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Discussion Starter #1
I have finished a frame-off restoration of a 1965 GTO with brand new gas tank; brand new fuel line insulated; brand new electric fuel pump; all new gaskets on the intake manifold closing off the exhaust cross-over; brand new Edelbrock 600 carburetor; brand new HEI distributor; total fresh engine.

I get out and go 10 miles on I65 or go into town and it stalls out in traffic and its done it 13 times. So many times that I've used AAA limit up for this year for towing me home.

The temperature is at 190-degrees and it happens when I'm taking off from a light making left hand turns.

I've checked to make sure I have a non-vented gas cap and I do.

I've replaced everything and I still can't trust to take my wife out in it anymore nor my daughter or the grandkids.

Does anyone have any idea what is going on to make it feel like its starving for fuel?

I don't think its a fuel issue anymore with all the new parts dealing with that and now that all the fuel lines are away from heat sources. I don't believe it is vapor lock.

What can it be?

Please help me. This has gone on now for close to a year replacing parts and still having the same problem.

Thanks.
 

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The first thing i would do is go to AutoZone, OReiley's or another parts store and get a free diagnostic check done.
Yeah, just plug it in to the OBD port....:wink3:. Being that it's a 1965, that ain't going to happen. I wouldn't trust an auto parts store to diagnose a vehicle that does have a diagnostic port, but they would be totally useless on one that doesn't. Are there any shops in your area that specialize in vintage vehicles?
 

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Yeah, just plug it in to the OBD port....:wink3:. Being that it's a 1965, that ain't going to happen. I wouldn't trust an auto parts store to diagnose a vehicle that does have a diagnostic port, but they would be totally useless on one that doesn't. Are there any shops in your area that specialize in vintage vehicles?
Sorry with the answer but i didn't read it close enough. I was thinking it was a 2005 as it was posted in the GTO 2004-2006 General Discussion. You need to diagnose whether it is a fuel or ignition problem. I had a similar problem and it was the coil when it got hot. When it stops, remove the air cleaner and check the squirters when you open the butterflies for fuel. I suspect it is an ignition [problem, a coil, condenser, or module. Good luck.
 

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Waaay over my pay grade, but....you mention a new gas tank and a non-vented gas cap. If Ames is correct, the original tank was vented via this vent kit. The details say that new tanks don't have the neck vent. So do you have a neck vent? If not, maybe a big vaccuum is being created preventing gas from making it thru the fuel lines to the carb. Also below is a link to photos of my '67 vent.
https://secure.amesperf.com/qilan/Detail_Web?part_num=L222B&order_number_e=NDMxMjM3Mw== &web_access=Y

GTO Tank Vent by pjw1967 | Photobucket
 

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Waaay over my pay grade, but....you mention a new gas tank and a non-vented gas cap. If Ames is correct, the original tank was vented via this vent kit. The details say that new tanks don't have the neck vent. So do you have a neck vent? If not, maybe a big vaccuum is being created preventing gas from making it thru the fuel lines to the carb. Also below is a link to photos of my '67 vent.
https://secure.amesperf.com/qilan/Detail_Web?part_num=L222B&order_number_e=NDMxMjM3Mw== &web_access=Y

GTO Tank Vent by pjw1967 | Photobucket

Have you let your car run in the driveway to get up to temp? I would get it up to temp and then raise the RPM's (1500-1800) and keep them up for about 15 minutes. See if it quits in the driveway.

X2 on the wrong gas cap - that was my opinion as well. When it quits, I would go open the gas cap and listen for a sucking sound as the vacuum inside the gas tank is released. A buddy with a '71 Camaro did the LS swap and his car would die. We went for a ride to put gas in it thinking the gauge might be wrong. I opened the gas cap to see if the cap was correct. Sure enough, big sucking sound. He had the non-vented cap. Left the cap loose and drove the car sensible, issues gone. He added a vented cap.

Did you install a new gas tank sending unit and sock on the pick-up tube? Had a rag floating around in a gas tank one time. Car would quit for no reason. Sit a bit, and it would fire up. Finally figured it had to be something to do with the pick-up in the tank. Pulled it apart and found a red shop rag. Know your tank is new, just sayin'.

Next, check all rubber fuel lines. One may be kinked or even collapsing, especially if you have any tight turns. Make sure you are using ethanol friendly gas line, which I am sure you have. Sometimes the line can separate internally and collapse under suction and you will not see this from the outside.

You could have a small bit of "something" plugging up a line/filter. Makes sure your filter is correct for your application and that it is installed in the correct direction. Some fuel filters have a flow direction and when installed wrong, won't work or will give you problems.

