strange problem need help

Hey everyone,

so i am driving my car for about an hour and it starts chugging like crazy then dies. using a basic troubleshooting guide i realize that the spark condenser is bad. we have that fixed now. The carb just got back from a company that cleaned/rebuilt/tuned it. we put the carb on the car and fine tuned it to our application and area of the country. the car idles perfect the engine is brand new. I took the car out for a test drive and now it acts almost as if i am towing a heavy trailer with the wrong size hitch. that is the best way i can describe it. while trying to maintain a speed the car lightly chugs a bit. it only does it while the gas is lightly depressed to maintain speed or accelerate slowly. with the throttle open halfway it doesn't do it so much.
with a (should be) perfect carb/ignition(all replaced and reset)/engine what else could be the problem. i only have a few ideas, but i want some more opinions with the matter.
the ideas i have is that the original generator might finally be on its last leg as the lights will dim slightly while trying to maintain speed, the only thing is that they stay bright while just coasting and the problem doesn't exist while coasting.
my dad seems to think that there is too much play in the drivetrain somewhere and it is causing it to act like this, but unless my mind is miscalibrated, it feels as though it is coming strictly from the engine.

Thanks for any ideas. i really just want to feel like i can trust the car and after all the times it has died on me, i think that this might be the last thing for me to trust it on a 3 hour trip to omaha.

Please don't take this wrong, but there are too many young folks out there who do not know how to drive a manual transmission. Are you sure you are not trying to run at too low a speed for whatever gear you are in and lugging the engine. When it starts to "chug", shift down a gear and try to accelerate and see if it helps. The lights going dimmer kind of indicates that the charging system is not turning fast enough to produce enough voltage to keep the spark going. All indications I can reason from the information given is that you are merely trying to run at too low an RPM.

Fred

Along with his thought on the clutch is it adjusted right. You said you had the engine rebiult? If it idles fine and will rev when out of gear check to make sure the clutch is adjusted correctly.

I understand that a lot of young people do not know how to drive a standard trans car, but I have only driven two with auto in the four that I've owned. It happens even at highway speeds where the engine is turning around 3800 rpm. But am I taking it wrong if you say that it could be the generator?

Fuel pressure and volume OK? Did you install an inline fuel filter. Has it sat for a while. Mine did the same thing. It was crap in the tank that plugged the fresh filter in the first 25 miles. If I held it wide open it would get enough pressure to squeeze through but under 3000rpm it starved for fuel. I put in a new fuel pump, filter and removed and cleaned the tank.

8) a few things to check;

1: ignition timing. not enough will cause problems as will too much

2: ignition advance operation. make the the vacuum advance is working properly

3: fuel pressure. i the fuel pump is failing it will cause the very problem you have.

4: if it runs well when cold, but truns to garbage after warm up then it is possible that the carb is running hot enough to boil the fuel in the fuel bowl causing vapor lock. you might look in to making a heat shield for the carb.

5: it is possible that the generator is dying, but that would cause a problem all the time not just when the engine is hot.

Thanks for all the advice. I will try to toy wit the timing a bit to see if a difference is made, but as far as the gas boiling we got that fixed. The fuel pump is new as well as the facume on the dist and car, but I will double check. As far as weather it is hot or cold running it happens at all temps buit mmore at colder temps that is why I think it could be generator because it takes less energy to spark properly when cold right? I dunno trial and error through the entire thing

My two cents - Had a similiar problem but at lower speeds. Have your coil checked out. Low voltage from that equals some chugging on acceleration.

Hmm. Is it possible that trying to drive around with fried points and condenser might have taken some kick out of the coil?

The coil was teplaced about 6 months ago. Just before we rebuilt the engine and replaced the dizzy

Today I tried to toy with the timing, double-checked the carburetor and vaccume, and everything seems fine to me. while looking over every inch of the engine i found that the spark plug wires seem to be just a hair loose on the plugs, a little char (probably from arcing) on the distributor cap and rotor, and the hot idle air valve isnt set as the 3 manuals say it should be. paid very close attention to it with light throttle in the garage today and you could hear it happening without a load which is unlike i thought.

We played with this rod and got it set right (with the little notch even with the valve) and it got worse, chugging all the way up the hill and back down and dying as i pulled back into the garage. i regapped the plugs down and it calmed down a bit.

honestly i am running out of ideas and i am starting to get a bit fed up with the darn thing. i just want to take it out of town without the worry of possible failure

Thanks all.

You should do a compression test. It's comparatively easy on these engines and will give you a few pointers. Warm the motor up first, and test each cylinder dry then with a tablespoon of motor oil squirted into the cylinder. Make sure the throttle is wide open when testing, and remove the coil negative wire to avoid any spark risk.

Also when the engine is warmed up, a quick test of vacuum at the intake manifold is useful.

170-3tree":qx6e7jaa said:

Hmm. Is it possible that trying to drive around with fried points and condenser might have taken some kick out of the coil?

Click to expand...

170-3tree":qx6e7jaa said:

a little char (probably from arcing) on the distributor cap and rotor

Click to expand...

I'd get the coil checked as well or try a backup if available...same with the cap and rotor. I would think the char there suggests something is definitely off ignition wise. For example, it is possible to carbon score a distributor cap and cause carbon tracking that allows spark to be diverted/misdirected/shorted across cylinders. Carbon tracking allows spark to travel path of least/lesser resistance this can usually be seen evidenced by small black(carbon) lines on the surface of the cap.

Also, it may be obvious but I'd double and triple check the firing order, as well as make sure the point gap is correct by dwell meter. Feeler gauge will get you in the ballpark, but need the dwell angle to be correct.
Good luck!

Have you checked the spark plug wires including the coil to dist wire with an ohm meter? I have seen wires with no apparent physical defects that had too much resistance or that the inner core was broken and arcing and was gradually deteriorating. You might also try to slightly tighten the connector to ensure a better grip and connection where the wire meets the spark plug under the boot.

Fred

Today we tried to give it another shot to try and find the problem with my car. the spark plug wires appear fine and the resistance was 10000 ohms each (i don't know what it is supposed to be for stock wires) toyed around with the timing with no more luck. the compression in all cylinders is just about 150lbs each maybe more for a few. i know that is a low number, but shouldn't it be with them bored out?
using the vaccume gauge on the manifold revealed an exact 18in of vaccume. the coil tested out properly and the vaccume can on the distributor is right.
I think the next thing we are going to do is back the valve adjustment off just a little bit and see if it helps. other than that my ideas include the possibility of worn valve springs, too low of compression, or as much as i hate to say it it could possibly be a spun bearing, but truly doubted. a while before we got the carb rebuilt i was driving when the car started chugging like heck in rush hour interstate traffic and it just snapped or backfired or something. nothing was found in or around the road and it makes no relavent noise.

if the generator were dying wouldnt' the battery die after a while?

thank you all for bein there to help me through this

well we just tested to see the condition of the spark and my dad decided to do the look and see the spark himself. i am glad that i wasn't holding it he couldn't move his arm or make it stop twitching for about five minutes. I am just glad he was laughing about it instead of the other options.
But i think that we might have found the problem i just hope its the only one. and it would explain why it got a bit worse after we removed and replaced the wires several times doing tests