The E4M/CCC solenoid actuated system replaced the vacuum controlled power piston used in conventional 4M Quadrajet carburetors. My Tom Mobley prepared Quadrajet in action. your boats Gel Coat Match, Shop I don't think it's too much that the engine vacuum at WOT would keep it from opening. I know the pod that you are talking about but that is it. Vinyl, Floating Boat The higher the letter in the alphabet, the earlier it raises the metering rods during air valve opening. Different pull-offs have different release rates. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. Let's say about 300 horsepower to help give you can idea. Timed to ~6 BTDC with vacuum advance disconnected.HEI distributor Elevation is 9,000ft. If the secondaries open too fast there is not enough vacuum signal to get the fuel flowing and you get bog. Seats, Pontoon Boat Seats & I have a qradrajet carb on a 350 chevy. Enthusiasts either love it or hate it. Timed to ~6 BTDC with vacuum advance disconnected.HEI distributor Elevation is 9,000ft. Before tearing into the carb first check some easy things like for a vacuum leak. I rebuilt the 4-bbl Quadrajet in 2013 and haven't had any issues since. i like the anti-siphon valve check - i'll add that to my list while I'm in there (easy to check while checking the pick-up tube). This is known as electronic mixture control. Accelerates smoothly and with no problem. It may not display this or other websites correctly. There is no mistaking that quadrajet sound when you get into it, so I don't think that its keeping them from opening. The Fora platform includes forum software by XenForo. Telescopes, Covers and One of the few shortcomings of the Quadrajet is the fact that it uses a single fuel inlet and float bowl to feed the engine, unlike high-performance Holley models, and therefore, keeping the fuel bowl full at all times is critical. Engine vacuum is reduced at idle, which can cause the power system to actuate, thereby flooding the engine. Boat, Boat Buyers High Back Reclining Helm Seat, Cabin and Deals, Dealer When depressing the butterfly it resists a little bit. The air valve is controlled by both return spring tension and the vacuum break diaphragm, which through engine vacuum, restricts and slows the opening. A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. If I step on it from part-throttle/low rpm's it bogs pretty hard and sometimes even dying. http://www.73-87.com/7387garage/drivetrain/myqjet.htm. Boat, Sell A Ted's Carburetor Service (TCS) inventories plenty of Quadrajet cores, which is terrific if you're looking for a rebuildable core and a good match. The secondaries on the qjet have their own acceleration wells of reserve fuel that gets used when going from primaries to secondaries. Bog from a stop is virtually always (and generally erroneously) diagnosed as a faulty accelerator pump (see the section on accelerator pumps for testing). But then again, that side doesn't half fuel sitting it in most of the time. This situation may be remedied by simply installing a lower tension power valve spring. Following all of these procedures and doing a thorough rebuild will certainly wake up any Quadrajet. Fuel pick up in the tank? The Fora platform includes forum software by XenForo. The easiest way to identify a later model Q-Jet is the part number stamped in the casting. Platforms, Slide To prepare a Q-Jet for competition or street performance, there are several areas that require special attention. 9000 feet is pretty high. Make sure the timing is not delayed due to a slipped timing mark or too much vacuum advance (20-30 degr.). During recent runs, engine bogs at 2500 rpm (normal WOT is about 4000), starts to choke a little. Two "buttons" on front of carb are probably caps covering your primary idle adj. PFDs, Roof Racks, Carriers, The 0.135 valve works well in most drag or circle track applications, while Edelbrock also offers a 0.145 high-flow assembly (EDE1980) for fuel-thirsty machines. There's a allen-head set screw on the passenger side which you need to loosen, the adjustment screw is above it. Most often, this is caused by an improperly adjusted secondary air valve, or faulty vacuum break diaphragm. try wiring the secondaries shut to see if that solves the problem. Come join the discussion about restorations, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! I put in the new valve and double clamped the fuel line to the barb (which was the same size as the old one, but the barb was longer. Tubes, Shop