Loss of power, torque, dead spot, hesitation whatever you want to call it!

fjc-man

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micruz60, just to keep confusion to a minimum. You were referring to blocking off the J - pipe at the exhaust manifold opening with a plate and gasket, right? So if the EGR valve has no vacuum source to open the valve you could just leave the EGR plumbing ( minus the J pipe ) in place.
 
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Beat it with a hammer while revving the engine might dislodge some carbon and free it. This has worked for me in the past. You may want to research this...not sure it the carbon will end up going straight into the intake and cause some other problems. A more conservative approach would be to remove the EGR valve and soak it with some kind of solvent. It's a major pain to break those large nuts loose. I believe one is a 27mm. I recently yanked my entire EGR system from the exhaust to overhaul it. It was a major pain to get out. It would be much easier to pull the dizzy and replace the springs, advance the timing and just leave the top vacuum line disconnected from the EGR valve.

Check out post #154 in this thread on page 8. I have the springs but not installed yet. If I can't get my EGR system to work I may try this.

I would be terrified to do that dizzy work! I can barely time a 60 right. I fear even pulling the dizzy from the block. And never get it back together right
 

g-man

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If the EGR is closed right now isn’t it blocked essentially or no?
Yes, if the EGR is clogged and closed then the exhaust gasses are blocked at the EGR valve. But I would disable it by disconnecting the top vacuum line. That way if you hit a hard bump and free the carbon and the valve starts working going down the road, it doesn't screw up your new dizzy curve and timing advance. Make sure you cap the Q port on the modulator though because it will be a source of a vacuum leak at certain rpms and engine temps. Q gets vacuum from ports P and R.

My understanding is that port P on the modulator gets vacuum from the carb (EDIT) really from the vacuum pipe it shares with the vacuum advancer line just downstream from the BVSV once the temp warms up and past a certain throttle position. Port R gets vacuum from the another port on the carb but opens via the EGR VSV which opens from a signal from the emissions control board/IG coil and the BVSV

1653133001717.png
 
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g-man

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When you pull the dizzy just make sure the pointer goes back in facing the same exact direction. Line it up with a spark plug or a 10 mm bolt on the side plate cover. And put it back the same way. It will turn a little as it comes out and again when it goes back. disconnect the green plug that sends signal to the coil. Once it's out you can clean up any carbon or sludge on the gear. Take the signal generator cover off ...just a plastic cover, pull the signal generator off and the breaker plate comes out with removal of a couple of retainer screws. The hardest part for me was breaking the advancer port screw loose. It is a retainer screw on the side of the dizzy. It was frozen on and I had to drive a socket over it to get it to turn. But the advancer had to come out first. Once you get the breaker plate out take it apart over a white cloth or rag. Lots of small bearings, clean it up, regrease and before you put it back go ahead and replace the stop pin bushing and the springs. If you can do a valve adjustment you can do this.
 
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When you pull the dizzy just make sure the pointer goes back in facing the same exact direction. Line it up with a spark plug or a 10 mm bolt on the side plate cover. And put it back the same way. It will turn a little as it comes out and again when it goes back. disconnect the green plug that sends signal to the coil. Once it's out you can clean up any carbon or sludge on the gear. Take the signal generator cover off ...just a plastic cover, pull the signal generator off and the breaker plate comes out with removal of a couple of retainer screws. The hardest part for me was breaking the advancer port screw loose. It is a retainer screw on the side of the dizzy. It was frozen on and I had to drive a socket over it to get it to turn. But the advancer had to come out first. Once you get the breaker plate out take it apart over a white cloth or rag. Lots of small bearings, clean it up, regrease and before you put it back go ahead and replace the stop pin bushing and the springs. If you can do a valve adjustment you can do this.
Is there a link to the stop pin bushing?
 
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Yes, if the EGR is clogged and closed then the exhaust gasses are blocked at the EGR valve. But I would disable it by disconnecting the top vacuum line. That way if you hit a hard bump and free the carbon and the valve starts working going down the road, it doesn't screw up your new dizzy curve and timing advance. Make sure you cap the Q port on the modulator though because it will be a source of a vacuum leak at certain rpms and engine temps. Q gets vacuum from ports P and R.

My understanding is that port P on the modulator gets vacuum from the carb (passenger side) once the throttle plate opens to a certain degree. And port R gets vacuum from the another port on the carb but opens via the EGR VSV which opens from a signal from the emissions control board/IG coil and the BVSV

View attachment 3014610
Cap it like this?

