couple of problems/questions...
10-20-2008, 10:13 AM
#1
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couple of problems/questions... ok guys...well i got a 1986 cutlass salon and just recently done a swap with a2004 LQ4, took off the fuel injection and put a carb, everything is is brand new, 700r4 trans, aluminum radiator, cam, roller lifters, holley double pumper 750 hp carb, eldelbrock intake, aeromotive fuel system..ect ect (too much to list)
my problem is when i take off the car has SERIOUS power...but once it gets going, it loses power and bogs out on top end, and when i step on the gas on top end it doesnt respond any more...does anyone know what this is from or where can i start to check?
Thanks a million!!!!
frank
my problem is when i take off the car has SERIOUS power...but once it gets going, it loses power and bogs out on top end, and when i step on the gas on top end it doesnt respond any more...does anyone know what this is from or where can i start to check?
Thanks a million!!!!
frank
10-20-2008, 02:25 PM
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thats what i thought too...but my fuel pressure gauge acts retarded, i'll set it to like 6.5 psi and when the car gets hot the gauge reads 2.5 psi, what should it be set to?
is there a company that make electric water pumps for these motors? if so what size belt do i use?
is there a company that make electric water pumps for these motors? if so what size belt do i use?
10-20-2008, 02:52 PM
#7
You've some reading to do on carburetors. They're rated by airflow in CFM, not horsepower as you indicated in your first post.
Understanding carb function is the key to tuning them properly...they're rarely tuned to your specific engine and intake/exhaust combo out of the box. Variables include metering jets (primary and secondary), power valve, accelerator pump cam and nozzles, float level...etc.
The problem you're having may be as simple as your fuel pump being unable to keep the fuel bowls full when the engine is running at high revs. Or the floats being adjusted too low.
(let me guess...you went with a carb because they're "easier" than injection?"
Understanding carb function is the key to tuning them properly...they're rarely tuned to your specific engine and intake/exhaust combo out of the box. Variables include metering jets (primary and secondary), power valve, accelerator pump cam and nozzles, float level...etc.
The problem you're having may be as simple as your fuel pump being unable to keep the fuel bowls full when the engine is running at high revs. Or the floats being adjusted too low.
(let me guess...you went with a carb because they're "easier" than injection?"
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10-20-2008, 03:01 PM
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yeah, the "mechanic" which now i find out is an idiot, told me it would produce more HP and be easier....i guess he was wrong...
the carb i have is: http://www.jegs.com/i/Holley/510/0-82751/10002/-1
the fuel pump i have is: Aeromotive Street/Strip Fuel Pump 027-11203
the carb i have is: http://www.jegs.com/i/Holley/510/0-82751/10002/-1
the fuel pump i have is: Aeromotive Street/Strip Fuel Pump 027-11203
10-20-2008, 03:41 PM
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ok...some one told me to check the float levels, you gotta turn on then off your car, take off the screws on the passenger side of the carb and if the fuel is even with the whole of the screw your fine...is that correct? because thats what i did and it was right till the whole but not comin out...
10-20-2008, 06:19 PM
#13
If both fuel bowls check out as you describe, then the floats are fine.
Time for tuning, starting with the jets. An engine falling on its face is usually lean, but I pull & read spark plugs right after a hard WOT run before I make the decision.
Time for tuning, starting with the jets. An engine falling on its face is usually lean, but I pull & read spark plugs right after a hard WOT run before I make the decision.
10-21-2008, 07:08 AM
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she does great right untill i hold wide open for too long (about 10-12 seconds)
10-21-2008, 07:16 AM
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Please go into some detail as far as your fuel system. What size and type of line are you using before pump, after pump, after regulator, any inline filters, what regulator are you using?
It sounds like you are running lean up top which could be as simple as jetting up the secondaries, but then you mentioned that at wot your fuel pressure drops. That makes me think you have a problem in the fuel system somewhere, and if that is the case and you try jetting up first all you are going to do is empty the fuel bowl faster and go lean sooner.
The first thing I would do is find out why the fuel pressure is dropping. Then work on jetting if it is still needed.
It sounds like you are running lean up top which could be as simple as jetting up the secondaries, but then you mentioned that at wot your fuel pressure drops. That makes me think you have a problem in the fuel system somewhere, and if that is the case and you try jetting up first all you are going to do is empty the fuel bowl faster and go lean sooner.
The first thing I would do is find out why the fuel pressure is dropping. Then work on jetting if it is still needed.
10-21-2008, 08:17 AM
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Please go into some detail as far as your fuel system. What size and type of line are you using before pump, after pump, after regulator, any inline filters, what regulator are you using?
It sounds like you are running lean up top which could be as simple as jetting up the secondaries, but then you mentioned that at wot your fuel pressure drops. That makes me think you have a problem in the fuel system somewhere, and if that is the case and you try jetting up first all you are going to do is empty the fuel bowl faster and go lean sooner.
The first thing I would do is find out why the fuel pressure is dropping. Then work on jetting if it is still needed.
It sounds like you are running lean up top which could be as simple as jetting up the secondaries, but then you mentioned that at wot your fuel pressure drops. That makes me think you have a problem in the fuel system somewhere, and if that is the case and you try jetting up first all you are going to do is empty the fuel bowl faster and go lean sooner.
The first thing I would do is find out why the fuel pressure is dropping. Then work on jetting if it is still needed.
my pressure "seems" to drop when the motor warms up, like after 20 minutes...i'll check it today...i'm take it to a carb specialist and see what they say... but it seems to be the carb tunning huh?