Re: Fuel Starvation
[Re: Challenger 1]
#343081
06/10/09 10:09 AM
06/10/09 10:09 AM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Maybe hookup a temp fuel pressure line at the carb and put the gauge temp somewhere where you can see it when the car falls off?
or if you have jets you can jet it up 2 or 3 jet sizes... if it does the same thing its more than likely a supply issue
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Re: Fuel Starvation
[Re: MR_P_BODY]
#343082
06/10/09 10:12 AM
06/10/09 10:12 AM
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Joined: Apr 2003
Posts: 3,968 North Riverside IL & Lowell IN
GTXKen
OP
super gas
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OP
super gas
Joined: Apr 2003
Posts: 3,968
North Riverside IL & Lowell IN
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Quote:
Quote:
Maybe hookup a temp fuel pressure line at the carb and put the gauge temp somewhere where you can see it when the car falls off?
or if you have jets you can jet it up 2 or 3 jet sizes... if it does the same thing its more than likely a supply issue
I have jets, I'm running 80s and 88s now and have a very minor bog at 1200 RPM. Are you saying jetting could be the issue?
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Re: Fuel Starvation
[Re: GTXKen]
#343085
06/10/09 10:25 AM
06/10/09 10:25 AM
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Joined: May 2007
Posts: 446 oregon
savoyracer
mopar
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mopar
Joined: May 2007
Posts: 446
oregon
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Quote:
I rarely post in the race forum but I think this the best place for this one...
I think I have a fuel starvation issue. I am running a carter M6903 with 3/8 fuel line through a 40 micron Russell in line filter from on my 500 inch stroker motor. Stock style fuel tank and pickup. Carb is a Quickfuel 830. It pulls fine up until about 4000 RPM and then it falls flat and bogs down completely until I let off the throttle. Like I said I think it’s a fuel issue but maybe I’m wrong. If it is a fuel issue where do I start troubleshooting? How do I check a mechanical pump? I don’t have a fuel pressure gauge in the car, just one on the carb.
Thanks Ken
Sure sounds like a fuel delivery problem. in my humble opinion everything you have is way to small for a 500 inch motor. you also might have another self-inflicted problem. If I were you, I would cut open my oil filter, and get a magnifying glass, and look in the pleats for brass. If it is there, time to put new bearings in it. Inadequate fuel delivery will cause a lean condition, which can take out bearings. not saying that it has happened yet, just saying you should look at it.
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Re: Fuel Starvation
#343090
06/10/09 11:17 AM
06/10/09 11:17 AM
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Joined: Apr 2003
Posts: 3,968 North Riverside IL & Lowell IN
GTXKen
OP
super gas
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OP
super gas
Joined: Apr 2003
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North Riverside IL & Lowell IN
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Quote:
I would think that the pump/line setup is your issue...A stock tank pickup with a 3/8" line and a mech pump pulling for fuel is asking alot to supply a 500cu.in. motor with a big carb. I would suggest a small electric pump (Like a Holley Blue) to push the fuel up to the mech pump. Install a regulator between the pumps to limit pressure to 6.5-7.0 lbs. This will insure constent fuel supply to the mech. pump..It is better to push the fuel rather than pull it...This will correct you problem and wiring the pump t the ignition will make it as stock as possible. (No switches to remember to turn on).I have seen this problem several times on street/strip cars...poppaj
Sounds like this is where I will be headed, is my (all new) 3/8 line big enough? Holly wants the regulator by the carb. I assume that you suggest putting it between the pumps because my mechanical dosen't require a regulator and we don't want the electic fuel pump over powering the mechanical pump?
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Re: Fuel Starvation
[Re: GTXKen]
#343091
06/10/09 12:45 PM
06/10/09 12:45 PM
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Joined: Oct 2004
Posts: 8,165 Left Coast
BobR
master
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master
Joined: Oct 2004
Posts: 8,165
Left Coast
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Quote:
Quote:
I would think that the pump/line setup is your issue...A stock tank pickup with a 3/8" line and a mech pump pulling for fuel is asking alot to supply a 500cu.in. motor with a big carb. I would suggest a small electric pump (Like a Holley Blue) to push the fuel up to the mech pump. Install a regulator between the pumps to limit pressure to 6.5-7.0 lbs. This will insure constent fuel supply to the mech. pump..It is better to push the fuel rather than pull it...This will correct you problem and wiring the pump t the ignition will make it as stock as possible. (No switches to remember to turn on).I have seen this problem several times on street/strip cars...poppaj
Sounds like this is where I will be headed, is my (all new) 3/8 line big enough? Holly wants the regulator by the carb. I assume that you suggest putting it between the pumps because my mechanical dosen't require a regulator and we don't want the electic fuel pump over powering the mechanical pump?
I would advise you to throw the mechanical pump in the trash and replace it with a BG HR220 electric pump. This pump has a return style regulator which is needed for street driving. Using an electric to feed a mechanical is not a good idea. If the diaphram in the mechanical fails you could get fuel pumped directly into your motor. I don't use cam driven mechanical pumps for anything.
