Strange gremlin preventing car from starting; pulling my hair out!

[marcd]

As the weather got colder here in Phoenix back in October, my car randomly would not start. At first it was very infrequent, and would only last for 3-4 key turns, maybe 5 secs each. Some times it will sound like it wants to start but won't. After starting, everything would act as normal, no other problems apparent.

As of Beginning of December, problem progressed to almost every time I needed to start car. In one week, I had to push start it 3 times to get to work.

Motor is an 1835 built by my dad (Frenchy) with 42's, mild 120 cam, full flow, port & polish, compu-fire (with coil) and 1 5/8" exhaust.

Some guys have told me "42's are pretty cold blooded, they do that sometimes." Since no other problems existed after startup, I was initially inclined to believe that. Some guys at work though immediately said it was the ignition switch. Their reasoning was that if it push starts, then the "Start" position of the switch must have a bad connection, and explains why it will push start when in the "On" position.

As I didn't have money for an ignition switch, and being semi capable with electrical, I decided to just put in a switch to bypass the ignition switch and send a 12v feed back to the coil. I installed a three position switch (On-off-on) and wired it so one of the on positions would be running the line through the ignition switch as normal, and the other would be a 12v line bypassing it.

After probing with the multi-meter and getting everything hooked up....no improvement. I had the multi-meter displaying voltage to the coil wire, and this is where things started to puzzle me. In either "On" position, line shows 12v. While cranking it shows 9-9.8v, but wouldn't start. At one point it rose slightly above 10v and the car acted like it wanted to start, but didn't. I finally ran a jumper line from the alternator directly to the coil and it fired right up first crank.

The next day the car acted fine, would start every time no problem throughout the day running errands. Next day same thing. On Monday though, it ran like crap on the way to work. Sputtering, stalling, acting like it was running out of gas, but was a full tank. Leaving for home at end of day, all is well, no issue, pulls as strong as ever on freeway. I was driving on the freeway later in the evening and it pulled hard from the on ramp all the way to 90mph with no problem or hesitation.

Next day, starting problem returns. I check the voltage on the battery (Optima red) and is >12v. Since battery is 5 years old I figure it might have a bad cell or something and is causing issue. Drop in a new known to be good battery and problem remains still!

Last night I was stranded at a gas station for 30 minutes when car wouldn't start.

The only two things left I can think of as being problems are:
1) Compu-fire (my dad swears this new fangled technology is no match for a good 009 or 010 with points)

2) Coil wire from fuse box to coil. I am leaning towards this myself; maybe the line is corroded or wire gauge is too small? But wouldn't problem be evident while running besides just starting?

I know this is a lengthy post but this is nerve-racking; and I'm hoping some other viewpoints could point something out I may have missed.

Thanks for any help guys!

[John Rayburn]

If by not starting you mean, not cranking intermitently, I'd say you need a starter relay. Fairly common problem.

[ian c]

do you have a spare coil to try ?
also , cold weather kills batteries . buy a new one .

to test compufire operation with a multimeter
meter positive lead goes to coil negative , and meter negative to engine case .
then crank it .
if it bounces between 1 and 13 its fine .

if it stays at 13v you have a bad connection at the coil

if it stays at 1v you have a bad unit (could be air-gap too big .)

[Wünderwolff]

I was also thinking about the starter relay, had the same thing happen to me and it drove me nuts. I never knew if I would be able to start or not, especially in colder (wetter) weather. Untill I changed to a new starter, the previous one was toast, some cracks in the housing made for bad coroded contacts.

Only thing is the bad driving one day MArc is talking about. But this might be a combination of things, having had to start so much empties battery, then not being able to charge properly because of bad old battery might lead to bad driving, sputtering and stalling.

[marcd]

If by not starting you mean, not cranking intermitently, I'd say you need a starter relay. Fairly common problem.

Starter relay is good, cranks but no fire.

I will try testing with the multi-meter as Ian suggests; and I'll repeat the test with another battery as well to make sure results are accurate. I've checked the air gap before as I suspected that also from looking at the compufire instructions. Perhaps it was borderline before and has now gotten worse? 

I just drove about 30 miles around town and freeway, and it was running really well, even started/fired first crank. Just as I pulled up to my house, pushed in the clutch while coasting in second gear and car puttered under 1000rpm and died. Tried cranking again and barely started; had to keep hitting the gas.

Bleh.

[ian c]

everything else is ok isnt it ?
fuel supply on spec , carbs clean , timing , plugs etc. ??

[marcd]

Fuel supply is good (mechanical), Carbs were rebuilt back in april, and checked again when motor was pulled for smog in july. Timing is 10º advance at 1000rpm, plugs i took out last night, cleaned and regapped. Plugs indicate it may be a bit rich.

