I got my maverick running today. 306 with 10.5-1 cast pistons. new bearings etc. trick flow stage 1 with 1.7rr GT40X aluminum svo heads that have been decked an unknown amount total. Carb is a 600cfm edelbrock junker, I am using a holley mechanical fuel pump and clear line from pump to carb. Today the car ran but did not like any amount of throttle or rpm...I had the timing at 15 degrees. I backed the timing down to 10. No change, you would hit any decent amount of throttle and it would sputter and die or sometimes catch itself and bring to an idle.... Put 25$ of premium in the tank because it felt like it was running out of gas. Driving back from the gas station it did not want to run under load at all. So I start tinkering, I was getting air in the clear line, like large amounts 1-2" long in the fuel hose going into the carb. Will a mechanical fuel pump still make pressure with air in the line? I thought maybe fueling issue so I adjusted the accelerator pump to the highest setting (one notch up) but did not test drive I then bypassed the mechanical holley pump and ran one of those 2-4.5psi inline booster pumps. used it to bleed all the air I could from the line and left it on. THE CAR RAN GREAT! NO ISSUES but only went a few blocks. No sputtering at all, then I started to get air AGAIN in the line, so I pulled it back into the shop It was still running good with air in the line on the electric pump! Is it coincedence the car was running solid with the same air in the line as with the mechanical pump? Can the mech pump not function with air in the line? Or was it the accel pump that made it come to life? I figure if the carb catches air...it can still run off the bowl for awhile right? even at WOT? It ran for like 2 minutes with no fuel hose connected to the carb! I will try a longer drive tomorrow with the electric pump, then go back to the mechanical, then figure out which way to go, also will probably run a new fuel line front to rear. Thanks yall, love this site!
If they're old don't check them, REPLACE them the $5 to replace them is a lot better than getting stranded or a fire.
I am confused why the electric pump works with air in the line! I looked underneath and all the soft hoses have been recently replaced.....I guess I will go over them again. I hope it is not a tank issue.
your car may run better with the electric righht now as it is a contant flow..WOT or anything will not effect the pressue it will stay the same, the manual one however runs off of the motor, faster it spins faster it sends fuel..which when you would be at an idle it wouldnt send like the electric would..but as stated above, it sounds like you have a crack or whole in the line somewhere..very dangerous..even if you have a few extra bucks just replace that old line with braided all the way, looks nice and its safe and NEW...i just dont trust that old fuel line stuff. anyways..just a guess, hope it helps. goodluck
if there is a air bubble in the fuel filter its hard to get it out unless you burp the system. but it shouldnt effect driveablity. If you want to get the air out unhook the hose from the carb and hod it straight up and crank it. catch the fuel in a car. air should come to the top. It may not be running right with the pump if the pump is too high of pressure and flooding the carb. It could feel like not enough fuel when its acually too much. some of these Mech. pumps can be 13 psi, most arent less then 8psi at idle. Edelbrock makes the only 6 psi pump out there that could be ran without a regulator and maintain 6 psi. Edelbrocks dont like high fuel pressure, a Holley can get away with 8psi maybe but more then 6 on an edelbrock is likely going to flood. You can get a cheap inline regulator for $20 or so to test it out. I use an Aeromotive regulator with inline gauge to set up my mechanical pump. But my mech pump setup is pretty custom and unique.
thanks for the tips. It was running so well off the cheapo booster pump....Im afraid to touch it! its even zip tied to the shock tower and isnt properly grounded! Oh and there is no hood on the car.... Ill drive it anyways Get out on the open road so I can test the trans shifting and see if it will pull above 4500 rpm or so now.
I would think if it was flooding due to over pressure, the car would be very hard to start after stalling. Granted it is, but not like a true flooded situation. Also on the fatter accel pump setting it seemed to really enjoy that much more with respect to throttle response and coming down to idle in gear...
I'm just saying had a buddy with a 77 f100 he lost to a fire because he wanted to be cheap. The rubber line that goes from the fuel pump metal line to the fuel filter let go, no more truck. No point in gambling on a cheap part that is known to fail after 40 years.
