Author Topic: No fuel on a '72 after other work  (Read 1298 times)

Offline dochawk

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No fuel on a '72 after other work
« on: May 27, 2017, 11:35:01 PM »
I dropped and cleaned the tank a while back, and then my water pump went.  I replaced it and the fan belts.  Before dropping the tank the contents had turned to varnish.

Now, with all reassembled, it turns over briefly, but no fuel seems to be flowing and it shuts off.  2 oz of fuel in the carb lets it kick over about twice.

The strainer in the (new) fuel pump was filthy.  I've replaced it (the filter coming into the carb is clean), but it still kicks one briefly and dies. 

I removed the strainer bolt, and no fuel comes out as I crank.

I'll clip the fuel line out of the tank tomorrow to add an in-line clear filter, but is there anything else I can do or examine?  Or does this make it time to install the switched electric fuel pump back at the tank?


thanks

hawk

1972 Eldorado convertible, 2001 Deville DHS (daughter), 1997 Eldorado ETC (and now my wife wants an Eldorado!)

Offline The Tassie Devil(le)

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Re: No fuel on a '72 after other work
« Reply #1 on: May 27, 2017, 11:50:28 PM »
The best way to completely prime the system is to remove the inlet from the Carby, and using a pump, suck all the air out of the fuel line, which at the same time, fills the system with fuel.

If this doesn't happen, then there is a problem somewhere.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
(Past President Modified Chapter)

Offline Jeff Rose CLC #28373

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Re: No fuel on a '72 after other work
« Reply #2 on: May 28, 2017, 06:18:07 AM »
As filters were clogged, it is possible that old crap in the fuel system is plugging the line. I would suggest disconnecting the line at the fuel pump and the tank (sorry) and cleaning it out with mineral spirits or something similar and trying it again.
Since you have gone this far, the he hard part is already done. While the lines are disconnected, plug 1 end and add light pressure to the other. If the metal line holds pressure then good. If not then you have a crack/pinhole leak in the metal line somewhere.
After all is good there, connect it at the tank and suck fuel from the tank to the pump priming the line as Bruce suggested.
After you drive thru a tank or 2, replace the filter's again.
Jeff
« Last Edit: May 28, 2017, 06:19:38 AM by Jeff Rose CLC #28373 »
Jeff
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1970 Coupe DeVille
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Offline TJ Hopland

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Re: No fuel on a '72 after other work
« Reply #3 on: May 28, 2017, 09:40:07 AM »
I too am thinking you have a leak or blockage in the fuel line.    Seafoam sitting for a while does a decent job of breaking up sludge.

Try running the suction hose from the fuel pump to a portable gas can and see if it will stay running that way.   At least then you will know your pump is good.   If you have an outboard tank around with an extra fitting that is a little safer than just a gas can and hose.

One of the first things I do on a new to me car is install a clear filter usually between the hard line from the back and fuel pump.   I leave it there for a tank or two.  If it stays clean I know the tank isn't too bad and remove it.   If it gets dirty you know the tank is bad and will have to be dealt with,  in the mean time you stock up on filters. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
75 Eldo rusty but trusty
80 Eldo Diesel
And other assorted stuff I keep buying for some reason

Offline Scot Minesinger

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Re: No fuel on a '72 after other work
« Reply #4 on: May 28, 2017, 11:17:38 AM »
Yes, likely you have a leak or even more likely clog and the fuel pump strainer is your indicator.  I worked on a mechanical restoration of 72 Eldorado a year ago and replaced the fuel pump plus all rubber lines.  I would disconnect the rubber lines at fuel tank and let them drop down into a vessel.  Then disconnect rubber lines at fuel pump.  Using compressed air blast the lines clear with fuel pump side and have contents discharge into the vessel - probably need to secure the rubber into vessel.  This way you know the lines are clear.  If a lot of debris was found, then you may need to blast the sock free (inside tank)of debris with compressed air too.  Then of course clear the fuel line from carb to fuel pump and replace fuel filter. 

Obviously you replaced all rubber lines front and back of steel lines.

Keep in mind the fuel filter is at the pump and the fuel strainer is at the carb.  If you have a fuel filter at the carb that is wrong and maybe the source of the problem.  Check shop manual.  The fuel filter was at carb in 75, but not sure when transition was made.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

Offline dochawk

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Re: No fuel on a '72 after other work
« Reply #5 on: May 28, 2017, 02:15:13 PM »
All of the rubber to the tank was replaced when I dropped the tank and remounted.  The old rubber was so petrified I had to cut most off . . .

