Fishhawk

After finishing my engine and drivetrain mods on my 85 GT I felt I needed a little help with fuel delivery. I installed a Carter mechanical fuel pump and larger pump to carb fuel line. The car ran great when I tested it, however I didn't really run it through the gears at WOT. So on Sunday its off to the track to make some 1/4 mile passes. First and Second gear were no problem. Flirted with the rev limiter in both gears, hit third and climbed to about 4500 RPM when the motor started to bog, acting like it was hitting the rev limiter. Shifted into forth and it continued to run like s---. At the end of the 1/4 mile when the motor had come to an idle it was running fine. It also was running fine on the drive back to my pit. Shut in off and everything checked out okay. Decided to make another pass and had the same results. Drove it home at highway speeds (75 MPH) with no problems. Just didn't hit any high RPM's. Did my new high volume fuel pump suck the stock line dry? Is my stock fuel sending unit and stock tank to pump fuel line to small? If so does anyone know of a company that sells a higher volume sending unit (say 1/2 inch outlet). I will of course need to install 1/2 inch line. I really would appreciate your thoughts and opinions. Thanks in advance.

vfast

carb?..... what psi is the pump rated at?...did you put in a new fuel filter? have new wires,plugs etc?...I would make a 1/4 and at the end shut the engine off coast out of the way and pull no1 spark plug to look at it

Fishhawk

New plugs and wires. The pump is rated at 7.5 to 8.5 psi. Thats why I'm thinking the line from my tank to pump isn't big enough. I think the pump may be sucking the line dry. Through the first two gears its fine, I get into higher RPM's in third and now the sender and stock line can't keep up with the new pump. The filter is about a year old. But its one of those little stone type filters. They usually last a pretty long time.

roundman

you really need to install a fuel pressure gauge that you can see when going down the track to see if you're losing fuel pressure. the gauge should be connected to a tee fitting right at the carb inlet so you can see the pressure at the carb itself. also check to see if the fuel pickup in the tank is getting uncovered and causing the pump to lose suction as you go down the track. you might try running more fuel in the tank to see if it still acts up or not. bigger lines will certainly help and you really need a good in-line filter between the pump and carb instead of just that sintered bronze one at the carb.

Fishhawk

I agree. A fuel preasure gauge is next up. Also, that little bronse piece of s--- is bothering me. I plan on putting an inline when I install a guage. As far as gas in the tank is concerned, I had 3/4 of a tank in it. I talked to a tech at Ford Racing and he seems to think the line is fine, I just have an adjustment problem with the carb. Maybe the floats aren't set properly.

roundman

That could definitely be the problem, what model carb are you running?

Fishhawk

The good news is, at the 1000' mark the car was at 9.97. I think the carb had already crapped out on me by then and I had let off. If I can just get the fuel to flow I have a 12 second street car. (A big if)

Fishhawk

I'm running the stock Ford Holley 600 cfm. (585 cfm.) I had it rebuilt and a metering kit installed. Unfortunitly I still have to take it apart to check on the floats. Can't just pull the float plug and look for gas.