How to PROPERLY Start a Car with a Quadrajet
ฝัง
- เผยแพร่เมื่อ 24 ส.ค. 2022
- Starting an engine is basic stuff, yet many vehicle owners seem to experience issues when starting an engine with a Quadrajet carburetor.
Why is that?
• Are Quadrajets problematic?
• Does the moniker Quadrajunk really apply?
The short answer is NO.
Quadrajets are excellent carburetors. The problem stems from poor adjustments or simple negligence by failure to keep these precision instruments properly calibrated.
Plus a lack of understanding of how these carburetors work and failure to use proper manufacturer-recommended starting procedures.
In this video, I give you a very simple and, I believe, easy-to-understand demonstration of how to PROPERLY start your vehicle with a Quadrajet carburetor.
It is estimated that General Motors used over 150 MILLION Quadrajets on cars, trucks, vans, and more during the years in which they were produced, so I think that's a testament to how popular and dependable these carburetors were and still are when properly maintained and adjusted.
By the way, the steps I describe in the video are not "secrets." These instructions have been around since the day Quadrajets were introduced for anyone willing to be educated on the subject.
Even the 1976 Corvette Owner's Manual has a clear paragraph on how to start a cold engine.
Anyway, I hope you find the video helpful.
Thank you for watching! 🙂👍🏻
======================================
CORVETTE PRODUCTS (sponsored)
- 76 Vette Assembly Manual: amzn.to/2GBuHrd
- 68-82 Corvette Manual: amzn.to/3devEEW
- How to Restore Corvette: amzn.to/35B6L0R
- 68-82 Vette Resto Guide: amzn.to/2QvvIG
======================================
DISCLAIMER: Even though I like to wrench on Corvettes and most of my videos are of a how-to nature, I am not responsible nor liable should you decide to follow my musings on the subject.
The repairs and other work I do are for my own benefit and entertainment, and even though my videos may sound and appear to give technical how-to advice, that's not my intention.
Working on a vehicle is inherently dangerous. If you're not confident, qualified, or lack the tools to do the job correctly and safely, hire a licensed mechanic.
#corvettec3 #c3corvette #carburetor - ยานยนต์และพาหนะ
![[4K] BABYMONSTER(베이비몬스터) “FOREVER” Band LIVE Concert “영원히” 베몬만을 사랑하게 되…💗 [it’s KPOP LIVE 잇츠라이브]](http://i.ytimg.com/vi/TQfC0xdpiw4/mqdefault.jpg)
I had a quadrajet on my small 256 in my HQ ute which replaced the 350 Holley it had when I bought it. The quad ran like a dream.
Great straightforward video, thank you.
Thank you for watching! 😊👍🏻
Great video of a seemingly lost technique to millennials who pump the accelerator. I am a older mechanic that can make most any carb start like that if it hasn't been butchered. I start my 76 Monte Carlo exactly like that. Its in the owners manual. Sits 3 months in winter. Cranks 10 seconds no unnecessary pumping, the carb refills with fuel and she kicks off and settles to fast idle
Glad you enjoyed the video. The Quadrajet is-in my opinion-the greatest and also the most misunderstood carburetor ever invented. Thank you for watching! 😊👍🏻
I had my gmc 350cu in, rebuilt in 2016, awesome and reliable! American knowhow has been entrusted to a few of us who enjoy the enthusiastic part of life! I've used Castrol 5 - 30W, since the rebuilt and it seems to be a good operation additive. Just saying, i did have an issue with the California added ethanol, so i was advised to use LUCAS ETHANOL STABILIZER, its a green liquid, in a clear plastic bottle. I use it religiously in all my cars engines, smooth idles and no octane ding knocking if u look at price look to your bumper to bumper parts supplier, i pay about $6-7.00 per bottle most common franchise suppliers don't even carry this item, because this generation has been bombarded with imports and no mechanical rebuilding experience, so they don't know jack!
Thanks for the tip about the Lucas Ethanol Stabilizer. I always add Marvel Mystery Oil to both engine oil and fuel and my car runs and idles great. I also had the motor rebuilt at about the same time you did yours. I do regular maintenance to ensure it lasts a long time. SB Chevy V8s are great, reliable engines. 😊👍🏻
@@76vette I've used the marvel mystery red bottle for years as an older motor and internal component lubricant. The Lucas ethanol stabilizer, primarily a water condensation minimizer in the fuel, it's quite amazing the way it reforms water to dissolve then blend into the fuel flow.
Thanks for this vid, I’m gonna make an attempt to rebuild and adjust my Qjet in hopes that it runs this well.
