Engine performance help

[J Shara]

I recently just installed my freshly rebuilt L24 back into my 73 240. Before i disassembled the engine the car had hard starting problems. Even after my father and i dropped the fuel tank and replaced the vapor, supply and return lines, it still had this problem of hard starting. The engine would crank run for a few seconds and then die like it wasnt getting enough fuel, but you could keep it running by working the throttle. Now, after engine has been rebuilt and installed, i hooked all the electrics and fuel and ignition system up it is still doing the same thing. I have spark and it will run with starting fluid but it dies. i dont have any emissions or PCV, or cooling equipment hooked up yet either and it needs to be tuned, but i have basic combustion, the engine did turn over a few times. but the carbs are the same as when i pulled them off and i havent rebuilt them. Is it possible that all the carbs need is to be synchronized or the choke system is faulty? Also with the key on, and while cranking, smoke comes from the ignition coil area but when i felt the components nothing was hot, the coil and the resistor and the wires were all normal temp. Im running crane cams fireball coil. I may have hooked them up wrong but i used my parts car as a reference and that car ran fine and i had not messed with the connections at the ignition on the parts car. Any help would be appreciated.

[J Shara]

This is about the stage im at now when i turned her over. except i have since the pic was taken hooked up the coil and ignition, the chokes, the throttle linkage, and the battery, and the fuel system.

Edited May 28, 2012 by J Shara

[Carl Beck]

Cracked distributor cap? Faulty condenser? If they are not new, I'd change them just to rule them out.

Did you rebuild the distributor? Or even disassemble and service it?

Have you put a fuel pressure gauge on one of the supply lines - to see what pressure you have coming out of the pump?

What else if anything have you measured or verified? What can we reasonably rule out?

[J Shara]

new condenser new distributor cap new points set already to correct gap, no the distributor was never taken apart. I dont think it is a spark issue because the engine turned over and ran for a few seconds and could be kept running a little longer with actuation of the throttle. well the fuel system isnt 100% hooked up, my father and i hooked the inlet end of the fuel filter up to an auxilary boat tank with a hand bulb pump, thats how we got it to turn over.

[Carl Beck]

Could be a bad fuel pump - but you would have to hook up a fuel pressure gauge to check it. There are no accel. pumps in the S.U.'s - so pumping the gas pedal should have no real effect - engine vacuum determines both quantity and fuel/air mix. Make sure you don't have any vacuum leaks in/around the intake and carb.'s.

Ignition and fuel problems have a way of looking like each other..

[tlorber]

I agree on the fuel pump issue. You could either try a new mechanical one or go to an electric pump. With the electric, at least you know the bowls will be full before cranking.

[J Shara]

it has a new mechanical pump too

[buysell]

Does your 73 have the flat top carbs? If so, I think that they also had the electric pump in front of the gas tank. Mine in my 260 if bad and caused the mechanical pump to work a lot harder. I'd check the pump and it's internal filter.

--Justin

[Wade Nelson]

I'd say the idle circuit in your carburetor is clogged up, or your float level set wrong.

Your'e making up for it with either the choke or pumping the throttle.

You only need enough fuel pressure to fill the bowls, this isn't an injected vehicle where PSI is critical.

Another possibility is a vacuum leak that's allowing air to bypass the carbs so it's ingesting air that hasn't been spritz'd with fuel. Power brake booster with a holy diagphram, perhaps? Cracked vacuum lines?

The fact that you can keep it running with faux fuel PROVES its a fuel starvation problem, not timing, ignition, etc.

[Captain Obvious]

Sounds like you aren't getting any fuel to the carbs. I would back up and start simple. Here's what I would do to start:

1) First, pull the filters out of the carbs and make sure they aren't plugged with crap.

2) If the filters were clean and not plugged, then pull the carbs off the car and verify that your needle valves are working and the float bowl levels are set correctly.

3) Then once you are convinced your float bowl levels are correct, put the carbs back on and fill them up (prime them) with fuel with a funnel and a short piece of tubing and then reconnect the fuel lines. The engine should run for a decent length of time (thirty seconds) off the fuel in the bowls, and during that time, you can look for other issues.

When you switched from the original flat top carbs to the round tops, did you keep your original intake manifolds or did you swap for older?

Edited May 29, 2012 by Captain Obvious

[J Shara]

no my 73 has no emmisions equipment on it and it has the early style round top SU's installed before i bought it. It also had no electric fuel pump although my 73 parts car did have the electric fuel pump, and round top su's I beleive its an E88 head and intake. Also the air cleaner is not installed nor the flow guide valve or the brake booster, or the pcv, or the evap. i new the car would not run 100% without these hooked up, i just wanted to see if it would run. but before i disassembled the car it had this problem. It did have some crummy old looking vaccum lines on it tho. Thanks to all for the advise i will try some of your methods. To check the fuel filters in the carbs and check the floats, do i have to disassemble the carbs?

[madkaw]

A member on Hybridz just had a similiar issue and it was as simple as clogged filter screens on the inlets. CAptain Obvious has given some good advice and it IS a good idea to keep any vacuum related components out of the mix until you get the car to idle.

Have you tried just removing the fuel line just aft of the pump and putting the line in a glass jar to see if the pump is pulling up fuel? These fuel lines are small on this car and can get clogged easy-ask me how I know;)

Known condition of the gas tank?

Tear into the carbs LAST, make sure the support systems are working first. Carbs aren't doing any good without gas