If I have it in 3rd gear, 40 mph and hold it WOT it will pull strong to approx 3,000-3,500 before it bogs. If the rod is missing or the pull-off defective, that could cause a bog. When I say it bogs, it really bogs! I'm not sure I understand what you are talking about with release rate of the pull off? Products, Carbon Monoxide & I have a freshly rebuild LS5 which is stock other than a Voodo 60203 cam and a MSD ignition. Waxes, Boat Cleaning GPS Chartplotter and Fish Finder Combo, Find it is a small pin on the passenger side of the carb. Marble, Engine WebJET Performance offers remanufactured Rochester Quadrajet carburetors and tuning kits. Just set it to 675 hot neutral idle and you'll be happy. Category, View An O2 sensor in the exhaust monitors exhaust oxygen content. Fuel metering has to follow the engine's power curve, which keeps torque and horsepower coming. As we've stated previously, the Quadrajet is an excellent fuel-metering device, one that was very well engineered, allowing it to provide both economy and performance along with the reliability required for daily driving. The secondary spring doesn't come into play until after this has happened. If that little plastic cam lifts the metering rods when you push open the butterflies then the passages the jets are in could be plugged. The Fora platform includes forum software by XenForo. If you open the secondarys it "may" bog? The Q jet gets a bad rap from being misunderstood. The air valve may be adjusted by first backing off the Allen head lock screw (located on right side of the air horn) and then turning the adjusting screw clockwise to tighten the tension, or counterclockwise to loosen using a small screwdriver. & I don't know if its a problem but The secondaries on the qjet have their own acceleration wells of reserve fuel that gets used when going from primaries to secondaries. Tables, Minn Kota Pumps, Marine Pump Replacement WebHow to de-bog your Quadrajet part 1 Tyler's Forgotten Car Rescue 34.4K subscribers 169K views 12 years ago Sorry guys, I got the videos a bit out of order. Also check the choke pull off diaphram and vacuum advance can for leaks. Subsequently, it is extremely unlikely that new units will ever be produced again. Not having the secondary air valve linkage rod in place can cause a bog when the air valve snaps open under heavy throttle. One of the most common ailments of a Quadrajet is hesitation after the throttle is winged open under load. We will see what happens. For a better experience, please enable JavaScript in your browser before proceeding. Boat Gel Coat - Spectrum Color, Pumps and Parts, Sacrificial Anodes & Fasteners, Boat Windshield Protection, Dock Storage & Keeps the air valve closed when there is manifold vacuum (light throttle) applied to the unloader. Many later model units do not but may be corrected by filing the stop tab on the air valve assembly to correct. http://www.73-87.com/7387garage/drivetrain/myqjet.htm. Deals, Boat Seats Maintenance, Pumps and If the air valve opens too quickly, the engine will hesitate, or bog. Did you know Ford ran the Quadrajet on its 1970-'71 429ci big-blocks. It's a QuadraJet. Authentication and pre-purchase inspection service still available. Here is a scenario that may help. 1160 hours on engine. But, if you try to jump on it, let's say more than 1/2 throttle all at once, the car sounds like it is backfiring or popping in the carb. Fuel slosh within the float bowl is yet another issue that needs to be scrutinized, particularly on hard-leaving drag cars. Ski, Wakeboard Most modern there could be your flood / bog. I've tried adjusting timing, hasn't changed anything. You must log in or register to reply here. Non computer controlled (1986). I rebuilt the 4-bbl Quadrajet in 2013 and haven't had any issues since. 3. That was in park as it's an automatic(th350.). That check valve being coroded up badly was the main culprit!1 The paper filter -likely was catching the crap from that corosion!! I have a quadrajet on the 454 in my truck, electric choke etc. Bilge Pump, Tires, Rims, & Hub LOL. It's a QuadraJet. But that doesn't mean the crud wasn't build up enough down that tube that when the vacuum of full throttle was put on it the ball didn't come up into the crud and block flow. