Engine running weird

[Mikes5ate]

hello, I have a 1973 grande 351 Cleveland 2v, it recently started chugging when driving like it wasn’t getting enough fuel before this it was fine, (note: was sitting for 21 years I did some TLC, new spark plugs and spark wires new distributor cap and points and condenser,) has spark and carburetor pumps fuel the fuel pump works the accelerator pump works, today it quit working on me it chugged for 10 seconds then shut off and I had trouble starting again eventually I did I cranked and cranked got it started but not for long this happened twice until I got home, any suggestions? I cleaned fuel tank there was gunk I put on a fuel filter last week put about 15 miles on it swapped it today after I broke down there were chunks of crap In there from gas tank, and suggestions? Do I need a new carburetor or is it an electrical problem with the distributor (I have spark) someone with experience please help if you can! Thanks!! - Michael.

 

[Sheriff41]

With debris in the fuel filter, I would say you have a fuel delivery issue. Did you clean out the fuel line from the tank to the pump? After sitting for so long this line may be corroded internally and depositing debris into your fuel, filter, and carb. You may need to replace the tubing, disassemble and clean your carb, and replace the filter to prevent the problem from reccuring.

 

[Steve McMahan]

Welcome from So Cal. I wonder since you had a clogged fuel filter, that some of the crud may have got past the full filter and into the carb, in the passages, etc. If you have tje experience, you could rebuild your carb or look locally for someone to rebuild it for you. I don’t suspect the spark, since it was running ok before you discovered the fouled fuel filter.

Where are you located in Oregon? Maybe a member there can offer advice on places that can help? Good luck.

 

[Mikes5ate]

Welcome from So Cal. I wonder since you had a clogged fuel filter, that some of the crud may have got past the full filter and into the carb, in the passages, etc. If you have tje experience, you could rebuild your carb or look locally for someone to rebuild it for you. I don’t suspect the spark, since it was running ok before you discovered the fouled fuel filter.

Where are you located in Oregon? Maybe a member there can offer advice on places that can help? Good luck.

Thank you, I’m located near Oregon city. I will try this

 

[Mikes5ate]

With debris in the fuel filter, I would say you have a fuel delivery issue. Did you clean out the fuel line from the tank to the pump? After sitting for so long this line may be corroded internally and depositing debris into your fuel, filter, and carb. You may need to replace the tubing, disassemble and clean your carb, and replace the filter to prevent the problem from reccuring.

Have not cleaned it but, the fuel is delivered to the carb so we thought it might have been fine? I will try cleaning the carb tomorrow.

 

[Sheriff41]

Have not cleaned it but, the fuel is delivered to the carb so we thought it might have been fine? I will try cleaning the carb tomorrow.

@Stanglover has some experience with, and may offer some advice on this.

 

[Stanglover]

As Sheriff41 put me in the hot seat, I'll say this. It certainly seems like a fuel problem. I'm not the expert on anything, but from my own experience, I would temporarily bypass the in car fuel system and see if it runs better that way. This is potentially dangerous, so be very careful. Fire extinguisher at hand.
First strip and clean the carb, just needs to be enough to get the junk out at this point.
Perhaps temporarily run a rubber line (I suggest getting some injector grade rubber fuel line as you're going to need it anyway to replace all old rubber line pieces) from the pump to the carb inlet filter. A line from the pump inlet into the gas can and see if it'll fire and run. If it does, don't run for long, just enough to prove the problem.
Or just bite the bullet and replace the entire system. This is what I did on my car.
Tank; Spetra Premium tank, Dorman 692232 fuel sending unit and a Delphi pump DE-MF0007 from Rock Auto ( best prices) SS line tank to pump from National Parts Depot (NPD) rubber Injector grade 3/8" hose from local supplier. Also VERY IMPORTANT!! buy correct fuel line clamps, spring type or solid band clamps, NO GEAR clamps. These are ok for setting up to test. The return line to the tank is likely ok at this point, but replace if you want to.
This is what your old fuel line might look like inside and this was not the worst bit.

 

[Stanglover]

By the way, there is a section at the top under "Forums" for introductions. When you have time please go there and tell us a bit more about you and your car with pics, we love pics!!
Welcome from SW Ontario, Canada.

 

[Mikes5ate]

hello, I have a 1973 grande 351 Cleveland 2v, it recently started chugging when driving like it wasn’t getting enough fuel before this it was fine, (note: was sitting for 21 years I did some TLC, new spark plugs and spark wires new distributor cap and points and condenser,) has spark and carburetor pumps fuel the fuel pump works the accelerator pump works, today it quit working on me it chugged for 10 seconds then shut off and I had trouble starting again eventually I did I cranked and cranked got it started but not for long this happened twice until I got home, any suggestions? I cleaned fuel tank there was gunk I put on a fuel filter last week put about 15 miles on it swapped it today after I broke down there were chunks of crap In there from gas tank, and suggestions? Do I need a new carburetor or is it an electrical problem with the distributor (I have spark) someone with experience please help if you can! Thanks!! - Michael.