"The temperature is at 190-degrees and it happens when I'm taking off from a light making left hand turns."

If the carburetor is flooding or float set too high, this will also cause an engine to stall out, but you typically can smell the gas and it usually runs rough just before quitting on you. Of course putting the pedal flat to the floor to get the engine to fire up will typically clear a flooded engine, but this may not work if the carb continues to flood the engine while cranking. You did not say what you did to get the car running again before calling AAA. - this might help in diagnosing the problem.

You may want to pull the top off the carb to make sure your float/needle is not sticking.

You upgraded to an HEI - what brand?. Did you eliminate the factory resistor wire used for the original points distributor? Must have a 12volt power source going to the HEI for it to work properly. Less than 12 volts could cause problems. First make sure you have 12 Volts, not the factory 6-8 volts for points.

Check all wire connections to the HEI. Might have a loose wire. With engine running, move/jiggle wiring to the HEI as well as any other loose wiring to make sure there are no bad connections or shorts. Did you install all your ground cables on the engine/firewall/frame? Bad/no grounds can be a big cause for electrical gremlins.

Next I might install a new module in the HEI if the gas cap, lines, carb, wiring, and grounds checked out. I know you said its new, but......... For what it will cost, it would be one more thing to eliminate. It could be problematic as it gets hotter as electronic/electrical things can do. Same goes with the already mentioned coil. These things do go bad even new.

A little more detailed info and what you have tried after the car quits might help. Check a few of the mentioned things and see if you can narrow it down. :thumbsup:
 

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Agree with everything the gang said,...those are spot on recommendations of where to check. I would add that fuel pressure is always critical, and when you are working with an electric pump you have to make sure that the pressure is in proper range....

You can get vapor lock with heat with the new fuels, but you say you checked that. The left turn usually is an indicator of a carb float, as when you turn, only left it dies. Check the floats for sure, and if you can swap out the carb for another carb and test,....does not have to be a perfect carb just for the test.

When you accelerate and turn left something is happening, a bad float is a good suspect here. Also a lean carb setting can cause a lean stall. If your mixture is riches up just a tick by slightly opening the mixture screws,....will it stall then?....

So say your float is not set right and your mixture too lean, when you turn the float does not move properly when the the car tilts a little, add in an already lean mixture and the two together could cause a stall.

Lot's to look at, but the left turn on acceleration from stop would make me look at fuel first,...but electric cannot be ruled out of course....

I Know it is frustrating but it likely is a small fix,...
 

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Discussion Starter #8
Thank you ever so much for your input guys.

So let me share the story about the gas tank to pass on to another poor soul that may be having this problem and trying to run this problem down.

I bought the gas tank fro AUTO CITY CLASSIC out of Minnesota that advertises in our LEGEND magazine so I called them about this gas cap being NON-VENTED and that I had learned from the PY forum that that little vent tube on the filler tube is to allow air to back off as you are filling the tank so the gas pump fill handle doesn't back off prematurely.

With that in hand I asked the guy on the other end for a VENTED cap part number and he gives me a GATES NO. 31722 which when you show up at the Auto Parts store it come up as a NON-VENTED cap cross referencing over to whatever brand they have.

So I came home and called GATES TECH LINE and got a guy on the phone telling me that that was the cap for this CGM37H tank but he was kicking me up to another level in the TECH department and a guy that really knows the numbers.

I get that guy on the phone and tell him I want a VENTED CAP and give him this GATES NUMBER and he comes back with STANT 10807 number that has a "DEEP CAM".

So I get off the phone and call my favorite O'REILLYS' store that has a gal that really knows her way around auto parts numbers and she comes up with a MASTER 6807 (which the 807 is the only thing she was looking for because that's what all the stores will use.) She had it sitting on the shelf so I went down and got it.

It is definitely different on the inside and fits fine.

So wish me luck with having this cap on the filler tube and this new sender and its vent pipe and 3' of hose coiled and hanging up under the trunk shelf above the rear so that it doesn't leak gas. This is what the gas tank guy wanted me to do.

Here's the thing in all of this that is so puzzling:

1. I have had a rebuilt Edelbrock carburetor on this 389 (bored out to 400); a Nearly new Edelbrock 650 (guy put it on his car and thought it wasn't enough and took it off and sold it to me); and now a brand new out of the box Edelbrock 600 carburetor and the same problem exists.
2. The old HEI distributor and replaced it with a new distributor, had it curved and still the problem exists.
3. The Auto Meter PSI starts off fine at 5.5-6 PSI and steadily goes down to zero and beyond while idling but the engine does run.

