LUVTruck.com

Hey all,
I am on a 6500 mile cross country road trip and stuck in Austin with my sick and tired ’79 (stock carb) (900 miles home to Tucson to go!) She cut out in Houston as I was pulling off the freeway. The GEN light came on and the engine died. I was able to restart her and coast to a gas station (still had about 1/5 tank of gas). Filled up the tank, put on a new ignition coil, readjusted the points (new as of 5600 miles ago). She then started up again but cut out intermittently. I made my way to an Auto Zone and put in a new battery (alternator checked out fine). That did not help, every time I started her up, she would die unless I kept the engine revved high. I went a few blocks to an old school mechanic who sprayed a bunch of carb cleaner in the carb and cleaned the outside of the carb with brake cleaner. He said it was likely float related and I should rebuild the carb. I replaced the fuel filter and made it another 100 miles or so and when I pulled off the road, it died again. A guy came to help and messed with the idle adjustment and said I may make it to Austin, but I need to rebuild the carb when get there. She still cut out every 20 seconds or so, and would restart, just to cut out again 20 seconds or so later. I took the carb out and got a lift to Austin. I spent 6 or 7 hours rebuilding the carb and cleaning everything carefully (it was missing a shim for one of the fuel jets (I fashioned a new one out of a .015 mm gap gauge). It also was missing a tiny e clip and because of that, one of the linkages had not been connected. I put the carb back in the truck and she rode fine for 30 miles, and then cut out again the same way. I replaced the fuel pump but that did not help. I drove the rest of the way to my friend’s house with the hazards on in rush hour, with it cutting out every 30 seconds or so (20 miles . I took out the brand new float needle valve and checked to see if it was sticking. It seemed like it was. I soaked it in deep creep overnight and tried it again this morning. The truck would still cut out after 20 seconds or so. I went and got another carb rebuild kit and put in a different new float needle valve. I am still having the same problem. I adjusted the float tang a lot too at various levels and that has not helped. The float bowl is not filling up to the middle of the window unless I floor the gas, it then fills up all of the way. At this point, it will run about 40 seconds to a minute before cutting out. I am getting a good flow of gas to the carb (I pulled the line and put it in an empty bottle and had my friend run the truck, good flow). I zip tie tightened the rubber hose to the vacuum advance on the distributor, that seemed to help a little. At this point, I am stumped, what else should I try? Thanks all!!!!! See attached videos…
http://www.youtube.com/watch?v=o0Q-WavZ ... re=related

http://www.youtube.com/watch?v=3SwmnniZ ... re=related

When you rebuilt the carb did you put in a new accelerator pump? Apparently sometimes the carb kits don't come with new ones. My LUV had that problem. It wouldn't run for very long and when it did run you had to keep your foot in it. I would look into that. Also did you check your timing?

Also did you make sure you adjusted the float to the correct position?

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When in doubt floor it. If you can't floor it then you've doubted yourself.

thanks for the advice yarpas.
I did not put on a new accelerator pump, the kit did not come with one (just the boot which I replaced). anyone know a good place to get one? I adjusted the timing as best as I could, the idle kept on changing rapidly, so it doesn't sit in one position well. I adjusted the float according to specs (1.5 mm distance for float valve needle travel), but the bowl does not fill up with gas to the middle of the glass (proper) level.... at that adjustment (unless I floor it in which case the GEN light goes off briefly and then goes back on and engine dies)...

Fuel filter?

thanks for the suggestion Ben,
I put a band new fuel filter on a few days ago. I also checked the fuel flow to the carb by pulling off the fuel line and running the truck with the line in a bottle. there was a very strong flow of gas coming out of the line. I am going to look at the accelerator pump today... any other ideas?

I just checked the accelerator pump by pressing down on the rod with the engine off. there is a tiny amount of gas that squirts out into the barrel each time that I push the rod down, so I am thinking it is not a bad accelerator pump... any other ideas? thanks!

well, a mechanic friend of mine suggested that the anti diesel solenoid may be sticking. I disconnected the wire, took the solenoid off and took out the needle and spring. I then screwed it back in (without needle and spring) and tried running it like that. It ran a bit longer, but still cut out after a minute. should this have worked? his suggestion was to replace it with a bolt to just plug the hole or grind off the needle flush with the cylindrical base... I am staring to think I may need to buy a weber...

Just a thought but you my be looking at the wrong end and check your electrical end for loose wires or a bad ballast resister and maybe check your coil wire for resistance as well as fit in cap and coil.