I also forgot to mention that my carburetor does squirt fuel and my fuel reached the carburetor, would I still need to change all the fuel lines?

 

[Stanglover]

I also forgot to mention that my carburetor does squirt fuel and my fuel reached the carburetor, would I still need to change all the fuel lines?

If you don't want to get stranded somewhere, that would be a good idea.
First though, I'd want to just get it running better, but as the car sat for 21 years, replacing the fuel system can't hurt.
I know it's a lot of work, but should at least be on the "to-do list".

 

[mrgmhale]

My first thought is to ask if the filter sock on the fuel sending unit was been changed. If the fuel filter at the carb was gunked up, certainly any such gunk would be clogging the sending unit filter sock, which is simply slipped onto the fuel pickup steel pipe inside the fuel tank. I know dropping the fuel tank is a real Pita, especially if it has 1/4 or more fuel in it. One quick trick in dealing with a clogged sock (do not do this with a full tank) is to remove the fuel filler cap, then at the sending unit steel fuel pipe outside the tank blow a quick shot of compresses air into the tank. I idea is to use the blast of air to push the filter sock off the pickup tube. Please note, I have not ever done this, and likely never will unless the fuel take is no more 1/4 full. If I suspected a clogged filter sock I would be inclined to drop the tank and remove the sending unit so I could do a proper inspection of the filer sock.

I would also want to test the fuel pump to make certain it is producing both the volume and pressure outputs. If either test fails the pump will need to be replaced. I would also, in the event of a fuel pump failure, I suggest sniffing the oil on the dipstick to see if it smells like gasoline is in the engine oil. The reason is when a fuel pump diaphragm fails it can result inan external and.orinternal leak. The internal leak can end up sending gasoline into the crankcase, which will contaminate the engine oil and compromise the oil's ability to properly protect the engine's internal lubrication.

If you have yet done so recently, I would also be replacing all the rubber fuel lines at the fuel sending unot and at the fuel pump's inlet (and at the fuel filter near the carb while you are at it). The reason for replacing the fuel sending unit and fuel pumo rubber fuel lines is because theya re often ignored over the years, and when they begin to harden and crack, they can introduce a leak where air is pulled into the fuel line instead of fuel being pulled forward by the suction caused by the fuel pump. Worse, they can leak liquid fuel (in addition to sucking air). For the fuel line at the carb fuel filter, it is a matter of not having an older rubber fuel line that begins to leak - right abouve or nrear the ignition distributor no less.

Clearly, there are other things that can cause the issue you are having, but I would start with the fuel system. Other things to consider are a possible failing ignition coil, a failed or failing ignition condenser, points thatare closing up that causes inadequate ignition point gap (or excessive dwell), an excessively worn distributor upper bushing or breaker plate that causes inconsistent ignition point opening. I have seen lots of other causes of issues like the one you are facing, even one case where a vented fuel cap was no longer venting, and the engine would fuel starve because of the vacuum pressure inside the fuel tank as the fuel level went down while the engine was running (the owner had gone to several shops before he came into our Ford dealership. I had it diagnosed within 15 minutes, lucky stroke).

I hope this helps. I look forward to future posts in this thread letting us know of your progress. And once you locate the problem and correct it I hope you will share that also.

 

[Mikes5ate]

My first thought is to ask if the filter sock on the fuel sending unit was been changed. If the fuel filter at the carb was gunked up, certainly any such gunk would be clogging the sending unit filter sock, which is simply slipped onto the fuel pickup steel pipe inside the fuel tank. I know dropping the fuel tank is a real Pita, especially if it has 1/4 or more fuel in it. One quick trick in dealing with a clogged sock (do not do this with a full tank) is to remove the fuel filler cap, then at the sending unit steel fuel pipe outside the tank blow a quick shot of compresses air into the tank. I idea is to use the blast of air to push the filter sock off the pickup tube. Please note, I have not ever done this, and likely never will unless the fuel take is no more 1/4 full. If I suspected a clogged filter sock I would be inclined to drop the tank and remove the sending unit so I could do a proper inspection of the filer sock.

