67 GTX stalls after 30 minutes
 

Hi all,

This is my first post here, so bear with me :-)

I recently purchased a Plymouth 1967 GTX, actually this winter.

Now on a hot summer day in houston, the car stalls on me after 30 minutes. This does not happen while I'm in a traffick jam, it just starts to bog, cough and spit and if I try to throttle it, it just bogs down with a very rough sound - just as if I'm missing a stroke or something, and eventually it dies just as if it is not getting air/fuel or sorts. The engine isn't that hot, my reading says 195/200. New and filled up cooling liquid as well.

This is a all manual 440 super commando, mild mopar purple cam, 4:10 rear, redone engine with 10.5:1 compression.

I have replaced and installed a new mopar performance distributor with 2 stiffer springs. makes it run very stable at idle. Jetted the 650 cfm edebrock carb so it works under wot. Everything was fine this winter in cool weather. Well, that is not a very accurate, as I did very few trips at around 30-45 minutes just testing it out...

So I just changed and installed a steel fuel line instead of the hose (which got a tad hot...). That didn't help.

i've just installed a new fuel pump, even though the one that was on the car was also brand new. Haven't been out for a longer test-ride yet.

And of course if you ask 10 mopar guys, you get 10 answers in different directions.... Please, I need some help here guys.

thanx

bjornw>

You have either fuel or ignition problems. My guess is fuel, as you will see in the post I will shortly make. But next time this happens, just to make sure, you can pull out a spark plug, and make sure you have spark. Or you can swap coils, they are cheap.

My guess however is that you have fuel delivery problems. A fuel pressure gage installed semi-permanently while you are test driving will help you diagnose it.

fuel line close to the exhaust manifold? or a big fuel filter could cause vapor lock, sounds like that could be it. dont think its a carb problem, unless....the tank is old and you ran it very low on fuel could of sucked up some dirt,

66 fury may be right. I had a similar problem with my other Imperial 2 years back. I also had done the mistake of having the fuel filter upstream the fuel pump (stock mechanical), and close to the exhaust manifold. Once I switched the filter downstream, the problems dissapeared.

The fuel filter is just before the fuel pump and well away from the manifoil

As I said in the first post, I just replaced the fuel hose with a steel fuel line. The reason was because the fuel hose was leaning on the manifoil and got very hot. Now it is like 2 inches clearance to the steel line.

I did a test drive after I mounted the steel line, but again it stalled after 30 minutes driving. Comparing this mounting to other friends cars, it looks exactly as they have rigged it so I think I am good when it comes to the fuel line. But then again, one idea is to install a quick heat shield just for test purpose.

I would move the fuel filter down stream the fuel pump.

The mechanical fuel pump sucks fuel and then pushes it out. If a small pressure drop occurs due to the filter, the incoming fuel could evaporate, filling the fuel pump with vapor instead of liqid fuel. That is vapor lock.

The fuel pump does not need to have clean fuel, so you should be safe moving the fuel filter downstream the pump.

I finally tracked down the problem and fixed it!

After changing the fuel pump, replacing the fuel hose with a steel line, buying a new fuel filter and moving it after the pump, borrowing a friends carb and distributor, and still having problems, I noticed that the coil-wire was oily! And yes, the brand new chromed coil from accell was leaking fluid! Replacing the coil fixed all of my problems! I mean, now she purrs!

Thanks all!

or it could be a bad coil?:p

at least its fixed after un-needed spending