My Desmog Thread (2 Viewers)

[S4Cruiser]

Drove 40 to work this AM...still some pinging (or what I assume is pinging...I don't hear it free revving the engine but do under load but not always like I did before).

Will retard timing slightly this evening to see if that remedies my issue.

I'm assuming there is no huge risk to drive the truck with slight pinging? I'm going max 45 mph and my commute home is less then 10 miles (I've put all of 50 miles on this truck since rebuilding).

 

[FJ40Jim]

If you have a 12mm wrench with you, loosen the dissy and twist clockwise a few degrees, before driving home.

Having recently presided at the autopsies of two dead engines killed by detonation, any audible pinging should be avoided.

 

[S4Cruiser]

OK...was able to procure a wrench to loosen and rotate dizzy slightly clockwise before lunch...noise is unchanged.

Maybe I'm actually dealing with an exhaust manifold leak??? Sounds very similar to the video below - which is NOT of my truck just a random youtube video.

 

[Ian Crawford]

Does it consistently sound the same through the RPM range? As the engine speeds up and slows down it's always the same?

Typically a ping is apparent when the engine is under load.

 

[S4Cruiser]

Does it consistently sound the same through the RPM range? As the engine speeds up and slows down it's always the same?

Typically a ping is apparent when the engine is under load.

The sound speeds up as rpms increase. For instance, if I remove pressure from the throttle the noise stops. Add back pressure, noise resumes. I can try to video on the way home this evening.

 

[Ian Crawford]

You could be dealing with an exhaust leak!

 

[S4Cruiser]

Retarded the timing a bit more before driving home to the point it didn’t drive the greatest. No change.

Got home...checked valves and made slight adjustments (initially set them cold a couple weeks ago) then swapped in JimC new rebuilt/recurved dizzy. Set timing to 7* and connected to the inner pot. Took for test drive around the neighborhood and...no change.

Next steps or assume it’s an exhaust leak?

I attempted to record test drive via my phone but it didn’t do a good job picking up the noise. It did do a great job picking up my just now squealing throwout bearing

Also having an issue with carb not returning to idle when stopped unless I tap the throttle and then it returns to idle.

 

[S4Cruiser]

^^^^^ yay / nay?

 

[Ian Crawford]

Having to tap the throttle to return to idle, I'd make sure you still have the return spring on the throttle linkage, if you do make sure it isn't stretched.

My bet is an exhaust leak. From a cold start you can get your hands or fingers in near the exhaust manifold gasket and feel for leaks if it is on top.

 

[mattressking]

Just checking in to say thanks to those that have done the legwork prior. Successfully desmogged my truck, kept the VCV for distributor vent and evap and using BVSV (1) for the evap vent. Also kept choke opener/breaker since they both function currently. Air cleaner is non-USA unit, non-USA 3F fj62 pcv hardline and Jim’s egr block off.

Truck runs silky smooth for a tractor motor. I'm considering a drop to a 138 1st main jet since that is what I see is the typical size for non-smogged trucks, where the 2nd main is consistently always 200, in some occasions I've seen 220 for certain 62 carbs...not worried about that. I still need to pull manifold off and make sure its sealed up well, but I usually hold about 20.5inHG so I haven't had a major driving force to take the truck off the road to machine and reseal, but it will happen as I find some free time to have the truck down for a few days.

Now one part I am curious about. I noticed on the USA carb we have the HAC port which is either threaded or pressed into the carb base, I didn’t attempt to remove at the time. I would assume threaded due to one flat being machined into the port. I also noticed the non-USA carb has the exact same fitting/location and one could assume it is removable and the port off the USA carb could be swapped over....effectively utilizing HAC on a non-USA carb. Anyone else noticed/attempted/have a spare carb to see? I don’t have one of the city racer reps or oem non-USA carbs to review.

 

[Gsw234]

Just checking in to say thanks to those that have done the legwork prior. Successfully desmogged my truck, kept the VCV for distributor vent and evap and using BVSV (1) for the evap vent. Also kept choke opener/breaker since they both function currently. Air cleaner is non-USA unit, non-USA 3F fj62 pcv hardline and Jim’s egr block off.

Truck runs silky smooth for a tractor motor. I'm considering a drop to a 138 1st main jet since that is what I see is the typical size for non-smogged trucks, where the 2nd main is consistently always 200, in some occasions I've seen 220 for certain 62 carbs...not worried about that. I still need to pull manifold off and make sure its sealed up well, but I usually hold about 20.5inHG so I haven't had a major driving force to take the truck off the road to machine and reseal, but it will happen as I find some free time to have the truck down for a few days.

