. I do not have the benefit of an old story with a race car driver who has "science", all I know is from hooking 2 vacuum gauges to one carbureted F/2F block and driving it around for a few months. I've always had an indash manifold vacuum gauge, then I T-ed into the line between the carb and dizzy with another gauge. Now i know, sorta, how much vacuum my particular engine pulls from where and when. I don't pull a lot of ported vacuum. None at idle but it goes up as I ask for acceleration. But only goes up to maybe 8 or 10"/Hg. with a heavy foot, more usually 5 or 6" with casual driving. If you hook manifold vacuum to the dizzy, you'll be at full advance while at idle and your advance would decrease as you applied throttle. And where my manifold vacuum is weakest, climbing a long hill in 4th, my advance will be least as well. Which might keep pinging down, now that I think about it. I wonder if it might be better to run without vacuum advance than get vacuum at the wrong time. And how much vacuum does a dizzy diaphragm need to give how much advance? That's something we need to know.

And the spot where the BB disappears is more like 17* BTDC than 10mmHg.