Poor ignition 86 chevy 74 350 motor

I meant ignition module.

But the HEI distributor has an electronic control module mounted inside it. The entire ignition system is completely self-contained.

CWright, does the distributor shaft have any side to side play in it? Any wobble in the shaft?. If the shaft has any side-play in it, the spark will become erratic…Also the vacuum advance breaker-plate that moves with a vacuum signal, that must be mechanically sound on its mounts and not flopping around in there…

It doesnt have any side wobble. I will work on it tomorrow morning and try to take out the distributor. I have never taken one out before but I will let you know what I find.

If the relationship of the rotor to the distributor housing is marked and the starter is not engaged the distributor will be easily re-set. Getting the distributor out may be tough. It will be seized up in rust and sludge. Once the hold down is removed you must patiently twist, push and pull to get it free. Before re-installing, polish the base and wipe it down with motor oil. The module is less than $30 as is the pick up coil and it might be worthwhile to replace them both. And if that grounding strap was left out you need to get it installed.

If the ignition checks out fine then maybe you’ve picked up some junk in the carburetor and now have a clogged main jet or air bleed or possibly an accelerator pump problem in what is assumed to be a Quadrajet carburetor.

A fuel related bucking and stumbling may often be thought of as an ignition miss.

If it ran good after the tune up, everything was assembled right. I’d suspect a bad module, pickup coil, or damaged rotor. Possibly something got disturbed and a wire got damaged. If it’s idling high and you can’t adjust it, it sounds like you may have knocked off a major vacuum line or cracked one.

I’ll take off the carb and clean the distributor and inspect for damage on any component. I’ll post sometime tomorrow and let you guys know what I found. Thanks for all the input, really helping out. If I had the money I’d just replace it all but all in due time.

Generally, the 5 and 7 wires get installed on the wrong plug. Sometimes the center electrode is left out of the cap. Sometimes the rotor center contact gets bent and breaks off when the engine is started. One of the plug wires may have backed off the plug. Make sure the wires on the ignition pickup aren’t frayed.

"Also it sounds like it’s reving to much and no carb screw adjustment hardly effects it. "

Start looking for vacuum leaks.

Did you put the little carbon button in the bottom of the cap correctly?

I can’t tell you how many times I’ve seen that put in upside down or on the wrong side of the insulating washer between the cap and the coil.

Removing those HEI units from a older vehicle can be difficult…The housing may be an interference fit against the firewall…As long as the shaft has no side to side slop, better to leave it alone…Sorry I even mentioned that…(removing it)…Replace the module and pick-up and clean things up with a little solvent and compressed air.

I just check for vacuum leak with some carb cleaner and didnt find anything. Idle screws still not effecting anything. I’ve never had a carb’d motor before so I don’t know if that is the problem or something in the ignition.

I just pulled one of my new plugs I just put in. It has spark but is very black and sooty. Where should I start looking for a problem on the carburetor? Maybe something is stuck open?

I would pull a few more plugs to see if they’re sooted up also. If they are then possibly a carburetor problem.

If they are not sooted up then maybe a compression test on the cylinder with the sooted up plug might be in order. In a case with only one sooted up plug it’s possible for the plug to be oil fouled or gasoline fouled due to low compression.

ok

With both idle mixture screws turned in snug, the engine should stall and not idle at all…If it will idle with the mixture screws bottomed, then gasoline is leaking in. With Quadrajets, this is usually caused by a “heavy float”, a foam and plastic float that has absorbed gasoline and can no longer control the fuel level in the float bowl…Or a particle of dirt has lodged in the needle and seat, allowing fuel to pour into the carburetor…You would notice this as the fuel would leaking out of the carburetor…

ok caddy. I’ma take off my carb tomorrow (first time) :slight_smile:

The QuadraJet is a fine instrument, maybe the best overall 4 barrel carb. Buy the right rebuild kit, the carb should have a tag with a number on it, sometimes called a list number…

Set up a clean orderly well-lit work area. Take some close-up pictures of the linkage so you can put it back together correctly…As you remove the top, study how everything slips / fit together…The float and needle and seat are installed in the top…Most rebuild kits do not include a float, that’s a separate part (usually). In any case, buy one. Use the correct tools to remove the various screws, clips, jets and valves…Watch for check-balls and where they came from…

Under the accelerator pump will be a check ball. Look for it. Remove the booster venturies and their siphon tubes carefully. These parts and the passages they connect to need a thorough cleaning. Remove the idle mixture screws and clean out those passages too…

Books have been written about the Q-Jet carb. They go into great detail about how to rebuild, maintain and set one up. When they are right, few if any carbs can match their overall performance…There are some tricks to them, like sealing the welch-plugs in the float bowl so they don’t leak and drain the chamber, resulting in a no-start…

Have fun, take your time, have no fear!

I am just now realizing that the OP has pulled out a fuel injected engine and replaced it with a carburated engine. Was the electric fuel pump removed? How much fuel pressure is going to that Q-jet?

Ok so here is the problem. Other than the carb and intake needing replaced in general. It was the secondary jets that were sticking up and not closing. Also my throttle shaft is loose. So to get me by I’m going to disable the secondaries until I can afford a new carb/intake.