Question for the masses...
#1
Question for the masses...
Hey all, I actually have a couple questions. As many of you know (or may not know), I have a 72 Cutlass Supreme with a slightly built 455. When I'm crusing at highway speed and stab the throttle, I'm not sure if 1) the secondaries are opening and, 2) if the kickd toown solenoid is engaging. I'm thinking it should throw me back in the seat, but I'm not getting that burst of acceleration like I think I should. The carb is a 670 Holley Street Avenger with vacuum secondaries, and from what the previous owner told me, it was recently installed new. As far as the solenoid, .the car upshifts and downshifts fine, so I'm not sure if maybe there's another issue with the solenoid, or does it seem like I'm overthinking this?
So if anyone could point the direction I need to go, I would appreciate it.
Dave
So if anyone could point the direction I need to go, I would appreciate it.
Dave
Last edited by 72455; September 28th, 2018 at 06:10 PM.
#3
I was gonna say, 570 CFM seems a little small for a 455, especially if it's "slightly built". The Street Avenger is a great carb, and I know they come in 770 and 870 CFM. They come with spring kits to adjust the secondary rate of opening, so if you're determined to keep your 570 you should be able to get one of these kits from Holley.
Your tach (or ears) should tell you whether or not the kickdown is working. Have you tried downshifting manually?
Your tach (or ears) should tell you whether or not the kickdown is working. Have you tried downshifting manually?
#4
#5
I was gonna say, 570 CFM seems a little small for a 455, especially if it's "slightly built". The Street Avenger is a great carb, and I know they come in 770 and 870 CFM. They come with spring kits to adjust the secondary rate of opening, so if you're determined to keep your 570 you should be able to get one of these kits from Holley.
Your tach (or ears) should tell you whether or not the kickdown is working. Have you tried downshifting manually?
Your tach (or ears) should tell you whether or not the kickdown is working. Have you tried downshifting manually?
Last edited by 72455; September 28th, 2018 at 02:50 AM.
#6
The suggestion was intended as a first step in trouble-shooting. If you downshift manually during full acceleration and you feel a burst of power, then your automatic downshift is not working.
In that case, let us know which transmission you have so we can help you identify the problem.
In that case, let us know which transmission you have so we can help you identify the problem.
#7
The suggestion was intended as a first step in trouble-shooting. If you downshift manually during full acceleration and you feel a burst of power, then your automatic downshift is not working.
In that case, let us know which transmission you have so we can help you identify the problem.
In that case, let us know which transmission you have so we can help you identify the problem.
#8
Wait a minute - how fast are you going at these "highway speeds" and what rear gears do you have? Depending upon these parameters, the engine may be above the safe downshift RPM point.
Try this instead:
1) Cruise along at a steady 35 MPH and punch it. That will be low enough speed for the trans to safely downshift (to either 1st or 2nd, depending upon the rear gear ratio).
2) From a stop, manually shift into 1st gear and drive at a steady speed, then go WOT. If the secondaries are opening properly, you will feel it.
Try this instead:
1) Cruise along at a steady 35 MPH and punch it. That will be low enough speed for the trans to safely downshift (to either 1st or 2nd, depending upon the rear gear ratio).
2) From a stop, manually shift into 1st gear and drive at a steady speed, then go WOT. If the secondaries are opening properly, you will feel it.
#9
Wait a minute - how fast are you going at these "highway speeds" and what rear gears do you have? Depending upon these parameters, the engine may be above the safe downshift RPM point.
Try this instead:
1) Cruise along at a steady 35 MPH and punch it. That will be low enough speed for the trans to safely downshift (to either 1st or 2nd, depending upon the rear gear ratio).
2) From a stop, manually shift into 1st gear and drive at a steady speed, then go WOT. If the secondaries are opening properly, you will feel it.
Try this instead:
1) Cruise along at a steady 35 MPH and punch it. That will be low enough speed for the trans to safely downshift (to either 1st or 2nd, depending upon the rear gear ratio).
2) From a stop, manually shift into 1st gear and drive at a steady speed, then go WOT. If the secondaries are opening properly, you will feel it.
#12
That is not too fast for a kick down. My typical run up in a car with 2.73 rear, stock 350, and quadrajet, is to be sitting at about 2000 at 60, punch it, downshift to second (up to ~3000) then hang on until redline shift at 4500 at 90, then it shifts to third on its own and I'm at 3200 rpm at 90 or so in high, and there's plenty more power to take me to 100, where I chicken out.
Do you have a tach? Can you temporarily install one if not? At 70 in 3rd you should be, with that rear @2800 rpm. In 2nd, you'd go to 3800. Definitely punching it at 60 would make it downshift, unless something is wrong.
Do you have a tach? Can you temporarily install one if not? At 70 in 3rd you should be, with that rear @2800 rpm. In 2nd, you'd go to 3800. Definitely punching it at 60 would make it downshift, unless something is wrong.
