1980 FJ40 2F… Dying Under Braking

[ASO544]

Ok… got to work on her this past week. I ended up chasing all the threads in the head and clean the bolt threads really good prior to gasket install. I started with 23ftlbs, then went to 24 ftlbs , and finished with 25 ftlbs. I went against advice and installed the City Racer carb my buddy used and got everything tightened down and vacuum lines properly run….along with the choke cable as well.

Added a little choke and after a few turn to get the gas flowing she started right up!!! After a brief warm up and running my hands along the exhaust manifold I didn’t feel nor detected any leaks.

I then installed the vacuum gauge and tweaked the mixture and idle. Ended up at 700 rpms with 19-20 psi of vacuum.

I was getting some smelly smoke from around the exhaust manifold but I couldn’t feel any leaks and it was hard to see where it was coming from exactly. Wonder if it was from the new gasket ???

I took her for a ride… drives and runs great and idles perfect. Best yet….zero dying issues under braking !!! When I got back and shut her down, it still had some smoke from around the exhaust manifold area when I turned it off but it was much less the earlier. I recheck the torque on exhaust / intake manifold bolts and all was fine at 25 ftlbs.

Seems I’m on the road to recovery but still got some gremlins to chase. Much thanks to all for the advice and help. I’m still going to leave this thread open until I get everything where I need it cause no doubt I’ll need more advice !!!

 

[ASO544]

Did some more tidying up today. I fixed my fresh air cable and got it attached to the door properly. Found 2 bolts missing from the bottom of the blower motor and replaced them. I made a tool bag and mounted it … also going to install a set of mounts for the jack / tool as well.

I now need to figure out the play I have in my shifter and how to eliminate it. Definitely need to tighten it up !!! Video is below

video / Shifter Play

 

[sggoat]

Every single time, no one ever mentions the most important diagnostic. Vacuum measurement. No point in guessing when you can have empirical answers to point you in the correct direction.

Connect a vacuum gauge and read the vacuum. Engine dying when braking means low vacuum when the booster takes over.

If you have under 19-20inHg of vacuum, fix the leaks, then set base timing at 7* and learn how to do a lean drop on the carb. Since it doesn't have smog testing needs, the final "lean drop" isn't necessary, just tune for best idle/strongest vacuum (650-750rpms, though I prefer to stick around 670).

Go download the 2F FSM and go STEP-BY-STEP in the tuneup section, don't skip a section or think it's correct. This is how you'll have a healthy running truck.

This is excellent advice! I have a permanent vac gauge hooked up--vaccum will tell you many things-here's a t'shooting chart-

 

[sggoat]

So does the distributor looked to be installed correctly ? The button seems to be pointing at #4 spark plug at TDC

that's about where it(the rotor) should be--

 

[sggoat]

Even when set by ear where it drives strong the Idle won’t go below 1000 rpm without starting to cut off.

The vaccum is 14-16 at idle from the intake manifold

The timing is 27-29 degrees from TDC but I’m betting that at the 1000 rpm the mechanical advance is probably kicking in and skewing the timing off. My carb seems to be an issue not allowing me to get the idle in the 650 range it needs to be .

One a side note… I cleaned up the intake vaccum ports and did locate an exhaust leak by the #4 cylinder. Gaskets on order!!!

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14-16 in Hg is low for idle-even at 900-1000rpm--at 950 rpm I'm running 20.5 inches vac when first started-after up to temp, still see 20" at my normal 700rpm idle(I'm in SW Fla. so maybe 15' above sea level). Your timing issue may be impacting this low vac.(or visa-versa)--new dizzy points and gap correct? get a piece of cardboard and stick it over the exhaust pipe at idle--does it seem to suck the cardboard back regularly? maybe check the valve adj(a mini tad loose might be better, and a cold adjustment would suffice)
BTW--this is a really clean rig--you are doing all the right stuff by it--wish mine looked as good!

 

[sggoat]

I do have a substantial exhaust leak around the 4-5 cylinder. You can feel it when idling and you put your hand over that area. When I sprayed that area with carb cleaner I also got an rpm increase. Not huge increase but a increase

you should NOT see any rpm change if you spray an exhaust leak--but, I don't know what the symptoms would be if the 4/5 exhaust valve were to be partially open during the intake stroke

 

[ASO544]

Got my shifter off and have new parts to install ( seems like some may not apply) but I noticed that I might be missing the cylinder shaped sim on the left side down inside or is that gap normal ?

What’s the best grease to use for re-install.

 

[ASO544]

This is the aftermarket part that came with 2 rubber spacers. Not sure it’s correct though

 

[ASO544]

Think I found my issue… 45 years of wear. Seems the lever isn’t available (3/80 build). So are there any good fixes ?

Video of play in shifter…..

Shifter play

 

[charliemeyer007]

Are you or got any friends that are welders? Those slots are worn - try to build up with weld and then file them back out with flat sides. does not need to be perfect A milling machine would make short work of the task. The pins are worn too - maybe you can buy them or just make new ones. Some one did a replacement thread.

 

[ASO544]

I actually found a shift lever in excellent shape. I’ll see how tight it is and if I need to also replace the retaining pins on the neck as well to eliminate the play/wiggle.

I’m also in the process of plumbing the oil cooler back in with a kit from city racer. Sure it can’t hurt… hoping the cooler wasn’t bypassed because of issues. Guess I’ll see !!!