CB64C0ED-1B1F-4D11-A9C8-1C9CEE1BBCA8.jpeg
 

g-man

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No real need to cap the metal EGR valve that I am aware of. It's just a port for vacuum hose to pull vacuum to move the diaphragm. Capping the modulator is the right move because it will open up and cause a vacuum leak at certain throttle positions unless you cap two of the vacuum ports on the side of your carb near the advancer port. Those are the same vacuum ports where the vacuum source originates that ultimately ends where you capped (Q port on the modulator)
 

g-man

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No real need to cap the metal EGR valve that I am aware of. It's just a port for vacuum hose to pull vacuum to move the diaphragm. Capping the modulator is the right move because it will open up and cause a vacuum leak at certain throttle positions unless you cap two of the vacuum ports on the side of your carb near the advancer port. Those are the same vacuum ports where the vacuum source originates that ultimately ends where you capped (Q port on the modulator)
Another better way to do this would be to plug the EGR R port on the passenger side of the dizzy shown here:
1653157617689.png


And...plug the #1 metal vacuum pipe that goes to port P on the modulator. show here (as number one) where the big white arrow is pointing. the dots are a visual looking at the ends of the vacuum pipes. Just follow the P port hose from modulator over to it.

1653157682929.png


I say this is better because less chance of a vacuum developing in a line or hose that is really going nowhere at this point.. You could remove and sell your modulator and EGR VSV...they are NLA.
 
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Ok got everything dialed and working good. Did a valve adjustment and they were all tight. So loosened them to spec and buttoned everything up. I have a ping now. Did a lean drop again because I assumed more vacuum was the issue. Lean drop didn’t help.

When I took off the top of the air cleaner off for the 456th time I noticed a loose vac hose. I can’t see where it ends up and hopefully it helps the pinging.

6581ACD2-0205-47A2-818C-22EAAAD8C310.jpeg
 
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Ok got everything dialed and working good. Did a valve adjustment and they were all tight. So loosened them to spec and buttoned everything up. I have a ping now. Did a lean drop again because I assumed more vacuum was the issue. Lean drop didn’t help.

When I took off the top of the air cleaner off for the 456th time I noticed a loose vac hose. I can’t see where it ends up and hopefully it helps the pinging.

View attachment 3015805
I found it it was the advancer port. so now that that is hooked up do I re time?
 
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AT THE END OF MY ROPE! Got the port hooked up withe vacuum line, checked timing it was right on. Re-lean dropped. Pings like crazy under load. I do not get it. Idles really smooth. its at 21 for vacuum. seems Fuel related? Has a newish Toyota fuel pump, 1/2 full on the site glass window, fuel filter in new and just over half full.
When I did the Valve adjustment everything was tight. I assume if something was left loose it wouldn't idle and the vacuum wouldn't be were it is. IF ANY ONE HAS A IDEA I" ALL EARS!
 
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If I run like 3 degrees advance and see if the ping goes away or lessens. would that solidify the stop pin is bad in my dizzy?
 
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Timing@1 degree advance. Not as much pinging but still there. Before I did my valve adjustment and after I figured out my timing it ran great. But the vacuum was aroun16-17 and the needle was bouncing. So then I adjust valves they were all to tight. Then the pinging happened but my vacuum was at 21. Help!
 

OSS

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I haven’t re-read this thread but if the EGR valve is inop but the distributor vacuum advancer vacuum hose is connected as per the factory — engine will ping like hell under certain RPMs & load.

Just for giggles sake, swap the vacuum hoses on the two vacuum advancer diaphragms on the distributor and take it for a test ride - after setting the timing back to 7° BTDC factory spec.

Does the pinging go away?
 
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I haven’t re-read this thread but if the EGR valve is inop but the distributor vacuum advancer vacuum hose is connected as per the factory — engine will ping like hell under certain RPMs & load.

Just for giggles sake, swap the vacuum hoses on the two vacuum advancer diaphragms on the distributor and take it for a test ride - after setting the timing back to 7° BTDC factory spec.

Does the pinging go away?
I will do this and report back to you.

One thing that I noticed I have vacuum at idle on the secondary vacuum port (away from the engine). No vacuum at idle at the primary.

Normal?
 

g-man

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I don't think normal, unless you are over 4k ft in elevation. You should download a 2f emissions manual. There is a free download in the Resources section at the top. Look over the HAC section starting on pg 3-31 on how to test the HAC. Also re check your vacuum lines at the piping and at the passenger side of the carb. pg 3-3.
 

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