Hoping for Guidance/Validation (1 Viewer)

[Solace in Solitude]

Okay, now that I've read your other thread...

-Did you ever check/adjust the valves? With 18" of vacuum you are probably in pretty good shape but just asking.
-Have you ever checked or replaced the fuel filter? New OEM are still available from Toyota and it sounds like you have a reasonably decent dealer close by. If your fuel filter is clogged it may be starving your engine.
-How are your timing adjustment and vacuum lines to your distributor?

Matt (and all):

First, I have to admit with that I have reported the wrong gears on my 40 - I said I have 3.73 - I was wrong - sorry!!

In speaking with Jim C, this morning, I rechecked the plate, on the firewall and what I read as K052 - what I have is K082, which is 4.11 gears - at least, that's what originally came with the truck.

So, that should mean that comparing my '78 FJ40, with H42 tranny and K082 axle to your '78 should be more of an apples-to-apples comparison

Jim also told me that he's sure the secondary is good - he rebuilt it and tested it - and that I definitely have a problem - probably a combination of problems, as well as commonly faced issues, resulting in fuel deprivation:

Common Issues:

a. outside temperature
b. climbing a hill means fuel pump trying to pump uphill
c. current gasoline becomes less and less efficient in our old 40s.
d. my gas tank was almost empty - I don't think I reported this - there was no shoulder to pull over, or I would have poured my jerry can contents into the tank.
e. new fuel pump could have actually been leaking, from the cross threaded 90* connector
​

Problems:

a. VERY hot under the hood.
b. exhaust headers.
c. fuel lines, above the headers, not shielded
d. potentially bad or leaking fuel pump
e. potentially plugged fuel filter
​

Also, I'm sure the fact that Jim tuned my carb for 2400' and I was climbing at 7400' could also be construed to be another 'common issue'.

Jim suggested I get the new oem fuel pump, test both the input and output ports, install it, fill up with gas from an airport or marina and repeat the climb... after heat shielding the fuel lines. Onur Fed-Ex'ed the replacement pump this morning - it should be here tomorrow. I'm gonna wait for the new pump.

Re: your questions:
1. I adjusted the valves (hot) about 3 months ago - and had only driven about 50 miles, prior to this 700 mile trip.
2. Fuel filter (oem) was also new, about 4 months ago - and had only driven about 50 miles, prior to this 700 mile trip. Note: I pulled and replaced it after this trip and found nothing wrong with it.
3. Timing set at 7* BTDC, about 4 months ago. Note: I was reading , this morning, trying to find out if there is a more practical setting than the 7* that the FSM states.
4. Vacuum lines are all new - I replaced all hoses (underhood) while re-installing my carb, 2-3 weeks ago.

So, my plan...
a. Test and install the new fuel pump
b. Already replaced fuel filter
c. Re-check/adjust valves
d. Re-check/set timing
e. pull, clean and regap plugs - Note: plugs, rotor, dizzy cap, plug/coil wires, PCV are also about 4 months old. Oil is fresh, oil and air filter are new. Coolant ne, about 3 weeks ago.w
e. Install fuel line heat shield sleeves - Should be here in a few days
f. Fill up with airport gas - BTW: I have a habit of topping off my tank, in older vehicles (like my 40 and my 2002 Tundra) - I read, this morning that doing so can cause some sort of fuel delivery problem in an FJ40. I didn't fully understand it. But, will quit topping off my tank, regardless.
g. Try the same or similar climb and see what happens.​

My Dec 78 FJ40 with 32" tires and 3.70 gearing used to run between Vegas to Reno and Reno to Ely all the time. Never was I down to 45 mph on hills.

Thanks Mace!

Turns out my gears are 4.11 redface - my 40 performed great on the trip - except when climbing - the steeper the climb, the larger the power loss.

But, couple that with the single instance of vapor lock, after cresting the climb out of Tonopah, and it certainly seems to be a heat-related fuel delivery problem that's resulting in fuel starvation.

So, I think I'll come out of my 'plan', above, with '44' searching out hills to climb
​

Thanks everyone!

I'll report the results, when I have them.

 

[Solace in Solitude]

I forgot: my axle gears are 4.11 and, I wouldn't mess with the carb if Jim just rebuilt it

So do I (4.11) - - rather than face the embarrassment of reporting my 3.7 gears are actually 4.11, I considered swapping to 3.7, just to save face...

Yeah, I fully trust Jim!

I bought a second Aisin carb and rebuild kit and plan to learn how it works this winter.

Thanks!

 

[subzali]

The problem with topping off the tank is that if too full, liquid fuel can make it past your vapor separator and into your charcoal canister, where it will oversaturate it. Probably best to practice filling only to the first click on anything with a charcoal canister.

