Engine hesitation (1 Viewer)

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Guys...I'm close to being able to drive this thing (1975 desmogged). I have spent so much time working on the electrical and thanks to @Cromagnon and @Coolerman I am almost there! Turn signals don't flash (hazards flash)...but getting there. Thanks to everybody on this forum.

My new issue...while driving the engine hesitates or skips. For some reason the PO put in an electric fuel pump, but kept the engine driven pump. So, I have 2 fuel filters (one OEM, one aftermarket) an electric fuel pump and engine driven pump (one fuel tank). I think I need to bypass the engine driven pump and cut out one of the fuel filters?

Things I have done on the engine...timing is right on, valves adjusted, new carb, adjusted rich/lean and RPMs at 660-670, vaccum reading close to 20. Engine runs great at idle and sometimes it runs great (2-3 min), but within a couple minutes it goes back to hesitating/skips/pops/stutters. Could it be the fuel delivery?

Any help is always appreciated!

 
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Yeah, it hiccups from the engine...I assume carb (doesn't do it in the garage)? I think I had too rich before I adjusted the lean/rich because I had the black carbon water spitting out of the exhaust on start.
 

Dizzy

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It is a sign of being too lean. I have had it for various reasons. If I'm partly choked, I get poor performance from medium to heavy throttle, so I run with the choke open this time of year. You could have a clogged passage, or just need a bigger jet (144 to a 156 seemed to work on mine). I'm measuring the exhaust with an O2 sensor, and I'm also a '75 stock Federal carb, but I'm trying to run it at high altitude.

Do you have the vacuum barb on the top of the carb, by the air cleaner, hooked up to anything? That is the power valve, and if you cap it it will allow for enrichment.

My preference is the engine driven pump. If stock, which they are not always, it will deliver the correct pressure to the carb. However, they are more pricey, and if they develop a leak, then they can fill the crankcase with gasoline (yikes!). Cruiser Corps set me up with an electric pump, but I might not use it on this vehicle, it delivers the correct pressure.
 
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I'm basically at sea level. The only port I see on the inside (closest to the valve cover) side of the carb is at the bottom and is the line hooked up to the distributor. I can look later today, but don't think I have anything capped off towards the top of the carb.
And when I say it idles fine...it idles...but every 10 seconds plus or minus you can hear it skip or hesitate. It's super mild, but you can hear it. Should I try to run it with the choke out a bit? I do think I need to bypass one of the fuel pumps...and the engine driven one hasn't been changed in forever probably.
 

Dizzy

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The power valve faces the front of the vehicle, right under the air cleaner assembly.

You might try a variety of choke positions to see if that helps.

What is the history of the motor? Is your spark good regarding timing, and dwell? Do the spark plugs look dirty? Is there a good PCV connection and has it been inspected for vacuum leaks?
 
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Here are a couple pictures of everything. I'll try to run with the choke in different positions tomorrow.

Engine history...this thing sat in a field for 20 years and I have changed all the things mentioned because it didn't run (had a couple stuck valves when I did the valve adjustment). I haven't messed with the points yet, but have a Pertronix system I can install (never checked the dwell...and honestly don't know how). Spark plugs, I will pull in the morning to take a look and will report. I'm not sure about the PCV connection, but I think that's toward the rear (passenger side) of the motor...should be in the pics). If so, that hose connects to the manifold below the carb. Since I have had this FJ40, I haven't had the motor running great for any consistent amount of time...it runs good, then does this kind of stuff. I assume it's because of the sitting in the field for 20 years.


UNADJUSTEDNONRAW_thumb_2324.jpg


This is the hose from the distributor to the base of the carb.
UNADJUSTEDNONRAW_thumb_231c.jpg


Distributor
UNADJUSTEDNONRAW_thumb_2320.jpg


Engine Fuel pump

UNADJUSTEDNONRAW_thumb_2322.jpg


I think this is the PCV...I pulled the hose off to show.
UNADJUSTEDNONRAW_thumb_231f.jpg
 

Dizzy

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You need a new (best is OEM) PCV valve, that one is rusted and it isn't a Toyota OE valve. Your carburetor isn't original, so it isn't easy to control the power valve. Do you have a vacuum gauge, or a compression tester? Do you have a timing light? I don't know if you would be able to replace that EGR valve, but they don't age well, and you might just be fine with its removal and capping. As far as your exhaust manifold goes, it is for a later 2F, so I wonder if the engine itself was also swapped?

The first thing in these matters is valves, which you did. Then run a compression test to confirm it.

Then figure out what you are going to do for spark, electronic or tune it with a dwell meter (I got mine from Harbor Freight which included a precise voltage meter, and a few other functions). This will get you a good baseline for other things. Post up pics of the numbered plugs, then clean them with a wire toothbrush and air or gasoline, check their gap, and return them to their original position.

If your spark plugs look black and shiny, then, likely, valve stem seals will need replacement. Do you get a puff of smoke at during deceleration? Do you get smoke at startup from the exhaust? The early 2F heads had one style of seal, so make sure your production date of head. With stuck valves, I'm thinking that inspecting valves is going to be important. A vacuum test is revealing here, in my opinion. The seals on my motor were shot (and two other heads), upon replacement and burning out some of the carbon deposits from the leak (driving it alot), I got a really tight 2F. Keep in mind that head removal is more work, but it ensures a complete cleaning and inspection of valves. I didn't remove the head, but I don't know if it was easier doing it that way.

