Hoping for Guidance/Validation (1 Viewer)

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Howdy,

I posted these two questions on my "My New '78 FJ40 "44-40"" link ( https://forum.ih8mud.com/threads/my-new-78-fj40-44-40.799358/page-3#post-9373073 ), but I seldom get a response to questions I pose in that thread... probably just me not fully understanding MUD etiquette...

At any rate, I just returned from a 700+ mile maiden trip, during which, I had two minor issues with 44 - and would appreciate your thoughts:

1. Acceleration really bogs down on tough climbs - heading into Austin, NV, on US 50, from the east, the grade is fairly severe (we encountered many other more severe grades off road), 44 bogged down to 35 mph (never lower) and the vacuum gauge dropped to 1.

I assume the deceleration on the climbs were the result of the low compression numbers I reported earlier, in this thread. Am I correct that there is a direct correlation between deceleration and low vacuum?
Stupid question? Perhaps... it seems obvious that when the engine isn't producing much power, it also isn't producing much vacuum, but I could be wrong.

2. 44 quit running, at 55 mph, just as we crested a grade, coming south out of Tonopah, NV- I coasted off the pavement, over the shoulder and up a hill (to ensure it would be safe to work on 44). I suspected 'fuel starvation' and pulled the air cleaner so I could check the (Aisin carb Jim C just rebuilt) sight glass. The glass showed no fuel and there was a ring of engine oil around the mouth of the carb.

I'm sure the engine oil was from the air cleaner - it always has a couple of tablespoons of oil in the air cleaner, from blow-by. I choked the carb and turned the key and the GR Starter got it started on the third try. I shut it down and restarted on the first try - no choke.

It was hot in Tonopah (about 100*) and the wind was BLOWING - I have a bastardized carb cooling fan, on a manual timer, so I turned it on for an hour and continued driving with the fan running and made the final 3.5 hour drive home, with no further problems.

I'm sure 44 died because the fuel boiled out of the carb - even though the engine never overheats (about half-way on the gauge), it is VERY hot under the hood.

Does anyone see this issue as something other than what I've diagnosed?

Thanks to all who respond!
 
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low vacuum comes from your foot buried in the throttle because there is little resistance to the air flow

your fuel problem - many engines suffer vapor lock (where the fuel actually goes to vapor in the line from the pump to the carb) the problem is the pump doesn't have enough pressure to overcome the air in the line - it's a similar problem with diesels when they get air in the line. The pump compresses the air, but it doesn't open the injector because there's not enough pressure in the line. Presuming the pump is okay (and it generally is), wrap the line in aluminum foil to create a fuel line radiator. companies also make wraps that accomplish the same thing.
 
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Thanks for responding!

Re: "low vacuum comes from your foot buried in the throttle because there is little resistance to the air flow "

So, how do you deal with deceleration, when climbing a steep grade and speed has dropped to 35mph and you are already in 3rd gear and 35mph is too fast for 2nd gear?

Is there something I can do or am I doing all I can by burying my foot in the throttle?


Re: "your fuel problem - many engines suffer vapor lock (where the fuel actually goes to vapor in the line from the pump to the carb) the problem is the pump doesn't have enough pressure to overcome the air in the line - it's a similar problem with diesels when they get air in the line. The pump compresses the air, but it doesn't open the injector because there's not enough pressure in the line. Presuming the pump is okay (and it generally is), wrap the line in aluminum foil to create a fuel line radiator. companies also make wraps that accomplish the same thing."

The pump is new and is definitely ok - the 'fuel line radiator' is new to me and is a great suggestion!

Thanks again, SuperBuickGuy!!!
 
