Some help getting engine started

e9Leveque

e9Leveque

Well-Known Member
Site Donor
Messages
586
Reaction score
445
Location
Seattle, WA
So as some of you may know, I had pulled my engine in order to paint the engine bay and in the process had upgraded/restored most of the non-engine components. I put everything back together and yesterday was trying to start the engine for the first time in a few months. No luck. I had Don on Facetime and we walked through some options but weren't able to resolve it. So that I take some of the burden off of him and his expertise, thought I'd post here for some thoughts.
So that we lay out the case correctly. 1972 CSi. Was running fine in December before I started this. Engine pulled by disconnecting every wire running to it but not removing distributor, which I left as-is. Changes to the car by me are as follows:
1. New Bosch starter (the smaller model most are recommending these days)
2. New battery moved to trunk but confirmed good power being delivered to engine bay area
3. Ignition coil changed from old Bosch blue to MDS black
4. Pertronix distributor not touched
5. Ballast resister (ceramic) not touched
6. Distributor to spark plugs wiring changed prior to engine pulling
7. New spark plugs installed after engine pull

The problem. Engine cranks but does not fully start. The steps taken to diagnose
1. Don had me disconnect starter electrically from system and run a "home run" wire to starter so that I can touch other end to battery and fire starter directly. That works, so starter deemed functional
2. Using multimeter to test, ignition coil has 12V at its positive side and had 5V at negative side (with MDS black coil). Ballast resister had 10V on top dropping to 1V by its bottom. Under Don's direction, removed ballast resister from system and wired both ECU lead (white wire) the other wire going to ballast directly to the ignition coil. Getting 12V on one side, 5V on the other. Firing the starter did not give me a spark out the top of the ignition coil. Question became whether my new ignition coil is the problem so I re-installed the old Bosch blue that was in the car at the time of it running. With that one, see 12V at positive and 1V at negative. No spark out the top when firing starter. Interestingly, when removing the black wire going from ignition coil to the distributor, the voltage at the negative side of the coil is 12V and voltage at tower is 12V. So when distributor is connected and car has key turned on but not cranking, the distributor being connected is causing 11V drop across the two leads of the ignition coil.
3. Pulled the top off the distributor cap to make sure the rotor is spinning. It is when starter cranks. The latest thinking is that perhaps the Pertronix unit has been fried in some way that it's shorting out or not firing correctly. When it's connected, firing off the starter causes that 1V at negative side of coil to rise to 4.5V
So, questions:

1. Utility in changing out the Pertronix unit? It does not have a model number on its side, only a lot or serial number, but from assessment online should be replaced with a 1868 Pertronix unit
2. Utility in a new Bosch blue ignition coil? The blue appears to have internal resister so would allow me to keep the ballast resistor out of the system, which may simplify things.
3. I'll recheck all of my ground points. I have two large grounds, one running from lower engine block to battery tray to side strut on the battery side, the other from screw on transmission to the inside wall of the transmission tunnel. Since I did paint the engine bay and tunnel, I'll make sure that paint is scraped off in these locations so that I know I'm getting good contact for the ground. The battery in the trunk is separately grounded to one of the large bolts that secure the seat belts bolted directly into the frame.

Sorry for the long post but thought better to put out all of the information I know so that you aren't having to ask as many clarifying questions.
I had been hoping to have this running in time for German day at the local large cars and coffee this weekend, but I may be a visitor instead of participant this year.
 
I mean that the starter fires and the engine whines but I'm not getting ignition. Fan turns and belts turn while starter turning. Overall appears to be an electrical issue somewhere between coil/distributor so that I'm not getting a spark.
 
Definitely don’t want resistor and blue coil so that is good. Pertronix needs full 12 volts even though blue coil puts out 9 volts. What if you disconnect black tach wire? If it is grounding car won’t fire.
 
We believe we tried disconnecting the black wire, that didn't solve the issue unfortunately - I'll try again. I'm a bit newer to this portion of the engine, so not clear on how if the blue coil puts out 9V but the Pertronix wants the full 12 how that would work. I understand not having the resistor at that point, but what do I need to make sure Pertronix gets all that it needs. Regarding the grounding, I was wondering whether it was a "partial" ground. I had this issue just this weekend in my MG where headlights wouldn't light - I could power them directly from an external battery and if I checked continuity on the ground wire it appeared fine, but no light when using standard harness. Adding a new ground directly from headlight to frame solved the problem.
 
Red wire to Pertronix is before it enters the blue coil, same with a ballast, it uses the terminal before the ballast resistor. Pertronix black wire goes to the other coil terminal obviously, you would have two black wires there.
 
I'll check that wiring when at home to make sure that's how it's set up. I did take lots of photos when disassembling and tried to make sure all was put back together in the same way, but a second check-through to be certain is easy enough to do.
 
I'm no expert here, but maybe 20 years ago I had a brand new pertronix I installed on my 2002 that was randomly bad. No start and I went through everything...maybe got fried or was a bad one, but is it possible yours checked out?
 
Before you swap in a new pertronix you can test it with a 12v power source and a multi-meter.

  • Use a jumper wire from the distributor plate (where the pertronix attaches) to battery ground
  • Connect a the power (red) pertronix lead to battery positive.
  • Touch or connect your multi-meter ,red lead to red wire and black lead to the black wire from pertronix.
  • As you spin the distributor shaft you should see voltage move from 12v to about 1v or less. If you don't see that variation in voltage you have a pertronix issue.
Check your engine grounds to make sure they are good. I recall you painted the engine compartment, you may want to check to make sure that there is no paint under the ground strap at the firewall and on the engine.
 
I’m trying to follow your travails via a tiny phone screen, so it is likely I am missing or misreading things. Have you totally bypassed your ignition switch to ensure that is not part of the no-start problem? Could you have inadvertently loosened or disconnected wiring at the fuse block? How about the center carbon button at the top of the cap? Could it have been jarred loose? Is ceramic ballast resistor still functional and intact? (They are robust, but not impervious to breakage.) Along same lines, could the pertronix be bad? Have you considered returning to Kettering’s tried and true points and condenser?

It seems fairly clear that the problem is ignition and not fuel related. Nevertheless, how about easy-to-check csi-specific items such as the djet relays, wiring/connection to the pressure sending unit or injection points at the bottom of the distributor?

1778621634837.png
 
All good ideas. I'll do the test on the Pertronix with a separate 12V battery and multimeter. And yes, will check to make sure that paint isn't interfering with getting a good ground. Regarding the ignition switch concern, yes I have bypassed it. First, I am getting power through by turning the key to the "on" position so there's at least that. Second, I have a wire running directly to the starter which I can touch to battery terminal to initiate the starter firing, which obviously should then be connecting to ignition coil/distributor. So I can fire off the system directly, the signal is getting snarled somewhere in those last two. Some good next steps. Finally, regarding changing back to points, yes, I suppose I could do that, but the car WAS running before I started on this endeavor and if the points is truly the best way to go I can do it, but if the answer is simply swapping out a bad Pertronix or correcting some wiring I did wrong that seems far easier.
 
Bottom line is no spark from coil wire to body ground when cranking.
Starter wire is home run to battery.
 
You must log in or register to reply here.
Back
Top