#13
That is not too fast for a kick down. My typical run up in a car with 2.73 rear, stock 350, and quadrajet, is to be sitting at about 2000 at 60, punch it, downshift to second (up to ~3000) then hang on until redline shift at 4500 at 90, then it shifts to third on its own and I'm at 3200 rpm at 90 or so in high, and there's plenty more power to take me to 100, where I chicken out.
Do you have a tach? Can you temporarily install one if not? At 70 in 3rd you should be, with that rear @2800 rpm. In 2nd, you'd go to 3800. Definitely punching it at 60 would make it downshift, unless something is wrong.
Do you have a tach? Can you temporarily install one if not? At 70 in 3rd you should be, with that rear @2800 rpm. In 2nd, you'd go to 3800. Definitely punching it at 60 would make it downshift, unless something is wrong.
I say that because I don't feel the kick.
#15
#17
A kickdown going from 2800 to 3600 or so on a 455 will be noticeable. You will see the RPM jump 1000 or so in a second, and the engine will go:
burrrrrrrrr-BLAAAAAAAAAAAAAAH. I had a car which did not downshift. Removing the carb and working on some other issues cured it.
I would start troubleshooting the kickdown circuit. Could be something as easy as a disconnected wire.
#18
Don't need to feel the kick, watch the gauge, and put the windows down. If it just sounds like it's accelerating, then your kickdown is not working.
A kickdown going from 2800 to 3600 or so on a 455 will be noticeable. You will see the RPM jump 1000 or so in a second, and the engine will go:
burrrrrrrrr-BLAAAAAAAAAAAAAAH. I had a car which did not downshift. Removing the carb and working on some other issues cured it.
I would start troubleshooting the kickdown circuit. Could be something as easy as a disconnected wire.
A kickdown going from 2800 to 3600 or so on a 455 will be noticeable. You will see the RPM jump 1000 or so in a second, and the engine will go:
burrrrrrrrr-BLAAAAAAAAAAAAAAH. I had a car which did not downshift. Removing the carb and working on some other issues cured it.
I would start troubleshooting the kickdown circuit. Could be something as easy as a disconnected wire.
#22
Wait a minute - how fast are you going at these "highway speeds" and what rear gears do you have? Depending upon these parameters, the engine may be above the safe downshift RPM point.
Try this instead:
1) Cruise along at a steady 35 MPH and punch it. That will be low enough speed for the trans to safely downshift (to either 1st or 2nd, depending upon the rear gear ratio).
Try this instead:
1) Cruise along at a steady 35 MPH and punch it. That will be low enough speed for the trans to safely downshift (to either 1st or 2nd, depending upon the rear gear ratio).
#23
Wait a minute - how fast are you going at these "highway speeds" and what rear gears do you have? Depending upon these parameters, the engine may be above the safe downshift RPM point.
Try this instead:
2) From a stop, manually shift into 1st gear and drive at a steady speed, then go WOT. If the secondaries are opening properly, you will feel it.
Try this instead:
2) From a stop, manually shift into 1st gear and drive at a steady speed, then go WOT. If the secondaries are opening properly, you will feel it.
#24
#25
Do as suggested. Or you can wire the secondaries shut and see what effect that has as well.
#28
Yes, that is the switch.
First, check the switch. A test light would be ideal, but sometimes the following gives enough information. Slowly push the cream-colored slider by hand--you should hear a faint click when the switch actuates. If you don't hear the click, you will need to use a test light and repeat the check.
Next, try the same thing by slowly pushing the gas pedal. You should hear the same faint click. You can figure out from these two tests if the accelerator pedal is actuating the switch.
You can physically adjust the position of the switch to make the downshift occur sooner or later. (I don't recall exactly how to do the adjustment, but I know it is apparent if you inspect closely.)
First, check the switch. A test light would be ideal, but sometimes the following gives enough information. Slowly push the cream-colored slider by hand--you should hear a faint click when the switch actuates. If you don't hear the click, you will need to use a test light and repeat the check.
Next, try the same thing by slowly pushing the gas pedal. You should hear the same faint click. You can figure out from these two tests if the accelerator pedal is actuating the switch.
You can physically adjust the position of the switch to make the downshift occur sooner or later. (I don't recall exactly how to do the adjustment, but I know it is apparent if you inspect closely.)
#29
Hey Koda,
How is that ride if you get up around 120 ? . . . . post #12
I ask because when you mentioned "chicken-out" at 100, I chuckled because I have been driving a Subaru WRX for 11-years, and it scoots to 100 real easy, and then _ _ _
the little car begins to feel LIGHT if you know what I mean, and that is where I normally "chicken-out" especially if there is a slight curve ahead ! hahaha
I am actually 'chicken' of finding out if it is truly governed at 142. _ _ _ a slight drift to the gravel shoulder followed by a rollover would be Catastrophic even at 100.
I wonder if 72455 got his kick-down switch working ?
