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I have a 1988 Pontiac Firebird that has been converted to RHD. I've recently removed the dash harness and replaced it with an untouched / non-cut-up one. This was prompted by several problems I was having with my old loom, (Gauges not working, dash lights not working, etc). The swap went well and everything works on as it should with the new harness. I now have dimmable dash lights, gauges all have power, lights work, indicators, and hazards, except I don't have any spark at my leads. My coil and distributor are both new, the coil has been tested for correct volts and Ohms. As far as I can tell the coil is passing 12V to the distributor via the pink wire. I'm getting 12V at the coil post too. Now when I turn the key to 'ON' the fuel pump primes as it should, I turn the key to 'RUN' and it won't fire. The starter motor engages, and the flywheel spins but no start. I have used an inline 'Spark tester' to test the spark from my coil to the distributor and it's not getting anything when I turn the key to 'RUN'. I'm only able to get a very small light in the tester if I connect it to the ignition coil post and rather than attaching the other end to the distributor I earth it out to the negative terminal on the battery.
I've got a feeling the issue is somewhere in the new dash harness but I don't know where to begin trying to test for power etc and I'm not good with electrical diagrams, any advice or help will be greatly appreciated.
You said you have +12V on the pink, did you check that with the key in the start position, as well as the run position? My thought is that if you only checked it with the key in the run position, perhaps the power is being lost when the key is turned to the start position.
G'Day mate, So as it stands I have 12V in the pink wire that leads to the ignition coil from the main harness, I also have 12V going from the coil to the distributor via that pink wire. Both of these are 12V when the car is in the 'ON' or accessory position. When I turn the car to "START" the volts drop to 8-9V on both of these wires. This is also the case for the ignition coil post, It has 12V when on the 'ON' position and drops to 8-9V when I turn the key to 'START'.
G'Day mate, So as it stands I have 12V in the pink wire that leads to the ignition coil from the main harness, I also have 12V going from the coil to the distributor via that pink wire. Both of these are 12V when the car is in the 'ON' or accessory position. When I turn the car to "START" the volts drop to 8-9V on both of these wires. This is also the case for the ignition coil post, It has 12V when on the 'ON' position and drops to 8-9V when I turn the key to 'START'.
Hi Aussie3rdGen, I think 8 or 9 volts should be enough to make some kind of spark, even a weak one. In your opening post you mention both the coil & distributor being new. Did you replace them as a result of the no start, or did you replace them while you were replacing the harness? I ask because if they were replaced when you did the harness (and not after) could one of them be defective? If you replaced them as a result of the no spark I'm not sure what to think, except that the new harness shouldn't be causing you grief if you've got +12 on the pink. One other outside thought, if the white Tach wire leading from the coil to the Tach was to be accidentally grounded, that would kill the spark. Perhaps just to rule it out, disconnect the white wire from the coil and see if it starts. Oh, and, when I'm cranking my starter, in the half a second or so till the engine starts, the Tach needle bounces with the engine's revolutions, does your tach bounce when cranking the starter?
PS, that's one sweet lookin thirdgen ya got there!!!!
G'Day mate, Sorry I haven't followed up with a reply to your question sooner. The wiring loom was replaced as I was missing functions that I wanted to have running. The dash light wiring was broken and left me without dash lights, Oil temp and coolant gauges were not working either. I had previously looked at the harness from the underside of the dash and assessed that it wasn't in a good state. This brought upon my decision to remove the harness that had been cut and fitted when the car was converted to RHD and replace it with an untouched / uncut version. I have done some more fault finding and this is what I have so far; I disconnected the Tach wire as you said to, but the car still didn't start. I tested the continuity of the wiring from the coil to the distributor, I checked the Ohms and continuity of the 4-wire plug on the distributor back to the C207 plug near the ECM, all of which had readings of 0.04 etc (low Ohms, good continuity). I tested a few other wires on the C207 plug to ensure they were getting power which all came back fine. I'm at a loss at this point.
Kind regards,
PS, thank you for the comment, when she's up and running she brings me a lot of fun and excitement.
