Very interesting take on explaining dwell. Ive worked with compu-quads in the past, cant say im a fan, but i have worked on them. We used a thin ruler to keep the tps plunger down when reinstalling the air horn, so not to break it. Good video!
The (MCS) Operate in a way that it is somewhat like a wave length, it pulses more to pull the rods in (lean) and less to richen the mixture, on cold startup (closed loop) the computer ignores the signals, as the engine heats up (open loop) the computer is controlling and monitoring all functions. I look at the CCC Feedback system as a Pre-fuel injection system.
Hi I have a computer controlled Quadrajet on my ‘86 Chevy c10 I’m having problems with. It doesn’t want to idle after it gets warm. Starts up great, but after driving around a little or just idling it runs super rough and wants to die unless you push down on the gas pedal a little. Any thoughts on what it could be? I’ve replaced the EGR valve, map sensor, pvc valves, O2 sensor, plugs/wires.
So my carb use to make the ticking sound when the key was turned on but not started. Now it doesn't and I'm getting code 45 which is O2 sensor , rich condition, I have replaced the 02 sensor but no joy. Is the mcs stuck ? and can it be unstuck. Or can it be replaced. Does the ecm control it ? This is on a 84 El Camino 305.
The MCS cannot be unstuck. It must be replaced. Sounds like the rods the MCS controls are locked in the up position/ out of the jets. The ECM does control the MCS. It's an easy component to replace. There's a vid on YT of how to replace it. I think Classic G Body Garage made it.
It does sound like you're having a problem with the MC solenoid. It's an easy fix. I'd replace it with a new one from Ebay. I'd also try to free up the assembly, while you're in there. Some Scotchbrite and WD-40 should do the trick. Once you've got it moving again, make sure you recalibrate everything before you put the air horn back on.
Another great video! If you were in Europe, I'd pay you to come look at my '86 Caprice with the CCC Quadrajet. I still have the stalling when cold issue. This issue appeared after my alternator died, which I have since fixed. However, it still stalls even now. I noticed today that 2 screws are missing on the electric choke; with the screw housing broken off and missing on of them. So there's just 1 screw holding the choke in, and I can rotate it by hand to some extent. Surely this isn't good, but could it explain the stalling on a cold start? If I keep my foot on the pedal a bit for 2-3 minutes, it eventually settles into an acceptable idle.
Thank you! The choke issue may explain your cold start problem. If the choke can't stay closed as far or as long as it needs to be, you would expirence a stalling issue when the engine is cold. I would take the air cleaner off and watch the choke valve during a cold start. Make sure it closes fully after you pump the gas pedal, then start the car. It should open slightly as the vacuum breaks engage, but you should still feel it "holding" itself closed for a minute or 2 until things warm up.
I have removed the cat and air pump from my 85 t/a ,305, automatic tranny. will the tps and metering rod sensor still operate the same with the computer or would it be wise to go to a non electronic quadrajet and eliminate computer control for better operating performance and to eliminate a rich condition?
In most cases, getting rid of the air pump really shouldn't affect the computer too much. It may run a little rich at start-up, but it should even out as it warms up. I would leave it as is and see what happens. You can always change it out down the road. Plus, this way, you won't have to make changes to the lock-up torque converter, which is controlled by the computer.
The dwell he is referring to for the MCS, mixture control Solenoid. See this video where he explains setting the mixture using a dwell meter. (Same tool for engine timing - but used on a different part of car).
I think you might be referring to the choke angle, which is still fully adjustable. I may have been unclear about that. My apologies. On the older choke, you could actually rotate the internals, to set the length of time the choke stays open or closed. turning it to the lean side would result in the choke opening sooner, the rich side would result in it opening later.
That's right. On the older model chokes, you could adjust it by turning the internals left or right to increase or decrease the amount of time it stayed opened or closed. The later model chokes were non-adjustable, meaning the amount of time they stayed closed was unable to be changed.
Very interesting take on explaining dwell. Ive worked with compu-quads in the past, cant say im a fan, but i have worked on them. We used a thin ruler to keep the tps plunger down when reinstalling the air horn, so not to break it. Good video!
Thank you!
Great idea! I just fought one back together last night and it was a bear!
You forgot to mention that quadrajet roar man i luv that sound❤
How do you test the electronic parts for proper operation?
The (MCS) Operate in a way that it is somewhat like a wave length, it pulses more to pull the rods in (lean) and less to richen the mixture, on cold startup (closed loop) the computer ignores the signals, as the engine heats up (open loop) the computer is controlling and monitoring all functions. I look at the CCC Feedback system as a Pre-fuel injection system.
