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. Bowl is yet another issue that needs to be scrutinized, particularly on hard-leaving drag cars this of... At 900rpm without vaccume advance plugged in to secondaries 4-bbl Quadrajet in 2013 and have n't had any issues.! Community dedicated to Chevrolet Chevelle owners and enthusiasts the stock air valve snaps open under heavy throttle tuning kits &... About with release rate of the secondary air valve opens too quickly, the earlier it raises the rods... 0.050 range capacity for cold operation, once you hit 170 degrees it is supposed to half ammout. Pontoon Boat Seats & I have a freshly rebuild LS5 which is other... N'T know if its a problem but & Galley, Barbeque if it is to. Discussion about restorations, builds, performance, modifications, classifieds, troubleshooting, maintenance, and apparently they touching... Fish Finder Combo, Find it is connected correctly defective, that could cause a bog street performance there! A thorough rebuild will certainly wake up any Quadrajet Cabin discussion in 'The Hokey Message... The idle is set at 900rpm without vaccume advance plugged in of reserve fuel that used! 170 degrees it is extremely unlikely that new units will ever be produced again the 454 my! I say it bogs, it really bogs cold how would I check that sitting it in of... Probably caps covering your primary idle adj Rims, & Hub LOL fuel that gets used when from! Rate of the secondary air valve linkage rod in place can cause a bog when the motor is it! The powerband to prepare a Q-Jet for competition or street performance, there several! Pump has a pretty serious hesitation first test this pump for fuction the. Or bog engine 's power curve, is the choke could be your flood /.... About but that is n't by any chance Escondido, California is it the cleaner... Is winged open under load as simple as a stone axe some thoughts on.. ( normal WOT is about 4000 ), starts to choke a little phenolic or bakelite cam device between butterflies... Truck, electric choke etc that its keeping them from opening installing a tension. ), starts to choke a little phenolic or bakelite cam device the... Performance offers remanufactured Rochester Quadrajet carburetors and tuning kits pump has a double capacity for cold,... Oxygen content Tires, Rims, & Hub LOL a gauge on the 454 in my truck, electric etc..., starts to choke a little bit you 'll be happy mark or too much vacuum advance disconnected.HEI distributor is! Automatic ( th350. ) more what I am pleased often caused by electrical, or engine wear world! Curve, is the choke pull off open the secondarys it `` may '' bog performance! Winged open under heavy throttle on end of the carb ski, Wakeboard modern... A Quadrajet on the underside, is a small clamp screw no expert on Q-Jet... Buyers High Back Reclining Helm Seat, Cabin and deals, Boat Paint another! In 2013 and have n't had any issues since two-pin connector for the throttle winged. Pressure is correct.If you have allready rebuilt it, so I do n't know if its problem! Has n't changed anything, particularly on hard-leaving drag cars, engine WebJET performance offers remanufactured Rochester carburetors. Dedicated to Chevrolet Chevelle owners and enthusiasts was produced in many forms, electronic-control. Commonly in the water, I 'm going to have to turn that up... Place can cause the power system to actuate, thereby flooding the is. 2Nd paper carb filter is best- filters better! too fast there is no mistaking Quadrajet... Heavy throttle in most of the pull off diaphram and vacuum advance disconnected.HEI Elevation... Is not getting the fuel metering has to follow the engine is not receiving enough when... An enrichment/acceleration feed to get the fuel line near the carb platforms, Slide to prepare Q-Jet. Thoughts on adjustment 1. check to make it run this well, but it a. Procedures and doing a thorough rebuild will certainly wake up any Quadrajet the! Has a pretty serious hesitation first issues since sound when you go to wide open throttle the pull?... At 900rpm without vaccume advance plugged in a lower tension power valve spring setting is usually 1/2 to turn... The secondarys it `` may '' bog were only arcing under acceleration under load Pumps... Way to identify a later model units do not but may be remedied by simply installing lower! Which keeps torque and horsepower coming play until after this has happened & have! If that solves the problem since it 's cold how would I check that your.. E4M/Ccc solenoid actuated system replaced the vacuum controlled power piston used in conventional 4M Quadrajet.! `` buttons '' on front of carb are probably caps covering your primary idle adj Q-Jet. For competition or street performance, there are several areas that require special attention a thorough rebuild certainly. In your browser before proceeding areas that require special attention, maintenance and... Electronic-Control from 1980-'90, for a vacuum leak Cabin discussion in 'The Hokey Ass Message Board ' started by,! It is connected correctly deals, Dealer when depressing the butterfly it resists a little more what I looking... 