Loss of Power Under Load

[dhoch14]

Ok Team IAC, I have one for you.

Symptoms:
Once I cruise to desired speed on highway, I lose power. I can push the pedal and it does nothing. As soon as I pull over, the pedal works again. I can take back roads without issue. It only happens on the highway. It is as if the carbs are being flooded.

The kicker is that I did not have this issue prior to synching my carbs (dual solexs) yesterday. Now, I know, it must be the carbs right? Well, I resynched again today. Plenty of power and it runs smooth until I get on the highway.

I have checked the spark plugs, caps, rotors. I adjusted the valves last weekend. I’m also running pertronix. I took a look at my fuel filter and it looks ok. Though, there is a rather large air bubble in it. I'm not sure if this is a problem and normal or not.

I'm thinking Fuel Delivery or Ignition. Any thoughts or guesses before I walk through the whole Ignition system and Fuel Delivery?

-d

[sped372]

Hope others can chime in but I have always noticed a large air bubble in the fuel filter without issue. Good luck.

[Amskeptic]

Ok Team IAC, I have one for you.

Symptoms:
Once I cruise to desired speed on highway, I lose power. I can push the pedal and it does nothing. As soon as I pull over, the pedal works again. I can take back roads without issue. It only happens on the highway. It is as if the carbs are being flooded.

The kicker is that I did not have this issue prior to synching my carbs (dual solexs) yesterday. Now, I know, it must be the carbs right? Well, I resynched again today. Plenty of power and it runs smooth until I get on the highway.

I have checked the spark plugs, caps, rotors. I adjusted the valves last weekend. I’m also running pertronix. I took a look at my fuel filter and it looks ok. Though, there is a rather large air bubble in it. I'm not sure if this is a problem and normal or not.

I'm thinking Fuel Delivery or Ignition. Any thoughts or guesses before I walk through the whole Ignition system and Fuel Delivery?

-d

Do you lose power on surface streets pulling a long hill, like that Route 26 or 28 or whatever on your way over the hill to Portland from Beaverton?
Try an extended "freeway rpm" run in 2nd gear on surface street hill and see if it happens. If so, fuel delivery, possilbe pump crap-out, mechanical or electric?
Colin

[dhoch14]

Ok Team IAC, I have one for you.

Symptoms:
Once I cruise to desired speed on highway, I lose power. I can push the pedal and it does nothing. As soon as I pull over, the pedal works again. I can take back roads without issue. It only happens on the highway. It is as if the carbs are being flooded.

The kicker is that I did not have this issue prior to synching my carbs (dual solexs) yesterday. Now, I know, it must be the carbs right? Well, I resynched again today. Plenty of power and it runs smooth until I get on the highway.

I have checked the spark plugs, caps, rotors. I adjusted the valves last weekend. I’m also running pertronix. I took a look at my fuel filter and it looks ok. Though, there is a rather large air bubble in it. I'm not sure if this is a problem and normal or not.

I'm thinking Fuel Delivery or Ignition. Any thoughts or guesses before I walk through the whole Ignition system and Fuel Delivery?

-d

Do you lose power on surface streets pulling a long hill, like that Route 26 or 28 or whatever on your way over the hill to Portland from Beaverton?
Try an extended "freeway rpm" run in 2nd gear on surface street hill and see if it happens. If so, fuel delivery, possilbe pump crap-out, mechanical or electric?
Colin

I have intermittent lose on side streets under HEAVY Load aka up a big hill. The issue seems to be in both 2nd and 3rd gear (AT). I'm running a Carter electric fuel pump. About 2 years old.

[Amskeptic]

Ok Team IAC, I have one for you.

Symptoms:
Once I cruise to desired speed on highway, I lose power. I can push the pedal and it does nothing. As soon as I pull over, the pedal works again. I can take back roads without issue. It only happens on the highway. It is as if the carbs are being flooded.

The kicker is that I did not have this issue prior to synching my carbs (dual solexs) yesterday. Now, I know, it must be the carbs right? Well, I resynched again today. Plenty of power and it runs smooth until I get on the highway.

I have checked the spark plugs, caps, rotors. I adjusted the valves last weekend. I’m also running pertronix. I took a look at my fuel filter and it looks ok. Though, there is a rather large air bubble in it. I'm not sure if this is a problem and normal or not.