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Re: Fuel Starvation
#343092
06/10/09 01:03 PM
06/10/09 01:03 PM
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Joined: Jan 2003
Posts: 732
mikemotorhead
super street
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super street
Joined: Jan 2003
Posts: 732
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"you also might have another self-inflicted problem. If I were you, I would cut open my oil filter, and get a magnifying glass, and look in the pleats for brass. If it is there, time to put new bearings in it. Inadequate fuel delivery will cause a lean condition, which can take out bearings. not saying that it has happened yet, just saying you should look at it" I assume you mean from missfires pounding the bearings??? If so I think it would take a lot of this to cause bearing failure! Mike
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Re: Fuel Starvation
[Re: BobR]
#343093
06/10/09 01:07 PM
06/10/09 01:07 PM
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Joined: Jan 2003
Posts: 11,721 Portage,michigan
B3422W5
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 11,721
Portage,michigan
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My guess is that its a pickup issue in the tank..
Few years back i was running low 11's with stock tank, mech pump and a 3/8 pickup..
I always left the tank full...one time i raced the car with 1/2 tank of gas in it and ran into same symptoms you are dealing with.(fuel sloshing around uncovered the pickup)
As others have stated, a cell and electric pump would solve your problems, but putting one of those sump/pickups in the bottom of your stock tank might well solve it as well....
69 Dart GTS A4 Silver All steel, flat factory hood, 3360race weight 418 BPE factory replacement headed stroker, 565 lift solid cam Best so far, 10.40 @127 1/4 1.41 best 60 foot 6.60 at 103.90 1/8
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Re: Fuel Starvation
[Re: B3422W5]
#343094
06/10/09 01:14 PM
06/10/09 01:14 PM
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Joined: Jun 2003
Posts: 9,225 Charleston
sixpackgut
Drag Week Mod Champion
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Drag Week Mod Champion
Joined: Jun 2003
Posts: 9,225
Charleston
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i have a 1/2" pickup in stock tank with a mallory 140 pump and return style regulator. works great
-8an lines for both supply and return
Gen 3 power 6.22@110, 9.85@135 Follow @g3hemiswap on instagram
performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
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Re: Fuel Starvation
[Re: GTXKen]
#343095
06/10/09 01:41 PM
06/10/09 01:41 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
Quote:
I would think that the pump/line setup is your issue...A stock tank pickup with a 3/8" line and a mech pump pulling for fuel is asking alot to supply a 500cu.in. motor with a big carb. I would suggest a small electric pump (Like a Holley Blue) to push the fuel up to the mech pump. Install a regulator between the pumps to limit pressure to 6.5-7.0 lbs. This will insure constent fuel supply to the mech. pump..It is better to push the fuel rather than pull it...This will correct you problem and wiring the pump t the ignition will make it as stock as possible. (No switches to remember to turn on).I have seen this problem several times on street/strip cars...poppaj
Sounds like this is where I will be headed, is my (all new) 3/8 line big enough? Holly wants the regulator by the carb. I assume that you suggest putting it between the pumps because my mechanical dosen't require a regulator and we don't want the electic fuel pump over powering the mechanical pump?
Exactly Ken, it will supply the mech pump with fuel without over running it. MSD makes a nice quiet inline pump that would be perfect for your car, and it is only $100. poppaj
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Re: Fuel Starvation
[Re: BobR]
#343096
06/10/09 01:45 PM
06/10/09 01:45 PM
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Joined: Apr 2003
Posts: 3,968 North Riverside IL & Lowell IN
GTXKen
OP
super gas
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OP
super gas
Joined: Apr 2003
Posts: 3,968
North Riverside IL & Lowell IN
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Quote:
Quote:
Quote:
I would think that the pump/line setup is your issue...A stock tank pickup with a 3/8" line and a mech pump pulling for fuel is asking alot to supply a 500cu.in. motor with a big carb. I would suggest a small electric pump (Like a Holley Blue) to push the fuel up to the mech pump. Install a regulator between the pumps to limit pressure to 6.5-7.0 lbs. This will insure constent fuel supply to the mech. pump..It is better to push the fuel rather than pull it...This will correct you problem and wiring the pump t the ignition will make it as stock as possible. (No switches to remember to turn on).I have seen this problem several times on street/strip cars...poppaj
Sounds like this is where I will be headed, is my (all new) 3/8 line big enough? Holly wants the regulator by the carb. I assume that you suggest putting it between the pumps because my mechanical dosen't require a regulator and we don't want the electic fuel pump over powering the mechanical pump?
I would advise you to throw the mechanical pump in the trash and replace it with a BG HR220 electric pump. This pump has a return style regulator which is needed for street driving. Using an electric to feed a mechanical is not a good idea. If the diaphram in the mechanical fails you could get fuel pumped directly into your motor. I don't use cam driven mechanical pumps for anything.
I can see where using both an electric and mechanical pump cpould be a problem. Before I jump to an electric fuel pump I need to remove any other issues there may be.
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Re: Fuel Starvation
[Re: GTXKen]
#343097
06/10/09 01:57 PM
06/10/09 01:57 PM
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Joined: Apr 2003
Posts: 3,968 North Riverside IL & Lowell IN
GTXKen
OP
super gas
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OP
super gas
Joined: Apr 2003
Posts: 3,968
North Riverside IL & Lowell IN
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Well, thanks for the replys I really need to do some troubleshooting here before I throw money at more parts. I have a checklist... Pull the outlet side of the pump hose off and use the started to see if its putting out the fuel it should. Pull the fuel pickup in the tank and see if there is anything clogging it or if its possible it could colapse. Check the lines and connections for any obstructions or leaks. Check the tank vent. Check the stator to rotor clearence to see if its a spark issue at speed. Check the powervalve size. Make a run without an air cleaner (new) Finally, get a fuel pressue gauge. This will take the better part of an evening, if anyone has any other ideas let me know. Thanks again
Last edited by GTXKen; 06/10/09 02:09 PM.
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