The fuel pump is also new, and the filters are the ones that pop up on Napa's computer.

Which of the lines on the fuel tank is the intake?  I have the big bolt with the filter, and two more small lines near one another.  For that matter, what is the third line.  In, out, and ???

I do plan on adding a clear filter, and leaving it--I was unable to come up with a sock for the tank (but if I drop it again, I figure I'll get an EZMasher to use in it's place, http://schmidling.com/empp.htm).

Is the line out of the tank 5/16?

And blowing out the line with a compressor makes a lot of sense (and I need to cut or remove at the tank, anyway, to put in the extra filter).

On a fuel filter note . . . a friend's family drove deep into Mexico to visit family each year in a VW hippiemobile.  His father added an extra fuel filter--from a Model T!  He'd stop every 100 miles or so and scrape it out with a screwdriver, but it got enough of the gunk out that he could run on Mexican fuel.

hawk
« Last Edit: May 28, 2017, 02:32:51 PM by dochawk »
1972 Eldorado convertible, 2001 Deville DHS (daughter), 1997 Eldorado ETC (and now my wife wants an Eldorado!)

Offline TJ Hopland

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Re: No fuel on a '72 after other work
« Reply #6 on: May 28, 2017, 02:43:27 PM »
I believe by 72 they feed line was a 3/8.    60's they used a 5/16, not sure when the change was.     Pretty much all GM in the 70's to the end of carbs was 3/8 feed line,  5/16 vent,  1/4 return. 

On the pump the big nut is the feed up to the carb. The 3/8" nipple is the suction from the tank.   The 1/4 nipple is the return back to the tank.

The nut one is often damaged from getting sized into the pump.  Its a fairly tight bend so if you end up having to install a section of hose make it fairly long so it doesn't kink.  I use marine hose for things like that, the marine hose had double wall thickness so doesn't kink as easy as the standard stuff does.

I'm not sure if the return has any sort of regulator or if its just a partial constant bypass.  It was standard equipment on AC equipped cars.  The idea is it keeps the fuel flowing to reduce the chances of vapor lock.    Its on AC cars because they figure stopped in traffic with the AC adds a lot of heat load so that is your best chance of vapor lock.   

Pump being new doesn't do anything for me these days.   My current new one is a Carter which used to be a good name but this one clanks.  Not sure what I am going to try next. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
75 Eldo rusty but trusty
80 Eldo Diesel
And other assorted stuff I keep buying for some reason

Offline Jeff Rose CLC #28373

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Re: No fuel on a '72 after other work
« Reply #7 on: May 28, 2017, 05:46:52 PM »
When you replaced the hoses, did you have them well marked as to which was the supply and which was the return? If you are trying to suck fuel thru the return line you won't get to far.
When you remove the rubber ones again be sure the metal ends are the same diameter.
Jeff
Jeff
Jeff
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1970 Coupe DeVille
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Offline dochawk

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Re: No fuel on a '72 after other work
« Reply #8 on: May 28, 2017, 06:48:23 PM »
I guess I'll jack it up and get a picture of what goes where tomorrow.

I'm *pretty* sure I drove it after the tank went back on and before starting on the water pump.  I remember going for gas, and it seemed empty to a knock yesterday . . . I put in about 3 gallons.

And if memory serves, the fuel line was the only nipple of the largest size (there are five in three different sizes).

Now I'm getting paranoid . . .
1972 Eldorado convertible, 2001 Deville DHS (daughter), 1997 Eldorado ETC (and now my wife wants an Eldorado!)

Offline Scot Minesinger

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Re: No fuel on a '72 after other work
« Reply #9 on: May 29, 2017, 07:30:08 AM »
There is a fuel diagram in your shop manual. 

Reading between the lines, it looks like you may have switched some of the lines with the rubber connections.  In the future best to do this one at a time or mark them, that is what I do to spare myself looking through the fuel diagram.  At the pump, that is easy - one with the nut is to carb, larger of two nipples is suction, smaller is return.  I think there are three steel front to back lines, supply, return, and vent to canister.  Make they are all connected correctly, as otherwise no fuel will be delivered to engine.  As I remember there are a few more than three at the tank, for venting and pollution control.

Generally the fuel lines are all different rubber hose sizes, partially to avoid a mix up.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

Offline dochawk

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Re: No fuel on a '72 after other work
« Reply #10 on: May 29, 2017, 02:00:15 PM »
Pieces of memory are drifting back into place.

