Engine Probs?

[BJDEALER]

Ok i have been trying to get this engine running better. It is a rebuilt 360 with electronic ignition system. I have a holley 4 barrel carb. The engine is running really rough. The car had been sitting a few years. When i put the motor in the car i siphoned the old gas out of the tank and then filled up the tank with fresh gas. This whole time ive thought it might be the gas tank so the other day i used a small gas can to run the car on. The engine is running the same off fresh gas in a 5 gallon can so that is not the problem. I checked the spark plugs and they were fouled. I cleaned them up and it still runs the same. The ECU box is old so i was wondering about it. I do have some exhaust leaks around the manifolds. What are the most likely things i should check and how do i check them thanks for the help

 

[67Dart273]

You need to list what you HAVE DONE exactly to improve the situation. It doesn't sound like you've done very much

Frankly the ECU box just might be the LAST of your worries

1 Definately run on fuel from a clean can until you get other things straight.

2 Did you clean /rebuild the carb? This would be no1

3 The dist might be rusted up inside, a few things: The mechanical advance might be sticky, and the reluctor / pickup may be rusty.. Rust is iron and iron is magnetic. This could affect how the reluctor generates spark. Clean or replace. the reluctor and pickup coil. Check and set the "reluctor gap." Check the mechanical advance for free movement, or even consider tearing the dist down and cleaning and lubing the advance mechanism, and check it for wear. Obviously you'll have to reset the timing

4 If it's been sitting "a few years" (they add up) I would just plain automatically replace the plugs, the plug wires, and the cap and rotor. period. End of story.

5 Change the oil, and listen for sticky valves/ lifters. Might want to add some solvent like Rislone before you change the oil and run that for an hour or so.

6 Does it have stock manifolds/ exhaust? Check the heat riser butterfly to be sure it has not rusted shut. Might probe up the exhaust with a flexible stick for hornets (mud) nests, etc.

7 Use a meter and check voltage to the key side of the ignition resistor, then check voltage (running) at the battery. If it's charging, it should be up around 13.5--14.3 or so at the battery. If there is a lot of difference in the two readings, it means you have a VOLTAGE DROP in the harness/ bulkhead connector, and you may be getting low voltage to the ignition system

8 How about intake/ carb manifold leaks? The carb gasket might have deteriorated sitting. take a propane torch UNLIT or some starting fluid and gently squirt around the carb base. If it affects the idle you have a leak.

How do you know it was running any better BEFORE you parked it? Get yourself a compression gauge and a vacuum gauge and Google around on using them.

 

[713404spd]

x2 tune up and rebuild carb should do wonders.... also with a bad exhaust leak, sometimes the engine is really running better than it sounds

 

[BJDEALER]

guess i misrepresented the prob. I recently put this rebuilt 360 in my cuda. It was running great in the pick up i took it out of the pick up was wrecked. My problem is the engine is running really rough. The engine did sit for about 3 months before i got around to putting it in and starting it. Will that affect the carb if gas was still in it. The distributor was the one on the engine when i got it and it was timed perfect in the truck. The ecu was in the car when i got it 8 years ago and it was sitting outside all that time. The wiring is all original with exception of the electronic ignition wiring which was also in the car. Basically the engine is brand new from heads to pan. That is why i am confused. Maybe that is a little better info thanks

 

[BJDEALER]

Ok i was out messing around and i decided to pull off the vacuum advance from the carb to the dist. It seems to make the engine run smoother. What does that mean? I also checked my battery while the car was running and i only have 12 volts across the post which means my alternator is not working. Could that be affecting the engine making it run rough? If anybody has any ideas please comment. Thanks

 

[67Dart273]

Both. The vacuum advance could mean that you have the advance hooked up wrong (normally "ported" vactuum to the distributor, which means NO vacuum at idle) or it could mean you have the timing set way too far ahead OR it could ALSO mean that the reluctor gap is wrong in the distributor.

Trying to run the car at only 12V won't do much good, either. Normal "running" voltage while the alternator is operating should be 13.5--14.2 or so, +/- a little

Also, some variations of Mopar ECU's do NOT like getting wet, if it's out in the weather. I used to have that problem with one in my 340 powered FJ-40

 

[BJDEALER]

67dart i was poking around with my volt meter and found some results. With key on Ground to the batt and + on the alternator main stud only 12 volts while the car was running. Same across the ignition field terminal. There was 12 volts across the full field on the alt. There was 10 volts coming from the field wire going to the other side of the voltage regulator which i thought was wierd. I thought that was supposed to be ground. I have 12 volts at the firwall fusable link into bulkhead. Can you tell anything from those #s?

 

[67Dart273]

I don't understand part of your terminology

What regulator are you using, 69/ earlier or 70/ later?

If 69/ earlier one wire "ign" goes to well...ign, that is switched power in "run" other wire goes to field. IF you have two field connections, second one gets grounded

If 70/ later, blue "ign in run" goes to ign terminal of regulator, field term. goes to one or other of two field terminals of alternator, and second field terminal goes to "switched ign" or ignition power in run.

The reading you gave simply show it's not charging

You can make a quick check to see if the alternator will work, by running a clip lead from the output stud to one (only?) field terminal. IF you have two, clip lead the other field terminal to ground. You should get a small spark when you hook it up. As you bring RPM up it should charge more and more. Don't go nuts, as you can build enough voltage to do damage if the battery is a lightweight or fairly charged.

 

[BJDEALER]

ok 67Dart i have a hard time explaining this stuff since i dont totally understand it. Reference this post i made earlier
http://www.forabodiesonly.com/mopar/showthread.php?t=132999
I have the green field wire spliced in with the blue ignition wire going into the middle stud on the Voltage Reg. Then i have another wire from the other field terminal to the other pin on the Voltage Reg. That is how i read that diagram. Is that correct? If so that voltages i gave you you are what i have.