just cant get the car to run right

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rp23g7

rp23g7

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Help someone give me some ideas.

73 Duster 318 2 barrel

I have replaced the distributor, and plugs and had ordered a new carb.

The old one idled fine, but put it in drive it falls on its face backfires, misses, dies etc. I got a new carb from Rock Auto, but i think the base was warped because it would idle fine, but just die when you put it in drive,

You could hold a rag around the carb and it would still run, sending that one back.

So i put the old one on again, messed around with it for a bit got it idling good, but i put in drive, and it just falls on its face if i try ti drive it. Not sure whats wrong with it.

Its timed at 10-12 degrees before TDC, and it seems to idle fine at 5-700 rpm
 
Is it timed at top dead center on the compression stroke on cyl #1? It's easy to get mixed up and put it 180 degrees out and set it up for #6. I've done it and it was doing the same thing idle ok then choke out as I put it in gear.
 
Ajp440 said:
Is it timed at top dead center on the compression stroke on cyl #1? It's easy to get mixed up and put it 180 degrees out and set it up for #6. .
Click to expand...

If it runs at all IT IS NOT "180 degrees out" and if it is running you can time it just as well on no6 as no1
 
You wont like this post... there is a small spot on the bottom of those cast iron 2 barrel intakes where they burn through. Result is a vacuum leak that simply cannot be found.
If you are exempt from local smog rules, block off the egr and by all means disconnect that electric choke assist and those knox switches on the right side of the firewall. If all else fails, pull the intake. Your local machine shop will hot tank it and weld the burn hole closed. Disconnect the vacuum spark advance, put a cap on that carb port, set the initial timming about 16 to 18 before and happy moparing. Worked for me.
 
vacuum advance hooked up to the wrong port?

If you have a vacuum gauge set the idle mix screws to highest leanest point and maybe 1/4 turn richer from there.
 
If you decide to pull the intake, I suggest getting an after-market aluminum 4-barrel one. You can find for <$100 w/ shipping on ebay or even cheaper on Craigslist. Sounds like you can drive it now, so you have time to get a deal. That will be about as cheap as shop work on yours and will allow many more carb options. If a stock cam, daily driver, don't get bigger than 650 cfm.

For best mileage, a 450 cfm like the Holley Economizer is best. I got an almost new one for ~$40 I recall. If you want to keep some power, the spread-bore ones Quadrajet or Thermo-quad have tiny primaries for good mileage but bring it on when the large secondaries open. However, TQ's are getting rare and parts expensive. Longer term, consider throttle body injection like Mega-squirt, Howell, Pro-jection.
 
No EGR on it, vacuum advance is attached to the left hand(standing in front of the motor)vaccum port on the carb.

It runs at idle, but you cant drive it. Not sure what you mean by the knock switches on the firewall.

A friend has a auminum 4 bbl with a 750 for a small block mopar so i may just get that.
 
I have some ideas. I hope they help. I have the same 2bbl/318 set-up on a '74 and I am having some idle/surging issues that I have been solving. I suspect you may have more than one problem.

First, I would do what has been suggested above: check for vacuum leaks.
  • All hoses.
  • If you have power brakes, do a bleed down test: shut off car and wait 15 minutes then actuate the brakes. You should still have power assist. If not, then the booster leaks.
  • Check the few bolts that you can get to on the intake manifold to see if they are tight. If not tight, you need to tighten all of them.
  • I usually check carb mounting nuts and carb cover for tightness. Since you have changed carbs, these may be tight.
  • You PCV system should not leak and the valve should operate freely when shaken.
  • You say no EGR. But if you mean that the vacuum hose has been disconnected, you can still have a problem. The valve may not be holding tight. Check by removing the valve and trying to blow (yuck!) through it. If air passes, that leak will cause idle problems.
Next, you may have an ignition problem: too much advance. Reason? You have backfire.
  • The car may idle fine with no load. But when you put the car in drive, the rpm drops. This small drop may put you over the "timing edge" so that the too early ignition actually trys to run the engine backward.
  • You have too much base advance. I would go back to 0 degrees until after I had diagnosed the problems.
  • My car's vacuum advance runs off the port that you described so I believe that you may be connected to the correct port. Here's how to check:
    • At idle, you should not have any "detectable" vacuum at the distributor vacuum advance or at the carb port. Remove the hose from the carb port when you are idling. If idle quality changes and you can feel more than a tiny amount of vacuum with your finger, you have a problem. (After a timing adjustment, when I reconnect my dist. vacuum hose, the timing does not change.)
    • If you have this problem, reconnect the hose at the carb. Then remove and temporarily plug the hose at the vacuum advance and see if the problem goes away when you go into drive. If it does, you found your problem.
Once you are sure your ignition timing is correct, I recommend going on to the carb.

You may have a carburetor adjustment problem. Because you have such early timing, your throttle plates are probably too far closed with the car adjusted to idle specs. With the very high manifold vacuum, your idle mixture adjustment be at a none ideal place. Do a "best lean idle" adjustment.