So even if the gauge was not true to read PSI and we set it to 5.5 PSI with a good Mechanics gauge and lock down the regulator "why the depletion in PSI as it warms up unless there was a vacuum in the tank after I fill it up and it stops the pressure and sending gas to the carburetor".

This tank to me is not vented and I have to step through this venting process (the gas tank is now down and up on a table waiting for the new sender) before I get into anything dealing with the float on the carburetor and any of the possible things going on in the distributor.

The carburetor has got to have fuel and what I have been calling Vapor Lock coming down the rail or up around the exhaust and mufflers (which is all fixed now with wrapped fuel line and re-routed) in my estimation it has been in the gas tank all along as I drive for 10 miles on I65 and get it heated up.

It just seems like there's this air pocket built up on the top of the tank that holds back the gas flow to the electric fuel pump and thus on up to the front of the car.

Your thoughts on this theory guys will be appreciated and thank you for your input.

Stew Long
 

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SL; that is a lot more info to go on and aid the discussion, your solution is in your facts.

1) First on the vented tank, my 66 probably has a similar tank. It has the filler neck vent that curves down and vent the tank all the time. The cap is not vented. Works great. If you have the neck vented another vent is not the answer. a vented tank is not holding any vacumn. The slightest leak eliminates vacumn. Gas does build a vapor pressure, an slowly vents out that tube, very minutely. the vent must be clear. but I don't understand the coiled 3 feet of hose around filler neck? so is that the correct gas tank with filler neck vent? if so that vent is enough. more vents won't matter.

2) you changed the carb with the same problem recurring, unlikely a flat problem, not impossible they were both identically wrong, just very unlikely.

3) you changed distributors and the problem is recurring, and you had the timing curve set. Again the distributor and Timing unlikely culprits...

4) But in your facts today you say the fuel pump goes to zero and the car still runs......The fuel pump pressure should not go to zero. it should maintain a regulated pressure, a constant pressure, from the regulator, that the needle seat on the carb regulates demand for.

5) You said the pressure gauge might be wrong, well it might be right as well.

6) you can change the gauge if that is a concern and re-check. So what would cause a electric fuel pump to drop out? one answer is electric problem from the wire feeding the voltage and for the grounds for that pump. Of course bad internal wiring as well. So if this condition happen with a mechanical pump before?

7) you had an engine rebuild and a tank removed and when that is done ground straps must be re-installed, near the coil, near the front fender and back near the tank maybe some others. Good solid new clean groundstaps, is a starting for electrical gremlins.

8) Heat causes resistance in electric wires and copper windings, that is why guys have so much trouble with starters near exhaust manifolds, the heat makes resistance in the copper windings of the solenoid, click, click.

9) when your car heats up, resistance can build up in a wiring circuit, and in your case since the fuel pump PSI drops to zero that is the first place to look.

10) Turning left could cause a loose connection or ground to move or be jostled by the suspension. other places this can happen should be looked at as well.

11) one really weak place is on the drivers side of the engine a metal heat tube runs down vertically near the exhaust manifold, the wires to the starter and eventually other feeds, run thru there. This is a weak design and the tube works as a heat stove and cooks the wire harness. it develops also a melting of the insulation, say at the bottom where it chafes on the hot tube.
As it sits straight down the now bare wire may not hit the tube,...but when it all heats up and resistance builds fast and you turn left,...Bingo it shorts on the heater tube, instant stall. The car can be restarted once the wires cool and drop staright down again, usually after the wrecker has left you at home.

12) so just a good place to check visually from the bottom, put it on a lift and look at it, but you can also just push the harness down an inch, for one test and pull it up an inch for another and secure it temporarily with zip tie or tape and see if there is any change, by changing the wires position from where it may be bare, it could help you locate such a problem.

13) Ignition switches with high resistance and loose contacts can also do this, when they heat up resistance builds, loose contacts can exhibit on left turns.

14) Sounds like your timing and distributor are good, but the wiring to that matters tremendously. Pontiac Jim mentioned the ballast wire and a full 12 volts needed. That is critical and the wire can do just these symptoms, it provides the designed low voltage for points, but when it is jostled in a turn and heated up from driving, it drops one more volt and kills the coil....especially if that wire is just haphazardly laying on the back of the hot engine....You must verify that the ballast resistance wire in the original car has been addressed, and fixed to provide a reliable 12 volt feed to the coil.

15) look back there behind the dizzy, is there a white cloth covered wire feeding the distributor, if so that is providing reduced voltage...unless it goes to a relay. if you have that you have to deal with it, ez fix is a relay. So a good place to look.

16) Fuel lines could be kinking, suspension crimping a gas line on turns, lots of things. but here are some basic checks.

