My sky is falling!

jwinkler · #1 (**permalink**) 05-12-2002, 08:39 PM

This isn't CR-specific, but I'm hoping to take advantage of the impressive depth of experience of the CR forum regulars.

I figured that was an apt subject line, because I'm hoping that this is a simple problem. I took my car out for a quick trip around the block, and about 10 minutes into the drive, I was slowing down to turn around, and the car went D E D dead. I was going too slow to start it by popping the clutch, so my only option was the starter. I opened the hood and looked around at everything - all wires looked good, no leaks in the line from the fuel pump (mechanical) to the carb, popped off a breather and saw nice oily rockers. With the hood up, I turned the key just to see if the belt was turning, and it fired. I got back in, and it started OK. I got most of the way home, which included a couple of stop signs, and some idling while rolling, and was almost home when it happened again. I was waiting for it, but even so, it caught me by surprise. I *think* it happened when I put the clutch in, and I had enough speed to pop the clutch and get it going. However, it didn't catch - the car's motion forced the motor to turn over, but it never started again. I coasted to the curb, and sure enough, a few minutes later, it started, and I managed to make it home.

I was originally thinking fuel deliver might be the culprit - an obstruction in the fuel line somewhere, maybe. Writing this up though, am I right in leaning more towards a spark problem? Can anybody detail a debugging procedure for both of these possibilities?

Thanks,

JLW

petek · #2 (**permalink**) 05-12-2002, 08:58 PM

I'm going to guess that it's the ignition switch. I had the same sort of thing happen to me in a Porshe 914. All of a sudden and for no apparent reason the engine would die. Like RIGHT NOW die.

The second time it died I jiggled the ignition key and popped the clutch and the engine started right back up. Turned out that one of the main hot leads going to the ignition switch had broken out of it's crimp (why? I dunno). Soldered it back together, no more problem.

jwinkler · #3 (**permalink**) 05-12-2002, 09:22 PM

Wow! Quick feedback. Thanks, Pete! Question - with the ignition wiring problem, would the starter still work? These intermittent things always make me think of some sort of loose connection, even though in the case today, the car wasn't jostled in any way to shake things back together (although maybe the simple act of turning the engine over with the starter did the trick).

Thanks again,

JLW

Double Venom · #4 (**permalink**) 05-12-2002, 09:29 PM

JW,
Could be lots of problems. All minor but a pain in the butt. Not always true but turn on the headlights the next time it does that. Or if it's dead now. IF the headlights work chances are it IS not the ignition switch. (Maybe Petek can explain this one as I have no idea why)

Check the two in line circuit breakers, supposedly mounted on your fire wall. If one or both are tripping this will also cause the problem. They could be weak or getting hot. These will shut down almost everything if they trip. A simple trick here is to use a heavy guage wire and "TEMPORARILY" jump the two breakers and see if it fires. If it does - there you go.

Another known problem. There is a large rectangular plug coming off your steering column. It has one heavy guage red wire and about 5 other white wires in it. Pull it apart! Look for any heating damage. If it's OK then put the plug back together--very tight. This is such a tight fit, I've use large channel locks to squeeze together.

If you haven't found it by now, it's time to check the engine electrical system. Coil, MSD box, etc.

Then it's time to check for fuel. Keep us posted! Someone will hit upon it.

DV -- soooo close! Are you registered?

xlr8or · #5 (**permalink**) 05-12-2002, 09:31 PM

Easy to check the fuel delivery if you have an electic pump... Just pull the line as close to the intake as you can and put it into a suitable empty container and turn on the key and let it rip. let it run for a couple of minutes... may need to pump out a gallon or two to be sure. I would try that first only be cause you said it took a minute and then fired... May have needed to let fuel pass an obstruction or restriction. Any soft lines in the fuel system? Maybe one got crimped and can't sustain flow..

flipper0007 · #6 (**permalink**) 05-13-2002, 05:21 PM

What distributor do you have? This sounds like the same problem i was having with a mallory unilite. Bad ignition module. It's a real pain in the a** driving in the fast lane of the freeway when this happens...

petek · #7 (**permalink**) 05-13-2002, 06:05 PM

If I remember correctly there are two hot leads coming from the column, one for the engine stuff, one for everything else. Oh, and of course, a starter lead.

