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By george - 9 Years Ago
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I installed a rebuilt 312 in my 57 tbird , tarted it up a few weeks ago it adjusted the valves, timing carb and it ran great.. I turned the car around in the carport and went to start in the next day it would not start.. I check compression (good on all cyl.) spark at plugs, fuel at carb, #1 cal. is on TDC and rotor pointing to #1 .. Check the value lash (good .018). with a little staring fluid and gas it will run for a minute smooth and it starts running ruff and quits ... any suggestion ??
Thanks
George
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By paul2748 - 9 Years Ago
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Off hand, I can think of some things. Some obstruction in the fuel system so fuel is not getting to carb in sufficient enough quantity.(possibility that something is blocking the fuel tank outlet that comes into play only when gas is sucked via the fuel pump). The second is a weak fuel pump. Third is a clogged filter.
Disconnect the fuel line at the carb, put a hose on the end of the line and direct it into some container and turn over the engine to see if there is good fuel flow. Do this more than just a couple of squirts. If you get poor flow, start backward toward the tank to find out where the problem lies.
Also make sure that the resistor is wired correctly. Could be some other electrical problem.
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By charliemccraney - 9 Years Ago
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If it starts and runs with a manual supply of fuel, then something is wrong with the fuel system, bad pump, clogged lines, clogged filter, for example.
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By george - 9 Years Ago
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fuel lines are all new , i disconnected the line and crank it over ,lots of gas. I pulled the holly apart three times now .. I can see fuel going into the intake
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By george - 9 Years Ago
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no problem with electrical, checked coil , points , spark at plugs , cap , rotor , checked volts on both sides of the coil. all looks good.. when i can get it started for a few minutes I put a O scope on the neg side of the coil and it looks the same all the way up to when it stops
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By 57RancheroJim - 9 Years Ago
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Have changed the condenser recently? Many of the new ones are off shore crap..
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By charliemccraney - 9 Years Ago
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If you have to use starting fluid to get it to run, then you have a fuel supply problem somewhere. The fact that it runs on starting fluid verifies that everything else is at least good enough for it to run.
Does this problem exist at idle, or also other throttle positions? Where and when exactly do you see fuel going into the intake?
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By Joe-JDC - 9 Years Ago
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Is it flooding? Is that where you see fuel going into the intake? If so, then either the float is fuel logged/pin hole in it, or the needle and seat is sticking open and flooding the carburetor bowl. Did you reinstall the spring holding the float up and level? Did you bend the float tab to get the float adjustment when turning the fuel bowl over to see if you had the 3/8" clearance? Do you have the bowl gaskets installed backward to prevent the fuel going to the accelerator pump well? Did you tighten the power valve/over tighten/leave out the gasket? Just a few ideas. Joe-JDC
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By george - 9 Years Ago
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condenser is good , replaced it. no flooding and I can see gas in the bowl and I can pump the accelerator and see gas going into the intake .. chacked the floats all good . even with starting flu it still takes a long time to start .. I would agree that it seems like carb issues but I've done everything i can think of plus followed up with your suggestion (thank you ) and still no luck... its crazy
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By george - 9 Years Ago
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it may be not enough spark so I will get one more coil (3rd one ) tomorrow, condenser and points and see what happens... I do appreciate everyones help ..
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By charliemccraney - 9 Years Ago
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Troubleshoot it. When it won't run, pull a plug wire and observe the spark.. Blue = good, not the ignition electronics. Red = bad, possibly the ignition electronics, maybe engine or distributor grounding.
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By Lou - 9 Years Ago
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It's not getting gas, everything else is fine,. Is there a fuel filter in the line between the fuel pump and carb? if so change it, that's the problem.
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By george - 9 Years Ago
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is there any way of telling if the timing chain jumped a tooth without pulling the cover ???
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By charliemccraney - 9 Years Ago
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If your compression checked out ok and it does run well when you do get it started, then it has not jumped a tooth.
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By brettnelson - 9 Years Ago
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Are you running an original glass filter with stacked brass washers? Mine would clog up after a few minutes of running. You couldn't see any particles stuck to the filter but when i would pull it, blast it with carb spray and re-install the car ran fine. I'd drive it for 10 minutes and it would clog again with a mud like film that you really couldn't see........... I would run a new filter and follow the advice on previous posts. If the car starts and runs for a few and then stops, it is not timing chains, valves or ignition.
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By george - 9 Years Ago
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after a lot of cranking and gas + starter fluid it will ruin for a few minutes and than starts to miss and quits .. I tried adding a little gas down the carb and it wants to stop... If I try to pump the accellorator it wants to quit
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By Ted - 9 Years Ago
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I didn’t see any mention to which carb you are running. From your descriptions, it could be flooding. I’ll suggest looking down the throats of the carburetor either during running or right after it quits and see if the discharge nozzles are dribbling excess fuel into the engine. If it’s a later model Holley, then removing the sight plugs in the sides of the bowls will give you an idea of if the needle seats are not adjusted correctly and/or simply bypassing additional fuel.
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By george - 9 Years Ago
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Ted, thanks for the info .. It's the stock holly carb(rebuilt) I did pull the sight plugs and check the float adjustments. I pull the bowls off and and the metering vavles are closing when you blow into the gas inlet. the only thing I can think is perhaps the timing chain jumped one tooth or shared the keyway??? look into the carb as it was running and no gas running in.... I pulled the intake and heads looking for a gasket issues but all looks good .. the vavles are carb up black shoot ...
I do appreciate you taking the time to help
George
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By Ted - 9 Years Ago
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I’ll suggest a cranking compression test on all the cylinders. Be sure to run the compression test with the throttle blocked in the wide open position. That will rule out almost all mechanical issues at which point you are left with carburetor and ignition at the top of the list.
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By george - 9 Years Ago
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thanks ,,, I'm going to have the trans rebuilt so I will pull engine and trans ,, I did run a compression test all looked good ..
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