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GMC V6 and V12 Engines Engine repair and rebuilding

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  #11  
Old April 21st, 2023, 12:27 AM
lizziemeister'sV6 lizziemeister'sV6 is offline
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Default Re: Fuel supply loss when in gear

Do you fellows who run electric pumps control them with an oil pressure switch so if your engine quits running the electric fuel pump stops? If not - how do you control them so they're not constantly running when your switch is on? I feel a mechancial pump is a lot safer - IF you don't have a power cut-off. I have installed electric pumps on hot rods only if I can wire them in an oil pressure switch.
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  #12  
Old April 21st, 2023, 02:15 PM
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Default Re: Fuel supply loss when in gear

i agree with you lizziemiester, i only use my electric pump for emergency. it also would make a good test pump to check for plugged tank sock.
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  #13  
Old April 21st, 2023, 03:25 PM
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Default Re: Fuel supply loss when in gear

Goodpal : After alot of suggestions and replacment and repair i pulled fuelline off fuel pump and noticed what looked like black pepper in fuel.Gas tank flushed and never had that problem again.Truck was low miles , just was not driven enough.jmf
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  #14  
Old April 24th, 2023, 05:04 PM
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Default Re: Fuel supply loss when in gear

Thanks again everyone for the continued ideas and sorry for the hold up in getting back to everybody.

I swung by the parking lot I'd left my truck in and, after venting the gas tank for a minute or two, started her up and we were off to the races. AZKen I followed your recommendation about driving without the gas cap back home and didn't notice any issues on the drive home (about 5 miles).

When I got home I screwed the gas cap back on and let the truck sit for a few hours and went out for another few mile drive. This time start-up wasn't happening so I removed the gas cap again and we got going pretty quickly. Ride to the auto parts store was uneventful, one short loss of power driving back over the bridge (pretty steep uphill) but I leaned in on the throttle and we powered through it and no problems after that.

I bought a new vented gas cap for the truck and once it stops pouring rain here am going to see how we do with that.

I did notice once I was back to the driveway and revving at idle some oil spitting out the tailpipe as well as what looks like a skim of oil on top of the fuel pump so I do plan to see if I can blow back into the gas tank with the fuel filter off to check for clogs, replace the fuel filter, and see if any of the fuel pump suggestions from above continue to help out.

I really appreciate the time and knowledge from everyone, I'll check back in once I have had a chance to do some more structured tinkering
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  #15  
Old April 24th, 2023, 11:31 PM
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Default Re: Fuel supply loss when in gear

Should not be any actual oil coming out of tail pipe. Probably condensation mixed with tail pipe carbon/soot. Don't worry about that. If there is no blue smoke at tail pipe or oil fill hole/breather hole, you don't have bypass. Conpression test will help with that theory.
Blowing out lines while connected is a NO!
You said you cleaned the tank and put in new sender with new sock? A pump flow test will tell you info. If you think lines are clogged, replace the rubber ones. Disconnect hard lines at both ends and blow out. DO NOT blow into the tank or pump or carb.

Yuo need more test miles before more remedy.

Last edited by AZKen; April 24th, 2023 at 11:44 PM.
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