kalli

well i'm getting sicik of this ... the more you modify the car, the more problems you get it seems :-(

MSD 6AL box, distributor is crane, magenetidc pickup (purple/green wires of MSD box)

anyway, I wanted to call over to a friend today, so yesterday I jumpstarted the car left it running for a good while to blow the cobwebs out. havent had the car started for months.
was hoping it was long enough to charge the battery

so this morning tried to start, starter would hardly turn so I jumped the car again but it wouldn't fire.

The fuel pump is electric over relay, carb is getting plenty of fuel. opening the throttle sprays fuel no problem. The engine is turning so I guess there's no spark.

now here's the weird thing:
- when turning the engine with key the engine turns but doesn't start
- when i let off the key in ignition (giving up, letting it go from start to ignition) it sounds like it's trying to fire just about to start and then stops
- and even more weird: wheni turn the key from ignition to off, then occasionally there's one spark (i can feel the engine turning by a couple of degrees)

so i tested: turn engine with key, stop, leave key in ignition position. then went to distributor and disconnected the connector between box and distributor (pruple and green wire) to see if the box fires. and it does. theres a spark and engine turns for a couple of degrees

so from all of that I gather: everything is fine ?!
I thought maybe there's not enough voltage at relay for MSD, distributor and fuel pump during crank.
Buit that never was a problem. Still i connected a temp wire fro starter selonoid 'I' port to relay (where my cable from starter switch is coming from)---> still the same

I then connected everything straight to the battery, so box, fuelpump and distributor always have power. used the key to crank and still the very same thing ?!


i'm out of ideas ... anyone ever had that problem?????

JMD

The first thing that comes to my mind is a bad pickup in the distributor OR a fouled connection between the pickup and the MSD Box.

Anyway, try a timing light on the coil wire and/or the rest of the plugs to check for fire. (I like checking for spark this way because I DO NOT like getting shocked.... )

I had a late model doing exactly like yours is doing, ended up being the ignition control module, which is about the same as your MSD box, failure was due to shorted wires.

kalli

well good idea with the timing light, never thought of that.
i believe as well it is the distributor, or MSD or connection between that.

what i tried to do was to connect a spark plug to col output and with ignition on: whenever I disconnect the wire between distributor and box I get a proper spark. when i plug it in/out/in/out/in/out ... i get a spark every time I disconnect and a whisteling sound at the same time which I can only guess is normal)

so even though the MSD-test went ok i'm still not convinced what is the problem.
If I had an oszillograph I'd hook that up to distributor to see if I get on/off from it with engine turning.

So I guess next thing to do is to try what you say: timing light at #1, then #2 to see if they all fire

kalli

test with the timing gun confirms. had it attached to coil wire (coil to distributor) to catch all cylinders:
no spark during start and as soon as I let the key go (from start back into ignition position) I occasionally get a single spark.

since I do get a spark when I provoke it manually (bridging the purple/green wire and disconnecting them again at box) I'm a bit stumped now on what exactly the problem is
I don't want to be replacing the box and then figure it was the distributor ... or the wiring (that I haven't changed)

kalli

i have a plan now.. I'll pull the distributor, take the cap off and with ignition on I'll turn the rotor (by hand)
If get no sparks doing that, but get a spark with the MSD false trigger test, then I know the magnetic pickup in distributor is fried.
I have the same distributor spare (without rotor/cap and gear) somehwere so tyhat would get me out of trouble ...

I'll post the results

JMD

I THINK you need to determine if either the pickup in the distributor, OR the MSD box itself is the problem.

I pulled this manual up, while the Crane distributor (I think it uses a Chrysler pickup) may change things just a little, the troubleshooting section starting on page 129 of the attached PDF should help in making the determination.

http://www.msdignition.com/instructi...PDF?terms=WDTN

frdnut

I had a duraspark system that did the exact same thing..In my case it was a bad ignition module..

jojobanks

if you hooked everything straight to the battery and still had bad spark then I would tend to think it's the ignition module. Although if you're using a crank trigger wheel then I would also check to make sure that's getting a good reading.

sethalot

my ignition module went out aswell on mine, did the same thing

MonsterBilly

mine did the same thing. it was a bad connection on the module. also check the ground!