Engine won't idle - UPDATE

[Mercury Mike]

Went through my entire ignition system. I had a new coil, alternator, and battery from when I installed my engine over a year ago (wow, has it been that long already?). I changed the points, condensor, and all last week. My car will turn over, start, and then just kind of thump around for a second before I die. If I give it gas, there's no effect, the thumping doesn't speed up or anything. Could it be a vacuum leak? Bad gas? I rebuilt my carb way back when, and it ran good, but since I figured it might be the carb, I swapped to another 1bbl I had laying around that had been kept in a dry place. Same exact effect. I went inside for a coke, came back out, turned it over, fired it up, and it idled and ran GREAT! I decided to put it in reverse and take it around the block, 'cause why not. I got home, put it in park, went upstairs. Came out today, went to start it, and again same problem. Could it be a float adjustment? Anywhere specific to look in the wiring? Give me some ideas, I'll go out tomorrow and try it all out, then come back and give a full report on what happens. =D Thanks all.

 

[addo]

The resistive wire, maybe? Check your voltage at the coil.

 

[Mercury Mike]

Alright. Why would it run perfect that one time, and then go back to running bad?

 

[addo]

Dodgy connection, maybe?

 

[Mercury Mike]

Alright, I'll check it allll =D Thanks addo. I'll give you an update tomorrow. How should I hook up the DVOM?

 

[fordconvert]

Hmmm Electric seems more likeley to be intermittent like that unless its bad fuel.

 

[JackFish]

Bad gas?

If it's been sitting any length of time there could be condensation in the system.

 

[Mercury Mike]

Soooo I went out, and started at the coil. I looked at the wire going from dizzy to coil, immaculate. I checked the other wire, and there is only 1 strand of wire, and all of the other parts of the end, right before the cap, are shooting off in every direction. I turned it a little bit to pull it off, and it broke. Really brittle. My question now... is where do I go from here? That wire is toasted for sure. I was probably only getting a volt or two to the coil. I don't have my DVOM here it's in my buddy's truck as we were doing lighting and such in his cab, but I am pretty sure that that's where the problem lies. Thanks guys! Do I cut, add a new wire, solder, or what? I wanna know the best way to repair this to get maximum voltage. I'm excited that this may clear it up!

 

[addo]

If there is enough length, just get a new crimp connector. Instead of only crimping it, lightly crush then finish the job with soft solder.

 

[Mercury Mike]

So far in prep while I was at my grandpa's, I got some wire, stripped both ends, put a wire end that I can put on the coil, and left the other side stripped. Tomorrow, I'll cut the wire in the car now, which sadly broke right at the connector, or I'd use it, and I'll connect the two wires. If I just tie them together, and wind them around with pliers, it should be fine, right? After I get them together, I'll fire it up. Hopefully it idles! =DDD Thanks for the help guys. I'll give you a heads up on what goes down tomorrow. It's too late, and it was my sister's birthday tonight. In any case... thanks. =D

 

[JackFish]

If I just tie them together, and wind them around with pliers, it should be fine, right?

Um, if you're going to do that maybe put a piece of shrink wrap tubing on first.

 

[fordconvert]

Parts stores will have the crimp tool and the ends. Sometimes you can find them in the $5 bin that come with the tool and an assortment of ends. Hardware/ home stores will also have inexpensive kits. The $5 ones are crap but if you only need to do a few now and then they work fine. Solder and heat shrink is always good. Fewer connections and splices are also good.

 

[ludwig]

If those ends have been out for a while, you shoud sand them a little before you reconnect, if you are just going to wind together and solder.

 

[Mercury Mike]

I cut new ends and stripped the wire for new usage. I reconnected, soldered, sanded. It turned over, fired up, then ran for a second, and quit. Then it buzzed around, and I found that the coil wire had come unconnected. I reset the choke, cranked it, and nothing. No pop, no backfire. Checked the timing, perfect. So I got out my voltmeter and started to probe around. Battery voltage steady 12~V. From positive terminal on the battery to the solenoid, 12~V. While the key was in the on position (not acc, on), there was no power to the S or I terminal on the solenoid, and there was no power to the side that the starter is wired up to. At the coil, there was 0 voltage in every terminal while the key is in on. Obviously no spark. Could it be my solenoid has gone out?

 

[addo]

The solenoid is only energised when you turn the key to its springloaded "start" position.

Your results suggest that in fact the problem lies around the back of your keyswitch - either the switch part itself, or wiring adjacent. Do you know how to remove the barrel? I'd suggest you disconnect the battery, remove the barrel, release the whole switch from the dash and reassemble hanging down by its wires. Then reconnect the power.

Now you can test supply to the switch by slightly releasing the plug on that switch's rear and slipping a probe in there. With no battery power, you can also test simple continuity from the keyswitch to the coil.