17) I for one cannot see how a gas tank already vented at the filler neck would benefit from another vent at the gas cap. Modern electric fuel pump systems work off a sealed vacumn system. they maintain vacumn all the time, it is only vented to a charcoal cannister in the engine compartment for emissions, those vapors are then sucked into the intake when the car is started.

18) when you put an electric fuel pump on you have to know from the manufacturer of the pump how the system is designed to work,.. that is with a vented tank or with a vacumn tank?

19) if you use the original designed vented tank with a pump designed for a vacumn tank,....well you will stall out, maybe on left turns.

20) The mechanical pump was designed to work on a vented tank at the filler neck tank and a no vent gas cap. It builds no vacumn, it is vented, so unless the vent is blocked, there is a slight gas vapor build p in the top of the tank. Just like when you open a gasoline safety can, you here the whoosh, that is the vapors escaping from the can, not vacumn. Vapors create positive pressure, vacumn is the absence of pressure. When you open the cap on the original design you can here a slight pressure, because the pressure build up is more that that tiny vent can totally dissipate. If it was larger it would seep gas vapors out in your garage and the pilot light on your gas hot water heater would cause those vapors to explode and blow you out of bed and into your neighbor's pool.

(So as a side note only store gas in your garage in a safety can, not plastic, not a cheap metal can that leaks vapors, but a safety can. Pay for one, they cost more, it has a spring loaded lid and a cork seal and a flame aresstor in the neck, so when you drop it while filling the mower, it seals and won't explode or let the flame travel up the liquid column. Sorry just don't want to see guys blow up their Lemanses!)

21) SL you will get this, proceed methodically by tacking one issue at a time and making some notes and moving to the next.

22) I would start with what that electric pump system requires in the tank, once that is right I would explore the electric to that pump, it should not drop pressure, and just because the car doesn't immediately die is not an indicator necessarily and with a carb the float bowl maintains some gas, so it the pump restarts it mat still run, a modern fuel injected car would die and the pressure in the fuel rail is maintained without reserve.

you will get it as perseverance always pays off!:nerd::nerd::nerd:
 

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One PS SL...Start with the Electric Pump Manufacters directions, or call and ask them..

1 how is the pump designed to work..

on a sealed tank or vented?
with a fuel return line to tank or none?
is a pressure drop somehow built in if carb shuts off demand?

when pressure drops to zero is the pump bad?
how is the pump grounded? to the tank only? separate wire?

must the tank be steel ?

talk to them they know how they designed it and their are many variations!
 

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OK, read all and still have a couple questions.

1. What type/brand of electric fuel pump? What is the rated GPH?
2. Where is the electric pump mounted? By the tank in order to push the gas or nearer the engine to draw the gas?
3. What are you using to regulate the electric pump's fuel pressure?
4. What size gas line does your car have, 5/16" or 3/8"?
5. If you have a vented tank at the filler neck, then you don't need the vented cap as Lemans guy stated. The guy who told you to loop 3 feet of hose around the neck was most likely thinking it will allow the tank to vent to the atmosphere with the coils preventing any sloshing gas to work its way around all the coils and dump out. It is possible the coils are kinked shut and not allowing air into the tank. You can fabricate a simple vent tube using steel tubing or purchase a kit to do the job. I found pics of the '66-'67 filler neck vent tube, but could not find a pic for '65.
6. It sounds like the fuel line will build pressure initially, but loses pressure as you run the car. It seems that you do not lose pressure completely as it maintains enough pressure to trickle into the carb so the engine will at least maintain an idle - any more than that and it will starve out of gas and quit.

That said, not knowing any more about your electric fuel pump/position or fuel regulator/position, I would pull the fuel line at the carb and let it dump/pour into gallon gas can to observe the flow. I suspect you can switch on the pump without running the engine? If it slows down to a trickle, then follow your line back towards the tank. If your pump is near the tank, then you have a fuel regulator somewhere between the pump and the carb. Pull the line that runs into the fuel pressure regulator and observe the flow of the gas into the gallon gas can. If it flows well, then you have a problem with the regulator. If the gas flow slows down to a trickle, then it is in the line or the electric fuel pump. It sticks in my mind that I read a post where the poster had a similar problem and it was the fuel pressure regulator - he was adjusting it backwards and kept reducing the fuel pressure instead of turning it up. Once he figured out his error, the fuel pressure problem was solved and the car ran great.

Don't know if you have an air compressor, but if you do, I might shoot a little air down the steel gas line with the tank out to see if the air flows through without problem - remove the rubber hose where it joins at the front to test just the steel line. You could have a crushed/pinched/kinked line that is not readily seen.
 
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