No fuel getting to my carb

[Sixt8Chrgr]

I have been chasing an issue where my car sits over night and it won't start until I prime the carb. Once it fires all good until the car sits. I thought the accelerator pump circuit was bad checked all of that. Have had the carb apart several times. Carb is dialed in. I installed a new Carter M6903. I am thinking either I have a bad fuel vapor canister or my fuel pump rod is worn out. My car is a 69 RT 440 restored, original drivetrain etc.

Any thoughts?


I apologize for the duplicate post, I could not find the original.

Lawrencer

[XH29N0G]

When you say prime the carburetor, you mean the fuel bowls are dry so you have add gas to it? or do you mean pump the gas pedal to squirt gas in via the accelerator pumps?

I have always had to do the last thing - pump the gas pedal to squirt gas in through the accelerator pump.  If the fuel bowls are dry, it is another issue. 

[b5blue]

How "fast" is it turning over? What carb. is it? If battery condition is kinda low or big draw when starting it could weaken spark and have low fuel delivery. Weak connections, old starter bushes and bad grounds can all hamper cold start.  

[Sixt8Chrgr]

I have to pour gas in the vents of the carb. The carb is the original Carter AVS.

Battery is new and the starter is newer. I suspect the turnover is normal. Wiring harness is new, grounds are clean no rust. There is no gas getting to the carb. Maybe the fuel filter/canister? Or the fuel pump rod? I will test the amount of fuel that is coming out of the pump when turning the engine over. See what I get.

[birdsandbees]

Someone's gotta ask... is there fuel in the tank? 

[c00nhunterjoe]

Sounds like classic fuel evaporation.  That is normal.

[b5blue]

  My 440 can sit for days but still lights up pronto. I've a Proform 750 vac. secondary w electric choke. New may not mean "good". I've had new cables AND wires with bad crimps that mocked other components being bad. (Starter-Alt.-regulator-ignition switch so on.)
  I do step on the accelerator before cranking, it releases the choke to position at cold start. Even with new fuels the car should start if it ran the day prior. 

[BSB67]

I suspect that you don't have a fuel not getting to the carb issue.  You have a fuel leaving the carb issue.

[Sixt8Chrgr]

Someone's gotta ask... is there fuel in the tank? 

Yes

[Sixt8Chrgr]

I suspect that you don't have a fuel not getting to the carb issue.  You have a fuel leaving the carb issue.

With the fuel line disconnected from the carb, and the end of the fuel line sitting in a jar. I turn over the engine with the coil wire disconnected, (engine spinning over) and I have NO fuel pumping into the carb from the fuel line.

That does not seem like evaporation, or a fuel leaving the carb issue to me? But maybe I am wrong?

[c00nhunterjoe]

If you "prime" the carb as you said, and then it runs all day, the pump is working. Crank the engine over longer with the line disconnected and see if fuel starts coming out. I would bet the fuel is either boiling out when sitting or draining out .

[Sixt8Chrgr]

If you "prime" the carb as you said, and then it runs all day, the pump is working. Crank the engine over longer with the line disconnected and see if fuel starts coming out. I would bet the fuel is either boiling out when sitting or draining out .

Yea, I agree with you. I was thinking that when I am starting the car the starter is not turning the engine over fast enough to pump the gas to the carb??

I have a phoenolic spacer under the carb for the heat.

How would it be draining out? It is not leaking on the intake. It is all dry and no gas smell overnight. 

Thanks for all the replies!!

[cdr]

If you "prime" the carb as you said, and then it runs all day, the pump is working. Crank the engine over longer with the line disconnected and see if fuel starts coming out. I would bet the fuel is either boiling out when sitting or draining out .

Yea, I agree with you. I was thinking that when I am starting the car the starter is not turning the engine over fast enough to pump the gas to the carb??

I have a phoenolic spacer under the carb for the heat.

How would it be draining out? It is not leaking on the intake. It is all dry and no gas smell overnight.  

Thanks for all the replies!!

Check the rubber hose at the tank for rotting, bend the rubber line looking for cracks, have seen this cause your problem many times. & while you are at it, check ALL the rubber lines.

[Sixt8Chrgr]

If you "prime" the carb as you said, and then it runs all day, the pump is working. Crank the engine over longer with the line disconnected and see if fuel starts coming out. I would bet the fuel is either boiling out when sitting or draining out .

Yea, I agree with you. I was thinking that when I am starting the car the starter is not turning the engine over fast enough to pump the gas to the carb??