Len
How is that ride if you get up around 120 ? . . . . post #12
I ask because when you mentioned "chicken-out" at 100, I chuckled because I have been driving a Subaru WRX for 11-years, and it scoots to 100 real easy, and then _ _ _
the little car begins to feel LIGHT if you know what I mean, and that is where I normally "chicken-out" especially if there is a slight curve ahead ! hahaha
I am actually 'chicken' of finding out if it is truly governed at 142. _ _ _ a slight drift to the gravel shoulder followed by a rollover would be Catastrophic even at 100.
I wonder if 72455 got his kick-down switch working ?
Len
Last edited by Greaser007; October 16th, 2018 at 07:10 PM.
#30
I hear the "click" when I move the switch by hand and when I press the gas pedal, but still no sudden jump off the tach when I stab the throttle .I also slid a piece of hose over the slider to see if the switch would engage sooner. What else should I troubleshoot?
Last edited by 72455; October 16th, 2018 at 07:32 PM.
#31
Make sure you have 12 volts to one wire of the switch when the throttle is at the idle position and then make sure it has 12 volts on both sides of the switch when the throttle is fully depressed. If yes to both, then follow the wire that goes down to the transmission and make sure the 12 volts is getting to the trans when fully depressed.
#32
Make sure you have 12 volts to one wire of the switch when the throttle is at the idle position and then make sure it has 12 volts on both sides of the switch when the throttle is fully depressed. If yes to both, then follow the wire that goes down to the transmission and make sure the 12 volts is getting to the trans when fully depressed.
#33
Thanks for the advice. What I'm going to do is turn the ignition on (but not start the car...don't wanna upset the neighbors...lol) then press the pedal and listen for the solenoid to click. If it does, then I'm guessing it would be a vacuum issue, correct? If the solenoid doesn't click then I will back track and check for voltage. Hopefully I won't have to replace the solenoid.
If you don't hear the solenoid click, you need to check for voltage, working backward or forward in the circuit. There is no vacuum involved with this kickdown problem.
As cjsdad said, check for 12 V at both terminals of the accelerator pedal switch when the switch clicks.
If that part is OK, disconnect the electrical connector on the side of the transmission and check for 12 V supply when the switch clicks.
If you don't get 12 V at the transmission, figure out where the voltage is stopping and fix or replace that wire or terminal.
If you get 12 V at the transmission, check to see if both sides of the connection are corrosion-free and the female terminal inside the electrical plug fits snugly to the electrical tang on the transmission . If all that checks out, replace the solenoid inside the transmission. Removing the pan is the messiest part. Once you have done that it's easy to replace the solenoid.
#34
Please forgive the late reply -- I didn't notice you called me out until now. The reason I brought that up is that there had been some conjecture about whether a 670 CFM Street Avenger would be a big enough carburetor for a 455. I thought my experience using one on a much smaller engine might be helpful in proving that it's probably too small. Sorry if I didn't make that clear in my post.
#35
Dave,
Once you get the kickdown working properly, you'll have a Big smile on your face
and earned a run down to the burger stand for a cheeseburger and fries. _ _ no romping on-it. hahaha
Once you get the kickdown working properly, you'll have a Big smile on your face
and earned a run down to the burger stand for a cheeseburger and fries. _ _ no romping on-it. hahaha
#36
Please forgive the late reply -- I didn't notice you called me out until now. The reason I brought that up is that there had been some conjecture about whether a 670 CFM Street Avenger would be a big enough carburetor for a 455. I thought my experience using one on a much smaller engine might be helpful in proving that it's probably too small. Sorry if I didn't make that clear in my post.
#37
Hey Koda,
How is that ride if you get up around 120 ? . . . . post #12
I ask because when you mentioned "chicken-out" at 100, I chuckled because I have been driving a Subaru WRX for 11-years, and it scoots to 100 real easy, and then _ _ _
the little car begins to feel LIGHT if you know what I mean, and that is where I normally "chicken-out" especially if there is a slight curve ahead ! hahaha
I am actually 'chicken' of finding out if it is truly governed at 142. _ _ _ a slight drift to the gravel shoulder followed by a rollover would be Catastrophic even at 100.
I wonder if 72455 got his kick-down switch working ?
Len
How is that ride if you get up around 120 ? . . . . post #12
I ask because when you mentioned "chicken-out" at 100, I chuckled because I have been driving a Subaru WRX for 11-years, and it scoots to 100 real easy, and then _ _ _
the little car begins to feel LIGHT if you know what I mean, and that is where I normally "chicken-out" especially if there is a slight curve ahead ! hahaha
I am actually 'chicken' of finding out if it is truly governed at 142. _ _ _ a slight drift to the gravel shoulder followed by a rollover would be Catastrophic even at 100.
I wonder if 72455 got his kick-down switch working ?
Len
It was getting a little light at 100 in the steering and starting to sway. I imagine 110 would be fun, 120 might be scary.
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