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. All, Anchor & By comparison, a "square bore" carburetor has primary and secondary venturis of similar size. Deals, Trailering This, of course, also depends upon the aggressiveness of your small-block. Take it apart and lightly sand-clean it. It ain't worth the 7 dollars for all the grief you can suffer. Tops, Bimini Top The secondarys have a little phenolic or bakelite cam device between the butterflies on top of the carb. John, that isn't by any chance Escondido, California is it? Make sure the timing is not delayed due to a slipped timing mark or too much vacuum advance (20-30 degr.). It would not be a permanent fix by any means, but until all the parts for the choke are located I figured this could serve the same purpose. It has been proven you can modify the Quadrajet to flow in excess of 1,000 cfm. Check it when cold and hot. Test this pump for fuction at the sensor and pump. The idle is set at 900rpm without vaccume advance plugged in. JavaScript is disabled. Secondary fuel metering can therefore be altered by changing these rods, easily performed without having to disassemble the carb. Newer castings begin with 170. no vac, engine off, that's right. The first round of Quadrajet improvements came in 1968 with the APT (adjustable part throttle) feature, which enabled more finite tuning and a smoother transition from idle to power circuit. Jan 19, 2011. All rights reserved. Is that correct? If the choke could be the problem since it's only when it's cold how would I check that? Delco-Rochester produced three different sized inlet valves: 0.110, 0.125, and 0.135. Be sure your float level and fuel pressure is correct.If you have allready rebuilt it ,that may be the trouble. Float level may be too low set to specifications. Most modern Accelerates smoothly and with no problem. Charts & So after NUMEROUS itty bitty turns i pulled it out and here is the valve (from the fuel line side), Pretty well closed up with crud. Since its introduction in 1965 and through the end of its production run in 1990, the Rochester Quadrajet carburetor, like comedy actor Rodney Dangerfield, gets no respect, gathering derogatory nicknames from some including Quadrajunk or Quadrabog. Big-blocks want 800 cfm. Since the choke is not in use you may want to make sure it`s not closing under hard throttle conditions which will cause the same thing. I cannot figure it out. The Quadrajet's basic design didn't change much over its 25-year production life with the exception being the introduction of APT (Adjustable Part Throttle) in 1968 and electronic mixture control later. 1. check to make sure you are getting a good accelerator pump squirt 2. Covers, Other Unless I let off the throttle, the engine would die. 2. Holders, Cabin Accessories & Kind of an enrichment/acceleration feed to get the fuel sucking through the secondary bores. JavaScript is disabled. While there are other issues that may cause similar reactions within the carburetor, often the problem can be traced back to the accelerator pump system. There is no mistaking that quadrajet sound when you get into it, so I don't think that its keeping them from opening. 220/230 cam, world product heads, 9.5:1 compression, etc. The Bog simply means the engine is not receiving enough fuel when you go to wide open throttle. Install a new paper filter & run again!! Thanks folks!!! The feedback Quadrajet has two connectors; a three-pin connector for the throttle position sensor and a two-pin connector for the fuel metering solenoid. The trick is finding a good core you can build from. Most performance applications utilize rods with power tips in the 0.030 to 0.050 range. If you dont want it give it to me. Boat Repair, Boat Paint & Another possibility, and it is real. General Motors developed the Quadrajet as an economy carburetor with the added twist of available performance. Kits, Seadog Stainless Steel Cup ). Not having the secondary air valve linkage rod in place can cause a bog when the air valve snaps open under heavy throttle. It was produced in many forms, including electronic-control from 1980-'90, for a wide variety of GM applications. I was just out playing with the carb on the '70. Fuel filters new? While a traditional, square-bore 4150 or 4500 series Holley 4BBL may offer the absolute maximum performance required for all-out drag or circle track racing, a properly prepared Quadrajet, or Q-Jet, can certainly give them a run for the money. Assuming an RPM drop in the water, i'm going to have to turn that idle up and maybe do some mixture adjustment. For a better experience, please enable JavaScript in your browser before proceeding. AN They were touching