YOU GUYS WILL NOT EFFING BELIEVE THIS! Went to start it today....no go dead as hell (no spark) verified no spark condition.... ordered a coil and ignition module for the hei (i shorted a tiny wire out at one point in a frenzy yesterday and had not started the vehicle since.) I remove the hei coil/cap, ohm it, seems ok, put it back in. Car starts and runs great but no tachometer....oops forgot to plug it in, so I did while running, engine dies.... Pull my gauges.... THE SPEEDOMETER CABLE WOULD MOVE WHILE ACCELERATING AND SHORT OUT THE TACH LEAD TO THE DISTRIBUTOR THERE WAS NO PROBLEM WITH FUEL PRESSURE OR ANYTHING F- MY LIFE TWO DAYS OF SCREWING WITH THIS THING. Luckily I can return the module and coil, but am considering keeping them around on the shop shelf in case..... BTW it runs like a FING beast! with 270 gears open diff and stock converter it really gets on it still! I also backed the AP linkage back down and it picked up some ooomph and bumped timing up to 17 degrees which also helped...Tomorrow I will actually cover the back of the gauges with vulcanizing rubber to protect them, and try to tape up the old speedo wire and what not. As for air bubbles, I still get some under HARD accel, I am almost positive it is sucking air in the tank/sloshing about. All the fuel fittings and lines/filter are tight and new in the last few months. No leaks or anything...... Thanks for the help btw.
you're guess is what I thought right away when all other line replacement had failed up to that point.. although you do need to replace ALL soft lines/clamps to eliminate that variable completely. If a minor air leak was on the pressure side of the pump.. you would have a leak and not pull air. On the suction side is where you need to be looking for very minor leaks and they can be tough to locate without a vaccum gauge to pinpoint them. If the car has sat for extended periods of time(or even if it hasn't those are probably the original 40 year old parts for the tank unless it was previously repaired).. you may have a leak inside the tank on the pickup/semding unit due to rust/pin-holing. An easy way to check that is to fill the tank up and see if the higher fuel level will go above the location of the pinhole, although the hole could still be above that point and it's a pain to get rid of all that fresh gas if you do have to drop the tank. Then there's the fact that sometimes a non-vented aftermarket filler cap and/or plugged vent on the tank can cause enough back pressure and introduce air into the system under vaccum created by the pump(which also reduces pump volume as the unit struggles harder to pull the necessary volume. All you need do to test that is remove the filler cap and recheck the aeration levels. Generally speaking.. unless you get into the more expensive high-performance inline electric pumps.. will flow less than most entry level aftermarket mechanicals.. so you may just be seeing less aeration(less vaccum created) from the electric pump in comparison. Also figured I'd just quickly mention as an FYI.. air in the lines, except in extreme cases where the pump can't even prime itself sufficiently to build any pressure, typically only causes loss of fuel VOLUME.. and not the pumps ability to make sufficient pressure for anything short of full power acceleration(in which case it's usually still down to a volume related issue which causes the bowls to run dry).. but does not affect the carburetors functionality..especially under no-load throttling. This is because the bowls are vented and aeration that may be present is quickly dissipated in the nearly always full bowl.. to the extent that it becomes a non-issue when not under load. Now, if the pump is severely undersized/has lower than required pressure and you add aeration into the equation?.. that's a whole different deal and is why a fuel pressure gauge is worth doing. Even a cheap underhood style is nice to have for knowing or troubleshooting and will keep you out of high speed lean out trouble if you plan to rev the snot out of it on ocassion. Probably a lot to absorb there all at once.. but just trying to cover some bases and help you along now.. and in the future.
It seems to be running good, but does bog sometimes, and the trans is shifting early and kicking down late.....any tips on the early upshifting?
I am going to test for vacum leaks soon enough. I have a BM megashifter that was in the car when I purchased it and it SUCKS. I think it is beyond adjustment as far as the shifter goes. I may try a manual valve body and a prostick. See if that will help it.