Then fuel delivery and vacuum connections are the home stretch.
 
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You need a new (best is OEM) PCV valve, that one is rusted and it isn't a Toyota OE valve. Ok, I'll order one. Not sure how to get that one off there.
Your carburetor isn't original, so it isn't easy to control the power valve. Do you have a vacuum gauge, or a compression tester? Do you have a timing light? Yes for vaccum guage and timing light. Vaccum (read from brake booster) is 19+ and timing is set to 7' (pretty much right on the bb). I don't know how or have a compression tester.

I don't know if you would be able to replace that EGR valve, but they don't age well, and you might just be fine with its removal and capping. As far as your exhaust manifold goes, it is for a later 2F, so I wonder if the engine itself was also swapped? I'm sure mine has been on there forever. I'll have to search on here on how to remove and cap that since I assume that was for smog? This engine is apparenlty out of a 1980...does that match the manifold?

The first thing in these matters is valves, which you did. Then run a compression test to confirm it. I'm going to rent a compression tool to do the test.

Then figure out what you are going to do for spark, electronic or tune it with a dwell meter (I got mine from Harbor Freight which included a precise voltage meter, and a few other functions). This will get you a good baseline for other things. Post up pics of the numbered plugs, then clean them with a wire toothbrush and air or gasoline, check their gap, and return them to their original position. I'm going to install my Petronix today. Pictures of the spark plugs attached. I think 5 looks a little suspect. I will set gap to .39.

If your spark plugs look black and shiny, then, likely, valve stem seals will need replacement. That seems like a big job? Do you get a puff of smoke at during deceleration? No Do you get smoke at startup from the exhaust? No smoke, just sometimes the black water.
The early 2F heads had one style of seal, so make sure your production date of head. With stuck valves, I'm thinking that inspecting valves is going to be important. Do I need to pull the head off?
A vacuum test is revealing here, in my opinion. The seals on my motor were shot (and two other heads), upon replacement and burning out some of the carbon deposits from the leak (driving it alot), I got a really tight 2F. Keep in mind that head removal is more work, but it ensures a complete cleaning and inspection of valves. I didn't remove the head, but I don't know if it was easier doing it that way. I'll have to search for the instructions on here?

Then fuel delivery and vacuum connections are the home stretch.
1B7R9LvDTdSSMbdOceuGZg_thumb_232e.jpg

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Dizzy

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Those plugs look great, aside from number 5 (oil or bad spark), and number 6 (lean).

BTW, don't buy NGK from any but those retailers that NGK states are okay - tons of phony plugs out there.

Leave the head on for now is my call, maybe the plug gap was the cause for the stumble?
 
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Yeah, 5 and 6 didn't look the same, but were gapped at almost .055. I think I got those at Oreilly or Napa? They are all at .39 now.

Also, the PCV (see picture) was totally clogged and no bb noise. Got to get some carb cleaner or find a new one.

Next step is to do the compression check, but need to go rent the equipment. But, as I was installing the Pertronix, apparently I got the wrong part (I got the part for the 1975 vehicle...not the 1980). So, that doesn't get here till Monday (and they won't take my old one back...so it's for sale!). So...probably won't test till I get the ignition since I don't want to put the points back in.

Do I need to cap off the EGR valve? If so, any pointers (pic attached).
UNADJUSTEDNONRAW_thumb_2335.jpg

UNADJUSTEDNONRAW_thumb_2336.jpg
 

Dizzy

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Usually, an EGR valve only needs to be disconnected, at the small barb to keep an exhaust leak out of the intake. But it is critical that you aren't feeding exhaust to the intake at idle. The later 2F has an easier delete plug on the exhaust manifold, and intake. A Toyota Land cruiser specialist with parts and service Jim C. will hook you up, if needed. However, I don't know much about the production dates. Where is everyone else on this thread? I hear crickets.

BTW, here are some images from my experiences on the valve stems. Valve Stem Seal Replacement
 
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Quick update...I installed the Pertronix and new PCV valve (after Pertronix sent the wrong part) and it fired up immediately. It ran for about 3 minutes, then suddenly quit running. (It seems to run great when it was running). While I was changing out the ignition, I did some other work and I bypassed the engine driven fuel pump (left the electric pump connected) and did some cleaning up of the fuel lines to make less of a hose mess...and thought that was maybe the cause. But, the carb was getting plenty of fuel, etc...so I called Pertronix. They said the coil went bad (it should have at least 3 ohms of resistance and mine had 0. So, now waiting on the new coil to arrive so I can install that. (I have read on here that coils very rarely go bad, but maybe that's with stock points, etc?) When I get the coil installed, I'll readjust the carb mixture and then test the compression and check vaccum and report back.
 
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Still waiting on parts, but it occured to me that I could run the compression test since the coil isn't working. #1 - 112lbs, #2 (this one was the one with the stuck valve) - 100lbs, #3 - 110lbs, #4 - 116lbs, #5 - 111, #6 - 108lbs.
Edit...I just read Solice in Solitudes post (#2 - Compression test 2f confused), and realized I didn't do the test correctly. Didn't warm up the motor or remove all the spark plugs...I need to redo it I think.
 
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3_puppies

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I would disconnect and plug off the line that goes to the distributor, the distributor you have is a vacumn retard. it would be better not to have it hooked up than to have it hooked up.

interesting your exhaust from the manifold down is 79-80 vintage.

those compression #'s are very low. all plugs out and throttle open when testing.
 

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