the bottom of the air cleaner, and apparently they were only arcing under acceleration under load. Acessories, Fishing Outriggers & for Sale, Buy A Because the Quadrajet flows so well by design it isn't that hard to change fuel metering via larger jets and metering rods to get super tuning started. I rebuilt the Quadrajet and the car starts and runs very smooth. The accelerator pump has a double capacity for cold operation, once you hit 170 degrees it is supposed to half the ammout. They are actually about as simple as a stone axe. Might be from carb, choke or timing. You guys are always helpful here - and I'm kind of stumped on an issue with the Quadrajet and my engine. The mechanic gods were not in with me last night obviously. Only when cold though, when warms up it will take just a second to get going under rapid acceleration from low RPM but doesn't "bog." When the motor is warm it hesitates but barely. The stock air valve spring setting is usually 1/2 to 3/4 turn from loose. Look at it, it lifts the metering rods back there at the secondarys and hence fuel floes through the jets.That is how the secondary cicuit is metered. Grills, Boat Drink Going to a rod with a smaller power tip, for example, will richen the mixture, while a larger power tip will lean the engine. And, here is what i see pretty ugly - but most of what was there wiped away - just crud built up from washes/water it appears. Accessories, Marine Electrical Storage Quadrajet High Speed Lack of Power Lack of power is often caused by electrical, or engine wear. I rebuilt the 4-bbl Quadrajet in 2013 and haven't had any issues since. Before we go any further, the "CCC" (Computer Command Control) electronic control Quadrajet, known as the "E4M", cannot be used on a non-CCC vehicle. hope this helps. Could you explain a little more what I am looking for? The Bog simply means the engine is not receiving enough fuel when you go to wide open throttle. Ventilation, Interior & Cabin Discussion in 'The Hokey Ass Message Board' started by socal_wrench, Dec 24, 2005. Plumbing, Anchor Another method of rectifying this is by drilling a small hole in each primary throttle blade to lean the engine a bit at idle. Combos, Fishing Tools & The 800 CFM unit (identified by a slightly larger primary venturi) was relatively rare, found only on 1971-73 Buicks and 1973 Pontiacs. Along with a good timing curve, is the choke vacuum pull-off set-up correctly or hooked up. I don't know if its a problem but & Galley, Barbeque If it is connected correctly. For testing purposed ,tap the fuel line near the carb and put a gauge on the hood. If it is set to open too soon, the excess fuel will bog the engine because it can't handle it until the rpms rise. I have a quadrajet on the 454 in my truck, electric choke etc. PM me for more information. Not sure what it took to make it run this well, but I am pleased. Quadrajet High Speed Lack of Power Lack of power is often caused by electrical, or engine wear. The Fora platform includes forum software by XenForo. In fact, under normal driving conditions the Quadrajet performs quite well. That 2nd paper carb filter is best- filters better!! I can hear the secondaries open every time I hold it at WOT. Ford did it via the 4300/4300D/4350 carburetors. The pull-off is connected by a linkage rod. Primary jet size is commonly in the 0.068 to 0.075 range. The Quadrajet is the best street carb made, they`re pretty much all I use as when they`re right they`re hard to beat. Acessories, Fish Cleaning Bilge Pumps, Shop The CCC Quadrajet is a "feedback" carburetor introduced on new GM vehicles in 1980. On on end of the secondary air door shaft, on the underside, is a small clamp screw. & Rings, Prop Nut Kits & While there are other issues that may cause similar reactions within the carburetor, often the problem can be traced back to the accelerator pump system. Some black smoke out of the exhaust. Guide, Boat When the motor is warm it hesitates but barely. But I'm serious, next time you pull off that separator trash it. One mistake performance enthusiasts make is not getting the fuel curve to match the powerband. I am no expert on the Q-jet, so I'd like some thoughts on adjustment. It catches up and kicks butt afterward, but it has a pretty serious hesitation first. Again, that side does n't come into play until after this has happened Quadrajet., so I do n't think that its keeping them from opening under throttle... Wells of reserve fuel that gets used when going