I have a phoenolic spacer under the carb for the heat.

How would it be draining out? It is not leaking on the intake. It is all dry and no gas smell overnight.  

Thanks for all the replies!!

Check the rubber hose at the tank for rotting, bend the rubber line looking for cracks, have seen this cause your problem many times. & while you are at it, check ALL the rubber lines.

Thanks--those have all been replaced. Replaced the sending unit last night.

[BSB67]

If nothing is coming out of the fuel line, it could be the rod, as you mentioned.

But, if there was fuel in the carb the previous day when you ran it, where did the fuel in the carb go?  When you turn the key and the car starts like it should, it starts on the fuel stored in the carb, not what's coming from the pump.

[Sixt8Chrgr]

I drove the car to work yesterday. It sat in my parking garage for 8 hours. Got in it to go home and it struggled to start. But started. When it fires it acts like it is firing off of a little fuel until the rpm rises to a point that the carb is replenished with fuel then it idles smooth and nice. Drove it home put it in the garage. This morning tried it and would not start. Same issue, fuel starved. I am going to check the amount of girl coming out of the pump after 15 seconds of cranking and check the fuel pressure, per my engine builder. Will report back. Thanks!

[BSB67]

I think those are good things to check.

Considering how easy it is to change the rod, you might consider just doing that too.

[XH29N0G]

I drove the car to work yesterday. It sat in my parking garage for 8 hours. Got in it to go home and it struggled to start. But started. When it fires it acts like it is firing off of a little fuel until the rpm rises to a point that the carb is replenished with fuel then it idles smooth and nice. Drove it home put it in the garage. This morning tried it and would not start. Same issue, fuel starved. I am going to check the amount of girl coming out of the pump after 15 seconds of cranking and check the fuel pressure, per my engine builder. Will report back. Thanks!

I assume you dictated that last message.  I had the fuel pushrod go and the symptom was that it would starve of fuel when running, but not when I shut it down.  It isn't a difficult thing to change, but I think it is a puzzle as to why the fuel would leave the carburetor.  The common things I can think of would be leaking and evaporation, but you seem to have both of those covered.  I don't know the geometry of the system, but I would think it would be difficult to siphon out through the inlet hose because when the fuel level dropped a little it would break the siphon.  Maybe someone else knows otherwise.

I wonder if it is a very very slow leak (so you aren't noticing it except after the carb sits for 8 hours or more).

[cdr]

Check the vent to make sure the tank IS venting

[Alaskan_TA]

Ethanol fuels evaporate faster under heat than gasoline does.

A dry fuel bowl is normal for some cars, one of mine does it too.

Even quicker though, I can fill the bowl, drive an hour or two to a car show where it sits for 1-4 hours & I have to fill the bowl again to get it going.

I use an old mustard bottle with a squirt cap, it works great.

[Sixt8Chrgr]

I drove the car to work yesterday. It sat in my parking garage for 8 hours. Got in it to go home and it struggled to start. But started. When it fires it acts like it is firing off of a little fuel until the rpm rises to a point that the carb is replenished with fuel then it idles smooth and nice. Drove it home put it in the garage. This morning tried it and would not start. Same issue, fuel starved. I am going to check the amount of girl coming out of the pump after 15 seconds of cranking and check the fuel pressure, per my engine builder. Will report back. Thanks!

I assume you dictated that last message.  I had the fuel pushrod go and the symptom was that it would starve of fuel when running, but not when I shut it down.  It isn't a difficult thing to change, but I think it is a puzzle as to why the fuel would leave the carburetor.  The common things I can think of would be leaking and evaporation, but you seem to have both of those covered.  I don't know the geometry of the system, but I would think it would be difficult to siphon out through the inlet hose because when the fuel level dropped a little it would break the siphon.  Maybe someone else knows otherwise.

I wonder if it is a very very slow leak (so you aren't noticing it except after the carb sits for 8 hours or more).

Looks like I dictated it for sure, awful grammar.
After the car sits for a long time there is evaporation, for sure. I get a little stream of fuel from the accelerator pump circuit after the first pump of the gas pedal, but nothing after that because the bowl is too low to fill the accelerator pump bore, and the fuel pump is not refilling the bowls. As a side note, there is a check valve between the fuel bowl and the accelerator pump bore that allows fuel to flow into the bore from the bowl. I have cleaned it and tests ok.
I have mentioned in another post that I read that the fuel/vapor canisters have been known to impede fuel flow. I want to first test the fuel pump flow and pressure prior to just removing and replacing that part. I just need time to work on it but work gets in the way.
Thanks for the replies.