Now, with more information, I too would doubt that the secondary diaphragm has anything to do with this problem. I also would doubt that valve adjustment, fuel filter, or timing really has anything to do with it either, but it never hurts to check. I would have doubted that a new OEM fuel pump would have problems, but I guess now you have an opportunity to find out.

Trying to think of other folks in Denver that run headers (I don't), whether they have vapor lock issues or not. Will have to get back on that.

 

[Solace in Solitude]

Thanks Matt!

Is there a way to refresh or purge a charcoal canister?

BTW: I bought the pump from Onur (Beno) - no good luck with local dealers - Onur is replacing it.

Thanks!

 

[subzali]

There are FSM tests for charcoal canister operation (mostly for check valve operation). I have seen some threads where people cut up the charcoal canister and replace the charcoal, other folks source a new or decent used one. In other words, it's not designed to be serviceable but depending on what you're trying to do you could maybe service it.

I think it can be heated in an oven as well to burn off trapped fuel vapors, don't remember all the details and would have to read up on it.

 

[Solace in Solitude]

Not really trying to do anything with the CC right now - just curious - I'll look for it in the FSM - thanks!

 

[sggoat]

Matt (and all):

First, I have to admit with that I have reported the wrong gears on my 40 - I said I have 3.73 - I was wrong - sorry!!

In speaking with Jim C, this morning, I rechecked the plate, on the firewall and what I read as K052 - what I have is K082, which is 4.11 gears - at least, that's what originally came with the truck.

So, that should mean that comparing my '78 FJ40, with H42 tranny and K082 axle to your '78 should be more of an apples-to-apples comparison

Jim also told me that he's sure the secondary is good - he rebuilt it and tested it - and that I definitely have a problem - probably a combination of problems, as well as commonly faced issues, resulting in fuel deprivation:

Common Issues:

a. outside temperature
b. climbing a hill means fuel pump trying to pump uphill
c. current gasoline becomes less and less efficient in our old 40s.
d. my gas tank was almost empty - I don't think I reported this - there was no shoulder to pull over, or I would have poured my jerry can contents into the tank.
e. new fuel pump could have actually been leaking, from the cross threaded 90* connector
​

Problems:

a. VERY hot under the hood.
b. exhaust headers.
c. fuel lines, above the headers, not shielded
d. potentially bad or leaking fuel pump
e. potentially plugged fuel filter
​

Also, I'm sure the fact that Jim tuned my carb for 2400' and I was climbing at 7400' could also be construed to be another 'common issue'.

Jim suggested I get the new oem fuel pump, test both the input and output ports, install it, fill up with gas from an airport or marina and repeat the climb... after heat shielding the fuel lines. Onur Fed-Ex'ed the replacement pump this morning - it should be here tomorrow. I'm gonna wait for the new pump.

Re: your questions:
1. I adjusted the valves (hot) about 3 months ago - and had only driven about 50 miles, prior to this 700 mile trip.
2. Fuel filter (oem) was also new, about 4 months ago - and had only driven about 50 miles, prior to this 700 mile trip. Note: I pulled and replaced it after this trip and found nothing wrong with it.
3. Timing set at 7* BTDC, about 4 months ago. Note: I was reading , this morning, trying to find out if there is a more practical setting than the 7* that the FSM states.
4. Vacuum lines are all new - I replaced all hoses (underhood) while re-installing my carb, 2-3 weeks ago.

So, my plan...
a. Test and install the new fuel pump
b. Already replaced fuel filter
c. Re-check/adjust valves
d. Re-check/set timing
e. pull, clean and regap plugs - Note: plugs, rotor, dizzy cap, plug/coil wires, PCV are also about 4 months old. Oil is fresh, oil and air filter are new. Coolant ne, about 3 weeks ago.w
e. Install fuel line heat shield sleeves - Should be here in a few days
f. Fill up with airport gas - BTW: I have a habit of topping off my tank, in older vehicles (like my 40 and my 2002 Tundra) - I read, this morning that doing so can cause some sort of fuel delivery problem in an FJ40. I didn't fully understand it. But, will quit topping off my tank, regardless.
g. Try the same or similar climb and see what happens.​

Thanks Mace!

Turns out my gears are 4.11 redface - my 40 performed great on the trip - except when climbing - the steeper the climb, the larger the power loss.

But, couple that with the single instance of vapor lock, after cresting the climb out of Tonopah, and it certainly seems to be a heat-related fuel delivery problem that's resulting in fuel starvation.

So, I think I'll come out of my 'plan', above, with '44' searching out hills to climb
​

Thanks everyone!

I'll report the results, when I have them.

