77 Hornet backfired now wont start

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[QUOTE=Boris Badanov]Last car that did something like that to me was a 1984
Buick with a 307 Olds power. It did almost exactly
the same thing and would not re-start, but this was
on the road, not at home. I junked it road side.
Cause was a skipped timing chain. The car was too
old and rotten to bother with, over 200,000 on the clock.
[/QUOTE]
My guess is fuel pump,  or clog in the line... Though, not having the carb mounted properly with possible leak when engine is warmed up may affect both boggy throttle and vacume control at the distributor. The electronic control is infamous for issues after time. As a previous poster suggested. A coil would cause a very similar issue. As for resistance, that cannot be measured properly without special equipment.

Worst case,  your distributor jumped time,  mostly due to worn gears, if that is the case.

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304-dude Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9082	Post Options Post Reply Quote 304-dude Report Post Thanks(0) Quote Reply Posted: Jan/26/2015 at 6:40am
	[QUOTE=Boris Badanov]Last car that did something like that to me was a 1984 Buick with a 307 Olds power. It did almost exactly the same thing and would not re-start, but this was on the road, not at home. I junked it road side. Cause was a skipped timing chain. The car was too old and rotten to bother with, over 200,000 on the clock. [/QUOTE] My guess is fuel pump, or clog in the line... Though, not having the carb mounted properly with possible leak when engine is warmed up may affect both boggy throttle and vacume control at the distributor. The electronic control is infamous for issues after time. As a previous poster suggested. A coil would cause a very similar issue. As for resistance, that cannot be measured properly without special equipment. Worst case, your distributor jumped time, mostly due to worn gears, if that is the case.
	71 Javelin SST body 390 69 crank, 70 block & heads NASCAR SB2 rods & pistons 78 Jeep TH400 w/ 2.76 Low 50/50 Ford-AMC Suspension 79 F150 rear & 8.8 axles Ford Racing 3.25 gears & 9" /w Detroit locker

Mr. Ed Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Nov/12/2010 Location: Sewell, NJ Status: Offline Points: 4916	Post Options Post Reply Quote Mr. Ed Report Post Thanks(0) Quote Reply Posted: Jan/26/2015 at 8:14am
	I have the same car but I have an Edelbrock manifold and 140x carb with electric choke. I have no air cleaner clearance problems but I do have a gasket between the carb and manifold. My air cleaner fits the carb fine. You will get 50/50 comments on your carb choice. Since the 1405 is new, I would look to other sources of your problem. Make sure the ported vacuum port is tied to the correct hose. Read the manual to determine which one that is. Re-check your tubing to assure they are connected to the correct ports. Later! Mr. Ed
	2014 Jeep Grand Cherokee Laredo "Gwendolyn." 1978 Concord Sport coupe "Mr. Black". 1982 Concord wagon. The Admiral. FOR SALE! 1976 Sportabout X, 304, auto, air. The Bronze Goddess

uncljohn Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jan/03/2013 Location: Peoria AZ Status: Offline Points: 5394	Post Options Post Reply Quote uncljohn Report Post Thanks(0) Quote Reply Posted: Jan/26/2015 at 8:15am
	Trying to come up with a logical direction is a little hard as the information here is a bit more than vague. Changing from your first carburetor which is stated to be a quadrajet and bolting on an AFB is a bit difficult, as a Quadrajet does not have the same base as an AFB, so assuming that it was a Quadrajet, it required a manifold change also. But that was not stated as happening. AFB's in my experience are carburetors that work quite satisfactory out of the box and except for rare circumstances can run for years with out having to mess with them. Lately I have buying them used at swap meets because carburetors are showing up in great quantities, and them rebuilding them to use them. I have used them on 225 Cu in 6 cylinder engines and up to my 390 V8 and a number of engines in between. There is a strip kit available for tuning them, but in general the out of the box configuration providing one does not go crazy on getting one too big, works just fine. It does sound to me you are having an ignition problem with the electronic ignition on your car (your pictures were not visible to me). Past that assumption and your statement of your not being too familiar with how things work, I am not sure what to tell you to test other than purchasing a service manual for the car you have is always worth the money spent as it contains step by step trouble shooting procedures tha are both well written and to some extent easy to follow.
	70 390 5spd Donohue 74 Hornet In restoration 76 Hornet, 5.7L Mercury Marine Power 80 Fuel Injected I6 Spirit 74 232 I-6, 4bbl, 270HL Isky Cam

toolmanxiii Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Oct/16/2010 Location: Moncton Canada Status: Offline Points: 1384	Post Options Post Reply Quote toolmanxiii Report Post Thanks(0) Quote Reply Posted: Jan/26/2015 at 8:28am
	My be a stupid Question .... But did you change fuel filter with the carb swap ? too many times I've seen them plug up . let them sit for a few min and the blockage settles and away you go for another 5-20 miles then they plug up again .
	71 360 Hornet sst 83 2wd 360/727 Eagle wagon (crashed)