Now one part I am curious about. I noticed on the USA carb we have the HAC port which is either threaded or pressed into the carb base, I didn’t attempt to remove at the time. I would assume threaded due to one flat being machined into the port. I also noticed the non-USA carb has the exact same fitting/location and one could assume it is removable and the port off the USA carb could be swapped over....effectively utilizing HAC on a non-USA carb. Anyone else noticed/attempted/have a spare carb to see? I don’t have one of the city racer reps or oem non-USA carbs to review.

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@mattressking I'm curious why you're not keeping the HAC? Never travel to higher altitude? I'm currently desmogging mine. I need to source a vacuum hose tee that is spoken of when connecting the HAC to the carb and gas filter.

 

[mattressking]

@mattressking I'm curious why you're not keeping the HAC? Never travel to higher altitude? I'm currently desmogging mine. I need to source a vacuum hose tee that is spoken of when connecting the HAC to the carb and gas filter.

The end goal is to keep HAC, i pulled it to simplify and when i have trips that take me into 3500+ I’ll just pop it on. I’d like to run the non-USA carb with hac and a recurved distributor with this motor ultimately.

 

[mattressking]

@mattressking I'm curious why you're not keeping the HAC? Never travel to higher altitude? I'm currently desmogging mine. I need to source a vacuum hose tee that is spoken of when connecting the HAC to the carb and gas filter.

Literally just a vac tee? I have a bunch of spares off other Toyota’s in my parts bin but can also get you a pn to buy new if you’d like.

 

[Spike Strip]

I'm currently playing with a 1.38 primary and, according to the A/F meter at least, it runs waaaay lean compared to the normal 1.47 - I only swap out the jet as a last resort when having trouble passing smog, then replace after. But at the same time I swapped in a new Smog Pump so it may just be pushing more air through the system now, too.

Is the CAT still there? Generally, with new RFG and even worse, Kalif-blend smog-district gas, you prolly need a bit richer than that for driveability.

I don't know if that HAC throttle body port is pressed in or threaded, my guess is pressed since that's what all those other ports are, but I've never tried to remove one. Would be nice to know if it's possible!

I'm sooooo envious of clean smog-crap-free engine bays!

 

[mattressking]

I'm currently playing with a 1.38 primary and, according to the A/F meter at least, it runs waaaay lean compared to the normal 1.47 - I only swap out the jet as a last resort when having trouble passing smog, then replace after. But at the same time I swapped in a new Smog Pump so it may just be pushing more air through the system now, too.

Is the CAT still there? Generally, with new RFG and even worse, Kalif-blend smog-district gas, you prolly need a bit richer than that for driveability.

I don't know if that HAC throttle body port is pressed in or threaded, my guess is pressed since that's what all those other ports are, but I've never tried to remove one. Would be nice to know if it's possible!

I'm sooooo envious of clean smog-crap-free engine bays!

I'd love to hook a wideband up to watch a/f while driving...you could be very correct that dropping to a 138 would be too lean even with desmog. I've been watching my new plugs and they are burning in nicely, want to give it a couple more thousand miles and see how they look.

 

[FJ40Jim]

The idle plug is not threaded, it is pressed in. There is a shape to it on the inside, so the external flat is there to be sure it is clocked correctly when pressed in. To permanently remove the HAC elbow, twist and pull. A 3.5?mm ball bearing can be whacked into the AL plug to close the hole.

As reported by @Spike Strip, for operation below 2000'ASL the 147 is the right size or possibly a 1.50, which is found in 81-82 carbs.

 

[ace7141]

Is there anything I should put onto the threads of the plugs (from Jim C. Plug Kit) going into the BVSV 1 and BVSV 2 holes?

 

[Spike Strip]

Is there anything I should put onto the threads of the plugs (from Jim C. Plug Kit) going into the BVSV 1 and BVSV 2 holes?

Best to use some thread sealant or pipe joint compound, or Teflon pipe tape or RTV in a pinch. But I believe those are pipe thread so they're supposed to seal without it, but you'll be unhappy if they weep.

 

[ace7141]

Roger that, thanks a on!!

 

[Gsw234]

Hey guys - question for you. I just finished my desmog with parts from JimC. All has gone fairly smoothly. I'm still awaiting a rebuilt carb and recurved dissy from him, but that may be month more. So in the meantime I'm doing what I can to get this running well.
Started up today, 5degrees F, and ran for about 10 minutes. It was a little rough. I've adjusted the timing. Then I noticed some loud muffler noises and looked down and saw the catalytic converter was red hot!

1. What is causing the red hot cat? Just way too rich?
2. Would it be beneficial to remove the cat? (Think I damaged it?)
3. What is the ideal timing on a desmogged rig? 7 degrees?
4. Why is it running so rich? Stock carb, with screw still capped from factory. (it was running rich before desmog, but I never noticed a red hot cat)

Thanks for all the help guys!!