[Sixt8Chrgr]

If nothing is coming out of the fuel line, it could be the rod, as you mentioned.

But, if there was fuel in the carb the previous day when you ran it, where did the fuel in the carb go?  When you turn the key and the car starts like it should, it starts on the fuel stored in the carb, not what's coming from the pump.

I agree. Have to be through evaporation I guess?

[Sixt8Chrgr]

Check the vent to make sure the tank IS venting

What is a good way to do this? When I fill up my tank I can only get about 12 gallons in the tank I am assuming due to a trapped air bubble. I had this same problem with my boat and stuck an air hose in the tank and blew air in the tank which worked. I tried the same thing in my Charger tank and really not sure it worked. So what should I do to confirm my tank is vented?

[303 Mopar]

Check the vent to make sure the tank IS venting

What is a good way to do this? When I fill up my tank I can only get about 12 gallons in the tank I am assuming due to a trapped air bubble. I had this same problem with my boat and stuck an air hose in the tank and blew air in the tank which worked. I tried the same thing in my Charger tank and really not sure it worked. So what should I do to confirm my tank is vented?

Drive around for a while, and listen when you remove the gas cap. If you hear a "swoosh" sound, chances are it is not vented.  Also, the fact that you only get 12 gal when empty is a good sign it is not vented. Do you have a vent line or at least a vented gas cap?

[cdr]

Check the vent to make sure the tank IS venting

What is a good way to do this? When I fill up my tank I can only get about 12 gallons in the tank I am assuming due to a trapped air bubble. I had this same problem with my boat and stuck an air hose in the tank and blew air in the tank which worked. I tried the same thing in my Charger tank and really not sure it worked. So what should I do to confirm my tank is vented?

The little steel line that hooks to the filler neck inside the trunk, make sure it is not plugged up, but where that vent is would not affect filling up the tank, that is another issue. I do have a fix for that.

[b5blue]

  With the fill tube in front the tank can trap air if the car is jacked up in rear or nose down up front. Not a factor for OP's issue. Is this carb. insulated from intake? I just can't see having to constantly shoot fuel to start any carb. motor, something is being overlooked. 

[green69rt]

You mentioned the vapor separation canister.  Have you changed it recently?  There was a time (years ago) when these things were not being made correctly.  The return nozzle in the canister is supposed to have a restriction orifice in it.  Something like a 0.050 orifice.  A while back someone was making them with no orifice!  It would starve a carb for gas because most of the fuel was being returned to the tank, especially at low RPM.  A simple test would be to run a hose from the return line into a gas can and run the engine.  A big flow of gas may mean the orifice is missing.  It should only trickle out.  This might also give some indication if you fuel pump is weak.

[doctor4766]

Just pull the rod. It'll take you 10 minutes to establish whether that's the problem.

[cdr]

 With the fill tube in front the tank can trap air if the car is jacked up in rear or nose down up front. Not a factor for OP's issue. Is this carb. insulated from intake? I just can't see having to constantly shoot fuel to start any carb. motor, something is being overlooked.  

I said that is not related to his problem, BUT he mentioned about filling up the tank problem, the cure is to drill a 1/4 hole into the filler tube, on the top side of it just to the inside of the fill tube sealing ring at the fuel tank, it solves filling issues & puking fuel out the cap & vent when the fuel in the tank get warm & expands. Mark the rubber seal location on the filler tube, remove tube, figure in the thickness of the rubber seal & drill the hole in the top side of tube as close to the sealing area that the rubber seal seals against.

He still needs to check the vent, what would happen if the tank had a vacuum on it sitting overnight

[c00nhunterjoe]

Ive yet to see a worn pushrod cause fuel to exit the carb when it sits for extended periods of time.

[BSB67]

Agreed, but her could have two things going on.

[c00nhunterjoe]

Agreed, but her could have two things going on.

Very true.

[flyinlow]

After driving pop the hood and put a window fan or two near the car to cool the carb/intake/engine as fast as possible. This should help post drive evaporation. See how it starts later. 

[Sixt8Chrgr]

Check the vent to make sure the tank IS venting

What is a good way to do this? When I fill up my tank I can only get about 12 gallons in the tank I am assuming due to a trapped air bubble. I had this same problem with my boat and stuck an air hose in the tank and blew air in the tank which worked. I tried the same thing in my Charger tank and really not sure it worked. So what should I do to confirm my tank is vented?