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1978 pro street step/side 455Buick, 4sp,4.11s, 31/18.5s

There might be something wrong in the evap system blocking the fuel from getting enough volume.If all else fails buy a weber!

Try running with the fuel cap loose to see if that might help.

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1978 pro street step/side 455Buick, 4sp,4.11s, 31/18.5s

Oops, just saw that you said you replaced the filter already.

I was gonna say this next as well.

It really sounds like it's the needle and seat in the carb though.

thanks for all of the tips guys! I didn't have a chance to try them today, will do tomorrow. I ordered a 32/36 weber, hopefully it arrives tomorrow. I decided that even if I got her up and running with the stock carb, I wouldn't trust it to go another 900 miles without breaking down again. I am at a friend's house now and it is a good location to install the new carb. I wouldn't want to have to do it in the middle of the west texas desert I checked out the videos by ethelkilledfred (thanks!) they seem very helpful for the install. he plugged the EGR port with epoxy. Is this necessary? what is the purpose of that? Rock on!
PS it has a brand new ignition coil, though the ballast resistor is old... bought new plugs and vacuum lines...

almost have the new weber fully installed! thanks again to ethelkilledfred for the videos!!! I plugged the vacuum line off the bottom of the carb (not with epoxy though). Do I plug the hole in the rear of the valve cover where the hose came out? Also, is there anything else I need to plug?

well, I am totally stumped. I spent 10 hours working on her today. I put in the new weber and it is still cutting out like before. I put in yet another fresh fuel filter and that did not help. I thought maybe it was bad gas, so I ran the truck from a gas can with 92 octane with some sea foam in it, that did not help. I thought maybe the brand new fuel pump was pumping erratically, so I took the gas line off the new carb and ran it into the gas can for 30 seconds. It had steady good flow. I replaced just about all the vacuum lines and plugged all ones that were not needed for the weber. I tried spraying some deep creep in the egr valve and that didn't help. I replaced the spark plugs. I did a compression test and all of the cylinders ran at the same pressure (170, with a cold engine). I also tried running it with the gas cap off and that did not help. any other ideas???

I had similar issues with my diesel.
Found it was fine cracks in fuel line rubber that sucked air.
another time it was the fuel filter canister gasket allowed it to suck air

I believe a diesel essentially "pulls" fuel from the tank, so air would cause the pump to lose it's prime. Leaks in the fuel line on a gas truck would just leak gas because the pump "pushes" from the tank. So the pump wouldn't lose prime. There is however a section of hose from the tank to the pump that could be leaking, and that WOULD cause the pump to lose prime. However, you probably would have noticed it by now because it would probably also leak gas when the truck was sitting.

Dottie, is the fuel pump running while the engine is running, or just with the key in the on position? I'm wondering if your pump is shutting off when the engine is started. There is some electrical relays that would cause that if they malfunctioned. I believe one of them is the voltage regulator. Which would also explain the "GEN" light. I think it's supposed to shut off the fuel pump if the engine dies for some reason. It could be messed up and shutting off the fuel pump.

thanks for the advice!

There does not seem to be a gas leak, no gas drips at all near the tank or anywhere...

The pump only works while the engine is cranking or running, it does not pump gas when the key is just turned to the on position (should it?) (I checked by pulling the fuel line from the carb and running gas into a gas can)...

the voltage regulator may be something for me to check out though, I have replaced it once before, but that was awhile ago. yeah, that GEN light is weird, it makes me feel like the truck's problem has something to do with electric...it turns off sometimes if I rev the engine really high for a few seconds...

what about the egr valve, someone said that it may be stuck in the open position, is this a possible culprit... I will keep you posted!!!

Ballast resisters aren't too expensive. That was a huge headache for me some time back. Also check to see if the dizzy shaft is still tight, it shouldn't move side to side. Any movement like that will allow the point gap to constantly change. Then there is the condensor on the side of the dizzy. You replaced the points already so chaffing on the wire from them shouldn't be an issue. To me it sounds electrical.

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I've never been wrong! Once I thought I was, but I was mistaken.
Rick
Loranger, La
1980 Stepside LUV (Again)

I am thinking as the coil gets hot its shorting out.

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Certified pilots, looking down on people since 1903.

I did not notice what brand coil you purchased, but with my MSD coil I HAVE to use the one they recommend. Tried a generic one and had that same problem, used the recommended one and it has been running ever since.

_________________
I've never been wrong! Once I thought I was, but I was mistaken.
Rick
Loranger, La
1980 Stepside LUV (Again)