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ok so I have a72′ nova straight 6 250 engine this car sat for nearly 8 years before I bought it. I’ve done nearly everything except actually rebuild the engine. about 3 days ago I was finished with everything and got the fuel tank back on put a hot battery in it, it fired right up with no problem I drove it around a few hours that day and parked it at night the next day I get up go start the car and it was idling extremely rough and dying like it cranks right up no problem idles like crap then shuts of and shoots gas back out of the carburetor I checked the inline fuel filter that I put in between the fuel pump and carburetor and it wasn’t filling up and pushing gas so I dropped the tank again and replaced the sending unit well now it’s getting gas but still idling rough, dying and shooting gas back out of the carburetor any help would be so gratefully appreciated. New parts listed below
starter
ignition coil
distributor and cap
spark plugs and wires
fuel pump
fuel tank sending unit
alternator
harmonic balancer
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Could be the carb float.
The solder seams on metal floats can develope pin holes, causing the float to take in fuel, become heavier, sink in the float bowl which causes the bowl’s fuel level to rise, causing flooding of the intake manifold and piss-poor running, if it runs at all.
Plastic floats can degrade over time and become fuel-soaked, causing the same problem.
EDIT: If the float checks out OK, make sure the float level is set correctly. Also, check the float valve and seat for any grunge that might be preventing it from sealing properly.
It might be an idea to just clean and rebuild the carb, if you can find a carb kit. Pretty simple job on a single barrel carb.
I cleaned and rebuilt the carburetor about 3 weeks ago. Do you think maybe the entire carburetor is failing?
Although that does make a lot of sense considering that the float was the one thing that wasn’t replaced
Regarding the fuel filter not filling… you didn’t say if you installed a new fuel pump. If not, you may also want to change the fuel pump. They are not very expensive, probably around $25-30. There is a rubber diaphragm in there that can harden due to age reducing the efficiency of the pump, and it could crack and start leaking if you start driving the car. There is a weep hole on the side where fuel will spill out if this happens.
EDIT, ok, I see you already changed the pump.
Checking the float, float adjustment, and needle valve is the next thing to do. It does sound like carb flooding could be the issue since the fuel delivery issue was corrected.
[quote=”nathanfkelton” post=140127]I cleaned and rebuilt the carburetor about 3 weeks ago. Do you think maybe the entire carburetor is failing?[/quote]
Didn’t mean to alarm you. I mentioned the carb because I didn’t see it mentioned in the work you did. The carb is probably fine overall, but I’d strongly consider replacing the old float. Checking for dirt at the float valve is important too. The auxillary filter you installed is a good move, but God knows what was in the old fuel line upstream between the filter and carb. Something could have dislodged and gone into the carb when fuel went through the system.
Another thing to look at is your distributor. Make sure the hold-down bolt is tightened. If you left it loose by mistake, the distributor could have rotated a bit and the timing would be off.
Once you get those issues looked at, tell us how things are going. If the problem is still there, the next thing I’d look at is the timing chain and timing gears. I didn’t see them listed in your maintenance. A worn stretched chain, worn gears or skipping a tooth on the chain is obviously going to mess up your valve timing and it could give you the issues you’re experiencing. The test drive you took the other day could have been the nail in the coffin for these old parts.
ok so I got the car running and driving I don’t know how it just magically cleared up and held a clean idle know my problem is once I shut the car off it keeps running VERY roughly then sputters off then all the pressure in the coolant system shoots out I have a gatorade bottle rigged up for a reservoir and my coolant sprays with a good bit of pressure into the bottle after the car is shut off almost like it’s running hot. Any ideas what could cause that? I was told before by another mechanic that a car does that when the timing is retarded? Do you think thay may be the issue here?
The running on is likely a timing issue.
Have you checked you timing? Or the distributor hold down as previously mentioned?Where is the coolant coming from? The cap? Do you still have the factory overflow reservoir?
The coolant is coming from the neck of the radiator right before the cap (not correct radiator) so the outlet is on the opposite side of the overflow reservoir. and no I haven’t checked the timing I’ve gotta figure out how to do that first.
[quote=”nathanfkelton” post=140164]once I shut the car off it keeps running VERY roughly then sputters off [/quote]
This is called “dieseling.” There should be an idle stop solenoid on the carb that is meant to prevent this. When the key turns on the solenoid is activated and opens the idle air passage (low speed circuit). This is in addition to the curb idle adjustment screw. The point of the solenoid is that when you turn the key off to stop the engine, the solenoid de-energizes and blocks this air passage preventing air from entering the manifold. No air, no fire. Sometimes these solenoids stop working or are removed, and only mechanical adjustments are made to set the curb idle. If the idle stop solenoid is stuck, improperly adjusted (the plunger screws in and out to set the adjustment), or is missing altogether and only a screw adjustment is used, this condition occurs because the throttle never fully closes. Dieseling can be temporarily prevented by turning off the engine while the transmission is in gear. The cause should be found and repaired properly, though. Some carbs have two solenoids, especially if the car was equipped with A/C. If this is the case, one is the anti-diesel solenoid and the other is the idle stop solenoid (to raise the RPM when the A/C is turned on).then all the pressure in the coolant system shoots out I have a gatorade bottle rigged up for a reservoir and my coolant sprays with a good bit of pressure into the bottle after the car is shut off almost like it’s running hot.
It is likely due to the wrong radiator and/or wrong pressure cap, and lack of proper coolant recovery bottle. When you first turn off the engine, the water pump stops turning. This causes a sudden rise in temperature due to the lack of circulating water around the still-hot engine. This causes a sudden pressure increase. If the cap cannot withstand this pressure increase, coolant will come shooting out of the overflow outlet to be caught by the bottle so that as the engine cools, vacuum against the recovery bottle will be created which sucks the coolant back in. With the incorrect configuration of parts in your case, it may just not be able to work well. I would put the correct radiator and new cap on there, and connect the proper coolant recovery bottle. If you still have the original bottle, make sure it isn’t cracked.
Grab the bottom rad hose and squeeze firmly. If you get the hose to collapse, the internal stiffener has rotted away, allowing the hose to collapse when the engine is running and it will diminish or completely block coolant flow to the rad, making the engine and coolant hotter than it should be. Then, after the engine is shut off it’ll be even hotter when heat soak sets in, and it could result in the violent burping and barfing your rad is experiencing.
The dieseling/run-on you’re having after shutdown could also be a symptom of an engine that’s running too hot.
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