 

[Mercury Mike]

How do you remove the keyswitch? Using that little hole? I'm supposed to have about 12V at the coil when the key is in ON right? Which terminals on the ignition switch to I check with my meter, and what values should I be looking for? I wish I knew more about troubleshooting electronics. =D

 

[fordconvert]

What year car and engine and ignition system are we dealing with here? Or did you change your name? Otherwise Im lost but others seem to know what we are talking about.

The 12 volts (or perhaps a bit less because of the resistor) is measured between the + of the coil and ground, NOT the - terminal of the coil.

If this is a pre 67, the key thing is released with a paperclip in that little hole, IIRC you put the key in and turn back to accy, if you look in the hole as you turn it there you will see a little button come into view in the hole, that is what you push on with the paper clip and rotate the key further to the left then the whole thing just pops out.

How are you concluding that the timing is 'perfect' during cranking?? Im asking because cranking speed is not really meant for timing. Do you have a reason to suspect the timing is off since last time it did run? What equipment and tests are you using to confirm this? What is the timing in this situation? If you are using a normal modern inductive timing light for this test and it is flashing you should have some sort of spark, it may not be perfect but you should have some sort of spark. For testing like this you could just clip the probe to the coil wire since all we are looking for is spark. I assume you have a dwell/tach meter??? You need one if you are getting this deep. Even during cranking the dwell should be steady and close to the spec. If its not go after your points. If you have the tach hooked up keep an eye on it also. If it drops you know you are back to points or soemthing else on the primary side of the system.

 

[Mercury Mike]

I changed my name from 65Stang200. Got tired of the generic name. =D 1965 Mustang Coupe, standard points/load-o-matic/1bbl holley 1940. I got a couple more questions before I go tackle this thing. I can get the ignition switch out no problem. My ignition switch wiggles a ton. Also, while the key is in the ignition, and the car is running, I can pull the key out. Could my whole assembly be shot? I never saw it to be an issue before. To answer your questions, though:

I mean that the timing has a base of 12* at a standstill. I checked it with my timing light. That was the last time it run. I did crank the balancer around to TDC and it was very close to the #1, about 12* off I'd say. =D My balancer mark is still good. I used a new balancer when I rebuilt the engine. (15k ago) It is definitely close enough that it would fire. I have no reason to suspect that the timing would be off at all. I pull the number 1 cylinder up, using a piston stop, and watch it 'til it hits TDC, which aligns with the balancer, on the compression stroke. I swapped the wires around just to make sure that I wasn't 180* out (but it did fire and run for a second, and then went back to not starting, only cranking.), but nothing happened at all. No backfire or anything. No spark.

I have a dwell/tach/voltmeter that I have been using. =D If I set it to dwell, on the gauge, do I turn the engine around, with the key in ON, and hook it to the coil? Dizzy side or firewall side of the coil? Dwell should stay steady, correct? Do the points need to be open to check dwell? Thanks.

Let me know if you need any more information.

 

[fordconvert]

I was just making sure we were talking to the same guy and working on the same car, I thought we were but I just noticed the name so I figured I would check.

Dwell and tach are done with a meter lead on the - terminal of the coil and the other wire (or wires depending on model) usually on ground or battery + or both (if its not clear check your meters instructions, online if you dont have them anymore) My meter (sears engine) has red batt+, black ground, and Green coil -. The dwell is measured with the engine running or you can get it in the ballpark cranking but like the timing it is meant to be checked at idle. On mine when I got it the points would stick open sometimes, took me a while to figure it out. I had never seen it happen before. I finally noticed it because I had the dwell meter hooked up when I was messing with things and noticed that when it cranked sometimes the meter would drop. Same thing would be true if you use it on the tach setting, meter drops means you lost the primary ignition for some reason. If you were to crank or turn the engine slowly by hand on the dwell setting you would see the meter peg when the points are closed and then drop to 0 when they open.. the reading comes from when its running at speed the % of time they are closed vs. open. If the dwell is not right things can act strange, also if the condenser is missing or bad the points will very quickly and do strange things. Is the ground wire inside the dizzy in good shape and clean? If you have a vac pump get the dwell meter hooked up and with the cap off turn the engine so the points are closed and flex the wires around and operate the vac advance. The reading should not change at all during this type of test, if it does you have a bad wire or connection somewhere.

Have you tried messing with things with the vacuum line for the dizzy unhooked? It wont drive worth a crap with it unhooked (and plugged) but maybe you got something wacky going on with the vacuum and thats messing with your timing?? Just a thought that would help you maybe eliminate a few things.

 

[Mercury Mike]

I checked all that. When I move the breaker plate manually, you can hear a hiss. I'm gonna go out and mess with it a little more. With the key in the ON switch, where am I supposed to get voltage in the engine bay, and what numbers am I looking for?