possible fuel delivery problem - need some experts
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From: wichita falls, Tx
possible fuel delivery problem - need some experts Here's what I have:
LT1 383ci forged stroker with eagle rotating assemble, GTP stage II heads, GTP #6 cam, 52mm throttle body, SVO 30lb injectors, hooker LT's, custom Y w/no cats, thru bullet and dumped, MTI tuned.
Here's my problem, a couple of weeks ago on my trip to houston, the car started detonating (knocking) under load and partial to full throttle. Jayson (MTI) had done the tuning on the car so I took it to him and told him my problem and he pulled some timing because he said there was alot in the bottom end with partial throttle. This seemed to help the problem but it knocked on me just a little going back home to wichita falls after the car had gotten good and warm. So yesterday I pull the plugs on the drivers side and find that the #1 and #3 plugs are pinkish on the insulator and the strap that hoods the electrode are white on the back - #5 and #7 are fairly dark but no pinkish discoloration and the electrodes aren't white. Today I pull the passenger side plugs (pain in my A$$) and find the same things #2 and #4 are slightly pinkish and the back two are not.
What could be the cause:
a. tank full of bad gas screwed up the injectors
b. fuel pump not supplying enough fuel to the rail to keep the front four cylinders rich enough
c. I'm a dumbass and this is normal
d. problem with cooling system
e. something else I haven't thought about
Please help with my problem and sorry for the long post.
Michael
LT1 383ci forged stroker with eagle rotating assemble, GTP stage II heads, GTP #6 cam, 52mm throttle body, SVO 30lb injectors, hooker LT's, custom Y w/no cats, thru bullet and dumped, MTI tuned.
Here's my problem, a couple of weeks ago on my trip to houston, the car started detonating (knocking) under load and partial to full throttle. Jayson (MTI) had done the tuning on the car so I took it to him and told him my problem and he pulled some timing because he said there was alot in the bottom end with partial throttle. This seemed to help the problem but it knocked on me just a little going back home to wichita falls after the car had gotten good and warm. So yesterday I pull the plugs on the drivers side and find that the #1 and #3 plugs are pinkish on the insulator and the strap that hoods the electrode are white on the back - #5 and #7 are fairly dark but no pinkish discoloration and the electrodes aren't white. Today I pull the passenger side plugs (pain in my A$$) and find the same things #2 and #4 are slightly pinkish and the back two are not.
What could be the cause:
a. tank full of bad gas screwed up the injectors
b. fuel pump not supplying enough fuel to the rail to keep the front four cylinders rich enough
c. I'm a dumbass and this is normal
d. problem with cooling system
e. something else I haven't thought about
Please help with my problem and sorry for the long post.
Michael
Re: possible fuel delivery problem - need some experts do you have a stock fuel pump still?
if they know where to put the tuning and you are not talking about wide open then i would go with the pressure regulator being bad or set too low or the fuel pump is bad/leak inside the gas tank
#1 check your fuel pressure
if they know where to put the tuning and you are not talking about wide open then i would go with the pressure regulator being bad or set too low or the fuel pump is bad/leak inside the gas tank
#1 check your fuel pressure
Thread Starter
On The Tree
Joined: Nov 2002
Posts: 132
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From: wichita falls, Tx
Re: possible fuel delivery problem - need some experts Alright guys, here's the data:
With fuel pressure regulator hooked up and with the key turned on - I get a whopping 40psi. here's the interesting thing, within 20 seconds it drops by 2 pounds.
Now with engine on and idling - the psi is 39. When you bump the rpm up to 2K the psi drops by 5 lbs and the higher the rpm - the lower it goes and never recovers. Me thinks my fuel pump is tired.
Now for my next question which set up to go with, Aeromotive adjustable regulator? Racetronix LT1 kit with GSS360 Walbro? I'm not real full up on fuel sytem needs like I should be but here is what I need. My 383 puts out 415rwhp and I'm going to go with a power adder in the future. what would you guys do if you were me?
Michael
With fuel pressure regulator hooked up and with the key turned on - I get a whopping 40psi. here's the interesting thing, within 20 seconds it drops by 2 pounds.
Now with engine on and idling - the psi is 39. When you bump the rpm up to 2K the psi drops by 5 lbs and the higher the rpm - the lower it goes and never recovers. Me thinks my fuel pump is tired.
Now for my next question which set up to go with, Aeromotive adjustable regulator? Racetronix LT1 kit with GSS360 Walbro? I'm not real full up on fuel sytem needs like I should be but here is what I need. My 383 puts out 415rwhp and I'm going to go with a power adder in the future. what would you guys do if you were me?
Michael
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From: Raleigh, NC
Re: possible fuel delivery problem - need some experts The GSS340 Walbro would supply all the fuel pump you need. It supports over 500 RWHP. IF you get more power than that, you may be able to hook two of them together. That's what I did in my '98 LS1.
TECH Resident
Joined: Jan 2002
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From: USA
Re: possible fuel delivery problem - need some experts You should be more like 44 lbs fuel rail pressure not 39 and cause of leaning out. Also the fuel filter may be to blame, it not then it is the fuel pump or regulator.
I would not have yanked timing, that was a band-aid to mask the real problem so I would correct fuel pressure and put the timing back.
I would not have yanked timing, that was a band-aid to mask the real problem so I would correct fuel pressure and put the timing back.
Alright guys, here's the data:
With fuel pressure regulator hooked up and with the key turned on - I get a whopping 40psi. here's the interesting thing, within 20 seconds it drops by 2 pounds.
Now with engine on and idling - the psi is 39. When you bump the rpm up to 2K the psi drops by 5 lbs and the higher the rpm - the lower it goes and never recovers. Me thinks my fuel pump is tired.
Now for my next question which set up to go with, Aeromotive adjustable regulator? Racetronix LT1 kit with GSS360 Walbro? I'm not real full up on fuel sytem needs like I should be but here is what I need. My 383 puts out 415rwhp and I'm going to go with a power adder in the future. what would you guys do if you were me?
Michael
With fuel pressure regulator hooked up and with the key turned on - I get a whopping 40psi. here's the interesting thing, within 20 seconds it drops by 2 pounds.
Now with engine on and idling - the psi is 39. When you bump the rpm up to 2K the psi drops by 5 lbs and the higher the rpm - the lower it goes and never recovers. Me thinks my fuel pump is tired.
Now for my next question which set up to go with, Aeromotive adjustable regulator? Racetronix LT1 kit with GSS360 Walbro? I'm not real full up on fuel sytem needs like I should be but here is what I need. My 383 puts out 415rwhp and I'm going to go with a power adder in the future. what would you guys do if you were me?
Michael
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Thread Starter
On The Tree
Joined: Nov 2002
Posts: 132
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From: wichita falls, Tx
Re: possible fuel delivery problem - need some experts Just to let everyone know - I got the fuel pump changed (cut through the back deck) and now have good fuel pressure. Does anyone know where I can find a good package inclunding a sending unit and in cockpit pressure gauge. Thanks for the replies.
Michael
Michael
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