Ignition problems 440

[thethee]

Back again looking for advice from you guys.

Right now I'm having two problems with starting '75 Imperial and maybe they are related to each other. First, sometimes my starter has a real hard time cranking the engine, like it barely turns over. Battery is charged and when it catches engine runs beautifully and battery is charging. Seems to only happen when engine is hot but not always.

Second, yesterday after about an hour long drive I was coming up the parking lot and it died, without warning, and wouldn't restart, but cranking speed was normal. Then on my final try it started as soon as I let go off the key so I could park up. Thought it was the ballast resistor but when I checked this morning it still looked good and resistances were good I think, ~1.2 and ~5 ohms.

If not the ballast resistor, would that mean starter relay? How would I check that? Could a bad relay cause both issues?

Thanks in advance!

 

[halifaxhops]

Relay would just be the starter. What ignition you have points or electronic?

 

[halifaxhops]

I would check first if the ballast resistor is getting voltage in the "start" position key cranking, could be a switch since it started when you released the key. BB do not like to much initial advance for starting check with a timing light where yours is at idle. with and without the vacuum advance line on

Thats with a 5 pin ecu if you have a four pin disregard pin 3 on the ECU. Hope it helps.

 

[thethee]

I've made a typo, where I said "starter relay" I meant "ignition relay"

Back again looking for advice from you guys.

Right now I'm having two problems with starting '75 Imperial and maybe they are related to each other. First, sometimes my starter has a real hard time cranking the engine, like it barely turns over. Battery is charged and when it catches engine runs beautifully and battery is charging. Seems to only happen when engine is hot but not always.

Second, yesterday after about an hour long drive I was coming up the parking lot and it died, without warning, and wouldn't restart, but cranking speed was normal. Then on my final try it started as soon as I let go off the key so I could park up. Thought it was the ballast resistor but when I checked this morning it still looked good and resistances were good I think, ~1.2 and ~5 ohms.

If not the ballast resistor, would that mean starter relay? How would I check that? Could a bad relay cause both issues?

Thanks in advance!

 

[halifaxhops]

If it is a stock system there is no ignition relay, should be like that drawing.

 

[Big_John]

Right now I'm having two problems with starting '75 Imperial and maybe they are related to each other. First, sometimes my starter has a real hard time cranking the engine, like it barely turns over. Battery is charged and when it catches engine runs beautifully and battery is charging. Seems to only happen when engine is hot but not always.

That is a classic bad starter problem EXCEPT (IIRC) you've been messing around with ignition timing. Too much initial timing can cause that too. Try backing the timing off a few degrees and see if it still happens.

Second, yesterday after about an hour long drive I was coming up the parking lot and it died, without warning, and wouldn't restart, but cranking speed was normal. Then on my final try it started as soon as I let go off the key so I could park up. Thought it was the ballast resistor but when I checked this morning it still looked good and resistances were good I think, ~1.2 and ~5 ohms.

Another classic problem that is usually the dual ballast resistor. Testing it (bravo!! ) shows it to be good, so the issue may be in the wiring or possibly the ignition switch.

Hops has given some very good advice regarding this.

f not the ballast resistor, would that mean starter relay? How would I check that? Could a bad relay cause both issues?

No, unrelated.

 

[Pax2001]

Going out on a limb here and thinking simple. Have you checked all of your earth wires? My truck died one time for no reason and it turned out to be the ground wire to the body connection had gone bad over time.
my 0.2 worth

 

[thethee]

This is interesting.

I disconnected the starter so I could check the ignition without having to crank the engine. Disconnected both sides of the ballast resistor and checked with my multimeter. Left side shows around 12V in run position and around 0V in start position. Right side shows around 0V in run position and around 12V in start position. I hooked both of them back up and decided to check voltage at the coil, which was around 6.5V in run position and around 9V in start position. Strange. So I just hooked the starter back up, pumped the gas two times and turned the key. It started like normal.. So whatever it was it just dissapeared on its own, who'd have thought a running engine could be frustrating?

Can a ballast resistor be good cold and bad when hot?

 

[Big_John]

Can a ballast resistor be good cold and bad when hot?

Resistance does go up with heat. While I've really never seen one fail like that, I suppose it is possible.

It's not an expensive part and one that it's a good idea to carry a spare, so plug get a spare and plug it in next time it happens.

You could just replace it too... Again, cheap part... Can't hurt. Get two and keep one for a spare in the glove box.

 

[halifaxhops]

This is interesting.

I disconnected the starter so I could check the ignition without having to crank the engine. Disconnected both sides of the ballast resistor and checked with my multimeter. Left side shows around 12V in run position and around 0V in start position. Right side shows around 0V in run position and around 12V in run position. I hooked both of them back up and decided to check voltage at the coil, which was around 6.5V in run position and around 9V in start position. Strange. So I just hooked the starter back up, pumped the gas two times and turned the key. It started like normal.. So whatever it was it just dissapeared on its own, who'd have thought a running engine could be frustrating?

