1980 FJ40 2F… Dying Under Braking (1 Viewer)
- Thread starter ASO544
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
- Thread starter
- #22
I agree and will address that as well.
I also did a test drive with booster vacuum line pulled and plugged and still get the dying issue on braking. If I coast to a stop she runs fine but if decent braking she slowly stalls down an cuts off.
I checked my fuel window while running and it’s visible but in lower half.
I’m going to get all the air intake fittings capped, run the PCV to the intake manifold , the valve cover breather to the air cleaner and run the vacuum line to the dizzy advance . Then I’m going to re time it properly and adjust the mixture/ vaccum / idle and see if that cleans up the stopping / dying issue.
One issue at a time!!! Again I appreciate all the help and positive support on these issues !!!! Love this place !!!
I also did a test drive with booster vacuum line pulled and plugged and still get the dying issue on braking. If I coast to a stop she runs fine but if decent braking she slowly stalls down an cuts off.
I checked my fuel window while running and it’s visible but in lower half.
I’m going to get all the air intake fittings capped, run the PCV to the intake manifold , the valve cover breather to the air cleaner and run the vacuum line to the dizzy advance . Then I’m going to re time it properly and adjust the mixture/ vaccum / idle and see if that cleans up the stopping / dying issue.
One issue at a time!!! Again I appreciate all the help and positive support on these issues !!!! Love this place !!!
I also had a dying under heavy breaking situation, looking forward to seeing the conclusion on this one! I had several vacuum leaks that I had to address (old hose, worn out PCV valve/bushing, air leaks on riser between intake manifold and carburetor), and I had to adjust timing and fix idle problems (clogged idle circuit, had to clean the carb).
Wishing you luck!
Wishing you luck!
mattressking
10 digits to freedom
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.
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.
- Thread starter
- #26
Just watched that video earlier today !!! My vaccum gauge is toast… got a new one coming. Once here going to start from scratch on engine timing, etc….
Anyone know the thread size on these 2 ports on the intake manifold. Was going to tap into the vaccum but the fittings I got would not fit.
( 1/4” MNPT) and 3/8 ) …. Guessing 1/8x28 BSPT ?
On top in front of the carb… 2 ports locations. 1/8x28 BSPT ?
Right by the brake booster … horizontal port with a hex head plug. Not sure but bigger than the 2 ports on top
Anyone know the thread size on these 2 ports on the intake manifold. Was going to tap into the vaccum but the fittings I got would not fit.
( 1/4” MNPT) and 3/8 ) …. Guessing 1/8x28 BSPT ?
On top in front of the carb… 2 ports locations. 1/8x28 BSPT ?
Right by the brake booster … horizontal port with a hex head plug. Not sure but bigger than the 2 ports on top
Last edited:
Im wondering if the problem could be either electrical, or a physical shift of something as you brake.
Does it stall out when you're running it stood on the driveway when you stamp on the brake every time, or only when you've been driving along?
If you turn on your headlights and repeat the same operation, do they flicker at all? Better still, a test light on the engine fuse?
Does it stall out when you're running it stood on the driveway when you stamp on the brake every time, or only when you've been driving along?
If you turn on your headlights and repeat the same operation, do they flicker at all? Better still, a test light on the engine fuse?
You could also look at the solders on the motherboard of your computer (if equipped). If they are busted it can cause stalling. Mine occurred intermittently when stopping but wasnt brake/vacuum related…
- Thread starter
- #29
Tomorrow I’m diving in to hopefully get this girl on the road to recovery. Got all my hoses setup and ready to install for the air cleaner setup and pcv setup. I’m going to check the timing and hook up the vacuum advance and ensure it’s working correctly. Then I’m going to get the carb mixture /idle squared away and see what vaccum number I’m getting.
Hoping these proper adjustments will fix the dying issue … fingers crossed. If this works… my next fix will be getting the charcoal canister properly plumbed in !!!
Hoping these proper adjustments will fix the dying issue … fingers crossed. If this works… my next fix will be getting the charcoal canister properly plumbed in !!!
- Thread starter
- #30
So… I really hate to post this but don’t have much choice I guess.
Got out this morning to check and set timing. Found where my BB once was and painted it. Unhooked the vaccum advance line and plugged it. Attached my timing gun to first plug from front, making sure the advance on the gun was at zero and started her up. The timing was very close but I made a small adjustment to fine tune it so it was dead on the BB. Shut her off and went to tighten the dizzy down. Of course I bump it cause there not much room down there and I got big hands. I went to start he back up so I could reset the timing again and the ignition stuck on the start position so I had to wiggle the key a few times to to get her to stop trying to crank when started . This kept happen a few times till I noticed I grabbed the wrong LC key off the seat.( too many LCs I guess !!! ) Grabbed the right key and started her up and now the timing is way off… like 15-25*…. I check the gun to make sure the advance didn’t get moved and it didn’t.
I can get her idle and sounding fine but the BB is way off to the right. If I advance the timing gun to around 15* I can bring the BB back and around 20* it’s dead on.
What the heck could have happened between the bad starts to mess up the timing and making it now where the marks are so far off from where the engine it running smooth .
Got out this morning to check and set timing. Found where my BB once was and painted it. Unhooked the vaccum advance line and plugged it. Attached my timing gun to first plug from front, making sure the advance on the gun was at zero and started her up. The timing was very close but I made a small adjustment to fine tune it so it was dead on the BB. Shut her off and went to tighten the dizzy down. Of course I bump it cause there not much room down there and I got big hands. I went to start he back up so I could reset the timing again and the ignition stuck on the start position so I had to wiggle the key a few times to to get her to stop trying to crank when started . This kept happen a few times till I noticed I grabbed the wrong LC key off the seat.( too many LCs I guess !!! ) Grabbed the right key and started her up and now the timing is way off… like 15-25*…. I check the gun to make sure the advance didn’t get moved and it didn’t.
