Still no start!

[millarg]

Morning all,

Still working a problem on my 78 SC, 3.0L with Bitz-Racing EFI (using 3.2L intake manifold). New Clewett plug wires, E3 spark plugs, dist cap and rotor last year.

Problem – car not being used much (needs new rear bushings) so I periodically leave running in driveway for about 30 mins, to allow oil to circulate. Several weeks ago car died and wouldn’t restart – in fact, no attempt to start, engine spins strongly so not battery, thought it was out of gas, added gas – still not start.

Original CDI box was whining as normal, original Bosch coil tested and gave poor readings, changed for Accel coil (all that was available locally), no power registering on green distributor trigger wire when cranking, no spark from coil (using plug like tester), no start.

BTW - Have a fuel pressure regulator and gauge fitted as part of EFI, showing 40lbs of gas pressure – I do not believe I have a fuel issue.

Ordered and installed MSD 6AL with Blaster 2 coil, did not order tach adaptor – wasn’t sure if it was necessary – seems it is as I have no activity on tach when cranking (grey MSD wire is connected to blue wire in original SC harness).

Is the tach part of the starting circuit? Does it need to work in order for car to start?

I am confident of all MSD connections (heavy red to starter, heavy black to transmission ground), red light on MSD flashes on cranking. No Start

Pulled distributor (marked carefully) everything looked OK, cleaned and inspected rotor and cap, removed old green trigger wire, cleaned contacts – spliced, soldered and heat shrunk new wires to old (had wanted to replace wires completely – but this wasn’t going to happen without cracking original green wire dizzy end plug – no power registering on green trigger wire when cranking, no spark from coil. No Start.

Can someone confirm ignition sequence which I think is -

1. Crank engine, distributor spins and sends trigger signal (how can I measure this properly and what should it read) via green wire to MSD
2. MSD sends voltage (how much??) to Coil
3. Coil sends spark to distributor.
4. Distributor sends spark to plugs.
5. Given fuel and air, Engine starts.

MSD seems to be acting correctly (red light flashes), BITZ EFI computer all looks ok and is getting power and indicator lights seem correct so, I am thinking that the distributor is the problem, particularly the trigger sequence, is there some way to check?

Are there any other connections which could prevent the car from starting? Oil Pressure? etc

Any help appreciated, and thanks in advance

[tirwin]

Are you 100% sure you're getting power on the power pin in the 6-pin connector? That goes to the top side of fuse 11 (and 16 - they are bridged on the top side) in the front fuse panel. The MSD uses that pin as a kind of trigger wire. If it's not getting power it doesn't know to turn on. I think #16 is the fuel pump relay circuit. Check the fuse and the relay.

[tirwin]

BTW I think your tach wiring is fine. I did the MSD StreetFire on my '83 and did not need the tach adapter.

[millarg]

Many thanks for your help Tim,

I removed the 6 pin CDI harness when I took out the original Bosch CDI (which sounded like it was functioning properly.

As I recall the 6 wires were - power, earth, 2 wires to coil and 2 to green distributor trigger wire, since none were needed - I pulled all out.

I am getting 13 volts of switched power to the MSD small red wire from the two prong power connector (1 hot - 3 red wires, 1 brown earth) which originally tied into the CDI harness.

I am using this connector to power the MSD - I will double check this voltage and the fuses this evening, but I am getting the Red idiot light on the MSD itself.

[timmy2]

Which MSD output wire to the dizzy is connected to the center "green wire". Purple or green?

[tirwin]

Ok so you do have power to the MSD. The green wire has an inner and outer sheath. I've never put a meter on it, but it is an alternating signal so I'm not sure what you would see.

Dennis, if I think you're thinking what I think you're thinking then you're wondering about whether the +/- mag pickup is wired correctly. I think we discussed this with Bob. I seem to recall that the StreetFire is a little different -- the purple/green wiring is opposite from the Bosch, Permatune and MSD 6A/6AL. Either way, if Glen can confirm which wire on the MSD is wired to the inner and outer wires of the green wire is a good sanity check.

I'm just wondering it's just as simple as you have a bad coil. Maybe just try the old Accel coil if it's still laying around.

Everything else in your thinking seems fine.

[timmy2]

Just asking as I know others have reversed the green and purple wires and had success.
I'm also wondering if Glen has the Bitz tach adapter installed on his coil wiring?
I have one on mine.