I would also want to test the fuel pump to make certain it is producing both the volume and pressure outputs. If either test fails the pump will need to be replaced. I would also, in the event of a fuel pump failure, I suggest sniffing the oil on the dipstick to see if it smells like gasoline is in the engine oil. The reason is when a fuel pump diaphragm fails it can result inan external and.orinternal leak. The internal leak can end up sending gasoline into the crankcase, which will contaminate the engine oil and compromise the oil's ability to properly protect the engine's internal lubrication.

If you have yet done so recently, I would also be replacing all the rubber fuel lines at the fuel sending unot and at the fuel pump's inlet (and at the fuel filter near the carb while you are at it). The reason for replacing the fuel sending unit and fuel pumo rubber fuel lines is because theya re often ignored over the years, and when they begin to harden and crack, they can introduce a leak where air is pulled into the fuel line instead of fuel being pulled forward by the suction caused by the fuel pump. Worse, they can leak liquid fuel (in addition to sucking air). For the fuel line at the carb fuel filter, it is a matter of not having an older rubber fuel line that begins to leak - right abouve or nrear the ignition distributor no less.

Clearly, there are other things that can cause the issue you are having, but I would start with the fuel system. Other things to consider are a possible failing ignition coil, a failed or failing ignition condenser, points thatare closing up that causes inadequate ignition point gap (or excessive dwell), an excessively worn distributor upper bushing or breaker plate that causes inconsistent ignition point opening. I have seen lots of other causes of issues like the one you are facing, even one case where a vented fuel cap was no longer venting, and the engine would fuel starve because of the vacuum pressure inside the fuel tank as the fuel level went down while the engine was running (the owner had gone to several shops before he came into our Ford dealership. I had it diagnosed within 15 minutes, lucky stroke).

I hope this helps. I look forward to future posts in this thread letting us know of your progress. And once you locate the problem and correct it I hope you will share that also.

Thank you for your help! I will update my progress and when it’s finally diagnosed or fixed!

 

[Steve McMahan]

I agree with Stanglover, if you’re gonna keep this car for a while, better to replace the entire fuel system. If it’s the original, it’s 50 years old. On my 73, that’s what I did. But as Mrgmhale indicated, for now, I think I would see how much junk is inside the carb. You can have a great accelerator pump output and still have plugged main jets, etc. Good luck; will be watching for your progress.

 

[Mikes5ate]

I agree with Stanglover, if you’re gonna keep this car for a while, better to replace the entire fuel system. If it’s the original, it’s 50 years old. On my 73, that’s what I did. But as Mrgmhale indicated, for now, I think I would see how much junk is inside the carb. You can have a great accelerator pump output and still have plugged main jets, etc. Good luck; will be watching for your progress.

hello, I have a 1973 grande 351 Cleveland 2v, it recently started chugging when driving like it wasn’t getting enough fuel before this it was fine, (note: was sitting for 21 years I did some TLC, new spark plugs and spark wires new distributor cap and points and condenser,) has spark and carburetor pumps fuel the fuel pump works the accelerator pump works, today it quit working on me it chugged for 10 seconds then shut off and I had trouble starting again eventually I did I cranked and cranked got it started but not for long this happened twice until I got home, any suggestions? I cleaned fuel tank there was gunk I put on a fuel filter last week put about 15 miles on it swapped it today after I broke down there were chunks of crap In there from gas tank, and suggestions? Do I need a new carburetor or is it an electrical problem with the distributor (I have spark) someone with experience please help if you can! Thanks!! - Michael.

we determined it’s not the carburetor since we poured fuel into the reservoir and it didn’t start right up, so it isn’t a gas problem my carb also sprays gas when we try it so it’s fine. The spark however is our next question we are going to test the coil I’m researching how to check voltage and resistance right now as I type this haha.

 

[Steve McMahan]

I would verify the points condition and gap first. Points s/b .017” gap, or 28 degrees dwell.

 

[Bobby]

hello, I have a 1973 grande 351 Cleveland 2v, it recently started chugging when driving like it wasn’t getting enough fuel before this it was fine, (note: was sitting for 21 years I did some TLC, new spark plugs and spark wires new distributor cap and points and condenser,) has spark and carburetor pumps fuel the fuel pump works the accelerator pump works, today it quit working on me it chugged for 10 seconds then shut off and I had trouble starting again eventually I did I cranked and cranked got it started but not for long this happened twice until I got home, any suggestions? I cleaned fuel tank there was gunk I put on a fuel filter last week put about 15 miles on it swapped it today after I broke down there were chunks of crap In there from gas tank, and suggestions? Do I need a new carburetor or is it an electrical problem with the distributor (I have spark) someone with experience please help if you can! Thanks!! - Michael.