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I had a 65 '40 that was terrible climbing hills, it'd either be at full rpms in 2nd or dying in 3rd - it made for slow climbs. Point is, is it a normal condition or something that just started?
Generally the fix is a bigger carb like a holley 2 bbl or a webber. I'd also put a fuel line pressure gauge on the line to see where it's normally at. many fuel pumps run at 3 psi, which is fine for most - but when you get a loaded vehicle that gets warm climbing a hill, it may not be adequate. Normal for carb'd motors is between 3 and 7 psi. 7 psi tends to be too much for the needle valve in the carb to control, but 5 psi is a good number to shoot for. If all checks out, you can also add an electric fuel pump in line that you only turn on when the pump is having trouble keeping up.
Also, the warmer fuel gets, the harder it is to move, and the leaner the motor will run as the fuel system stops keeping up with the engine requirements.... thus, once it starts getting warm, it gets warmer pretty quickly as the system fails.
 
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On your first question, have you checked your secondary for proper operation? If it feels underpowered your secondary diaphragm may have torn or your throttle linkage may not be allowing your secondary to open for some reason.

Also, was it windy while these symptoms were occurring? Remember the fj40 has the aerodynamics of a brick, and wind can suck up hp quick. If your vacuum is almost 0 when driving that just means that you have the throttle wide open. It's the vacuum at idle that folks are usually concerned about when doing an engine diagnosis.

On your second question, do you have the fuel return line hooked up? It sounds like you might be starving the carb for fuel, which may indicate a failing fuel pump. I know you said it's new but You can check by hooking up the fuel line to a gas can and timing how fast it fills it up. Some guidance here on mud. The Aisan carb has plenty of cfm for a normal 2F engine.


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Thanks for responding!

No, I haven't checked the secondary function - I just re-installed my Jim C rebuilt carb around Aug 25th and it works really well - except on the more severe inclines. This is the first time I've driven 44 on anything other than flat streets and the first time I've driven an FJ40 on hills and mountains - so, I'm not really sure what to expect on those inclines.

Background: I reported earlier the results of my post-hot-valve-adjustment compression tests (dry and wet) - I will post them again at the end of this post - you can see that my compression numbers are not good - could my low compression numbers have some bearing on my (1st question) acceleration bogging down on tough climbs?

It was somewhat windy the day I was climbing the grade into Austin, NV, but was much windier and hotter during the incident reported in my second question.

So, I won't worry about the low vacuum on the climb - both you and SuperBuickGuy indicate it is more of an effect than a cause.

I'll perform the paper clip test tomorrow and report back, about the secondary.

Re: My second question -

Yes, I do have my return line hooked up.

Both you and SuperBuickGuy have questioned the pressure generated by my new oem fuel pump - I plan to test it tomorrow, just to be sure - I'll report that back, as well.

Thanks!

Here are my compression numbers (post-hot-valve-adjustment) - FWIW I plan to readjust valves, re-time engine and re-test compression tomorrow, if I have time.

Cyl. Dry. Wet. Incr%

1. 110. 119. 8.1%

2. 110. 121. 9.1%

3. 104. 116. 11.5%

4. 110. 120. 9%

5. 109. 115. 5.5%

6. 115. 130. 13%

 
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FJ40s are notorious for burning the middle valve - what's ironic is that they bought the rights to produce the motor from GM, and similar GM motors don't have the same issue.

I'm not that concerned about your compression levels - as long as they're within 10% of each other, it's fine. It does give some concern that the valve that most generally goes south is the one that's low.

FJ 40s are not fast, and the 78, although it's a 4 speed, could also have 3.73 gears - thus, it would not be fast under any circumstance. Add the emissions crap, and the lower compression ratio and they are not... well, speedy. It's why swapping to small block chevys is so popular. The motor weights less, gets better fuel economy and has more power at all points of the power band. The purists hate it, of course, but if you're going to use it - there are 100 million SBCs made, and parts are so much cheaper for them. To recap, cheaper, lighter, faster, and better fuel economy... plus, it's a GM motor in there already, so you can simply say it's an updated Toyota motor :D

You mentioned header - where is the fuel line from the pump in relation to the header? Headers allow more heat to stay under the hood, you can wrap the headers - but the downside of that is it traps moisture against the pipes and rusts them out pretty quickly.

