My motor is running like crap...

[JamesRR]

84 dodge d150 with a 1973 360. A little bit of cam. Carter AFB carburetor. stock heads. Mopar distributor with orange box... Truck was running excellent. For miles and miles. Went to start it the other day and it wouldnt start. Went out the day after and it started and all seemed well. Normal warm up procedure per usual. bump the pedal to release the choke and it died. Started right back up and ran for a little. I revved it up and there was a popping/missing/coughing effect. Let the throttle off and it wants to die. Then when I try to give it gas again it dies instantly. Black soot in the primary section of the carburetor. timing is set about 9-10 initial and then 34ish all in. rotor pointing at #1 at TDC. Are all MP distributors curved like this? I think the engine would like more initial. anywho.. I checked to make sure the balancer was in its correct place today and it was. It has not jumped time. Pulled #1 plug only and it looks redish brown. Not oily. I will check the others and pull the carb next. I also have a brand new distributor from 4secondsflat laying around and plan to put that in because the mopar distributor looks like its seen some miles. I did notice when playing with the timing that the current distributor did not want to spin very freely. I will dig into it more but wanted to know if anyone has experienced anything like this. Went from bitchin to a ***** in moments. Thanks

James

 

[GEO]

Those orange boxes are junk and fail often , move up to the chrome box.

Your problem sounds like dirt in the carb to me

I'd start by putting gumout in the gas tank , and spraying the top of the carb out with spray gumout, preferably while the engine is running.

If you have to rev it some to keep it running while spraying that is normal and will sound like it's missing while you are spraying but should clear up immediately when you stop.

Kicking off the choke early before it warms up can make the engine backfire back into the carb and make it black and clog up the carb and make it not run right

 

[69_340_GTS]

Those orange boxes are junk and fail often , move up to the chrome box.

I have had 2 Chrysler ignition boxes burn out. The symptoms are exactly as you describe. If I had to buy a new one today, I'd just get a generic one from NAPA. Make sure the case is grounded. Run a wire from the case right to the engine block if you can. Seems to help the Mopar type boxes last longer. I finally trashed all the Mopar stuff and went 100% MSD (distributor, coil, box). Car runs so much better it is amazing.

 

[JamesRR]

I have had 2 Chrysler ignition boxes burn out. The symptoms are exactly as you describe. If I had to buy a new one today, I'd just get a generic one from NAPA. Make sure the case is grounded. Run a wire from the case right to the engine block if you can. Seems to help the Mopar type boxes last longer. I finally trashed all the Mopar stuff and went 100% MSD (distributor, coil, box). Car runs so much better it is amazing.

Thank you for the reply. The stupid orange box is brand new. Is it common for them to go that quickly?

 

[tekslk]

You never no on the boxes, also research trailbeast post on hei conversion it doesnt cost much and will give you great spark.

 

[RedFish]

Examples of sudden carb faults. Some carburetors have whats called venturi bleed tubes staked into the upper casting. Those can fall out. Some have a check ball in the accelerator pump cavity that gets blocked.
I would look over everything easy and obvious first, the battery/ charging system, electrical connections from ballast resistor to coil, pcv and other vacuum components. whatever can be checked without getting my hands too dirty.
I have spent 2 days digging for a problem that turned out to be bad fuel too. That gal stopped somewhere to pee and bought 10 bucks worth of fuel just because she felt obligated. She learned, next time buy a map or something off a shelf.

 

[Aaron65]

I'll add to the bad fuel comment...

My '65 Skylark is my "old reliable," and the other week, it would barely idle as started missing and surging going down the road. I had recently installed a Pertronix module, but it had plenty of spark. I added some of that blue enzyme cleaner to the tank, and pulled the idle needles out and blew out the idle passages with compressed air. It instantly ran 80% better. I drove it on a 200 mile round trip the next day, and now it's back to running normally. I just think I got a tank that had water/junk in it. I changed the filter but the old one wasn't even remotely plugged. Give it a shot.

 

[moparlover]

I revved it up and there was a popping/missing/coughing effect.

sounds like a cracked distributor cap to me

especially the part about soot in the carb... they will backfire and do all kinds of crazy stuff (keep a towel handy if it backfires with the air cleaner off you will need to smother the flame lol)

small blocks especially susceptible to this if you jack the engine up at all for any header/trans etc maintenance the dizzy hits the firewall

 

[69_340_GTS]

Thank you for the reply. The stupid orange box is brand new. Is it common for them to go that quickly?

You never know. Someone on here can probably tell you how to test it.

Could be bad right out of the box. All this stuff is now made by the lowest bidder, most likely in Asia somewhere.