Truck won't start after using a fuel system cleaner..

[Jayman931]

1969 C10 w/ edelbrock carb

So my brother bought two things of fuel cleaner and gave me one. Despite a little voice telling me not to put the cleaner in for fear of dislodging 47 years of "gunk"....i filled my tank and added the cleaner. I drove it for about 30 minutes then all of a sudden it started sputtering. Then it would run good for 5 seconds....the sputter....repeat. it was acting like it was out of gas. I was trying to limp home but didnt make it finally it wouldn't run continuously anymore so I pulled over. Now if I try to start it....it turns over but as soon as the key goes from start position to "on" position it cuts out. I lookeded in my fuel filter (clear glass type) and could definitely see debris. Most of it was get fine but some were the size of sand...a couple bigger.

Bought a new fuel filter and took apart carb and cleaned it. Nogo....still turns over....i get spark and combustion. As soon as I let go of key....it stops...

What say You?

Fuel pump? Clogged line? Other?

Thanks for any and all help.

J

[Lugnutz65]

I'm guessing the fuel sender filter is clogged. Still have tank behind the seat? Might be time to remove the tank and rinse it out.

[68gmsee]

A quick test to see if it's carb, fuel delivery or fuel tank.

-One gallon container with fresh gas.
-App. 2 feet long fuel hose same size as fuel pump inlet rubber hose.
-Remove inlet hose and connect new fuel hose in it's place going to one gallon container under the fuel pump.

If it runs fine, it's a fuel delivery from the tank problem. If not, it's after the fuel pump. (in your case it may be both)

Don't overlook fuel pump itself. You should get app a pint of gas into plastic container in less than 30 seconds.

Other possibilities...

My 68 GMC had a filter under the cab between fuel tank and fuel pump that previous owner had installed. At another time, I had a clogged and severely restricted fuel line from tank to fuel pump.

[Jayman931]

Thanks for the help guys. Today I will be switching our the fuel filter between fuel tank and pump. I'm also bringing my small compressor and going to blow air through the system when I am switching out the filter. If that doesn't work I suppose I'll reply e the fuel pump (its only 2 yrs old) Hopefully that works. I will change out the tank in the very near future.

[Jayman931]

Well.....i decided to remove the fuel line from the carburetor and put it in a water bottle and crank it to see how much fuel is coming out and to me it looks like plenty. Roughly 4 oz from just turning the key to start twice for maybe a second each....now what to do

[ray_mcavoy]

Originally Posted by Jayman931

Now if I try to start it....it turns over but as soon as the key goes from start position to "on" position it cuts out.

The fact that it wants to run with the key in the "start" position but cuts out when you release the key back to the "run" position sounds like you are dealing with an electrical issue. Could just be a coincidence that it happened shortly after adding the fuel system cleaner.

Hook up a test light (or multimeter) to the positive coil terminal (or BAT terminal if you have converted to HEI) to see if it is receiving power when the key is in the "run" position.

[toolboxchev]

Hey that is some insight there. It may be more than one problem. As with anything when I work on my rig, I am always on the lookout for new problems and potential problems.

[Jayman931]

***so after taking apart carb and cleaning it (there was a fair amount of small black dust in it)...replacing fuel filter...checking all plugs and distributor I agreed with "ray" that it had to be electrical...i probably should have started with the ignition switch in the first place since when I released the key from start to On is where the engine cut out. Sure enough there was a loose wire behind the ignition switch. Just me touching the wires behind the switch enabled the truck to start and continue running. Maybe this will help someone in the future...kinda feel like I got punked as it was such a easy solution...

[Boog]

Good deal. That Ray Mc knows his electrical bidnez.

[68gmsee]

Great going... Always helps to post the fix so others can benefit. Thanks.