Still chasing a miss in the fury suburban 400

Well, I had back surgery, been away from the game for awhile. This past week with the nice weather has me back outside messing with the plymouth (1973 plymouth fury suburban 400ci). I put in my rebuilt holley 2210 carburetor, hooked up an auxiliary gas tank with new filter and away she went. It runs decent (idles now) and even takes feedback with the accelerator pedal now. The problem is she still has a very intermittent miss. For getting it on the road and the quest to make it reliable again I've already replaced: coil, cap, rotor, plugs, wires, fuel pump, rebuilt holley 2210 carb., front brake calipers, master cylinder. Still want to do a few things before it actually hits the road (quite a few exhaust leaks to start), the miss doesn't make it not drive able it just makes me nuts lol. Any specific areas I should be looking that I may have overlooked? Thanks in advance.

 

I'D LOOK AT THE ELECTRONIC IGNITION AND IF ITS THE ORIGINAL I'D REPLACE IT. THEY GET TIRED WITHOUT DYING SOMETIMES. THEN THEIRS THE BALLEST RESISTOR, BUT THEY USUALLY DIE AN UNTIMILY DEATH WHEN THEY GO, THAT'S WHY YOU NEVER LEAVE HOME WITHOUT ONE

 

Danged, I thought this thread was gonna be about chasing wild women!
Don't overlook a dirty fuel filter and dirt in the tanks. Of course that doesn't seem possible with aux tank and new filter. That electronic box could very well be the miss. On my old 440 The module would overheat then miss.

 

Bigbarneycars, the car sat for over 20 years prior to my resurrection. The box is cheap, probably my next move.

CatModelT, marriage ensures the pursuit of wild women stops LOL. Yea, when the miss started happening I wanted to isolate my fuel source since the gas in the tank is questionable (at least over 3 years old is when I originally started messing with her). I will try that box, shall see what happens.

 

My riding mower, used only once before, sat five months this winter here in Florida. Today it took 30 minutes to get it to stay running and run smooth. A reminder about our modern expensive gas.
As for the pursuit of wild women, been married over half a century and still chase them. I'm just not allowed to catch any or touch those I do get close to. Kinda like a dog chasing a car!

 

DZ, "Orange box" is the only way to go. It should work for the 400 even tho' it was produced for the 440. Mopar piece BTW. Try your local Chrysler dealer in their Mopar Preformance Catalog. Or contact Mancini Racing in Roseville Michigan. (Their on the web) Jer

 

CATMT. STA-BEL has been formulated to keep the crap burning that we're forced to use in todays world. Fired up the ZTR Wednesday after 5 months of sitting just by pulling the choke and turning the key Mowing on the 28th of March, OUI BUT IT WAS EITHER THAT OR WAIT 'TIL NEXT WEEK AND HAVE TO BUY A BAILER

 

If your just feeding the carb by a fuel tank and no pump then it could be just not enough pressure to fill bowl completely... running lean.

The other guys seem to know of Mopar ignition issues, there is also possibility of the relctor and pickup in distributor being faulty. Many times they will still run though not correctly. Also a worn distributor shaft can change gap here.

1973 had electronic? I was going to suggest setting points with dwell meter and not by gap alone...

For fuel in old cars that sit and running in lawn mowers that sit all winter or snow blowers that sit all summer or baots stored all winter etc... fuel stabilizers help. But not as much as running non ethanol gas all year long and storing with fuel stabilizer.

Look around town or ask the lawn mower repair shops, or Co-op. We have a few places in town now. Using the 93 octane non ethonal fuel in all my freinds equiptment at his property has reduced yearly maintenece of draining fuel systems and cleaning carbs and flushing etc... to nothing! Just good running equiptment all year and next season. Cost is about a buck a gallon more but yearly cost is nothing compared to damage and repair let alone frustration!

 

Eaglemark,
I have my auxiliary tank running through a brand new fuel pump. And yes this ethanol fuel is junk. If I have to leave fuel in something I use stabil and I still start the engine every few weeks and let it run for a bit just to keep things moving. I believe 1973 was the first year for this car to have electronic ignition. I may also replace the other items you mentioned since the ones I have are most likely original, and am trying to make the car as reliable as possible, not to mention parts are fairly cheap.

 

You can look at the menu, but you must eat at home..

 

Yes dear ! Where have I heard that before?

 

Ok, an update. I've replaced the ignition control module, ballast resistor (mine was cracked underneath), and the voltage regulator (mine lost most of its plastic/epoxy). I still have the miss although the engine seems to run a great deal better now. I was double checking my timing and it seems that every few seconds the spark drops out or gets weak or very quickly double flashes as indicated by the timing light. I checked my light on another car and it seems to operate correctly with no abnormality like on this plymouth. I've pretty much replaced everything in the way of my ignition except for the distributor. I guess I could have some shaft play or the pickup is on its way out. Any suggestions? Thanks.

 

Shaft play is easy enough to check just see if shaft is loose.

What your describing is exactly what happens when a pickup module fails...

 

I have had 2 vehicles with a miss that about drove me nuts, as well. One was a 318 Dodge and the other was a 350 Chev. I isolated the cylinder that was weak on both it was #s 4&6. The culprit, both times was a vacuum leak. On the Dodge, the power brake plastic fitting was sucking air, and on the Chevy, the vacuum tree behind the carb, where small lines hook on to was broken. Both easy fixes, just hard to find.

 

It has to be something like that, DG, since it has happened with 2 different engines.