Can a ballast resistor be good cold and bad when hot?

Can be but if your getting 0 VDC in the start position which should be 12 VDC something is going on, poor bulkhead connection or a bad starter switch. So it started when you released the key from start to run? Did someone turn the key in the start position to check the voltage? Just checking.

 

[thethee]

Resistance does go up with heat. While I've really never seen one fail like that, I suppose it is possible.

It's not an expensive part and one that it's a good idea to carry a spare, so plug get a spare and plug it in next time it happens.

You could just replace it too... Again, cheap part... Can't hurt. Get two and keep one for a spare in the glove box.

Yeah I've read about the spare in the glove box before so that is exactly what I'll be doing.

 

[halifaxhops]

If needed I sell them.

 

[thethee]

Can be but if your getting 0 VDC in the start position which should be 12 VDC something is going on, poor bulkhead connection or a bad starter switch. So it started when you released the key from start to run? Did someone turn the key in the start position to check the voltage? Just checking.

Maybe I wasn't clear so I'll try to explain.

I disconnected both plugs from the ballast resistor so I could make a better connection with my multimeter. One side stuck in the plug and the other on good ground. Then from within the car turn the key and see the readings. Change plug and repeat. With both of them sort of hanging in the air the blue wire was 12Vrun/0Vstart and brown were 0Vrun/12Vstart. You're right, with them connected brown wire should give voltage in both start AND run position, which it does right now.

If needed I sell them.

Will shoot you a PM.

 

[thethee]

BB do not like to much initial advance for starting check with a timing light where yours is at idle. with and without the vacuum advance line on

That is a classic bad starter problem EXCEPT (IIRC) you've been messing around with ignition timing. Too much initial timing can cause that too. Try backing the timing off a few degrees and see if it still happens.

Interesting points about the initial timing and slow cranking. My initial timing is set at 17.5 BTDC right now so that should be okay. Could very well be problem with my starter but it rarely happens and mostly with hot restarts, but even then less than one in five times I think. It being intermittent makes me wonder if something in the advance, vacuum or mechanical, could be binding causing slow cranking. But distributor is new so I would still suspect starter. Maybe time to have a look inside.

 

[Big_John]

Interesting points about the initial timing and slow cranking. My initial timing is set at 17.5 BTDC right now so that should be okay. Could very well be problem with my starter but it rarely happens and mostly with hot restarts, but even then less than one in five times I think. It being intermittent makes me wonder if something in the advance, vacuum or mechanical, could be binding causing slow cranking. But distributor is new so I would still suspect starter. Maybe time to have a look inside.

Try knocking the initial timing back... Cheaper and easier than a starter.

It is very, very typical for too much timing to cause that and I think you are in that spot where you might have a problem.

 

[Ripinator]

Try knocking the initial timing back... Cheaper and easier than a starter.

It is very, very typical for too much timing to cause that and I think you are in that spot where you might have a problem.

17.5 degrees initial appears to me to be very advanced. My TNT 440 calls for 12.5. . .

 

[thethee]

Okay I understand that too much initial timing causes hard starting, but shouldn't that cause hard starting all the time? Instead of just sometimes?

 

['66 Fury I]

your starter could have worn bushings. Trouble will show up first when timing is overadvanced or engine is hot. Time for a starter rebuild? These starters look difficult, but check out your FSM and YouTube and you can do it! LC

 

[halifaxhops]

Hot it definitely affects start. My 440 broke 3 starter noses before I realized the Vac advance was kicking in. Big pia to figure out!

 

[Mike66Chryslers]

Okay I understand that too much initial timing causes hard starting, but shouldn't that cause hard starting all the time? Instead of just sometimes?

It will be worse once the engine is hot. I found the same problem before. I found that my cam would idle very nice with about 16* advance, and got rid of a bog that I was experiencing when trying to launch hard from idle. Unfortunately that was too much when trying to start the engine hot because ignition would happen too early and fight the starter, so I had to cut the timing back. It started fine when cold though.

As for your other problem with the engine cranking at a normal rate but not starting, I suspect your ignition was not firing while you were cranking. No ignition therefore not kicking back against the starter. Usually a bad ballast will exhibit the opposite behaviour of what you describe: it fires while cranking but dies when you let off the key, because the ballast is bypassed while cranking. I have no experience with the dual ballast though, only single ballast and 4-pin ECU.

@Ross Wooldridge was having a similar intermittent problem last year, with the engine dying and not restarting in his wagon. It turned out to be a chafed wire to the ignition coil which was intermittently shorting to part of the engine block.