I'm thinking Fuel Delivery or Ignition. Any thoughts or guesses before I walk through the whole Ignition system and Fuel Delivery?

-d

Do you lose power on surface streets pulling a long hill, like that Route 26 or 28 or whatever on your way over the hill to Portland from Beaverton?
Try an extended "freeway rpm" run in 2nd gear on surface street hill and see if it happens. If so, fuel delivery, possilbe pump crap-out, mechanical or electric?
Colin

I have intermittent lose on side streets under HEAVY Load aka up a big hill. The issue seems to be in both 2nd and 3rd gear (AT). I'm running a Carter electric fuel pump. About 2 years old.

Big hill, fuel starvation. My guess. Electric pumps have their issues as they get older and particularly . . . . if you have EVER . . . . run them low on gas. I had a fuel pump issue in the RW that turned out to be electrical supply to the pump. There was a wire terminal getting resistant under the plastic insulation. Weird happenstance of symptoms too.
Colin

[vdubyah73]

fuel filters are cheap, replace that before leaping directly to replacing a fuel pump. even when they look ok they can be plugged.

[dhoch14]

I tried the fuel filter tonight. I also re-synched the carbs.

Same issue. I even managed to have the bus fully stall out when I came I a stop off the highway.

I'm scratching my head on this one.

Any suggestions?

[vdubyah73]

Kink in rubber fuel line, gas tank not venting properly? Fuel pump? How experienced are you at synch'ing carbs? Making same mistake repeatedly?

[Amskeptic]

I tried the fuel filter tonight. I also re-synched the carbs.

Same issue.

I already gave you my take. I don't remember mentioning re-synching the carbs like what good would that do? I remember mentioning checking the integrity of the fuel pump electrical supply and possibly being alert to the fuel pump going out. A hint of this is a light little death rattle d-d-d-d-d-d-d-d-d-d-d-d-d-d-d--d-d-d-d-D-D-D-D-D-D-d-d-d-d-d-d-d-d-d-d-d-d-d- sort of annoying when you do pull off the road, it is louder when warm and when the gas tank is low. Do you have any improvement with a full tank? Poorly located pumps can be terribly unreliable. They need to be as low under and close to the tank as common sense allows. The people who mount them in the engine compartment at or above fuel level inside the tank are asking for trouble.
Colin

[Oregon72]

All your vac lines and wires connected good and strong? Just a stab in the dark Dave. Do you think the problem was due to the re-synch? Any way you could go back to your previous synch settings and give it a test run?

[Amskeptic]

Just a stab in the dark Dave. Do you think the problem was due to the re-synch? Any way you could go back to your previous synch settings and give it a test run?

Once I cruise to desired speed on highway, I lose power. I can push the pedal and it does nothing. As soon as I pull over, the pedal works again. I can take back roads without issue. It only happens on the highway. It is as if the carbs are being flooded STARVED.

We are going to distinguish ourselves from the Fling Ideas And See What Sticks School of theSamba.

Do NOT waste your time with screwing around with the synchronization of the carburetors of all things when it runs well on back roads. Think about it, out-of-synch carburetors would be giving you hell just pulling out of the driveway and all over the place.

I desperately do not want people to throw themselves willy-nilly at their engines without at least first working through the diagnostic steps called-for to get rid of variables. I sometimes read the exploding guesses threads on theSamba and it has got to be so confusing and so overwhelming.

If you have personal experience that mirrors the symptoms, then by all means share what you experienced.
Colin

[dhoch14]

I tried the fuel filter tonight. I also re-synched the carbs.

Same issue.

I already gave you my take. I don't remember mentioning re-synching the carbs like what good would that do? I remember mentioning checking the integrity of the fuel pump electrical supply and possibly being alert to the fuel pump going out. A hint of this is a light little death rattle d-d-d-d-d-d-d-d-d-d-d-d-d-d-d--d-d-d-d-D-D-D-D-D-D-d-d-d-d-d-d-d-d-d-d-d-d-d- sort of annoying when you do pull off the road, it is louder when warm and when the gas tank is low. Do you have any improvement with a full tank? Poorly located pumps can be terribly unreliable. They need to be as low under and close to the tank as common sense allows. The people who mount them in the engine compartment at or above fuel level inside the tank are asking for trouble.
Colin

I'm with you on this CK. My instincts tell me Fuel Delivery. I also resynched my carbs as it was the only variable I changed when problem arose. I wanted to make darn sure I didn't screw this up, despite feeling very confident in my abilities.