[millarg]

I am not using the Purple/Green Mag pick-up wires, I had read that the MSD Mag pickup was not usable in my circumstances. I have the original 3.0L Bosch Distributor. Am I wrong??

I am using the white wire from the MSd connected to the core part of the distributor green trigger wire. No Start.

I have also connected the white MSD to the exterior shield of the green wire. No Start.

I have also tried the purple of the MSD mag harness to the core of the distributor green wire (with the MSD green to the shield). No Start.

I have not tried the MSD purple to distributor shield with MSD green connected to distributor green core - because I spliced the short purple/green harness to the distributor green/shield and it can only be connected one way, should I try this option?? Again I had through that this was not a mag pickup??

Thanks again

[millarg]

Hi Dennis,

Originally, I had the Bitz tach adaptor attached to the blue engine harness tach wire, which then went to the coil. I have had this adaptor fail in the past (managed to rub on something and get grounded), car ran very badly, but limped home.

I have tried, MSD grey to Bitz tach adaptor to blue Porsche tach wire. No Start.

I then removed the Bitz tach adaptor and connected MSD Grey to Porsche Blue, No Start.

Are you running MSd iginition with your Bitz?

To confirm the initial start problem occurred prior to MSD installation, but the problem remains unchanged, so I'm feeling that it is not ignition box or coil.

[timmy2]

White MSD wire is for points.
The SC dizzy has no points.
You need to connect the green and purple MSD wires to the core and shield wires of the green wire from the dizzy. It is a magnetic style triggered pick up.
You said you had no spark so you need to get that up and running.
The purple and green wires may need to be reversed from instructions due to the ramping action of the dizzy pick up.

[millarg]

Ok, well that did it, plugged in Mag pickup and she lives!!! Crazy thing is, I had done this before, promise!!!!
Runs like ****, but I need to tidy things up, had pulled O2 sensor so need to refit and square everything else away.
As is, purple MSD wire is connected to green dizzy trigger wire core, had read this was correct, can anyone confirm this is the best way?
Thanks all for help )

[timmy2]

Glad it worked.
Swap the purple and green wires to the dizzy to see if it runs better or worse is all I can suggest....
For the MSD streetblaster the green seems to be the one to the core wire.

[millarg]

Thanks for the help Dennis,

Will switch purple and green tomorrow and get the O2 sensor reinstalled,

Then I'll reinstall the BITZ tach adaptor,

Final problem, which is funny considering, now she won't stop!!!!, turn off the key and she keeps running, had to pull the power to the MSD to shut her down.

So somehow I'm feeding power back into the switched circuit! Could this somehow be connected to the Tach not working? I know that circuit was only energized by the key prior to the car starting.

TIA.

[timmy2]

Glen,
I read your post on Bitzracing and you said you connected the grey tach output wire of the MSD to a blue wire? The blue wire for the bitz tach input would connect to the Orange wire from the MSD (Coil Positive)
The MSD Grey wire should be run to the purple/black wire normally just above the red wire in the factory six pin connector to the engine harness.

The only blue wire in the car's harness is for the Voltage Regulator D+ and is always hot, so that may be why it won't shut off...(If that is what you connected to.

Slow down, take some photos and make a list of what is connected to what for us.

Do these help?

[T77911S]

Originally Posted by timmy2

Glad it worked.
Swap the purple and green wires to the dizzy to see if it runs better or worse is all I can suggest....
For the MSD streetblaster the green seems to be the one to the core wire.

here is the deal with swapping the wires. (based on my CCW 930 dist.)
how to explain this and keep it short and simple....
the MSD wants a negative to positive pulse to trigger it. if the dist puse is "upside down" the MSD is triggered on the wrong place on the pulse. the part is triggers on varies in time as the RPM's go thus advancing the timing. not only that, the timing will be VERY advanced at idle. thus the "give away" that the wires need to be swapped.
dont think of the output of the dist as a positive and ground like the electrical system, but more like the AC system in your house.

think of the pulse out of the dist as triangle with the hypotenuse going down left to right. the short side that now goes up is where it triggers.
now turn that triangle upside down with the hypot goiing up left to right. the MSD will trigger SOMEWHERE along that hypot. but now it triggers earlier than when the short side would have triggered it.


if you have to pull the dist to make the timing work, the wires are backwords.
mine ran like this but very very bad. it also sounded very "thin" or "tinty"