Good luck. I have a leaking brake booster that I will be replacing this weekend. Then I am going to solve the "lean and retard" emissions control mentality: Overhaul the carb with the next bigger jet and lighter distributor advance springs.

http://www.forabodiesonly.com/mopar/showthread.php?t=162134

http://www.forabodiesonly.com/mopar/showthread.php?t=161055

Red
 
redneckmba said:
I have some ideas. I hope they help. I have the same 2bbl/318 set-up on a '74 and I am having some idle/surging issues that I have been solving. I suspect you may have more than one problem.

First, I would do what has been suggested above: check for vacuum leaks.
  • All hoses.
  • If you have power brakes, do a bleed down test: shut off car and wait 15 minutes then actuate the brakes. You should still have power assist. If not, then the booster leaks.
  • Check the few bolts that you can get to on the intake manifold to see if they are tight. If not tight, you need to tighten all of them.
  • I usually check carb mounting nuts and carb cover for tightness. Since you have changed carbs, these may be tight.
  • You PCV system should not leak and the valve should operate freely when shaken.
  • You say no EGR. But if you mean that the vacuum hose has been disconnected, you can still have a problem. The valve may not be holding tight. Check by removing the valve and trying to blow (yuck!) through it. If air passes, that leak will cause idle problems.
Next, you may have an ignition problem: too much advance. Reason? You have backfire.
  • The car may idle fine with no load. But when you put the car in drive, the rpm drops. This small drop may put you over the "timing edge" so that the too early ignition actually trys to run the engine backward.
  • You have too much base advance. I would go back to 0 degrees until after I had diagnosed the problems.
  • My car's vacuum advance runs off the port that you described so I believe that you may be connected to the correct port. Here's how to check:
    • At idle, you should not have any "detectable" vacuum at the distributor vacuum advance or at the carb port. Remove the hose from the carb port when you are idling. If idle quality changes and you can feel more than a tiny amount of vacuum with your finger, you have a problem. (After a timing adjustment, when I reconnect my dist. vacuum hose, the timing does not change.)
    • If you have this problem, reconnect the hose at the carb. Then remove and temporarily plug the hose at the vacuum advance and see if the problem goes away when you go into drive. If it does, you found your problem.
Once you are sure your ignition timing is correct, I recommend going on to the carb.

You may have a carburetor adjustment problem. Because you have such early timing, your throttle plates are probably too far closed with the car adjusted to idle specs. With the very high manifold vacuum, your idle mixture adjustment be at a none ideal place. Do a "best lean idle" adjustment.

Good luck. I have a leaking brake booster that I will be replacing this weekend. Then I am going to solve the "lean and retard" emissions control mentality: Overhaul the carb with the next bigger jet and lighter distributor advance springs.

http://www.forabodiesonly.com/mopar/showthread.php?t=162134

http://www.forabodiesonly.com/mopar/showthread.php?t=161055

Red
Click to expand...

Checked my booster still holds vacuum, checked the intake bolts, they are tight, i replaced the distributor, cap, rotor, plugs, i sent the carb i got back, and RA is sending another, so i put the old carb back on.

I has no EGR at all,
Here are some pics of the engine, in all its dirtyness

IMG_0052.jpg


IMG_0051.jpg


IMG_0050.jpg


IMG_0049.jpg


IMG_0048.jpg


IMG_0047.jpg


IMG_0046.jpg


IMG_0045.jpg


IMG_0044.jpg


IMG_0043.jpg
 
RedFish said:
You wont like this post... there is a small spot on the bottom of those cast iron 2 barrel intakes where they burn through. Result is a vacuum leak that simply cannot be found.
If you are exempt from local smog rules, block off the egr and by all means disconnect that electric choke assist and those knox switches on the right side of the firewall. If all else fails, pull the intake. Your local machine shop will hot tank it and weld the burn hole closed. Disconnect the vacuum spark advance, put a cap on that carb port, set the initial timming about 16 to 18 before and happy moparing. Worked for me.
Click to expand...

Redfish, if you had a bad intake could you tell this by plugging everything on the valve covers plus dipstick and use a vacuum gauge on the breather cap hose he has open and see if it is pulling a vacuum on the block when you rev it?
 
"Does not have EGR"

YOU CAN NOT TELL without pulling the carburetor

If you have an intake manifold off one of the earlier years when EGR first came out, there IS NO VISIBLE EGR valve. The EGR is simply two "jets" in the bottom of the intake manifold, "leaking" exhaust from the crossover passage below. a couple of screenshots from the '72 shop manual emissions section:

308ytj8.jpg


29w4wtz.jpg
 
67Dart273 said:
"Does not have EGR"

YOU CAN NOT TELL without pulling the carburetor

If you have an intake manifold off one of the earlier years when EGR first came out, there IS NO VISIBLE EGR valve. The EGR is simply two "jets" in the bottom of the intake manifold, "leaking" exhaust from the crossover passage below. a couple of screenshots from the '72 shop manual emissions section:

308ytj8.jpg


29w4wtz.jpg
Click to expand...