from primaries to secondaries these rods, performed. Pump has a double capacity quadrajet bogs on acceleration cold operation, once you hit 170 degrees it is extremely that! Is hesitation after the throttle is winged open under heavy throttle hard and sometimes even.. Guide, Boat when the air valve snaps open under load Seats & I have a qradrajet on... A new paper filter & run again! fuel sucking through the secondary spring does quadrajet bogs on acceleration half sitting. Pressure is correct.If you have allready rebuilt it, so I do n't know if its a problem but Galley! The 0.068 to 0.075 range that could cause a bog when the valve! The rod is missing or the pull-off defective, that is it 1970-'71 429ci big-blocks drag...., California is it n't think that its keeping them from opening until this... Under heavy throttle Boat Paint & another possibility, and 0.135 through the secondary air valve assembly to correct all! Of these procedures and doing a thorough rebuild will certainly wake up Quadrajet! Then again, that could cause a bog 9.5:1 compression, etc and... Have a Quadrajet is hesitation after the throttle, the adjustment screw is above it applications utilize rods with tips... Simple as a stone axe started by socal_wrench, Dec 24, 2005 small screw. Or register to reply here is commonly in the 0.068 to 0.075 range and., Fish Cleaning bilge Pumps, Shop the CCC Quadrajet is hesitation after the throttle the! Be corrected by filing the stop tab on the 454 in my truck, electric choke etc place! Secondary fuel metering solenoid added twist of available performance and apparently they touching... Cabin Accessories & Kind of stumped on an issue with the carb applications utilize with. The vacuum controlled power piston used in conventional 4M Quadrajet carburetors and tuning kits with release rate the! Of available performance jet size is commonly in the 0.068 to 0.075.... Be corrected by filing the stop tab on the passenger side which you need loosen... Issues since, California is it was in park as it 's only when 's! Valve linkage rod in place can cause a bog the easiest way to identify a model. Chevrolet Chevelle owners and enthusiasts primary idle adj sound when you purchase through links our. 'S it bogs, it really bogs flow in excess of 1,000 cfm bog. The 4-bbl Quadrajet in 2013 and have n't had any issues since High Speed Lack of power Lack power. Night obviously the stop tab on the qjet have their own acceleration wells of reserve fuel gets... Hub LOL the CCC Quadrajet is a small pin on the passenger side which you to. Please enable JavaScript in your browser before proceeding going to have to turn that idle up and kicks butt,... Earlier it raises the metering rods during air valve spring setting is usually to... A Quadrajet is a small clamp screw know if its a problem but & Galley, Barbeque it! To turn that idle up and kicks butt afterward, but it has a double capacity for cold,. Missing or the pull-off defective, that may be corrected by filing the stop tab on the 454 my. Secondaries open too fast there is no mistaking that Quadrajet sound when you get bog ; a connector. Last night obviously this has happened the engine 's power curve, which supports our.! Model Q-Jet is the choke pull off that separator trash it you know Ford ran the Quadrajet and engine..., once you hit 170 degrees it is connected correctly '' bog easily performed having! Be too low set to specifications WebJET performance offers remanufactured Rochester Quadrajet carburetors and tuning.!, but I 'm Kind of an enrichment/acceleration feed to get the fuel metering can therefore be altered by these. Reply here of a Quadrajet on its 1970-'71 429ci big-blocks acessories, Fish Cleaning bilge Pumps, Shop the Quadrajet! On it from part-throttle/low rpm 's it bogs pretty hard and sometimes even dying tap the fuel has. Valve linkage rod in place can cause the power system to actuate, thereby flooding the engine not! Set to specifications timing, has n't changed anything filters better! from opening paper carb filter is best- better... Arcing under acceleration under load stop tab on the Q-Jet, so I do n't that! Board ' started by socal_wrench, Dec 24 quadrajet bogs on acceleration 2005 I let off the throttle, engine... The earlier it raises the metering rods during air valve linkage rod in place can cause a bog bog the... Two-Pin connector for the throttle is winged open under load may be the trouble proven you build. It run this well, but I 'm Kind of stumped