RedLeader289

iTrader: (2)

Ok, I've let this go for long enough and now I'm going after it.

The situation: Absolutely randomly the car will not start. It will just turn over until you use up the battery. Yesterday marks the third time it has done it in about 5 months or so. The last time it did this was over a year ago.

I have fuel, I have air, but no fire. Using a test light (homemade, haha) I was able to determine that I have power going to the distributor (via the red wire that plugs in on the driver's side of the cap. But, when you crank the car there is no spark in the #1 boot (verified by staring into the boot while my wife cranked the car).

I believe the connection of the hot wire to the dizzy is not the best because the last times this has happened I've been able to "fix it" by unplugging (and then wiggling, flicking, etc) the connector on the end of the hot wire and plugging it back in. Waiting an hour (to let some of the fuel evaporate) and then boom, it goes.

This afternoon I am going to take the connector apart inside the distributor cap and make sure the male end isn't bent or something that would cause it to not hook up correctly. I will also clean the female end that is on the hot wire.

If none of that works the only other thing I know it could be is the control module inside the dizzy.

If anyone has any other suggestions, feel free to post. Also, if you know how to tell if a control module is bad please let me know. I'm really hoping it's just my connection at the hot wire.

The last time I drove the car was Saturday, ran strong, no issues/stumbling/anything to make me think anything else could be wrong.

aliceempire

iTrader: (14)

I'm guessing you're working with a coil in cap large HEI? If so, I ran into a problem where the wire leading to the coil had broke but made enough contact to work most of the time. I'd pull the cap off the top of the coil and check it all.

RedLeader289

iTrader: (2)

Yup. I did that last night, took the cap off the coil and checked all the connections, took it appart, cleaned all the connectors with some 800 grit(even though they were spotless), wiped them down, reinstalled. nothing.

Did it all a second time. nothing.

Took the entire distributor cap off, cleaned the contact on the rotor, put it back together, took the cap off the coil again and AGAIN checked all the connections. nothing.

This is where is gets crazy.

I took the cap off the coil one more time, checked all the connections (unplugged and plugged them back in). Put it all back together, cranked it, and boom. ran like a charm.

Hasn't given me any trouble since. I'm still left not knowing what the heck the actual problem was. All the wires looked good, the connections are clean.

I'm going to trace every wire that plugs into my distributor later this week just to make sure nothing is getting funky anywhere else. I do plan to replace the connector that is on the hot wire that plugs into the coil on the driver's side, since it was pretty corroded. Hoping that's it, but can't be sure.

Open to any other ideas anyone may have.

Mayt13

Check your grounds. It could even be corroded/lose battery terminals. If the cap and rotor work, they usually they work. Grounds not so much (usually cause intermittent electrical problems). If you have a poor connection, the high amperage of the starter motor could be flowing despite a poor connection, while the coil is not receiving enough power.

RedLeader289

iTrader: (2)

That makes sense! Come to think of it, there is some corrosion build up on my negative battery post. I will definitely be cleaning that off and checking my other grounds.

thanks!

RedLeader289

iTrader: (2)

The gremlin strikes again!

Update: grounds are clean. connections are clean. I have power to the distributor but no spark. Everything worked like a charm the last time I drove it (a few days ago).

I'm at a loss, if it were reproduceable then i'd be having a much easier time, but I have no clue what's causing it (and it's totally random and not reproduceable). It'll just crank and crank until you kill the battery.

For more info on what "fixed" it last time read my posts above.

I'm open to more suggestions.

OrangeBird

iTrader: (1)

Hi Red Leader ,

I saw mention of you having the coil in cap HEI and was wondering if this has a vacuum advance also ? I ask because one time I saw a situation where the wires going to the pickup coil has weakened from the flexing caused by the advance and occasionally the car didn't start . Funny thing was you'd expect that revving the engine which would be flexing the wires while running would cause it to stumble (which does happen usually with this type of failure) but no , it ran perfectly when it decided it would run . Using an Ohm meter on the coil's two wires showed that when moved in just the right way , contact was lost .

In Brief , have you checked the pickup coil ?

RedLeader289

iTrader: (2)

The only connector that is questionable is the power connector, I found this on ebay which would give me brand new connections for both it and the tach(not needed, but still nice).

For $11 bucks I figure it's worth a shot. Thoughts? How hard is it to trace these two wires with the engine and everything still in?

http://www.ebay.com/itm/Power-Tach-wires-for-all-6-8-Cyl-HEI-Distributor-/291117705116?pt=Motors_Car_Truck_Parts_Accessories&hash=item43c7f7a79c&vxp=mtr

RedLeader289

iTrader: (2)

Hm, I have not checked the pick-up coil. Yes it is vacuum advance. That is now on my list of things to do. Is an ohm meter required to do that?

RedLeader289

iTrader: (2)

Mmk, replaced the wiring, no change. I will check my grounds once again when I get back to it. The coil appears to be fine (it doesn't show any typical signs of being or going bad). I'm thinking that this could be something in my ignition control module.

samiel_00

lol I feel your pain. Mine won't start about 1 outta 5 times typically. Intermittent problems with a mixture of 25 year old hacked and/or worn parts is a pita. I bought this car thinking more than half of it was salvageable but I may have overestimated.

I started with the grounding though since its cheap and simple and was obviously horribly done. Then I moved to fuel since my gauge also didn't work and replaced sender(and pump while I was there).

I'm leaning toward the module too but thinking maybe I'll wait and replace module, cap, rotor, coil, wires, and plugs all in one go when I can scratch up the dough. I just don't trust a single part on that car that I haven't put on.

RedLeader289

iTrader: (2)

Ha, yeah, do it all at once, I get that. I'd have wherever you get the icm from check it when you buy it because I've heard many stories of people getting duds right out of the box.

The frustrating part for me is that this car wasn't hacked up when I got it, it was practically empty, so almost every part is new or newish haha. Oh well, if stuff didn't go bad we'd never learn anything. I meant to test some things last night but didn't get around to it, it's raining today so all the more inspiration to do something inside the garage lol.

8Mike9

ON my '78 many years ago, I too lost spark...pulling to coil cover revealed nothing (thinks same setup you have)

I pulled the coil out, I recall two wires with 90* male spade connectors, crimped coming of the coil wires...one had corrosion. I had just enough room to cut that connector off, and crimp a new one on...just before I put the coil back in, I looked into where the spade connector went, and noticed more corrosion.

I recall cleaning it, but don't recall the process I used (about 30 years ago).

Just another place for you to look at.

RedLeader289

iTrader: (2)

Yeah, I checked those the last time I had it all apart(checked again this time too). Good and clean.

Good news though, replaced the ICM this weekend and she fired right up. I suppose I will buy another one to keep as a spare soon.

Glad to have finally fixed it.