Thank you for watching! 😊👍🏻
Thanks for the video. 😁
Thank you for watching! 😊👍🏻
great information!👍
Thank you for watching! 😊👍🏻
I have Edelbrock on my 1976 and after a few moments stays at 700 all the time
Thanks for sharing
Thank you for watching! 😊👍🏻
The audio was ok, but kinda distant. Thanks for the attention to replay with a closeup. Awesome tutorial!
Thank you for watching! 😊👍🏻
I would like to knew you got to Start so easy
شكرا جزيلا
I have that linkage completely off and it seems to work way better
I used to pump the gas two times, had my high idle at 1000 rpm. Worked good for me.
If it ain’t broken… 😊👍🏻
Very informative video,
How long should you let it run on the fast idle setting before blipping the gas to bring the idle down down a notch ?
It seems like you literally give it just a few seconds before blipping it...
I have a Rochester single barrel in my 77 Camaro but have never known how long to let the fast idle run - I was giving it about 30 seconds to a minute - but I’ve found if I give it too long and then blip the gas the idle will fall too low and sometimes die off...
But after trying it your way with just a few seconds the idle drops down a notch perfectly...
So could leaving it on fast idle too long cause what I’ve been experiencing ?
Thanks.
I am not familiar with Monojet carburetors or how their fast-idle circuits work, but I don’t see how allowing it to run for a minute then blipping the gas would idle it down too much.
AFAIK, all Rochester carbs were mechanical until 1980 I think, and they can only idle down to a certain point.
I don’t find it necessary to warm up my car with the choke fully closed, so after it starts I give it a little gas so it opens a bit, and that approach works for me.
Hmmm very strange - not sure what the issue with mine is then...
Perhaps im just not letting it warm up long enough....
Runs fine when warmed up and starts easy from cold...
But while the car is warming up it just seems to be very irritable and unstable at idle...
Maybe rebuilding and thoroughly cleaning the carburetor is necessary? 🤷🏻♂️ Sorry I don’t have any other suggestions.
You really don't need to let a carbureted engine "warm up" any more than a vehicle with EFI. If everything is set correctly, you should be able to drive off any time you wish. You can just drive on the choke - it should come off automatically as you drive the vehicle. If the idle falls too low and the engine dies off, your choke cap needs to be adjusted a bit tighter to stay closed a little longer.
Hello friend, hey, the carburetor on my Monte Carlo 82 350 is the same as yours, but I have a feeling that the secondary throats do not open completely. Do you think the lock that stops them doesn't move? I'm talking about the insurance that goes behind the thermostat. If I take it off, will anything happen?
The secondaries open by vacuum and the lock should only engage while the choke is being used to warm up the engine. When the engine is close to operating temp the lock releases. If I’m understanding you correctly, behind the choke is the fast idle mechanism. I would not remove any of those components. Have a professional diagnose and fix the problem.
Hello,
My car idles really high at cold start. Takes good 2 -3 minutes to go down to normal idle speed. Any suggestions or fixes for that.
If adjusting the fast idle mechanism does not solve the issue, the vacuum brake may be faulty or installed improperly. You can visually determine if that’s the problem. Good luck. 👍🏻
I'm working on 69 Vette 350 and I am contending with the exhaust passage under the carburetor for cold start assist you know but seems no one else has that problem maybe no one else has an original Corvette
Hi Richard. I’m not sure I understand what you mean by “exhaust passage” under the carburetor. Are you having issues with the divorced choke? Can you describe the issue you’re having. Thanks. 😊👍🏻
Well I have no idea how to send a picture but I have what looks like the original 350 with GM intake it has an exhaust passage that comes up opens at the surface the carburetor mates to on the intake itself I have one metal heat shield they call it which is cut like the base gasket for a quadrajet but I don't really know just what gaskets should be there and as it is I have an exhaust leak under the carburetor acting like it's got an EGR valve stuck open I'm working on 69 model
Your best bet is to contact a specialist like Quadrajet Power and order the right parts for your carburetor, which I assume is a 702.
quadrajetpower.com/about-us/
Email: info@quadrajetpower.com
I am sure these folks can help you find the answer to the issues you’re having with your Quadrajet. 😊👍🏻
What if my fast idle is not coming up after the first pump of gas?
It was working for a year but suddenly the high idle cam would not engage and my motor would idle low during warm up.
Maybe it’s time to rebuild it. Things can get disconnected, parts do wear out, springs can fatigue or even break, and so on. If you’re not familiar with Quadrajets, have a specialist rebuild it completely. Good luck.
Soooo. And If the motor doesn't start, do you repeat pressing the gas pedal each time until it catches or just turn the key until it catches cause the carb allready has fuel in it ?