More fuel is good, transfer pumps work well - whether you run the pump through a valve to the motor or the other tank - here's the "deal" about that... transfer tanks require something that everyone I know who's had one (including me) have done. You turn on the pump when the gauge is at 1/4 tank, then you continue driving down the road.... see a pretty vista... talk to the wife.... and pump 1/4 tank of fuel out of your filler cap. The tank in the '40s have some issues; and getting the tank out of the cab is a good thing - adding a pump to where you can pump fuel into your cab could be disastrous.

Are you required to have the emissions stuff? if not, put it all in a box and cap off the lines - your issue could be as simple as a vacuum leak.
 
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Without trying to sound like a d*ck, I wonder if your performance expectations are on the high side?

Looking at the photos (Nice, BTW) it looks like you were carrying a fair bit of gear. The 2F in stock form only puts out 135 HP. Tonopah is a tad over 6,000, and Austin, NV is 6,600. The general rule of thumb is you lose about 3% of your horsepower per 1,000 feet of elevation gain. So you're down roughly 20% and it was hot, which doesn't help.

I totally agree with SuperBuickGuy regarding the general lack of power of the 2F. Further, as he correctly pointed out the engine design came from GM, but the GM design dates from the 1930s. The 2F's strong points are that it's reliable and durable. But (also pointed out by SuperBuickGuy) it's heavy, gutless and thirsty. Has engine technology improved much since the 1930s or since 1978? You betcha!
 
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Again, SuperBuickGuy, great information! I sincerely appreciate your insights!

So, to recap...

It might behoove me to pull the head and have a valve job done.

When and if I ever do an engine swap, (I'm not a purist - just want to rely on being able to return home from very remote locations) you feel a better engine replacement is the SBC. Is it a difficult swap? ...and "YES" I do have 3.73 gears.
The fuel line feeds from the fuel pump (on the passenger side of the block) - the feed line wraps around the front of the valve cover and connects to the carb, directly above the intake manifold (with a carb insulator/isolator between the carb and the manifold) and the headers directly under the intake manifold.

I've 'shot' my headers with an infrared theromenter and know that the six header pipes generate heat just over 400*F and the 40 engine compartment is extremely hot - I've ordered the fuel line insulation sleeve and won't be going far before I get that on the fuel line. I'd rather not wrap the exhaust, it's ok now (no rust-thru), but could rust fairly easily - although, I am in Vegas and it's generally dry here in Nevada.

I'll rethink the transfer pump - I can easily use the aux as a secondary tank, with an electric fuel pump and merely switch to the aux when the 'fuel starve' condition pops up - I really appreciate the warning!

I register my 40 as 'Classic Car' and am thereby emissions exempt for up to 5k miles per years and, as I said earlier, the EGR was gone when I bought it. I can easily remove the rest and box it all up. I sincerely doubt all emissions components are working correctly, so I think I'm gonna finish the desmog this winter.

I'm gonna try to do a number of things (suggested by you and subzali and some on my own) today, but I have to drive several hours to recreate the conditions that I'm chasing...

But, I'm getting a much better understanding and am much less concerned than I was.


Thanks!
 
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Without trying to sound like a d*ck, I wonder if your performance expectations are on the high side?

Looking at the photos (Nice, BTW) it looks like you were carrying a fair bit of gear. The 2F in stock form only puts out 135 HP. Tonopah is a tad over 6,000, and Austin, NV is 6,600. The general rule of thumb is you lose about 3% of your horsepower per 1,000 feet of elevation gain. So you're down roughly 20% and it was hot, which doesn't help.

I totally agree with SuperBuickGuy regarding the general lack of power of the 2F. Further, as he correctly pointed out the engine design came from GM, but the GM design dates from the 1930s. The 2F's strong points are that it's reliable and durable. But (also pointed out by SuperBuickGuy) it's heavy, gutless and thirsty. Has engine technology improved much since the 1930s or since 1978? You betcha!

