Why won't it run?

[FiatDavidFiat]

Car trouble (1976 Fiat 124 Spider).. anyone have insight as to what might be wrong?:

I've replaced the entire ignition system (battery, ignition coil, plug wires, plugs, distributor cap, points, rotor, condensors), rebuilt the carb, replaced the intake manifold gasket, replaced the fuel pump, and it still won't run.. It starts again, but it dies right away.. maybe a few seconds. I'm going to check the compression on Friday, and I plan on replacing the fuel lines and even cleaning out the gast tank to ensure a clear path.. if it isn't those than I'll be clean outta ideas =(

The problem started with it bogging out in high rpm in 3rd gear, which declined into the lower gears until it just stopped running altogether. Like I said, it starts again, but that's about it... it dies within a few seconds unless I press the gas, at which point it dies immediately or doesn't start at all if I'm pressing the gas.

[Weelan]

I'd guess any of 3 things,
carburetor came out of tune? the idle and richness screws may have gotten messed up, that was causing mine sorta similar symptoms. It'd only run for a bit and if I pressed the gas it'd die.

the gas lines could be collapsed.

or maybe a vacuum leak? do you hear a hissing sound when you start to press the gas? If you can get it running long enough to check.

[baltobernie]

Sure sounds like a fuel delivery issue. Since you've replaced the pump, I'd guess obstruction in the lines.

The '76 should have an electric fuel pump. Disconnect the fuel inlet hose at the carb, and direct it into a bucket as an assistant turns On the ignition key. You should see a robust flow of fuel.

[So Cal Mark]

are you sure you power to the + side of the coil with the ignition on? If the ign switch is/has failed, you can get power while cranking and lose it when the key is returned to "run"

[FiatDavidFiat]

How can I check if the ignition switch is/has failed? I remembered that I also meant to check the fuses to ensure that I'm not losing power to the new fuel pump or something else.. After checking my pre-pics, I also think I may have crossed a hose when I put the carb back on.. Will be checking on Friday. =/ I'll also make sure to check the fuel flow before I go pulling the tank for cleaning over the weekend!

Thanks!

[johndemar]

I know that this sounds simplistic, but it's either fuel or spark. Try one thing at a time and eliminate it as you go.
As stated above make sure you have fuel at the carb, should be about 2 PSI. You should have 12V to the coil.

If those prove OK look to make sure the points are set and opening correctly.

[majicwrench]

Needs fuel, spark, AND a way for the waste to get out!! You are describing a plugged exhaust. If indeed you have fuel and spark, try loosening the exhaust before convertor (does it still have one?)
keith

[FiatDavidFiat]

Needs fuel, spark, AND a way for the waste to get out!! You are describing a plugged exhaust. If indeed you have fuel and spark, try loosening the exhaust before convertor (does it still have one?)
keith

With that in mind, having read up on it a little, considering that the fiat generally runs clean enough to pass smog without it (is that the case in CA?), would you recommend that I put a rod through it? I can't afford a new one, and I'm not comfortable just putting a test pipe on it, in case of a ticket, if I were to put a rod thru the center how big of a hole should I make or would multiple smaller holes be better?

[majicwrench]

DO NOT PUT A HOLE THRU IT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! (yet)

TEST IT!!! Unhook some part of your exhaust. Or dirll an 1/8" hole in pipe, and test with cheapy pressure/vacuum gauge you can get at any parts store. Stick gauge over hole have someone crank engine. Wheels Chocked!! Should be almost no pressure in exhaust.
Keith

[FiatDavidFiat]

Okay, so you mean that if there is pressure than it's not getting out the way it's supposed to? Will be doing this tomorrow.. Will I have to replace a gasket when I loosen something? Don't really want to have to plug a hole that I drill.. I will if I have to..

[So Cal Mark]

after re-reading your initial post I see you replaced the fuel pump. Your original problem sounds like fuel starvation. Did you replace the hoses from the tank and to the pump?

[majicwrench]

Plug hole with small screw.

Yes, if exhaust if plugged near solid car will not run. So, yes, if there is pressure in exhaust system up by engine you can be assured that something downstream is plugged up. May start briefly on first crank as yours does. Plugged exhaust will certianly cause power loss issues. You may have run it till plugged solid. At any rate, is easy to find out. I would drop pipe at exhaust manifold if I wasn't gonna drill small hole.
If you drop pipe you shouldn't have to replace gasket, but you may tear it. You won't need to drop it far, just need to get some way for the exhaust to get out!

If you have a buddy and a cheapy vac/pressure gauge that is a bit more professional. You will know right away, drill little hole, have buddy start engine (it will start briefly still, yes?) if system plugged it will blow pretty good out hole. Safety glasses!
Keith

[So Cal Mark]

if the engine is/was running so poorly that you've plugged the cat, you have some other issues to sort out

[FiatDavidFiat]

Thanks everyone for your help.. Here's what happened.. I checked the compression (145, 150, 135, 145psi), rebuilt the carb, replaced the intake manifold gasket and it started.. then died.. I checked the tank, it's clean.. I then checked the gas flow. The gas was trickling out the line at the carb.. I checked the new fuel pump to see if it was functional and found out that it, and the old one, were both functional; by connecting them directly to the battery. I then checked the power source and it seemed to be getting some power, but I couldn't be sure it was the problem. I decided to take it to be diagnosed by a local shop and they told me that it was in fact not receiving sufficient power. They ended up installing a relay switch directly connected to the battery for power.

I picked it up this morning and was happily driving it all around. It runs great, after I get it started! Getting it started is a problem. I have had to crank it endlessly. The battery died. I'm recharging it. I took out the check valve that's right before the carb. It seemed to be receiving more fuel. I'm going to check again when I have my battery charged, but hopefully it's fixed by allowing it to have a little extra flow. =}

[FiatDavidFiat]

Last update for this post.. I ended up changing out the check valve between the gas tank and the fuel pump also, because it wasn't performing quite right, and everything seems to be working great now! Thanks for the help, all!