The little steel line that hooks to the filler neck inside the trunk, make sure it is not plugged up, but where that vent is would not affect filling up the tank, that is another issue. I do have a fix for that.

Checked this today and it is not plugged up.

[Sixt8Chrgr]

Rain here again tomorrow, so can't do much...unfortunately.

[Sixt8Chrgr]

Changed the fuel pump push rod, problem solved.

[doctor4766]

Changed the fuel pump push rod, problem solved.

Nice work

[c00nhunterjoe]

Was the old one worn down? Im still not following how a fuel pump pushrod is causing a carb to lose its prime and not run until primed but then runs great afterwords. Still thinking there is more then 1 concern going on here.

Edited: i see the other post where the rod was worn. Still doesnt explain the hard start you are still having. May have other concerns still.

[doctor4766]

Was the old one worn down? Im still not following how a fuel pump pushrod is causing a carb to lose its prime and not run until primed but then runs great afterwords. Still thinking there is more then 1 concern going on here.

Edited: i see the other post where the rod was worn. Still doesnt explain the hard start you are still having. May have other concerns still.

Lack of fuel pressure to top up the bowl as he's idling into his parking location?

I know when my rod failed I had to keep the revs up or the car would starve of fuel and stall.
Was ok once I hit the freeway but it didn't take long once I was off that that the car was starting to splutter

[Sixt8Chrgr]

Was the old one worn down? Im still not following how a fuel pump pushrod is causing a carb to lose its prime and not run until primed but then runs great afterwords. Still thinking there is more then 1 concern going on here.

Edited: i see the other post where the rod was worn. Still doesnt explain the hard start you are still having. May have other concerns still.

The check valve in the accelerator bore may be leaking? I tore the carb apart and checked the valve and it seemed to be ok? I agree. Seems like the carb should have fuel in the bore for a few days after the car is sitting. I am going to check it out today and see if it will fire up easier than it did yesterday. Yesterday, it turned over more than what it should had before firing. Like it had to get fuel pumped up to the carb.

I still wonder if the vapor separator is faulty?

[c00nhunterjoe]

Was the old one worn down? Im still not following how a fuel pump pushrod is causing a carb to lose its prime and not run until primed but then runs great afterwords. Still thinking there is more then 1 concern going on here.

Edited: i see the other post where the rod was worn. Still doesnt explain the hard start you are still having. May have other concerns still.

Lack of fuel pressure to top up the bowl as he's idling into his parking location?

I know when my rod failed I had to keep the revs up or the car would starve of fuel and stall.
Was ok once I hit the freeway but it didn't take long once I was off that that the car was starting to splutter

He said it runs great once he dumped gas in the carb to get it started cold in the morning and had no other fuel issues until it sat overnight.

[c00nhunterjoe]

Was the old one worn down? Im still not following how a fuel pump pushrod is causing a carb to lose its prime and not run until primed but then runs great afterwords. Still thinking there is more then 1 concern going on here.

Edited: i see the other post where the rod was worn. Still doesnt explain the hard start you are still having. May have other concerns still.

The check valve in the accelerator bore may be leaking? I tore the carb apart and checked the valve and it seemed to be ok? I agree. Seems like the carb should have fuel in the bore for a few days after the car is sitting. I am going to check it out today and see if it will fire up easier than it did yesterday. Yesterday, it turned over more than what it should had before firing. Like it had to get fuel pumped up to the carb.

I still wonder if the vapor separator is faulty?

Its not uncommon for the fuel to evaporate quicker with the ethanol blends, but you may still have a boiling issue on top of that.

[Sixt8Chrgr]

Was the old one worn down? Im still not following how a fuel pump pushrod is causing a carb to lose its prime and not run until primed but then runs great afterwords. Still thinking there is more then 1 concern going on here.

Edited: i see the other post where the rod was worn. Still doesnt explain the hard start you are still having. May have other concerns still.

The check valve in the accelerator bore may be leaking? I tore the carb apart and checked the valve and it seemed to be ok? I agree. Seems like the carb should have fuel in the bore for a few days after the car is sitting. I am going to check it out today and see if it will fire up easier than it did yesterday. Yesterday, it turned over more than what it should had before firing. Like it had to get fuel pumped up to the carb.

I still wonder if the vapor separator is faulty?

Its not uncommon for the fuel to evaporate quicker with the ethanol blends, but you may still have a boiling issue on top of that.