AMXburnout Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Dec/03/2014 Location: Winnipeg MB Status: Offline Points: 170	Post Options Post Reply Quote AMXburnout Report Post Thanks(0) Quote Reply Posted: Jan/26/2015 at 1:52pm
	I agree it could be ignition but it ran ok before the carb swap.. Even with vacuum advance not hooked up or incorrect it should run. The quadrajet to AFB is a mystery to me as well, as the secondary's on a quadrajet are the size of tennis balls.
	Marty 1974 AMX 401 4-Speed 1928 Ford Roadster P/U

amx2bfast Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Aug/07/2013 Location: middlesex nc Status: Offline Points: 217	Post Options Post Reply Quote amx2bfast Report Post Thanks(0) Quote Reply Posted: Jan/27/2015 at 8:00am
	turn motor by hand to find top center on the harmonic balancer. pull dist cap and rotor should point to #1 or # 6 plug wire depending on which stroke of the engine you are on. if that is ok , I would be looking at the dist pickup and the electronic module. Pull the module and look at the back side. If it looks grainy or is melted, replace it. the modules go bad over time. I think the color of the connectors make a difference when you get the new one.
	1975 gremlin 1973 javelin 1976 pacer wagon

Green AMX Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Feb/16/2012 Location: Florida Status: Offline Points: 521	Post Options Post Reply Quote Green AMX Report Post Thanks(0) Quote Reply Posted: Jan/27/2015 at 10:13am
	Sounds like a ignition issue
	69 AMX 390 4speed go pack 72 Javelin 360 auto(sons) 82 Spirit (wife's 1st car)still not done

tufcj Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Supporter of TheAMCForum Joined: Jul/10/2007 Location: Watkins, CO Status: Offline Points: 4097	Post Options Post Reply Quote tufcj Report Post Thanks(0) Quote Reply Posted: Jan/27/2015 at 11:40am
	Have you checked for spark at the plugs? If it has spark, then pull the distributor and check the drive gear on the cam and the distributor. Could be the gear has worn and it's out of time. That's the old Prestolite distributor. I had that in my 77 Jeep. The ECU box on the passenger fender (next to the voltage regulator) failed several times without warning. I carried a spare in the glove box. if no spark, either replace the ECU or swap out the distributor for a complete Motorcraft or aftermarket system. Bob tufcj
	69 AMX 74 Javelin AMX 67 Rogue If you need a tool and don't buy it... you'll eventually pay for it... and not have it. Henry Ford

Rogue401 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Nov/26/2010 Location: New York Status: Offline Points: 1280	Post Options Post Reply Quote Rogue401 Report Post Thanks(0) Quote Reply Posted: Jan/27/2015 at 1:45pm
	Sounds like a bunch of possible problems stacking up. If the first carb was a Quadrajet, it would need an adaptor for the manifold. So now there wouldn't be an adaptor, but is the base gasket right? I've had passages in the carb base be exposed because I had the wrong base gasket and caused a vacuum leak. I'm suspicious of pumbing the PCV/Power brake port on the back of the carb to the manifold vacuum. Is the PCV hooked up now? I made the mistake of hooking the brake booster to a port on one intake runner and causing a lean misfire. X2 on checking TDC and the rotor position. Made that mistake too many times and also had the tab on the rotor break so that the brass contact moved.

Boris Badanov Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Dec/14/2013 Location: NH USA Status: Offline Points: 4210	Post Options Post Reply Quote Boris Badanov Report Post Thanks(0) Quote Reply Posted: Jan/27/2015 at 3:37pm
	Got to go with the logical sequence. It ran good with the new carb for a while. Ask yerself what can go wrong in this fasion when the thing is previously running good. Make a short list, avoid an expensive Easter Egg Hunt. If it were my car..... Checks to make... Ignition, see if you have a spark. cam timing, overlap at top dead center 180 off on #1 should be pretty close to equal. Compression test, if you skip time the compression will tank to under 80 psi. Carb and manifold would be last thing. But there is always a chance you have a stuck heat riser crossover valve. That's my 2C worth.
	Gremlin Dreams