Dream quickly becoming a nightmare...

-
W

wheelman21

Mopar noob
Joined
Jan 1, 2011
Messages
208
Reaction score
0
Location
Bing NY
Ok guys, my dream 73 dart sport 340 is quickly becomming my nightmare. Lets do a quik timeline of events...

-Got 340 swapped in and running...drove great
-cut a transmission cooler line on a belt, blew oil everywhere
-fixed it, cleaned it all up, tried to go to a cruise in, about 5 miles away the car coughes stutters backfires like crazy and quits. Rollbacked it home.
-Talked to Don at FBO, ordered some stuff, took it apart, cleaned the floatbowls, cleaned it all, new needles and seats, tuned it all up, she runs great.
-took it out for a spin, got it home, it idled, choked up, backfired, and died. Cleaned the carb again, put it back, and it ran.
-Blew out a exhaust gasket
-Got a new one, didn't pull the header completely off, just loosened and retorqued.
-Took it for a drive with new aircleaner, ran great for about 2 miles and she started caughing and wheezing and backfiring and died. I got it restarted, and got it running enough to pull a u-turn and drive it the two miles home. I kept decent RPM and just kept the speed up so could coast is as far as possible. Got it to the barn door, it did the same thing. Restarted it, and limped it in.
-To top it all off the rear header bolt is now leaking coolant. I tightened it even further and it is still leaking. I can't pull that bolt out without removing the whole header.

Why the f#&@ won't this thing run right. The timing is correct, the idle mixture should be darn close. Here are what I know of the engine:

73 340
Stock bore and stroke
J-heads with 2.02s
Demon 650 mighty demon
Mopar M1 intake
Ultradyne cam est. 509 with 242 duration @ 50
Hooker comp headers.

I'm going crazy...and quickly running out of patience.
 
Lets take it one thing at a time.
My first though is the fuel tank clean, and not putting a bunch a garbage thru the carb?
Pump some fuel out of the pump into a clean glass jar and let it sit for an hour.
Do you see any crap or water in it.
 
Rust in the fuel system?

Are the internals of the carb dirty after each time you pull it apart?
 
Hmm,is the exhaust black? Sounds like the carb is loading up the engine with fuel. Maybe a step or two down in jet size will help. Or perhaps you have a very small pinhole in a carb float.

Have you ensured good and consistant spark? What ign system is being used?
 
If I were you, I'd swap out the carb for something different.......I went through something similar with an Edelbrock on my Demon years ago......the carb turned out to be an absolute lemon from the factory.......NEVER stopped causing problems.......

If it were ME, I'd swap out the carb and see what happens. Just my humble opinion.
 
Tightning the header bolt will not help.... front and rear exhaust bolts need thread sealant due to passing through water jackets.
 
Last time I cleaned it I didn't see any garbage but that doesn't mean it wasn't there I guess. The ignition is a FBO ignition block with a mopar distributor. No black smoke, but it does seem like it's loading it up with fuel after running.

As far as the header bolt it never leaked before.
 
pastortom1 said:
If it were ME, I'd swap out the carb and see what happens. Just my humble opinion.
Click to expand...

Yup, that's what I'd do. You'll have to pull those bolts and get some non hardening sealant on them, or replace them with studs.
 
totally sounds like trash in your float bowls. I would take off the Fuel OUT hose off the line going to your carb and crank it over to pump some fuel into a Clear Root Beer Bottle or something...so you can see it clearly.

If there is trash coming through your pump from your tank.....you need to drop your tank, and flush it.

Then put a inline fuel filter on BEFORE your carb...but AFTER your pump, and refill your tank with fresh fuel.

Then restart your tuning process.

If the fuel is clear, and yellowish, with no grit or trash in it.....I would suspect the carb for hanging floats or needles.

If you have a known good carb...throw it on and see....but make sure to always run a PRE-CARB fuel filter.
 
Well here is what it looked like when it came out this morning. I cleaned the carb. Cleaned all the lines north of the pump. There is an inline filter right before the carb. I got that fuel from before the filter. I put another filter inline before the pump, and pulled more fuel and got the same stuff. Any ideas what this is?
 

Attachments

  • photo(4).jpg
    64.8 KB · Views: 475
X2 what Slatscamp stated. Either replace your tank with a new one, or take it so a shop that can clean it properly, or have the inside coated. Usually your local radiator repair shop can do these.
 
Could be fuel pickup sock in the tank coming apart and that sock could be clogged. Might have rust in the fuel lines too. If the lines are real rusty might think about replacing them along with pulling the tank. When you pull the tank take the sending unit out and look inside and see if its rusty. You would be amazed how much better a car can run with a new tank, budget allowing.
 
what? No..... thanks for me....I got it right, sight unseen didnt I?
 
You really need to clean your fuel system.
From what I can tell in the picture the black slivers looks like small pieces of rubber, most likely from 40 year old fuel line.
 
Hold your horses fellas we have a new development. Trying to figure things out I unhooked my fuel line before my filter and before my mechanical pump. I hooked up an electric pump I had laying around and pulled fuel direct from the supply line. Fuel is clean. It seems the contaminants are coming from somewhere in between the fuel filter, 6" of line, the fuel pump, and a steel braided line that goes to the carb set up.

Now on a separate note, is it possible that the fuel pump is too big, and without a FPR it's delivering way too much fuel and loading up the engine with fuel after a certain amount of time? I can't tell what the pump is. All it says is "Made in the USA" and a part number: FBO (or 0) 107126. It is clearly aftermarket performance, but I can't seem to figure anything else out.
 
What pressure are you running at the carb?
Very important, depending on carb and needle seat pressure.

I had a mechaical stock carter pump that made over 8 psi that give me fits.

Throw a gauge on it "AT THE CARB" .

It still does not explain the black strands on the previous pics.
 
I've got to put a new gauge on it. It has one of those liquid filled ones and I think it's screwy.
 
Second try take the braded line off and see if it has a rubber core.
Rub your fingers in it, if it feels soft pitch it in the trash.
The cheap crap from china will fall apart in a matter of weeks when soaked in gas.
 
wheelman21 said:
I've got to put a new gauge on it. It has one of those liquid filled ones and I think it's screwy.
Click to expand...

What psi are you seeing at the carb?
Why do you think it is acting up?
 
I think it's screwy because when the engine is cold it would sit a 6 psi consistently, sometimes around 6.5 -7. When the engine got warm it dropped to 3, and then to 0, but the engine kept running and revving fine.
 
Maybe a vapor lock problem. Do you have metal lines touching the exhaust or block? The fuel could be boiling in the line and this is why your fuel pressure is dropping to 0 when warm.
 
Nope, no lines touching the block or exhaust. I've heard of liquid gauges doing this.
 
You must log in or register to reply here.
-

Back
Top