Hi I have a computer controlled Quadrajet on my ‘86 Chevy c10 I’m having problems with. It doesn’t want to idle after it gets warm. Starts up great, but after driving around a little or just idling it runs super rough and wants to die unless you push down on the gas pedal a little. Any thoughts on what it could be?
I’ve replaced the EGR valve, map sensor, pvc valves, O2 sensor, plugs/wires.
So my carb use to make the ticking sound when the key was turned on but not started. Now it doesn't and I'm getting code 45 which is O2 sensor , rich condition, I have replaced the 02 sensor but no joy. Is the mcs stuck ? and can it be unstuck. Or can it be replaced. Does the ecm control it ? This is on a 84 El Camino 305.
The MCS cannot be unstuck. It must be replaced. Sounds like the rods the MCS controls are locked in the up position/ out of the jets. The ECM does control the MCS. It's an easy component to replace. There's a vid on YT of how to replace it. I think Classic G Body Garage made it.
@@toecuttre Thank you for the quick reply. I'll hunt down the vid.
It does sound like you're having a problem with the MC solenoid. It's an easy fix. I'd replace it with a new one from Ebay. I'd also try to free up the assembly, while you're in there. Some Scotchbrite and WD-40 should do the trick. Once you've got it moving again, make sure you recalibrate everything before you put the air horn back on.
Just came back to say I did replace the mcs and things are back to normal, no cel
Another great video! If you were in Europe, I'd pay you to come look at my '86 Caprice with the CCC Quadrajet. I still have the stalling when cold issue. This issue appeared after my alternator died, which I have since fixed. However, it still stalls even now.
I noticed today that 2 screws are missing on the electric choke; with the screw housing broken off and missing on of them. So there's just 1 screw holding the choke in, and I can rotate it by hand to some extent. Surely this isn't good, but could it explain the stalling on a cold start? If I keep my foot on the pedal a bit for 2-3 minutes, it eventually settles into an acceptable idle.
Thank you!
The choke issue may explain your cold start problem. If the choke can't stay closed as far or as long as it needs to be, you would expirence a stalling issue when the engine is cold. I would take the air cleaner off and watch the choke valve during a cold start. Make sure it closes fully after you pump the gas pedal, then start the car. It should open slightly as the vacuum breaks engage, but you should still feel it "holding" itself closed for a minute or 2 until things warm up.
Can you still use this carb after deleting the emissions, computer, etc? Or would the carb just stay stuck on lean or rich
It wouldn't work. You're gonna have to replace it with a mechanical Quadrajet.
I have removed the cat and air pump from my 85 t/a ,305, automatic tranny. will the tps and metering rod sensor still operate the same with the computer or would it be wise to go to a non electronic quadrajet and eliminate computer control for better operating performance and to eliminate a rich condition?
In most cases, getting rid of the air pump really shouldn't affect the computer too much. It may run a little rich at start-up, but it should even out as it warms up. I would leave it as is and see what happens. You can always change it out down the road. Plus, this way, you won't have to make changes to the lock-up torque converter, which is controlled by the computer.
Why would your dwell change if you’re adjusting fuel/air and not timing or electronic?
The dwell he is referring to for the MCS, mixture control Solenoid. See this video where he explains setting the mixture using a dwell meter. (Same tool for engine timing - but used on a different part of car).
@ oh I see! Thank you 🙏
interesting vid, but pls check audio in the future (just mono them in the editor or something, this vid has audio just on left channel)
I adjusted my Choke, why did you mention that the choke is non adjustable ??
I think you might be referring to the choke angle, which is still fully adjustable. I may have been unclear about that. My apologies. On the older choke, you could actually rotate the internals, to set the length of time the choke stays open or closed. turning it to the lean side would result in the choke opening sooner, the rich side would result in it opening later.
@@rporestorations And I was, yessir
Pulse width modulation at 60 hertz
Use an oscilloscope. Pulse width modulation used with idle airr control valves in fuel injected cars
Use and oscilloscope to see change pulse width
10 times per second. 10 Hz. Not 50. If it ran at 50 Hz it'd wear out too quickly. ben/ michigan
??? choke isnt adjusrable? but theres notches for lining it up. ...🤔🤔🤨
That's right. On the older model chokes, you could adjust it by turning the internals left or right to increase or decrease the amount of time it stayed opened or closed. The later model chokes were non-adjustable, meaning the amount of time they stayed closed was unable to be changed.