Oh gotcha, that explains the other post where someone said that it could have a small hole burned in it.

Didnt know about the jet things. That may explain why you can see some blow by coming out the choke stove/exhaust crossover sometimes when you rev the motor. I will have to look in there when i get the new carb.
 
daredevil said:
Redfish, if you had a bad intake could you tell this by plugging everything on the valve covers plus dipstick and use a vacuum gauge on the breather cap hose he has open and see if it is pulling a vacuum on the block when you rev it?
Click to expand...

That might work.
I honestly dont know of a sure way to diagnose it.
 
I just noticed in one of the picks that the spark advance is rotated way back toward the firewall. That suggests to me that the timing is set too low.
 
RedFish said:
I just noticed in one of the picks that the spark advance is rotated way back toward the firewall. That suggests to me that the timing is set too low.
Click to expand...

I think someone didnt put the engine back together correctly, its timed at 10-12 degrees BTDC. The short time that it was running good it seemed to run fine, so i put it back there when i put the new distributor in.
 
Was there a time when it ran fine with the new dist' ?
Firring order and reluctor gap correct ?
If a sudden running problem inspired your replacing the dist' it may have jumped time at the chain.Just a one tooth jump will result in the symptoms you have
 
RedFish said:
Was there a time when it ran fine with the new dist' ?
Firring order and reluctor gap correct ?
If a sudden running problem inspired your replacing the dist' it may have jumped time at the chain.Just a one tooth jump will result in the symptoms you have
Click to expand...

There was a time it ran right with the old distributor and carb. I got it and drove it a total of about 30 miles or so, then one day in a paking lot after It had driven fine, it started spitting and puking gas out of every carb orriface.

It had some crap feedback carb on it, so I came upon a 73 dodge truck carb, rebuilt it and put it on, ran better, but about the same as it does now. So I got that Autoline carb from Rockauto, I think it was bad, cause it ran worse then it does with the old carb, so I replaced the dist, cap, rotor etc and RA is sending another carb and we can see what happens
 
RedFish said:
I just noticed in one of the picks that the spark advance is rotated way back toward the firewall. That suggests to me that the timing is set too low.
Click to expand...

RedFish said:
Was there a time when it ran fine with the new dist' ?
Firring order and reluctor gap correct ?
If a sudden running problem inspired your replacing the dist' it may have jumped time at the chain.Just a one tooth jump will result in the symptoms you have
Click to expand...

The advance diaphram in my 74 318 is almost parallel to the engine crankshaft. Compared to my car, your timing would be way off. If this comparison is valid, and your timing light is showing 10 degrees BTDC, then I might start looking for a slipped distributor timing gear or a slipped timing chain....
 

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  • distributor.jpg
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You can put the distributor in any position, as long as you move the shaft with it; if it is timed, it is timed.
 
green1 said:
You can put the distributor in any position, as long as you move the shaft with it; if it is timed, it is timed.
Click to expand...
I disagree. Not only does the spark need to fire at the correct time relative to the crank, the distributor rotor must be pointed at the correct spark plug. If in between 2 towers, it can fire the wrong cylinder, termed "rotor phasing".

If you have a factory distributor, either with points (early) or magnetic pickup ("reluctor wheel", later), the phasing should be correct if you install the "intermediate shaft" at the correct clocking. The FSM shows how (below).

Step 1 is to bring cyl#1 to TDC, based on the timing mark on the damper. Remove the dist. cap and verify that the rotor is pointing at either #1 or #6. The FSM shows that the slot on the int. shaft should point directly at the intake bolt next to #1 cylinder (driver' side). If not, your phasing won't be correct. Of course, you must know whether #1 or #6 is on the compression stroke, but since your engine runs, your rotor can't be 180 off (some claim it still runs but poorly, I wonder how).

Even better, remove the #1 spark plug and hold your finger in the hole and feel the pressure rise to verify #1 is on compression. Better still, stick a wire in (bend so it can't fall in) and note the max position of the cylinder to insure your damper mark didn't slip (rubber fails).

The very best way to verify phasing is to cut a hole in an old dist. cap in-line with a rotor tower and shine a timing light clamped on that spark wire. Insure the rotor points directly at the tower. It will shift ~15 deg w/ vacuum advance, but shouldn't shift from engine speed.

Even if you install the shaft per FSM, the phasing could still be off if you installed an after-market pickup such as Pertronix Ignitor or Crane Cams optical. Less likely with Pertronix since it only fits one way. Crane has many optical wheels and pickup mounts, so you must verify. I dealt with that last week in my Dart. When I got it perfect (Mopar dist.), my vacuum advance was aligned similar to rp23g7's photo, though "about" isn't good enough to know.
 
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