I would replace the all the fuel lines. The steel replacement lines are pre bent and not very expensive. As others have stated, replace your rubber lines with ones rated for ethanol mix fuel. In addition to overhauling your carb and replacing your filter, a new fuel pump is also suggested and those are also a cheap fix.. Consider removing your sending unit and flushing your tank out and then letting it air dry before reinstalling your sending unit and fueling up.

 

[Hemikiller]

I'm cheap, and prefer to diagnose a problem before I start throwing parts at it.

First thing is to check the gap and dwell as Steve suggested.

When I buy a car that's been sitting, I'll run the it off an external can with fresh gas. Disconnect the fuel pump from the rubber line from the tank and drop a fresh length of hose into a 1 or 2 gallon can. Disconnect the line from the carb and the Coil (+) lead, then crank it over. Let the pump pick up fuel and flush the lines into a container. Once the flow clears up, you can hook everything back up and fire it off as normal, running off that small tank of fresh gas. This reduces the chance of getting varnished fuel and rust into your pump and carb.

If you can replicate the problem, do two things. First, pour a little gas or spray some carb cleaner down the carb throat and see if it fires right off. If it does, and dies shortly after, then it's a fuel problem. If not, then you likely have an ignition problem.

 

[Stanglover]

If you go down the replace it all rabbit hole, or just replace the sender, there is one important part to mention and that is checking the accuracy of the fuel sender at the gauge.
I'll not go through checking the Ohms measurements as I don't have that info at hand.
However when I did my tank and system replacement, I found the Dorman sender, which I found to be very good quality, made in SS, was out of whack with 5 US gallons in the tank (20 US gallon tank). 5 gallons ought to have read 1/4 tank, but was higher if I remember.
Ok, so now I have a tank 1/4 full. How do I remove the sender to adjust the float arm?
I used two floor jacks to raise the left side high enough to pull the sender without spilling gas. Don't forget the jack stands for safety!!
With the car jacked really high, and if I remember, I needed to bend the arm down slightly so it would read 1/4 on the gauge. I may have had to do this a couple of times. Afterall, it's the bottom 1/4 tank that's important, so i don't care if it's out a bit when full.

NOTE! The Spectra Premium sender that was listed (may have been corrected by now) on RA, was incorrect. The outlet tube was pointing the wrong way. They exchanged it for the Dorman sender.

 

[Mikes5ate]

I'm cheap, and prefer to diagnose a problem before I start throwing parts at it.

First thing is to check the gap and dwell as Steve suggested.

When I buy a car that's been sitting, I'll run the it off an external can with fresh gas. Disconnect the fuel pump from the rubber line from the tank and drop a fresh length of hose into a 1 or 2 gallon can. Disconnect the line from the carb and the Coil (+) lead, then crank it over. Let the pump pick up fuel and flush the lines into a container. Once the flow clears up, you can hook everything back up and fire it off as normal, running off that small tank of fresh gas. This reduces the chance of getting varnished fuel and rust into your pump and carb.

If you can replicate the problem, do two things. First, pour a little gas or spray some carb cleaner down the carb throat and see if it fires right off. If it does, and dies shortly after, then it's a fuel problem. If not, then you likely have an ignition problem.

Yea I have poured gas into the carb and it didn’t wanna start we have an electrical problem, tested the coil yesterday (the original one) yellow top coil it was 7480 ohms which I think is fine? I then got a coil from our old 67 dodge which also worked fine and tested it with that, it turned over and wanted to start but didn’t unfortunately. I think the carb is fine the fuel lines aren’t horrible I installed and changed a fuel filter at the back where the tank is it had some gunk in it, note: I have already taken out the tank and threw some chains in it and flushed it cleaned it pretty good. Has 8/10 of a tank of gas in it, we think maybe it’s distributor because the points have the correct 17” gap with the points, has a new condenser and points and rotor and distributor cap, we might need new distributor but not sure still diagnosing but narrowing it down. Also I haven’t changed the fuel pump in the engine bay yet maybe that’s a possibility of it not starting I’m not sure this is my first car I am still learning I am 17 so I’m taking advice from you guys on here and still figuring it out haha. I’ll let y’all know if it’s the conductor or if someone else has an idea what it could be-…. Thank u all for input!

 

[Hemikiller]

If you poured a small amount of gas down the carb and it didn't start, it's not a fuel delivery or starvation problem.

It could be flooded, pull a plug and see if they're wet and smell like gas. If so, hold the pedal to the floor while cranking it over. If that's the issue, then you should look at rebuilding the carb, as the needle and seat may be sticking, allowing too much gas into the bowls.

The coil resistance looks pretty "ok". Specs are Primary 1.4 ~ 1.54, secondary 7600~8800. Sometimes coils can fail when the engine warms up due to heat.