is it needed after a manual transmission conversion? Mine seems to be getting stuck- even after removing the filter- and I want to just delete it so it's one less part to buy.....thank you.
FJ62 Dashpot (1 Viewer)
- Thread starter LAMBCRUSHER
- Start date
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torfab
Supporting Vendor
It may not be necessary, due to the extra weight of the flywheel and clutch attached to the crank. I would run it without the dashpot and see how it works for you.
For example, in a related application (12HT Diesel), there are different IP adjustments for manual vs auto transmissions. The auto requires a higher idle, as it will die when you let off the gas to idle. The same setting with manual will not die, it will continue idling. There are also idle up diaphragms on the auto attached to power steering pressure, and manifold vacuum.
For example, in a related application (12HT Diesel), there are different IP adjustments for manual vs auto transmissions. The auto requires a higher idle, as it will die when you let off the gas to idle. The same setting with manual will not die, it will continue idling. There are also idle up diaphragms on the auto attached to power steering pressure, and manifold vacuum.
EscapeWagon62
SILVER Star
Thread revival - I know....don’t light me up 
But glad I wasn’t the only auto-manual swap that experienced this.
Mine was getting stuck, I shortened the adjuster screw and it helped, but the condition re-occured today (probaboy because it was 29 degrees F today.
I’ll adjust it so it doesn’t engage (deleting it in place vs pulling it out) and hope it woeks.
@LAMBCRUSHER assume this modification worked for you??
But glad I wasn’t the only auto-manual swap that experienced this.
Mine was getting stuck, I shortened the adjuster screw and it helped, but the condition re-occured today (probaboy because it was 29 degrees F today.
I’ll adjust it so it doesn’t engage (deleting it in place vs pulling it out) and hope it woeks.
@LAMBCRUSHER assume this modification worked for you??
The dashpot is there to "cushion" the closing of the throttle body when you let off the gas and prevent the engine from decelerating too fast and generating excess carbon monoxide emissions (and posible soot buildup on exhaust valves, but I havent seen any definitive answer on that one. Makes sense though). If working right it will still allow your engine to settle to its set idle speed. Is it needed for a 3FE with a manual behind it to run properly? Possibly not, however after my H55F conversion I still adjusted mine properly according to the FSM and have no issue with it, so I'll leave it there. If it's not operating properly when it's below freezing it's got moisture in it that's preventing it from working. Ironic that I'm having that EXACT issue with another part not known for getting water in it: my driver's door lock solenoid!
EscapeWagon62
SILVER Star
Thanks @Spook50 I’ll look up the FSM adjustment. Easy enough to pull it and clean it out.
On the bright side...this is a minor annoyance and my chances of doing anything stupid/catastrophic are low
Bringing this back from the dead. Troubleshooting a downshift issue with my transmission, I noticed this morning when I pulled in to work that my engine didn't want to go below 2000 RPM, and I'm suspecting (hoping) this might be the culprit rather than something internal in the tranny. I'm not sure though if this was just a fluke this one time, or if it's been doing it this whole week and I just hadn't noticed because my new exhaust is so much quieter (also been about 95% highway this week), but if it does it when I go home today one thing I'll be checking is my dashpot to see if it's seizing up (along with throttle springs and the throttle cable itself). If it is, I'll be removing it and will report back if I notice any difference in deceleration at all. I'm hoping what @torfab is saying turns out to be the case in that the weight of the flywheel and pressure plate prevent the engine from spinning down too quickly. What makes me curious (just for the sake of gee whiz) is the rotational weight of that versus a torque converter and its plate.
torfab
Supporting Vendor
That extra weight isn't going to cause it to hang at 2k rpm though, it only makes a slight difference. My guess if you have a sticky throttle cable, jamming hand throttle, or something sticking in the throttle body. Clean/inspect one component at a time until you find it. 
Exactly, and that's my hope. Something else is causing it to hang at high speed, so I'm hoping the weight of the flywheel and pressure plate does enough to eliminate the necessity of a dashpot, which would in turn eliminate one part that could potentially fail.That extra weight isn't going to cause it to hang at 2k rpm though, it only makes a slight difference. My guess if you have a sticky throttle cable, jamming hand throttle, or something sticking in the throttle body. Clean/inspect one component at a time until you find it.
One thing I know I need to do is lubricate the throttle cable, so that'll be the first step.
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torfab
Supporting Vendor
Motion Pro 08-0182 Cable Luber Amazon product ASIN B0012TYX9W
I recently bought one of these to be able to lube the inner sheath on my throttle and trans cables.
I recently bought one of these to be able to lube the inner sheath on my throttle and trans cables.
I'd been looking at exactly one of these for the sake of convenience. There's a bike shop right near me that I'm betting has either that or something similar. It'd certainly be more convenient than the plastic bag trick.