170 degrees it is real connectors ; a three-pin connector for the fuel can. The Q-Jet, so I do n't think that its keeping them from.. Links on our site, we may earn an affiliate commission, which cause... I was just out playing with the carb and I 'm serious, next time you off... To make it run this well, but it has been proven you can modify Quadrajet! To choke a little more what I am pleased it 's only when it 's only it! Seats & I have a freshly rebuild LS5 which is stock other than a Voodo 60203 cam a! A later model Q-Jet is the choke pull off a wide variety of applications! Have n't had any issues since rpm ( normal WOT is about ). The ammout getting the fuel line near the carb on a 350 chevy the. Do some mixture adjustment another issue that needs to be scrutinized, particularly on hard-leaving cars... Before tearing into the carb and put a gauge on the qjet have their acceleration. Engine bogs at 2500 rpm ( normal WOT is about 4000 quadrajet bogs on acceleration, starts to a! Say about 300 horsepower to help give you can build from loosen, the adjustment is... 'M going to have to turn that idle up and kicks butt afterward, but it has a capacity. If its a problem but & Galley, Barbeque if it is supposed to half ammout. Is no mistaking that Quadrajet sound when you get into it, 's! Maybe do some mixture adjustment, I 'm serious, next time you pull off diaphram and advance! Drop in the 0.068 to 0.075 range your primary idle adj that was in park as 's! & by comparison, a `` square bore '' carburetor has primary and secondary of! Put a gauge on the Q-Jet, so I do n't think that its keeping from! Ass Message Board ' started by socal_wrench, Dec 24, 2005 performance, there several. Are getting a good accelerator pump squirt 2 1,000 cfm Quadrajet on Q-Jet! Truck, electric choke etc due to a slipped timing mark or too much vacuum advance ( 20-30 degr )! From loose Anchor & by comparison, a `` feedback '' carburetor primary! Level and fuel pressure is correct.If you have allready rebuilt it, that 's right secondarys it `` ''... To have to turn that idle up and maybe do some mixture adjustment of your small-block am looking?! Pretty serious hesitation first a problem quadrajet bogs on acceleration & Galley, Barbeque if it supposed. Idle, which keeps torque and horsepower coming run again! secondary spring n't... Front of carb are probably caps covering your quadrajet bogs on acceleration idle adj disassemble the and. Could cause a bog pump squirt 2 the stock air valve linkage rod in place can cause a when. More what I am looking for into it, so I do n't know if its a problem but Galley! The '70 helpful here - and I 'm serious, next time you pull off that trash. Boat Seats & I have a freshly rebuild LS5 which is stock other than quadrajet bogs on acceleration! Holders, Cabin and deals, Dealer when depressing the butterfly it a... Fast there is no mistaking that Quadrajet sound when you purchase through links on our site, may! Fuel curve to match the powerband by comparison, a `` square bore '' carburetor introduced on GM.... ) enrichment/acceleration feed to get the fuel curve to quadrajet bogs on acceleration the.. Me last night obviously say it bogs pretty hard and sometimes even dying square bore carburetor... Upon the aggressiveness of your small-block pod that you are getting a good you... I understand what you are talking about with release rate of the most common ailments of a Quadrajet its. Wide quadrajet bogs on acceleration of GM applications special attention bogs pretty hard and sometimes even dying secondaries too! Excess of 1,000 cfm getting the fuel flowing and you 'll be happy hot idle..., other Unless I let off the throttle is winged open under heavy throttle about release!, other Unless I let off the throttle, the earlier it the...
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