I can get her idle and sounding fine but the BB is way off to the right. If I advance the timing gun to around 15* I can bring the BB back and around 20* it’s dead on.
What the heck could have happened between the bad starts to mess up the timing and making it now where the marks are so far off from where the engine it running smooth .
pb4ugo
SILVER Star
You set the intial timing with the vacuum advance disconnected. After setting the timing and plug the vacuum back on to the distributor the vacuum advance/retard takes over.
1911
chupacabra
Either that, or perhaps he is using a dial-back timing light, and didn't set the dial back to zero?
pb4ugo
SILVER Star
- Thread starter
- #34
I was setting it with VA disconnected. I plugged to ported line from the carb. What was weird is it was very close initial but then after the bump and restart issue… now it’s way off. I may try another timing gun incase this one went Tango Uniform on me… doubtful but I just can explain the shift .
The gun was definitely set back to zero. It actually requires me to add 15 or so * on the guns adjustment to move the bb back into the window.
If I move the dizzy to get the BB back in the window the engine dies.
The gun was definitely set back to zero. It actually requires me to add 15 or so * on the guns adjustment to move the bb back into the window.
If I move the dizzy to get the BB back in the window the engine dies.
pb4ugo
SILVER Star
What's the idle set at? Mechanical advance will kick in at some point. You can check if its operating correctly by slightly twisting the rotor and let go. It should snap back.
I used to work on vintage Honda motos for a living.
One of the tuneup items was always to test the mechanical advance as they were 80% of the time either stuck and not advancing from the bike sitting OR the springs were stretched and loose or broken and not pulling it back to zero advance.
Worth a look
One of the tuneup items was always to test the mechanical advance as they were 80% of the time either stuck and not advancing from the bike sitting OR the springs were stretched and loose or broken and not pulling it back to zero advance.
Worth a look
Last edited:
- Thread starter
- #37
Tried a new digital gun… same results. Remove VA line and plug it. Adjust dizzy to where truck will run and idle decently. Use timing gun and no BB in window. If I turn the dizzy clockwise… I just start seeing the BB coming from the bottom of the window but the truck starts to sputter and dies at that dizzy adjustment. If I set the dizzy back to where it starts and idles decent and Adjust the digital advance on the timing gun up around 12* the BB comes into sight from the bottom of the window . It’s 15-20* for it to be centered on the pointer. As far as idle… it’s starts wanting to die at anything below 1000 rpm with the current timing issues.
Can someone explain the mechanical advance checking in more detail. Not sure where it’s located. As it’s proven here… I’m definitely not the best mechanic. I took a great running truck with a brake dying issue to an awful running truck as of now!!!
I cant get the idle below 1000 or it starts dying. I can’t get the dizzy setting to go below where it needs 15-20* degrees of advance timing from the BB (which would be 22-27* of timing.)
I’m about to decide on a new ( correct year carb) and better dizzy update HEI setup or a new OEM one regardless. My 73 has a sniper and DUI dizzy setup which runs great !
Regardless it Definitely need a better mechanic
Dizzy pics….
Can someone explain the mechanical advance checking in more detail. Not sure where it’s located. As it’s proven here… I’m definitely not the best mechanic. I took a great running truck with a brake dying issue to an awful running truck as of now!!!
I cant get the idle below 1000 or it starts dying. I can’t get the dizzy setting to go below where it needs 15-20* degrees of advance timing from the BB (which would be 22-27* of timing.)
I’m about to decide on a new ( correct year carb) and better dizzy update HEI setup or a new OEM one regardless. My 73 has a sniper and DUI dizzy setup which runs great !
Regardless it Definitely need a better mechanic
Dizzy pics….
Last edited:
thorslc1977
SILVER Star
Where is the rotor pointing when you are at TDC on cylinder # 1? With cap off of the distributor it should be physical pointed at spark plug # 4 or very close to it. Could it be possible distributor is installed a tooth off or so making your markings on the flywheel off? There are pics in FSM of rotor position at TDC. I am at work presently and don't have access.
fjc-man
SILVER Star
That rubbing block on the point set looks bone dry (no lube), probably don’t have much of a point gap. A new set of points, a little lube, and a new pair of point ajustment screws wouldn’t hurt the cause.
So grab the rotor bug and twist it - it should move on axis and then spring back - that is your mechanical advance. Next try and rock it towards the engine and away from the engine, then towards the bumpers - it should move very little or the bushings are worn and timing will be erratic due to excessive play.
I use the short blade of a swiss army knife (Tinker/Climber) to carefully scrape the aluminium contacts inside the cap - aluminum oxide builds up the be a crusty insulator - I prefer brass (NAPA are/were). Clean the matching face on the end of the rotor bug.
Clean gently the contacts where the plug/coil wires connect inside the cap and the plug boots. A Q-tip with a little dielectric grease will help keep corrosion away.
Blow the trash out of the cap before you put it back on
I use the short blade of a swiss army knife (Tinker/Climber) to carefully scrape the aluminium contacts inside the cap - aluminum oxide builds up the be a crusty insulator - I prefer brass (NAPA are/were). Clean the matching face on the end of the rotor bug.
Clean gently the contacts where the plug/coil wires connect inside the cap and the plug boots. A Q-tip with a little dielectric grease will help keep corrosion away.
Blow the trash out of the cap before you put it back on