I don't burn Ethanol

[c00nhunterjoe]

You have 100% ethanol free fuel in your area? Lucky you. Lol. Best i can get is the 10% blends here. Does not effect any of my street cars though. A simple jet adjustment when it 1st came out and ive been good to go.

[Sixt8Chrgr]

Yes we have ethanol free fuel. We use to have 93 octane ethanol free, but now the best we can get is 90 octane.

[c00nhunterjoe]

Yes we have ethanol free fuel. We use to have 93 octane ethanol free, but now the best we can get is 90 octane.

Still better then most. Im not aware of any 93 ethanol free in my area. I just rejetted our cars to accomadate it and went on my merry way.

[Sixt8Chrgr]

I was running ethanol for several years and about a year ago changed over to non ethanol but giving up at least 3 points of octane. May be imagination, but seems my cars run a ton better on non ethanol. The fast idle chokes work better for sure. Now I have not changed the jets. Not sure whether to go up or down?

[alfaitalia]

Yes we have ethanol free fuel. We use to have 93 octane ethanol free, but now the best we can get is 90 octane.

Still better then most. Im not aware of any 93 ethanol free in my area. I just rejetted our cars to accomadate it and went on my merry way.

Luckily we don't have to worry about that.....yet. We have about 5% on 95 octane fuels....and none at all in 97 and up fuel. Don't forget our ratings are different to yours...we don't use rocket fuel!! Our 95 is about the same as your 90 or 91 and our 97 is about 92 or 93 on your scales. Both commonly available. Shell and others regularly stock 99 or even 100 (about 94 US rating).....only any use if you have a car that can take advantage of it though....otherwise you are literally burning money!

[Q5XX29]

Changed the fuel pump push rod, problem solved.

How much was your fuel pump pushrod worn down? I've been having a similar issue with what seems like weak fuel pressure causing a weak pressurization of the fuel system until I get it running, and then its OK, for BOTH my Daytona and my 1970 Charger 500. I just pulled the fuel pump pushrod out, and it measured at 3.06", and I see that it should be 3.22".  That is quite a measurable, visible shortage, but is that enough wear to cause THAT much of a problem? I hope so- easy and cheap fix!

Also, what brand of fuel pump pushrod are people using with success?

[XH29N0G]

I replaced a faulty one with a Comp Cams PN 4626 about 3000 miles ago.  So far so good.  I never had to replace the original one.  The one I replaced was after a rebuild.  I do not know if there are specific brands that are better or worse.

[Q5XX29]

I replaced a faulty one with a Comp Cams PN 4626 about 3000 miles ago.  So far so good.  I never had to replace the original one.  The one I replaced was after a rebuild.  I do not know if there are specific brands that are better or worse.

Thank you.

[Sixt8Chrgr]

Changed the fuel pump push rod, problem solved.

How much was your fuel pump pushrod worn down? I've been having a similar issue with what seems like weak fuel pressure causing a weak pressurization of the fuel system until I get it running, and then its OK, for BOTH my Daytona and my 1970 Charger 500. I just pulled the fuel pump pushrod out, and it measured at 3.06", and I see that it should be 3.22".  That is quite a measurable, visible shortage, but is that enough wear to cause THAT much of a problem? I hope so- easy and cheap fix!

Also, what brand of fuel pump pushrod are people using with success?

Mine was worn down .25". I bought the one that Mancini has on their site. It also came with a new threaded plug for the rod hole in the block.
Coincidentally, today, I started my car after it has been sitting for two and a half weeks. After not too long of turning over it fired right up. Happy to have that issue behind me.

[Q5XX29]

Changed the fuel pump push rod, problem solved.

How much was your fuel pump pushrod worn down? I've been having a similar issue with what seems like weak fuel pressure causing a weak pressurization of the fuel system until I get it running, and then its OK, for BOTH my Daytona and my 1970 Charger 500. I just pulled the fuel pump pushrod out, and it measured at 3.06", and I see that it should be 3.22".  That is quite a measurable, visible shortage, but is that enough wear to cause THAT much of a problem? I hope so- easy and cheap fix!

Also, what brand of fuel pump pushrod are people using with success?

Mine was worn down .25". I bought the one that Mancini has on their site. It also came with a new threaded plug for the rod hole in the block.
Coincidentally, today, I started my car after it has been sitting for two and a half weeks. After not too long of turning over it fired right up. Happy to have that issue behind me.

Cool, good to hear. Thx