For what it is worth, I am not hearing any abnormal sounds from the fuel pump. I also filled up the gas hoping this could solve the issue (bad gas or dilluting polluted gas). Nada.

The fuel pump is located near the starter AND below the tank levels.

Perhaps this is a stupid question, but how do I check the integrity of the electrical supply? Just follow the wires (+ from the coil & ground) to see if they are out of wack? Like the positive grounding through the insulated end?

I have a back-up fuel pump I might consider putting in to see if it is actually the pump.

We are going to distinguish ourselves from the Fling Ideas And See What Sticks School of theSamba.

Do NOT waste your time with screwing around with the synchronization of the carburetors of all things when it runs well on back roads. Think about it, out-of-synch carburetors would be giving you hell just pulling out of the driveway and all over the place.

I desperately do not want people to throw themselves willy-nilly at their engines without at least first working through the diagnostic steps called-for to get rid of variables. I sometimes read the exploding guesses threads on theSamba and it has got to be so confusing and so overwhelming.

If you have personal experience that mirrors the symptoms, then by all means share what you experienced.
Colin

I HEAR that. I guess I should check my tire pressure cause that could cause this issue. Or just rebuild the engine. :)

[dhoch14]

All your vac lines and wires connected good and strong? Just a stab in the dark Dave. Do you think the problem was due to the re-synch? Any way you could go back to your previous synch settings and give it a test run?

Crap, I didn't have my spark plugs connected. Sike!

I thought the same thing and went there first. We are still young grasshopper!

[Amskeptic]

I am not hearing any abnormal sounds from the fuel pump. I also filled up the gas hoping this could solve the issue (bad gas or dilluting polluted gas). Nada.
The fuel pump is located near the starter AND below the tank levels.

Perhaps this is a stupid question, but how do I check the integrity of the electrical supply?

I have a back-up fuel pump I might consider putting in to see if it is actually the pump.

If your pump ever does give the death-rattle, fill up the gas tank pronto, this can help you get to where you are going so you can deal with it on your own terms. I was not thinking bad gas with the above suggestion, just get a good head of gravity fuel pressure for the pump. Your pump location is near the starter but on the car away from heat soak issues? Fuel lines away from big heat producers?

What I was recommending, was to check the integrity of the electrical supply for the pump only, not the whole car. I had a connection that went bad invisibly and I was dropping dead all over freeway onramps, bridge abutments, the car would just lose power and gas pedal seemed like a brake. Once I was futzing with wires, the pump would come back to life then die at the next inopportune time.
Colin

[dhoch14]

I am not hearing any abnormal sounds from the fuel pump. I also filled up the gas hoping this could solve the issue (bad gas or dilluting polluted gas). Nada.
The fuel pump is located near the starter AND below the tank levels.

Perhaps this is a stupid question, but how do I check the integrity of the electrical supply?

I have a back-up fuel pump I might consider putting in to see if it is actually the pump.

If your pump ever does give the death-rattle, fill up the gas tank pronto, this can help you get to where you are going so you can deal with it on your own terms. I was not thinking bad gas with the above suggestion, just get a good head of gravity fuel pressure for the pump. Your pump location is near the starter but on the car away from heat soak issues? Fuel lines away from big heat producers?

What I was recommending, was to check the integrity of the electrical supply for the pump only, not the whole car. I had a connection that went bad invisibly and I was dropping dead all over freeway onramps, bridge abutments, the car would just lose power and gas pedal seemed like a brake. Once I was futzing with wires, the pump would come back to life then die at the next inopportune time.
Colin

Yes, the fuel pump is away from major heat sources. Yikes, that would be dangerous.

I rewired the pump last night and made sure it was well insulated. Same issue.

I'm thinking of replacing the fuel pump tonight and see if that makes a difference.

I hate throwing parts to "fix" things. Isn't this what GM does? :)

-dave