340 heartache

-
VonCramp said:
Running perfect! I don't know what's going on. It is something weird because I can't seem to isolate it. Maybe the filter at tank is clogged. I will check that after I do the vacume test.
Click to expand...

Cant see the filter being clogged if you got 8 psi
 
GEO said:
What is your initial timing set at?

Start with 10-15 degrees
Click to expand...

This??

You said you've tried everything BUT a ballast?? Not being a smartass here(well kinda) EVERYONE NEEDS A SPARE BALLAST..for the low low price of $5, that is the cheapest insurance you can buy. Put it in the glove box with the rolling papers..
 
Bad Sport said:
This might be a silly question, but does it run good for a minute and THEN develop the symptoms you describe or is it right from the git go?
Click to expand...
That is a great question actually. Seeing how cold natured the car is I can't say for sure. I do know with choke closed it will stay running. I have a demon 650 on it with no choke.
 
4spdragtop said:
This??

You said you've tried everything BUT a ballast?? Not being a smartass here(well kinda) EVERYONE NEEDS A SPARE BALLAST..for the low low price of $5, that is the cheapest insurance you can buy. Put it in the glove box with the rolling papers..
Click to expand...
You're right. Cheap Insurance! I will install a new one in case! However the 340 seems to keep running as long as throttle is being worked.
Before I removed the Edelbrock it would run with choke closed.
 
It sure sounds like a vacuum leak, but it seems odd that it would be fine and then the next time not.

Have you checked your rubber lines, it is possible this fantastic crappola they call gas has deteriorated it inside?
 
May not be related or worth the effort to type. Years ago, my 1st car, 71 Gremlin 232 inline 6. It was running perfect, at about 80K miles. Drove it about 200 miles to Carowinds in Charlotte. During the slow crawl into their parking it ran a bit hot. I didn't consider that a big issue. Got parked, turned it off, and didn't come back to it till after 10 pm. Took a few minutes to determine it fault not something I could see. It was hidden inside. The timing chain jumped 1 tooth, maybe during start but more likely when I turned it off. After screwing with timing and carb settings to get a decent run, I drove it home. Best I could do was about 40 mph though. Long way home for sure.
I think I read a mention of a couple of pops out the carb in one of your posts.
Anyway... Keep determining what the problem aint, then you'll know what it is.
Good luck
 
VonCramp said:
You're right. Cheap Insurance! I will install a new one in case! However the 340 seems to keep running as long as throttle is being worked.
Before I removed the Edelbrock it would run with choke closed.
Click to expand...

Choke closed and still running seems to point a vacuum leak...I think anyway LOL.
Good way to chk for leak is propane torch with a 8" blubber hose. Turn propane on a little(don't light it...LOL) and run the rubber hose all around the intake, carb, vac lines/fittings. If it revs up with the propane, there is a vac leak.
 
4spdragtop said:
Choke closed and still running seems to point a vacuum leak...I think anyway LOL.
Good way to chk for leak is propane torch with a 8" blubber hose. Turn propane on a little(don't light it...LOL) and run the rubber hose all around the intake, carb, vac lines/fittings. If it revs up with the propane, there is a vac leak.
Click to expand...
I want to try this. Problem is I would have to start the car but it would be hard to work the throttle and turn on propane bottle at same time. can I keep throttle closed and use the propane?
 
VonCramp said:
I want to try this. Problem is I would have to start the car but it would be hard to work the throttle and turn on propane bottle at same time. can I keep throttle closed and use the propane?
Click to expand...

If the car will idle at all, the propane should work.
Even if you step up the idle screw to increase rpm enough to run, you should be able to use the propane trick.
 
mine did that once it would idle fine put it in gear it would move and run till i stepped on it then it would back fire spit and sputter it gradually got worse to the point it would idle till i put it in gear then it would quit changed ballast and it was fine spark was jumping across break so it would idle but when you needed more spark wouldnt work also orange box i believe is for racing cant take heat could be suspect desigined for short runs ballest is a cheap fix

good luck




VonCramp said:
I am posting a new thread because I am convinced my issue is not fuel related as originally believed. So far, I have changed carbs three times. I put in a brand new distributor. I have a resistor that is one year old and tried two different coils. It also has a one year old orange box. No matter how I set the timing the 340 dies immediately if I don't constantly give it gas by working the throttle. She will start and run and can even be driven as long as I don't quit massaging the throttle. I put on a new carb base gasket as well. I did get a couple of small pops out of the carb, but nothing big. I checked all electrical connections, but haven't found anything out of the ordinary. Fuel pressure is a steady 8lbs out of Holley regulator and blue pump. I'm at my wits end here. The only things I haven't done is changed the intake gaskets or tried a new resistor. Please help.
Click to expand...
 
Today I was busy, but I had an extra couple of minutes to look at the 'Cuda. I thought I would choke the Demon carb by placing a rag over the front two barrells. The car idled up and continued to run unaided. After I removed the rag the engine idled up for about five seconds and then promptly died just like I'd shut the key off. I will replace intake gaskets next. After that I am borrowing my friend's 357 and shooting that 340.
 
Did you shut off the engine and then restart without the rag to find it would idle for only 5 seconds, or did you just keep the engine running and remove the rag? Did the engine stumble at all before dying? Not sure it makes much difference but am looking for clues.

Try the same 2 things with a vaccum guage on the engine before you get the 357 or change the intake gaskets. Some measured data may save you a lot of unecessary work.

The other common possible problem is fuel supply. How are you measuring the fuel pressure, by putting a T in the line and measuring off of the side port of the T with the enigne cranking/running, or by terminating the carb fuel line into the pressure guage? Or is this some sort of gage on the regulator?

I have to wonder if there is a restriction between the pump/regulator and the carb; this could cause your symptoms and possibly elevate the pressure reading at the regulator output at the same time. Is there a filter just before the carb that could be clogged? Is there some sort of screen in the line at the carb connection that could be clogged? Is there just one fuel feed to each of the carbs you have tried? Is there a lot of rubber line between the fuel pump and the carb and is any of it old? An inside piece could have cracked off and is plugging the line internally.

How old is the fuel in this car? Has the car set in a place where there is a lot of moisture, so that water could have gotten in the fuel? Was the gas cap on and tight? I am just trying to figure out what could have changed after sitting for just a few weeks....

Have you check ignition timing and looked at the gap that the spark will jump, as well as spark color? Just trying to eliminate those things.

Lots of questions......
 
did you fill up right before this happened ,I have seen people put diesel fuel in by mistake and they will run (idle) only with the choke on. this was a problem with harry homeowner and rental trucks many years ago and now with the firetrucks they fill them with gas once a week.
 
VonCramp said:
I will purchase a vacume gauge today and get those readings. I have a Crane 509" cam but no power brake booster. Motor is .040 over with x-heads. Edelbrock Performer intake and Hooker Super Comp headers. Mopar distributor tuned advance with orange box. Mallory coil and Moroso 8.8 wires. A-body 18 spline 4-speed. As I stated in a previous post the car was running fine before sitting for three weeks. I went out and started it up and it wouldn't idle. Thanks again for the advice!
Click to expand...
Running fine and then sitting for a while definitely sounds like a carb problem!
 
You must log in or register to reply here.
-

Back
Top