If the engine lead were to become open, the engine will stop running but the lights would still work. Or, depending upon how the ignition switch is wired up (for example, both hot leads tied together) the lights won't work if the ignition switch is shot.

Intermittant problems are the worst types to figure out. Could be the fuel pump, could be the ignition module, could be any number of things.

If it dies again... and if it stays dead for any length of time, a DVM or one of those inexpensive voltage tracer lights might lead you to the problem.

You noted that it might have something to do with the clutch pedal being depressed. As a real long shot, take a look at the pedal and see if any wires are chafing (sp?). Real long shot but a wire may be shorting out on the pedal and causing a thermal circuit breaker to trip.

Best of luck... it might take a few times before you're able to trace the problem.

jwinkler · #8 (**permalink**) 05-19-2002, 09:31 PM

Thanks for all the responses, guys. Got a DVM this weekend, and checked continuity everywhere, and so far everything looks good. I searched the forum, and found some reports of unilite optical module failures - is it possible that this could be the problem? I'm somewhat doubtful, since I would guess that when the module goes bad, it's finished. Since my failure's intermittent, that wouldn't seem to be the issue. Didn't have the time to drive it until it failed, and go from there.

Thanks again,

JLW

John Wais · #9 (**permalink**) 05-19-2002, 09:46 PM

If you have a Unilite, be sure to get the filter. It just plugs inline.
I lost a module in the middle of the 101 and 23 interchange in Ca.
BAD BAD place to pull this stunt. Found out there was a filter to protect the module. No more problems since although I carry a spare and the tools to replace it.
John W.

flipper0007 · #10 (**permalink**) 05-20-2002, 10:29 AM

The unilite problem i had was also intermittent. Bad module. This is what i did. Called summit and ordered new module, cost about 100 bucks. Like John said it's a good idea to have a back up anyways. I installed the new module and no more problems. I then called unilte co. and complained about the module. I had only driven the car for about 500 miles when the problems started. I sent them the bad module and they sent me a new one. I now have a back up module. Terry

niles · #11 (**permalink**) 05-20-2002, 11:27 AM

The first thing is to determine the first decision block; fuel or electrical.
I would guess a "hot" inducted elect prob. but you have to confirm that you have fuel when it stalls; pop off the air cleaner and looking inside the carb throat and pump the throttle at the carb; you should see signs of acelerator pumps. etc squirting fuel.
If you see fuel that would put you on the electrical gremlin hunt

gn

John Wais · #12 (**permalink**) 05-20-2002, 09:39 PM

I still say get the filter. I think I got mine from Summitt also. Unilites are known for this without the filter. Its relatively cheap, I think about $30.
John W.

jwinkler · #13 (**permalink**) 05-21-2002, 10:07 PM

Thanks for all the replies - I'll get the filter. There's a web site that showed up in one of the other discussions about the unilite that discussed the filter as well.

Another question - is the rotor a friction fit piece? I had the cap off this weekend, and it didn't seem to want to come off easily. Do I really just need to quit worrying and pull it hard enough to get it off? I went through all the manuals that came with the dist and ignition, as well as what was available online through Mallory, and never saw anything that talked about removing the rotor - I guess most car guys have dealt with this before and don't need instructions.

Thanks again,

JLW

dscott · #14 (**permalink**) 05-22-2002, 08:44 AM

JLW, Give it a good pull! It is a friction fit.
Don

jwinkler · #15 (**permalink**) 05-24-2002, 09:59 PM

Don (et al) -

Exactly how much pull does it take? I played with it tonight, and first I tried getting my fingers under the black circle, and then the red rotor, but never got enough leverage to move it. The black circle started to bend, but I don't think the rotor itself came close to starting to come off.