I had remembered going to get the gas, but that could have gone into lawnmowers.

But I took the car around the corner for gas.

More importantly, I drove it the 6 or 7 miles to church:  I remember dithering about whether using the 5 gallon kegs of water that I'd filled in the summer would be a problem, or if I needed to change the water in them.

So it's near certain that this car drove at least 10 or 20 miles with the fuel hoses in this configuration.

It's occurred to me that it might be useful to keep around something, such as a glass funnel connected to fuel hosing, and perhaps a stand for it, that could be used for debugging . . .
1972 Eldorado convertible, 2001 Deville DHS (daughter), 1997 Eldorado ETC (and now my wife wants an Eldorado!)

Offline Jeff Rose CLC #28373

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Re: No fuel on a '72 after other work
« Reply #11 on: May 29, 2017, 04:16:35 PM »
Make it simple.... just suck on the supply line to the pump. If gas comes out you are good-if not then time to jack it up and have fun.
Jeff
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1970 Coupe DeVille
1955 Series 62


Offline dochawk

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Re: No fuel on a '72 after other work
« Reply #13 on: June 10, 2017, 06:10:03 PM »
I went another round or two today.

The pump definitely draws:

http://dochawk.org/caddie/pump_works.m4v 
(video even includes a splash!)

I then replaced the 3/8" hose from the fuel line to the pump, and after the pump (the former was limp, while the latter was chewed up from having been rubbed by the belt.

And then I added 11 gallons to the tank, just to be *sure* there was plenty of fuel in there and it wasn't sucking air.

Still wouldn't start, just the coughs from the priming gas.

I then connected the fuel line to the compressor rather than pump   The fuel in the tank gurgled.

I also disconnected the output of the fuel pump, and nothing came out as the starter span for several seconds.

So I'm obstructed in the hard fuel line, the couple of inches of 3/8" fuel line connecting it to the tank, or the tank itself, correct?

What should I do next?
1972 Eldorado convertible, 2001 Deville DHS (daughter), 1997 Eldorado ETC (and now my wife wants an Eldorado!)

Offline The Tassie Devil(le)

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Re: No fuel on a '72 after other work
« Reply #14 on: June 10, 2017, 07:10:57 PM »
I then connected the fuel line to the compressor rather than pump   The fuel in the tank gurgled.
I also disconnected the output of the fuel pump, and nothing came out as the starter span for several seconds.
Did you re-fill the line following the blowing back into the tank?   Fuel pumps don't like sucking on an empty line.

Bruce. >:D

'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
(Past President Modified Chapter)

Offline dochawk

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Re: No fuel on a '72 after other work
« Reply #15 on: June 10, 2017, 08:37:26 PM »
Did you re-fill the line following the blowing back into the tank?   Fuel pumps don't like sucking on an empty line.

err . . . uhm . . .

How do I do that?

hawk
1972 Eldorado convertible, 2001 Deville DHS (daughter), 1997 Eldorado ETC (and now my wife wants an Eldorado!)

Offline The Tassie Devil(le)

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Re: No fuel on a '72 after other work
« Reply #16 on: June 10, 2017, 08:44:30 PM »
Well, suck the petrol back up the line till it reaches the pump, then re-connect the hose to the pump.

Bruce. >:D

PS.   How much pressure did you use to get the bubbles in the tank?   Simply blowing? or full compressor pressure?
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
(Past President Modified Chapter)

Offline dochawk

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Re: No fuel on a '72 after other work
« Reply #17 on: June 11, 2017, 09:26:39 AM »
Well, suck the petrol back up the line till it reaches the pump, then re-connect the hose to the pump.

Isn't that likely to give me a mouthful of gasoline?

PS.   How much pressure did you use to get the bubbles in the tank?   Simply blowing? or full compressor pressure?

I slowly turned it up from off until it engaged, and then a bit more.  Probably 15-20 psi.
1972 Eldorado convertible, 2001 Deville DHS (daughter), 1997 Eldorado ETC (and now my wife wants an Eldorado!)

Offline 35-709

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Re: No fuel on a '72 after other work
« Reply #19 on: June 11, 2017, 09:34:39 AM »
Not sure how the system works on your car, but I would try with a vacuum pump at the inlet of the carburetor. Just remove the pipe from the carburetor and pump on it and see what comes out, if anything. Might also be some air or debris that is removed this way. If you have a vacuum pump its a fast test.