Headers installed on my '77 have lowered the underhood temps significantly. I used to get severe fuel boiling in the float bowl with the OEM manifold, but that has completely stopped now that the headers are installed(they have way less mass than the OEM exhaust, so the heat dissipates more quickly)
I also am somewhat confused by the differential gear ratios suggested--a 3.70 diff will cause the engine to labor much more than 4.11 at a given speed it's a higher gear ratio- kind of like you are driving up a hill in 1st gear--the engine is humming along at some RPM--let's say 2000, if you shift up to 3rd, the engine will drop rpm and labor hard to keep the same speed, if it can-your foot will be in the firewall.
I like the gas tank low level as a major culprit-couple that with a suspect pump and you have somewhat of a smoking gun.--waiting for the test----

 

[Solace in Solitude]

Thanks Gary!

My 40 had headers when I bought it - if mine was hotter (under the hood) with the exhaust manifold, the hood must have glowed red most of the time! Of course, my headers are not new (no idea how long they have been there) and not nearly as purty as your's!

I don't profess to understand the physics behind the gear ratios - I keep going in circles (pun intended) trying to understand it - I plan to run it regardless of the outcome of the tests.

Jim C told me the optimum is to climb hills with a full tank (not always possible, of course), a good fuel pump, fuel lines insulated from the heat of the headers, timing and valves properly set and a tuned carb.

He also suggested and 'on demand' electric fuel pump (in addition to the mechanical pump), that could be temporarily switched on, if and when the fuel starvation issue occurs.

Since I will be installing my aux tank this winter, I can implement his suggestion as part of that install.

 

[sggoat]

Thanks Gary!

My 40 had headers when I bought it - if mine was hotter (under the hood) with the exhaust manifold, the hood must have glowed red most of the time! Of course, my headers are not new (no idea how long they have been there) and not nearly as purty as your's!

I don't profess to understand the physics behind the gear ratios - I keep going in circles (pun intended) trying to understand it - I plan to run it regardless of the outcome of the tests.

Jim C told me the optimum is to climb hills with a full tank (not always possible, of course), a good fuel pump, fuel lines insulated from the heat of the headers, timing and valves properly set and a tuned carb.

He also suggested and 'on demand' electric fuel pump (in addition to the mechanical pump), that could be temporarily switched on, if and when the fuel starvation issue occurs.

Since I will be installing my aux tank this winter, I can implement his suggestion as part of that install.

An observation on this: Regardless of the type of fuel pump you have, if the tank fuel level is lower than the suction to the pump(whatever kind it is), you will get starvation.
I have wanted to figure out a way to get the tank suction to the pump oriented so that no matter how far off level you are, the suction still is in the gas(sort of like a weedeater-that has a floating{sort off} suction line)

 

[Solace in Solitude]

An observation on this: Regardless of the type of fuel pump you have, if the tank fuel level is lower than the suction to the pump(whatever kind it is), you will get starvation.
I have wanted to figure out a way to get the tank suction to the pump oriented so that no matter how far off level you are, the suction still is in the gas(sort of like a weedeater-that has a floating{sort off} suction line)

Certainly seems doable to me!

FYI: I'll be gone all week and then need to fix my toxic, black, sooty smoke problem ( this thread --> https://forum.ih8mud.com/threads/black-smoke-at-idle-burns-my-eyes.819607/ ) before I can get back to this thread.

Thanks!

 

[Solace in Solitude]

Just to update those of you who tried to help... turns out the choke breaker was stuck - so, I was flooding the carb and creating VERY black, sooty smoke.

Once I corrected that, I was able to correctly adjust the idle and idle-mix and return to the corrections suggested in this thread.

I have since, re-timed to 10*BTDC, re-adjusted the valves, installed the replacement oem fuel pump (remember, I found the factory installed 90* fitting cross-threaded and it actually fell out of the output port on the pump, when I went to disconnect the fuel line - Beno replaced it), installed two glass fuel filters (replaceable elements), heat shield sleeved the fuel lines and removed the air injection portion of emissions (air pump, ABV, air rail and hoses).

44 is running great - in two or three weeks, I'll make another trip and see if the deceleration issue (on steep highway inclines, while loaded) is any better.

Thanks for your help!

 

[Solace in Solitude]

I'm posting this resolution in hopes that it saves others some time and frustration.

It turns out my loss of power, under load and on steep inclines was the result of a glass fuel filter (with replaceable element) that would not seal completely. It was not allowing a fuel leak, but was allowing my fuel pump to suck air under load.

If you want the whole story, see my Nov 4, 2014 post ->
https://forum.ih8mud.com/threads/my-new-78-fj40-44-40.799358/page-3

Thanks everyone and @FJ40Jim!!