For us weaklings, is there a tool or trick to removing the rotor?

Thanks,

JLW

Double Venom · #16 (**permalink**) 05-25-2002, 07:22 AM

JLW,
Had a Mallory that did the same damned thing. I took a small hammer and just tapped on it, even downward a couple of times, and finally got it off. It is a pressed fit, but they shouldn't be that tight! A hint when it's time to put it back on, take the new one, (I'd almost bet you are going to destroy the original one getting it off) and put a very small amount of "anti-seize" on the shaft first.

Ain't it always something?

DV -- we are soooo close! Have you bought your raffle tickets yet?

jrichard · #17 (**permalink**) 05-25-2002, 09:10 AM

I had a Jacobs ignition module that did EXACTLY what you described.

jwinkler · #18 (**permalink**) 05-25-2002, 09:43 PM

... and all the wires are apparently connected the way they should be. I spent a fair amount of time this afternoon looking at the Mallory manuals, then the car, then the manuals, then the - you know the drill.

Anyway, tried to do the Mallory module test, but since the HyFire is apparently a capacitive discharge system, and I have *no* idea how to bypass it, I wasn't getting the voltages the doc said I should. However, it occured to me that there must be some other way to test the module. I've included a picture of it (or will try to - I don't think it's too big) - the module has three wires - red for power, brown for ground, and green for signal, right? It seems that putting the volt meter on the green lead would provide an indication of it working.

What the volt meter told me was that with the optical sensor open, there was a 6mV signal (between the green lead and ground). When I blocked the sensor, it went to negative negligible voltage. This was on the suspect module - I managed to short the pos and ground and blew the ignition fuse, and spent a fair part of the afternoon finding and replacing the fuse.

Anyway, does this seem like a reasonable way to test the module, and any ideas as to what I *should* see at the green lead? I'm planning to call Mallory tech on Tuesday, but I'm betting I'll get more valuable information here!

Thanks,

JLW

jwinkler · #19 (**permalink**) 05-27-2002, 10:38 PM

... "rule out the impossible. What is left, however improbable, is the answer."

Or Inspector Cluseau:
"Zeh kehhs iz zolv-ed."

First, the solution (as far as I can tell): bad connection from at the coil and coil wire.

I managed to get a good test of the unilite ignition module - with all three wires attached (from dist to HyFire box, as opposed to my previous notion of taking the green wire straight to ground), a (parallel?) voltage test between the green wire (at the dist-to-box plug) and ground showed 11.09 volts when the optical sensor was open, dropping to .750 volts when blocked - roughly what Mallory indicated would be the case for their module test using negative from the coil to ground. What it also showed was no malfuntion in the unilite module, so I started looking at everything else. First stop, coil wire - when I pulled it off the coil, it just came off without any resistance, which felt wrong. So I took the coil plug that came with the Taylor wires I had (that was too short to reach from where the promaster coil is mounted to the dist), and popped it on, and got a "click" sensation. Examining the two caps, I saw that the cap for the coil wire I was using was about 1/4" deeper than the Taylor wire cap. If I pushed and compressed the cap, I could get the positive "click", but it hadn't been there when I pulled it off.

So I cut the extra 1/4" off the cap, and went out for a few spins (first with my son, then with a new neighbor who heard it start up, then with the whole family - youngest son and wife in passenger seat, oldest boy in the middle - for a golf-cart-speed jaunt around our block) with no failures. Made for a nice holiday evening drive!

What I am hypothesizing is that the cap was making enough of a connection with the coil *most* of the time, but a combination of heat (making the cap even bigger and the connection more tenuous) and vibration rattled it loose the two times it shut down on me during my last drive. Would a disconnected coil wire just shut the motor down? Seems like it would.

I still installed the signal filter/surge protector piece, and now have a spare module for the time my first one does kick the bucket!

Once again, thanks for all the help!

JLW