Engine Problem
- Thread starter Zack
- Start date
Zack
Member
Hey Lee. Here is my fuel pump. Yes, as i recall the previous owner of the carbs did tell me he was running them on a blower.
EXTREME SERIES HIGH VOLUME CHROME MECHANICAL FUEL PUMP FOR SBC CHEVY ENGINES. 150 GPH
Fits most all sbc small block Chevy engines requiring a mechanical fuel pump.
This fuel pump has 1/4" NTP inlets and outlet.
- High Output Fuel Flow
- Shutoff Pressure Pre-set 8.0 PSI
- Fuel Pressure Regulator is Not Required, but recommended.
- Heavy Duty Construction For Continuous High RPM Operation
- Fuel Body Casting Can Be Rotated to Accommodate Various Plumbing Situations
- Inlet & Outlet Tapped For 1/4" NPT
This fuel pump has a lifetime warranty, and we will back it up 100% regardless of what type use or mileage. This pump is heavy duty rated for street, strip, or off road use.
Extreme series fuel pump for most all small block Chevy engines. This pump has a 150 gallon volume at 6 psi. At wide open throttle this pump may run a max pressure of 7-8psi. This is the fuel pump you want for high hp street or strip applications from 200-450 hp. The fuel demands under wide open throttle on an engine are very high, especially those with large cfm carbs. Never would you want to run a stock fuel pump on an engine that has been built up to any degree. Remember, most stock Chevy engines produced around 180-210 hp. The oem style fuel pumps were designed to accommodate a very low fuel demand.
Fuel pressure should be regulated to between 5 and 6 psi for normal driving. Off-roading might require less pressure, while all out drag racing might require 6-8 psi. Too much fuel pressure can cause the carb to run rich at low speeds, while too little fuel pressure might cause the carb to run lean during high engine speeds and loads. It is our recommendation that you run a fuel pressure regulator and gauge to set the pressure where it needs to be. The regulator will keep the pressure much more consistent, and eliminate problems caused by to much or to little pressure.
Zack
Member
The saga continues. Tonight i adjust all the floats back to factory setting. The rods,jets and spring are all factory stock. Nothing has been modified from original that i can see. When i started it, it still was popping out the exhaust. I think it has to be an ignition/electrical problem somewhere. The carbs are working great as far as i can see. Any other ideas?
PS...... I think the previous owner of the carbs flat out lied to me about them being modified because he ran them on a blower. I now see no evidence of that at all.
PS...... I think the previous owner of the carbs flat out lied to me about them being modified because he ran them on a blower. I now see no evidence of that at all.
Lee_in_KC
Active Member
What are the numbers on the jets and rods? What color are the springs?
Zack
Member
Don'tCallMeJimmie
Member
Your fuel pump specs out at 6-8psi. Edelbrock carbs don't "like" pressures that high, more like 3-1/2 to 4-1/2 is more realistic for them.
Zack
Member
I did read that somewhere. I will be installing a regulator soon. I don't think the "rich" mixture is much of a problem anymore since i adjusted the floats. This popping back sounds to me like an electrical miss instead of a burning fuel in the exhaust.
Mike
Well-Known Member
Check your fuel pressure before you go any further. Sales ads don't tell anyone anything. If that ad is anywhere close to being accurate, you obviously have a pressure issue. For the record, a friend from this division we used to race with now does a lot of carb work. His customer list reads like a who's-who of National Champions and record holders in Pro Stock. Allow me to quote from his most recent newsletter -
In nearly all applications, 4.5 psi is going to be more than adequate. As long as you have enough incoming pressure to overcome the float, you have adequate pressure. 6 psi doesn't make any more power than 4 psi. And if you have any more than 6 psi on those Edelbrock carbs, you're flirting with disaster.
Pull the dipstick and give it a good whiff. Smell any gasoline odor? What's that telling you, other than you're flooding the cylinders with more raw fuel than they can handle? And if you do smell gas, add an oil change to your list of things to do.
Have you had a vacuum gauge on it, yet? What's the gauge telling you? Using a vacuum gauge as a tuning tool.
Hydraulic lifters or mechanical lifters? How have they been adjusted? Properly adjusting mechanical lifters. Properly adjusting hydraulic lifter pre-load.
Develop a plan of attack and then start testing things, to see what the motor is trying to tell you. It's saying it's not happy, so listen to it, instead of trying to use a shotgun approach. Don't guess at anything, check everything. Don't assume anything, check everything. And then go back and check it again.
After going back and re-reading that fuel pump propaganda, I had myself a good laugh. This is meant to be a double, throw-down, whiz-bang fuel pump, allegedly used by this eBay-er, on "most of the engine build-ups" they sell. With a retail value of $69.95, no less. Aye. Right.