If the Quadrajet is rebuilt and set up properly, the engine will start. If it does not, chances are the carburetor is not calibrated properly and/or there are other issues that prevent a normal start up.
I would not keep pumping the gas pedal in an attempt to start the vehicle as the carburetor will flood. Maybe just one light pump as it cranks, but that’s it. Hope that helps. 😊👍🏻
I have a quadrajet on my 84 riviera 307 but cant get anyone to get it to run right. If they leave the idle load compensator hooked up the idle speed at stop makes the car run way to fast, but if they take it off and the idle speed is perfect at stop in drive but if you put the air on the car dies.....what next? Its been rebuilt and I have guys that are specialists working on it but they say the carb computer sets all the things....what to do???? Thanks.
Not sure if the “Idle Load Compensator” is the same thing as an idle stop solenoid, but if it is, it may be defective. Is yours controlled by electricity or vacuum?
If it’s ok, then it may be time to look at the computer. That’s all I can think of.
My 76 Corvette does not have an idle stop solenoid, and it usually runs at 750 RPM with the air off. If I turn the air on there’s a 200 RPM drop, but the car idles and runs just fine. 🤷🏻♂️
Just rebuilt my carb, notice my quad acts a bit different. Start it the same, 1 pump takes about 6 seconds cold. Then it idles high but it only takes 1 throttle blip to take it to curb idle. I’m your video it seems there are 3 different stages, high at first, quickly to medium, then finally to curb. Any idea what is wrong with mine? Same mechanism.
It could be a fast-idle adjustment issue or just a worn fast idle cam.
@@76vette ok thanks, Ill have to check it out.
@@76vette just verified by hand with the carb off the car, seems it does work, I have my high idle set pretty low, 1100 rpm, just cause I don't need 1800 rpm so I probably don't notice the medium setting.
@@ZachIsOP Glad to hear you figured it out! 🙂👍🏻
Hello, I have a question.
Do you have any idea why a CE smells like fuel. I am having this problem.
Not without looking at the car. Sorry.
On my 78 caddy coupe, I've done this and when it starts it idles rough and stumbled and it'll cut off. What I've done is when I start the car and its running I just give it gas all the while the car is shaking due to it not running fine at start up and it'll eventually smooth out and run fine and I release the gas pedal. So brings me to this, if it's not running fine at first start up then I need to see if the fast idle is working properly? I had no issues with cold start up back in 2022 then just last year it started acting up. I've made no adjustments to carb at all nor mess with the electric choke. Any input is helpful. thanks
It’s very hard if not impossible to diagnose something like this without actually being there, but it sounds like what you’re experiencing is possibly related to either fuel delivery, air blockage, or even a combination of both.
My suggestion is to start by replacing fuel and air cleaner filters and even the PCV valve. From there if the problem persists, is to use a vacuum gauge to see if that system is working properly.
If all those items are addressed and the car is still running rough maybe it’s time to have the carb rebuilt. Again, I’m just guessing. Have a professional mechanic (ideally familiar with carburetors), diagnose the problem.
Good luck. 😊👍🏻
@76vette that's very true. It's hard to diagnose over simply a comment I made. Once it warms up, the car runs perfectly fine and will have no issues restarting it later in the day. It's only at cold start-up. And once it's running/idleling, you can't even tell it's on while at a red light or coming to a stop. All vac lines are fine. The air filter has recently been replaced. Not the fuel, as mentioned, runs perfectly fine. No hesitation or bogging when it's floored (which I rarely do) but do appreciate your time to respond. Honestly wasn't expecting a quick reply. And I'll look into that PCV valve. I'll replace that tomorrow. Again thanks.
@@edgarherrera5085 I hope it’s something simple. Chasing those little gremlins can be very frustrating. Sorry I couldn’t be of more assistance. Good luck! 🍀👍🏻
@76vette Thank you, sir. Oh, this only happens, well has only happened when the weather is cold here. I'm in Texas (West Texas), so it's not super freezing like below 0 temps. But during warmer days, there were no issues at start-up while cold. I'll take your advice and go from there. Again, thank you for replying.
@76vette think I found the issue. There's no power going to the electric choke wiring. I had key ignition in the on position checked it with a test light and there's no power to it. I checked with my service manual and the fuse is good (which send power to the oil pressure switch) from there it should go to the choke and it isn't. The oil pressure switch is a 3 prong. Has main wire to power it, as a way to let you know the idiot light works when in run. The other is when oil drops in pressure while car running, it'll illuminate the idiot light on dash. The other is to the electric choke. So I'd need to get a 3 prong engine oil pressure switch.
👍👍