I never mind candid responses - thanks!

I now know my expectations were somewhat unreasonable and that's really what I needed - e.g. information to use in setting more reasonable expectations. This is the first 40 I've ever driven and the first time I've driven it in those conditions (long, steep climb into Austin, NV and steep climb , in hotter conditions, into a headwind, coming out of Tonopah, NV).

...and, yes, I was loaded (well... I wasn't loaded, 44 was)... I thought of all of this, but didn't know what to expect ... in retrospect, I should have asked a different question ... "is it typical for an old 2F to bog down that much, on a long, steep climb, in hot conditions, when loaded?"

When I ask it that way, the answer seems obvious... :doh:


Thanks for pointing the way, guys!
 
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My 77 with 4.11s has no problem pulling 3rd gear at highway speed (50 mph or so) all the way up vail pass here in Colorado (11000 feet). So it shouldn't be a 2F vs sbc problem. Oh by the way my 2F has compression numbers like yours, even with a proper valve adjustment and solid vacuum readings at idle. No vapor locking even at altitude either, 100+ degrees in Denver at times.

It may be a 4.11 vs 3.73 problem, as I've never driven a 3.73 geared 2F powered rig and not sure what they can do.

So start with the fuel pump and secondary diaphragm tests and see where to go from there.


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Thanks Matt - I'm sure the different gears don't make it a true comparison.. But gives me something to compare to nonetheless.

Thanks Claudia - even more apples-to-oranges comparison... My 40 is max out at 40mph in 3rd gear and you are able to hold 60 in 3rd gear...

The incline I referred to is legendary, on US 50 ("The Loneliest Highway") - it's called the "Austin Summit" - the summit is around 7500' - I've driven to 12k' in my Tundra - but the Austin Summit is one of the steepest slopes I've climbed.

That's not to say there isn't a problem with the fuel pump or secondary on my 40 - I didn't have time to run the tests today - I should get to them tomorrow though.

But, Jim C just rebuilt my carb, including secondary...

Unfortunately, there is no nearby grade to use to try to recreate the problem - so, even the paper clip test may not fully validate the secondary...
 
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I finally got a chance, this afternoon, to test my new OEM fuel pump (bought from Onur (Beno) in April, as a spare) but, while attaching my fuel pump gauge, the 90* oem fitting, in the output port, (assembled by Toyota's supplier), fell out.

I picked it up and checked it and found it cross threaded - not sure how it held thru my 700 mile trip - since it fell out, with very little wrench-pressure, it could easily have been leaking (especially when the engine compartment got hot) but, certainly wasn't leaking noticeably...

Anyway, I sent pictures to Onur and described the problem and he replied that he will overnight a replacement and send the bad one back as a warranty claim. :cheers: Onur!

So, I re-installed my old oem pump and will test it tomorrow, after the RTV cures.

I may be wrong, but couldn't the fact that the 90* was able to fall out with very little wrench-pressure on it, be part of my fuel starvation issue?
 
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I don't know what happened to josh (chamba), but he had a 3.73 geared 2F powered fj40 and I'm sure could comment on expected speed. I will try searching some posts to see if he ever mentioned anything.

Another thought - does your air pump spin freely and does it put out a decent volume of air? It might be a culprit for robbed hp if not working correctly.


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I don't know what happened to josh (chamba), but he had a 3.73 geared 2F powered fj40 and I'm sure could comment on expected speed. I will try searching some posts to see if he ever mentioned anything.

Another thought - does your air pump spin freely and does it put out a decent volume of air? It might be a culprit for robbed hp if not working correctly.


...via IH8MUD app


Thats an interesting question!

When I re-installed my Jim C-rebuilt carb a couple of weeks ago, I replaced all under hood hoses (including the air pump hoses) and found that the air pump hoses were hooked up backwards. I didn't check the pump function, at the time, I register as a Classic Car (smog exempt). I had actually forgotten about that... I'll check it.

Thanks!
 
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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?
 

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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.
 

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