[ian c]

get the meter (or points and coil) out again , and eliminate the compufire .
fit a new battery .
if its still bad , youre checking wiring and earths

[JS]

Marcd, does the battery measure 12v when the engine is stopped? As in 12.0v? If so, it´s broken.
Have you checked that the alternator does charge properly? Not only the correct voltage but also Amperes?
You seem handy with the multimeter so you know these tests are very easy to do.

[WCB Hitler's Hot Rod]

I had a problem very similiar to yours and it turned out to be a dirty gas filter screen in the tank.. I also blew out the gas line through the tunnel and noticed it was full of debry as well.

[marcd]

I think tomorrow I'll be checking all the grounds; Alternator is new but I will check it anyways. When sitting the battery will read about 11.46v or somewhere around there.

Maybe I can convince the old man to put an 010 on it instead of an 009.

I was planning to put an electric fuel pump on before Bug-in, and that would probably be a good time to blow out the lines and check the tank out.

Thanks for all the help guys, I really appreciate it.

[ian c]

I had a problem very similiar to yours and it turned out to be a dirty gas filter screen in the tank.. 

i was thinking this , or bad mech. pump .
but plugs are showing rich .

[ian c]

I think tomorrow I'll be checking all the grounds; Alternator is new but I will check it anyways. When sitting the battery will read about 11.46v or somewhere around there.

get a new battery .
should be approx 12.6 across open terminals at standstill
approx 9.6 cranking
approx 13.6 running
(all my rough guidelines ... 98% of all my winter problems have been battery)

[nicolas]

not sure if it fully relates to your problems, but i have a bit the same thing with my 42 DCNFs. the starter needs to crank the engine a few times and i have to blip the pedal at the same time to get fuel and then it starts. otherwise nothing much happens. once i get it going it all works fine and i have no problems.
i installed a cutoff switch as well and now i first crank the engine without juice and then i turn it on and that seems to have cured most off the problem.
i suspected the floatbowls emptying because off the short manifolds... but i never had a problem when i have driven the car.
so from what i first read i thought off this, but it seems like you encounter the problem more often and even after driving the car. mine starts just fine when the engine has run.

[Wünderwolff]

This dawned on me when reading Nicolas' reply, are you sure the carbs are not leaking? I had this happen to me on the T3, where the plug of the floatbowl came loose, spilling gasoline over the engine. At first it must have been a few drops, by the end of it, it was gushing out.

This sure made for bad starting and then even bad driving because of lack of fuel. I noticed before burning the bus down, better check, even though it's probably not that.

[Sarge]

I'd listen to your dad and lose the Compufire.  I had mine for a week before pitching it.  Try a regular old 009 and a blue coil just for the hell of it.  A stock Bocar fuel pump will work fine, too... try a new one; they're cheap. 

[Neil Davies]

I'd listen to your dad and lose the Compufire.  I had mine for a week before pitching it.  Try a regular old 009 and a blue coil just for the hell of it.  A stock Bocar fuel pump will work fine, too... try a new one; they're cheap. 

And only change stuff one piece at a time if you want to find out what the problem is. I chased a cracked rotor arm for a couple of weeks, changing coil, condensor, points, electronic ignition, plugs, cap and leads and all sorts of connections before I found the arm was KO'd. But at least I knew that the other stuff I'd changed was ok and could go back on, leaving me with good spares.

[Sam K]

I'd have to agree with Sarge, ditch the compufire. Throw in a 009 with a set of "tiger tail" points and that should solve your problems. I've lost count of how many bad compufires that I've taken out of friend cars. I have had one of the first Pertronix ingitor electronuic ignitions in my bug since 1995, but it seems to be the exception. i still carry points and a condenser though.

[JS]

Like ian c says, if your battery reads 11,5v without ignition on, the battery is gone, the charging not working properly OR BOTH!
Of course the compufire will give you trouble if it does not get enough juice...

The fact that your plugs show that the engine is rich isn´t so strange if you have to pump the gas pedal all the time to keep the car running I guess?

[Tony M]

I have had many a customers car in that would not start, all had the came Compufire system, put back in the points and presto. no more problems. Get a MSD box and be done with it 

[Dougy Dee]

The 'shoe' that holds the Compufire to the dizzy advance plate can loosen off providing an intermittent ground. Pull the plate and clean both the shoe and dizzy plate. Screw it all back together and you should be OK.
All electronic ignitions need a healthy 12 volts or no fire

[Frenchy Dehoux]

   I told my son Marc that tomorrow we should put the 009 back in with the blue coil and see what will happen. After this  the new fuel pump.

   Thanks everyone for your help

   Frenchy

[simon uk]

I had trouble with my 66 starting and it turns out the ignition switch was knackered and needed replacing. If there are voltage drops elsewhere that probably explains it, but if it is still dodgy swapping that might be the next option (but you end up losing the use of the original key  )

Hope its fixed now!

Si.