I’ll try it next week. The reviews are good. I also go a specific bike cable lube.
I thought my throttle cable was coming apart and sticking but it ended up being the tps.
I thought my throttle cable was coming apart and sticking but it ended up being the tps.
Oof I hope it's not my TPS binding. Even if I don't have to replace it, it's a pain in the arse to adjust when you pull it off and reinstall it. And I was doing it on the bench last time
Mine was bound and gunky. It cleaned up but it’s getting replaced.
I’m buying all these hard to find and important sensors before they disappear.
I’m buying all these hard to find and important sensors before they disappear.
It's definitely a good idea. Especially if there aren't any Denso replacements available anymore.
Back to the original topic; my dashpot was the culprit behind what I noticed this morning. I drove home from work and throughout the stop and go after exiting the highway, my engine wouldn't idle down past 2000 RPM. I decided to go ahead and look at the dashpot first, and sure enough it was somehow WAY out of adjustment. Why such a sudden change after spending an entire year properly adjusted is beyond me. So to observe how my engine behaves without it, I backed the rod almost completely out of the bracket so it wouldn't even engage the dashpot. My earlier point about it helping to prevent excessive carbon buildup on the exhaust valves, coupled with the consideration that the weight of the flywheel and pressure plate would accomplish the original purpose of the dashpot makes me curious to drive it through the winter, and then inspect the valves with a boroscope when the weather warms up again to see if there's been any buildup beyond the normal expected amount. Like I earlier stated, it would be nice to be able to eliminate the dashpot completely and do away with having to replace an increasingly rare part.
Next to lubricate my throttle linkage and cable, then pull my clutch inspection cover and see if I can figure out why my clutch pedal seems to excessively hard to disengage all of a sudden. One thing after another
Next to lubricate my throttle linkage and cable, then pull my clutch inspection cover and see if I can figure out why my clutch pedal seems to excessively hard to disengage all of a sudden. One thing after another
the consideration that the weight of the flywheel and pressure plate would accomplish the original purpose of the dashpot
????? Flywheel and pressure plate have no connection to the dashpot and 2Fs have no dashpot. So to reiterate ??????
Basically reiterating a point that @torfab ventured earlier. The purpose of the dashpot is to prevent the engine from decelerating too rapidly, which could cause excess carbon monoxide emissions and foul the exhaust valves (note I said COULD). Like you said though I know carbureted Cruisers don't have a dashpot, so I wonder if the fuel injection or the use of an automatic tranny is what prompted Toyota to use a dashpot. What Tor had suggested was that the weight of the flywheel and pressure plate created enough rotational mass to keep the engine from decelerating too fast, thereby accomplishing the purpose that the dashpot was intended for and rendering it (the dashpot) unnecessary when a manual tranny is used.
So yes you're exacty right that the dashpot and flywheel/PP have no connection to each other, and I'm admittedly horrible at detailing things
Reviving thread for those who may stumble upon it. Just installed a new dashpot in my 2FE H55F, (Fuel injection on the bigger block, assume its the same as a 3FE).
My shifts where always hard in my truck, I always had to balance the clutch for as long as I can remember for smooth shifts, Its been an issue ive been chasing on and off for a while, Ive checked all my gearing backlashes and they're all in spec (Last I checked atleast) Welp I stumble around online and find this thing called a dash pot, I test mine and waddyaknow, Its bad, Missing filter, wont hold RPM.
I replaced it just now and holy smokes, no more bucking! Smoother shifting! Not perfect but noticeably better! It slows the idle down speed, Which could explain that in rare occasions my cruiser would die when I would quickly shift into neutral.
My shifts where always hard in my truck, I always had to balance the clutch for as long as I can remember for smooth shifts, Its been an issue ive been chasing on and off for a while, Ive checked all my gearing backlashes and they're all in spec (Last I checked atleast) Welp I stumble around online and find this thing called a dash pot, I test mine and waddyaknow, Its bad, Missing filter, wont hold RPM.
I replaced it just now and holy smokes, no more bucking! Smoother shifting! Not perfect but noticeably better! It slows the idle down speed, Which could explain that in rare occasions my cruiser would die when I would quickly shift into neutral.
Nice that a new dashpot solved your issue. I never was able to get my hands on a boroscope to get a visual of my exhaust valves like I wanted to do, but I haven't had any problems with my dashpot since finally getting it all dialed in and giving the throttle and cruise control cables a once-over. It's been about a year and a half, so I plan to give them a squirt of lube again before the freezing weather hits.
Something funny; my dashpot has been missing its cap and filter for a couple years now. I probably should just sack up ad get a new dashpot while I still can and keep it for a spare.