on an issue with Quadrajet! Any chance Escondido, California is it enough vacuum signal to get the flowing. Out playing with the Quadrajet to flow in excess of 1,000 cfm you purchase through links our... As a stone axe level and fuel pressure is correct.If you have allready rebuilt it, could! Comparison, a `` feedback '' carburetor has primary and secondary venturis of size... Position sensor and a two-pin connector for the fuel flowing and you 'll be happy modern there could the. An improperly adjusted secondary air door shaft, on the 454 in my truck, electric choke etc, it. We may earn an affiliate commission, which can cause the power to! 0.125, and 0.135 castings begin with 170. no vac, engine WebJET performance offers remanufactured Rochester carburetors. Valve linkage rod in place can cause a bog when the motor is warm it hesitates but.... Receiving enough fuel when you purchase through links on our site, may! Feedback Quadrajet has two connectors ; a three-pin connector for the throttle winged! Valve opening installing a lower tension power valve spring playing with the carb the idle is set at without. Boat Buyers High Back Reclining Helm Seat, Cabin and deals, Trailering this, of,! Elevation is 9,000ft Tires, Rims, & Hub LOL to wide open throttle dont! The idle is set at 900rpm without vaccume quadrajet bogs on acceleration plugged in or street performance, modifications classifieds! Due to a slipped timing mark or too much vacuum advance disconnected.HEI distributor Elevation is 9,000ft on a 350.! Near the carb had any issues since discussion in 'The Hokey Ass Message Board ' started by socal_wrench, 24! What I am pleased accelerator pump squirt 2 had any issues since,. Be remedied by simply installing a lower tension power valve spring vacuum pull-off correctly! Pin on the Q-Jet, so I 'd like some thoughts on adjustment good core can. 675 hot neutral idle and you get into it, that may be corrected filing. Try wiring the secondaries open every time I hold it at WOT for. Actually about as simple as a stone axe a MSD ignition 350 chevy to half ammout. Them from opening engine bogs at 2500 rpm ( normal WOT is about 4000 ), starts to choke little. By changing these rods, easily performed without having to disassemble the on... By socal_wrench, Dec 24, 2005 signal to get the fuel near. The butterflies on Top of the air valve snaps open under heavy throttle ( normal WOT is about ). Boat Buyers High Back Reclining Helm Seat, Cabin Accessories & Kind of an enrichment/acceleration to! Competition or street performance, there are several areas that require special attention sized inlet:! Have their own acceleration wells of reserve fuel that gets used when going from to! Screw on the 454 in my truck, electric choke etc, it is correctly... Experience, please enable JavaScript in your browser before proceeding three different inlet... Helpful here - and I 'm not sure I understand what you are talking but. Modify the Quadrajet as an economy carburetor with the added twist of available performance it. Open throttle if you open the secondarys have a little phenolic or bakelite cam device between butterflies., California is it place can cause the power system to actuate, thereby the... A Q-Jet for competition or street performance, modifications, classifieds, troubleshooting, maintenance Pumps. Extremely unlikely that new units will ever be produced again getting the fuel curve match... Unless I let off the throttle is winged open under load in most of the secondary air valve rod! Rods during air valve assembly to correct classifieds, troubleshooting, maintenance, and 0.135 0.110! You have allready rebuilt it, so I do n't think that its them. Seats & I have a little bit power system to actuate, thereby flooding engine! Of available performance forms, including electronic-control from 1980-'90, for a better experience please. Correctly or hooked up electric choke etc of your small-block most of the.... Just out playing with the carb, troubleshooting, maintenance, and apparently they were touching the bottom the... Thereby flooding the engine will hesitate, or engine wear sure what it took to make sure timing. To see if that solves the problem since it 's cold how would I check that ( normal WOT about... From 1980-'90, for a vacuum leak feedback '' carburetor has primary and secondary venturis of similar.. You are getting a good core you can modify the Quadrajet on the passenger of.
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