Emphasis mine. Remember, you are not only relying on the needle and seat closing off properly, but also the action of the float working with it.
In nearly all applications, 4.5 psi is going to be more than adequate. As long as you have enough incoming pressure to overcome the float, you have adequate pressure. 6 psi doesn't make any more power than 4 psi. And if you have any more than 6 psi on those Edelbrock carbs, you're flirting with disaster.
Pull the dipstick and give it a good whiff. Smell any gasoline odor? What's that telling you, other than you're flooding the cylinders with more raw fuel than they can handle? And if you do smell gas, add an oil change to your list of things to do.
Have you had a vacuum gauge on it, yet? What's the gauge telling you? Using a vacuum gauge as a tuning tool.
Hydraulic lifters or mechanical lifters? How have they been adjusted? Properly adjusting mechanical lifters. Properly adjusting hydraulic lifter pre-load.
Develop a plan of attack and then start testing things, to see what the motor is trying to tell you. It's saying it's not happy, so listen to it, instead of trying to use a shotgun approach. Don't guess at anything, check everything. Don't assume anything, check everything. And then go back and check it again.
After going back and re-reading that fuel pump propaganda, I had myself a good laugh. This is meant to be a double, throw-down, whiz-bang fuel pump, allegedly used by this eBay-er, on "most of the engine build-ups" they sell. With a retail value of $69.95, no less. Aye. Right.
bigfrank330
Member
Hey Zach
If you think it is mechanical
pull the valve covers and watch the valves -- look to see that they are all moving the same
I had a similiar situation on my last bucket.
I found one of the valves were not working properly
After I pulled the missing 5/16 intake bolt out of the valve seat - it ran fine
Frank
If you think it is mechanical
pull the valve covers and watch the valves -- look to see that they are all moving the same
I had a similiar situation on my last bucket.
I found one of the valves were not working properly
After I pulled the missing 5/16 intake bolt out of the valve seat - it ran fine
Frank
Zack
Member
Wow, thanks for the good info guys. YES Ron, I will take one. I will call you today and get it ordered. Thanks for the offer.
I will pick up a new set of plugs today as well. I bought this engine from a professional engine builder, we ran it on his stand with his electrics and intake and it ran like a dream, no noise, popping or anything. I brought the long block home and installed my electrics and intake then the problems started. I am still waiting for my E-coil to arrive and see if that helps anything.
We did a vacuum test on all cylinders and all 8 of them range between 185-190 consistently.
Please keep the ideas and suggestions coming guys. I am basically throwing darts at it right now.
I will pick up a new set of plugs today as well. I bought this engine from a professional engine builder, we ran it on his stand with his electrics and intake and it ran like a dream, no noise, popping or anything. I brought the long block home and installed my electrics and intake then the problems started. I am still waiting for my E-coil to arrive and see if that helps anything.
We did a vacuum test on all cylinders and all 8 of them range between 185-190 consistently.
Please keep the ideas and suggestions coming guys. I am basically throwing darts at it right now.
2old2fast
Active Member
Here's something you may want to try ; unhook 1 carb, close the throttle plates ,close the idle adj. screws , see how it idles on 1 carb, if it's o.k. on 1, try the other one by itself, if it's good that way as well then the carbs are probably o.k. internally ,they're just to big, then you may have to take another approach. Look back in this forum a few threads & you'll see that mr. fixit had some issues w/ his similar setup, & what he did to "cure" it. dave
Zack
Member
I might just try that. I will also follow up on mr. fixit's post. Thanks.
one finger john
Active Member
Hi Zack, my buddy has a 327 in a 21 Dodge roadster. Ran an Edelbrock Street Tunnel Ram with two 500s. Carb set up was progressive. Primary jets were 83, secondary jets were 77, metering rods were .065 x .052, springs were blue, light weights in the distributor, initial timing 16*. You don't say what ignition, heads, cam you have and whether the engine is rebuilt. Ck. for gas contamination of the oil, replace the plugs (gas fouled?) get a vacuum guage. Got timing light?
Don't throw darts at it, change one thing at a time. Oh, by the way, you might have an intake manifold vacuum leak in the valley, don't think it would show up with an outside check.
Best of luck, John
Don't throw darts at it, change one thing at a time. Oh, by the way, you might have an intake manifold vacuum leak in the valley, don't think it would show up with an outside check.
Best of luck, John
Zack
Member
I would like to sincerely thank everyone person on here who has offered advise and suggestions to fix my problem. On my way home today i stopped by and picked up some new plugs (R43TS). I gapped them at .040 and installed. Fired it up and she runs like a sewing machine, NO misfire or anything. I am very happy at this moment. I knew the plugs in there were black but i had no idea that the fuel washed them so much that they would misfire. I learned something new today for sure. Now, if i can get the exhaust fumes to stop scorching my eyes i will be totally happy.
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