Slant dies when cruising.....

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clementine

clementine

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Hey FABO!
I was going out for a cruise and here are the events.

topped off top half of tank before heading out. Admittedly 92 octane ....but from ARCO. At cruise it starts to fall on its face and I have to feather it to keep her lit. Shift to Neutral and floor it to clear it out and possibly see if the dizzy has moved...no backfire or hesitation. Somewhat of a limp home.

Next day, take her out armed with a fuel filter....starts the same symptoms after 5 miles. Jump out and change filter, starts right up but has similar symptoms now starting to fall on face off idle. Limp home. cut open filter....not too bad.

Next day, check carb for issues, find air filter totally oiled up and cracked vacume plug on carb down low on drivers side and the PCV is plugged into the top of the bowl which doesnt seem to have ANY vacume at all. Install clean air filter and new PCV connected to manifold vacume via the lower plate on carb. Also find loose ish bolt on carb plate. tighten.

Start.....symptoms persist as off idle stumble. tried to adjust idle circut screw.

I have a carb rebuild kit.
Have not checked for loose dizzy.
fuel pump?
accelerator pump?
clogged pickup?
seems like it is air/fuel situation.
waiting on carb brushes.
going to dis-assemble carb and soak in toxic bath if someone doesnt have a better idea.

thanks
wasnt sure if this should go under fuel carb heading or slant....so here I am.

thanks again.
 
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Have not tried that. The maiden voyage after picking it up a couple of weeks ago was flawless. About 70 miles.
 
Kendog 170 said:
Sending Unit screen collapsing ?
Click to expand...
It has the off idle stumble right away. Previously it took a couple miles to develope, but now right at startup it has the stumble. Its tough because it all started a few miles after the fill up so I agree that it should be a pickup or filter. Anyway to test pickup being collapsed? Or is that a drop the tank situation?
 
One of those A body from Chrysler.....Ha Ha ...Im just kidding....72 duster. It seems like the collapsed screen thing would take a second to develope.
 
My 68 Dart it's on the front side of tank.

Gas Tank.jpg
 
I have a trick for doing that. Ill attach a gas can and gravity feed it to omit the tank to see if it continues. I have tried to do just one thing at a time to isolate the problem. Ill check the dizzy next and then do my gas can trick. I have no problem rebuilding a carb, but I would like to improve my diagnostic skills and not just throw parts at stuff. Learnin.
 
clementine said:
One of those A body from Chrysler.....Ha Ha ...Im just kidding....72 duster. It seems like the collapsed screen thing would take a second to develope.
Click to expand...

Merely a suggestion. If it's collapsing it may be getting worse as to affect you now at lower RPM's ? Check fuel pressure or remove line at carb. and pump into jug with someone cranking it over.
 
Kendog 170 said:
Merely a suggestion. If it's collapsing it may be getting worse as to affect you now at lower RPM's ? Check fuel pressure or remove line at carb. and pump into jug with someone cranking it over.
Click to expand...
Thanks... Ill give you the report after. Ill get to it possibly after sleeping the day away. Im working nights nowadays.
 
Sounds like dirt and debris in the tank. You say "not too bad" about the fuel filter. What the heck does that even mean? If you found any dirt at all there, then pull the tank and inspect. Clean the tank and put it back, or if it's rusted badly, replace it. You will not solve this until it is clean at the source.
 
It could just be a kinked hose from the sending unit to the hard-line (or maybe that's what other people meant)?
 
RustyRatRod said:
Sounds like dirt and debris in the tank. You say "not too bad" about the fuel filter. What the heck does that even mean? If you found any dirt at all there, then pull the tank and inspect. Clean the tank and put it back, or if it's rusted badly, replace it. You will not solve this until it is clean at the source.
Click to expand...
No chunk of rust or debris. a general yellow filter, not varnished. yknow...'not too bad' :poke:

It was running so good.....
 
Kendog 170 said:
If you flow fuel into container check for water.
Click to expand...

How do I check for water friend? I guess I could google that and not show my ignorance. meh......Keeping the flow of the thread for future.

Ill check the tube.

thank you all for advice. I thought it would have been the filter. Everything about it screamed clogged filter.
 
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That is what it seems like. that would be an easy fix.....I think.

Ill keep you updated. Thanks!
 
Not knowing what carb you're using..
IF you have a plunger style accelerator pump, and it is leather, instead of newer Viton material.
Check that. The leather can shrink and stop functioning.
 
clementine said:
How do I check for water friend? I guess I could google that and not show my ignorance. meh......Keeping the flow of the thread for future.

Ill check the tube.

thank you all for advice. I thought it would have been the filter. Everything about it screamed clogged filter.
Click to expand...

Actually it screams lack of fuel in general (clogged filter is just one reason it could be)
Another instance of a lack of fuel would be sucking air, like a rubber section being cracked.

Of course a weak fuel pump can do the same thing as already mentioned, but maybe the pump is getting worse as you go and now barely pumps anything at all. (you did say it wasn't this bad before)

Usually in a case like this I disconnect the fuel line from the pump and blow back into the tank.
Not only will this tell you the line is clear enough to make bubbles in the tank, but it will temporarily clear the sock in the tank a little so you can get an indication if it made a difference for a little bit.
Of course if this is the problem it will come back soon, but it gives an indication of where the problem is.

If for example it's a rubber line allowing air to be pulled into the fuel you don't really see an indication of that anywhere, because even though the line has a leak it's getting air pulled into the line so it doesn't leak a lot of fuel out of the line.

Another easy diagnostic if it hasn't been mentioned yet is to connect a fuel hose from your pump (tank side) into a gas can and see if the problem persists.
This will give you an indication of whether the problem is from the pump back, or from the pump forward.

I have also seen pickup tubes inside the tank cracked or rusted holes in them allowing air to be sucked in instead of fuel being pumped. (again, you did say it seems to be getting worse and worse)

Heck I have run motors with a 1 gallon gas can tied to the antenna just to get the car home.
This doesn't use any of the existing fuel supply system at all except the carb.
Gravity feeds the carb, so none of the tank, fuel line or fuel pump is involved at all.
This can also be done to run the car and let the fuel pump empty into a bucket to check if there was a lot of air in the fuel or a low fuel volume.

Blow back into the tank (it takes a bit to clear the line of fuel and start making bubbles in the tank)

Do you hear bubbles?
If yes, suspect air being sucked in when the pump is in use, or the pump itself being too weak.
If no, try again as like I said you need to clear the line of fuel first and it takes a little bit.
Still no bubbles?
Look for any slightly wet spots in any rubber lines, or a cracked or rusted through pickup tube in the tank.
Can't blow bubbles in the tank no matter how hard you try?
Disconnect the line at the tank and fuel pump and see if air goes through that.
Eliminate the blockage section by section instead of trying to figure it out with the whole system involved.
 
Drain some fuel from bottom of gas tank, (siphon). Put it in a clean dry glass jar, give it a day then you will see your problem
 
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