Okay guys here is the scenario.
As some of you know I just installed a tunnel ram with dual Holley 600's and now when I am at WOT she starts stumbling over itself and sputtering. I pulled the plugs and I am running WAY LEAN.I noticed the same issue with the Holley 800 and the Torker intake I just removed but it was very slight and the tunnel ram has magnified the problem greatly. Anything over 4600RPM's and she starts sputtering but the minute you back off the throttle a bit she smooths right out under 4600rpm's.
We tried cranking up the fuel pressure at the regulator but can't get it above 6lbs at idle.
Could it be that the mechanical fuel pump just can't provide enough fuel to feed 2 Holley 600's and she is just flat running out of fuel on the top end? Or maybe it's just crapping out on me from age.
Give me some feedback please.
There are a few things to check:
Make sure your tanks or fuel caps are vented
Are you drawing from both tanks at once, or are they valved seperate.
The pickup tube in the tanks could be partially clogged, broken, or sucking air
The fuel pump could be dying on you.
Restriction in filter/water seperator.
Fuel Line size too small.
Just some things to check.
T.J.
www.tjsperformance.com
There are a few things to check:
Make sure your tanks or fuel caps are vented
Are you drawing from both tanks at once, or are they valved seperate.
The pickup tube in the tanks could be partially clogged, broken, or sucking air
The fuel pump could be dying on you.
Restriction in filter/water seperator.
Fuel Line size too small.
Just some things to check.
T.J.
www.tjsperformance.com
Tanks are valved
Not sure if they are vented or not. (where would the vent be a side saddle tanks?) I believe they are the stock tanks installed by Sanger.
Pickup and filter are clean.( Just cleaned them when boat was stored last fall.)
1/2 line from tank to pump. 3/8 line from pump to regulator and carbs
Not a very good pic but it will give you an idea of what style cap is on the tanks. I was also told that the pump is probably an 80 gallon per hour pump which according to my info source isn't enough to supply the needed fuel for this tunnel ram setup. Need 110 gallon pump.
Just talked to my dad regarding this and the fuel pump that is on the motor is original equipment from 1978. Guess that answers the question huh.
Pump isn't gettin' the job done.:idea:
Keep in mind that you can't just plop on a tunnel ram and a pair of carbs that were most likely calibrated for another motor and expect it to run right out of the box. Alot of things have changed. Yes it might be your fuel pump contributing to the problem but the rest of the package will need some help. If I remember correctly your motor is more on the stock side. You probably wont see any performance improvement with the new setup. Just a bigger gas bill. IMO.
Keep in mind that you can't just plop on a tunnel ram and a pair of carbs that were most likely calibrated for another motor and expect it to run right out of the box. Alot of things have changed. Yes it might be your fuel pump contributing to the problem but the rest of the package will need some help. If I remember correctly your motor is more on the stock side. You probably wont see any performance improvement with the new setup. Just a bigger gas bill. IMO.
Actually I have already seen some performance gains. Most noticable is my mid-range acceleration which has dramaticly improved with the tunnel ram,and secondly I am getting the same speeds or slightly better at 2/3 throttle as what I was getting at fuul bore with the "Torker" intake and 800 Holley.
I can't really say if the motor is stock or not. My father bought it used about 18 years ago and he isn't sure what has been done to it. I know it has a pretty snotty bark at idle so it would surprise me if the cam has been stepped up a bit. I bought the tunnel ram solely for looks and didn't really expect any gains from it so you can imagine my surprise when I felt the harder acceleration and same top speed as before but not even at full throttle yet.
The fuel pump comes in today and it will either be the cause of my problem or it won't. A sea trial will tell all.
scott, i had this same problem when i switched carbs on my 460.....at wot it sputtered like it was running out of gas but as soon as i backed off it picked back up,.....i can't remember but all i think i did was go up 2 sizes in the jets in the secondaries
Posting Permissions
Reply With Quote