I bought my 91 Z28 about 9 months ago and liked the motor so much I put one in my son's 69 Impala. Everything is stock except the custom wire harness, which I had built without VATS, some pollution controls etc. I'm very excited about it, and am very close to starting it. All I need is spark..... or so I think that is all, we'll get past that hurdle and see what's next.

Not being a mechanic, I am looking for some idea what and where to check. I have power coming into the coil, the motor turns, the fuel pump primes things seem fine, except there is no spark leaving the coil.

Any suggestions?

 

When I built your harness, keep in mind that I did not bypass VATS through the harness. I reprogrammed your memcal to remove VATS. I should mention that it's not crazy to think that VATS can be eliminated through the harness. In fact, I'm building TPI harnesses that include a VATS bypass module that is about the size of a pencil eraser. It receives 5v power from the gray TPS circuit, ground through the harness, and sends a signal to the ECM to imitate the VATS signal. The module can be tucked inside the wire loom and hidden very easily. Just thought it was worth clearing up for this post and avoiding replies that would say VATS can not be eliminated in the harness.

It's worth mentioning that your first coil burned up for some unknown reason. I'm still unsure what caused that. You simply had ignition power going to the coil and it started smoking...I would be curious to know if someone in this forum has some ideas about that. Maybe it'll help you in figuring out your current spark troubles. You did tell me that the coil was mounted on the firewall and your friend had the same problem with a coil mounted on the firewall. I currently have the coil mounted on my S-10's firewall and have never had any problems (a few years now).

I don't mean to hijack your post, just explaining a few things to get a better answer for you. We're all here to help!

 

My coil is mounted on my firewall too, and I can't say that there is a problem with it.

I *can* say that the coil wire is much longer than it would have been stock, and the old wire I initially used when I installed the setup, was a piece of junk and spark was jumping through the boot to the coil bracket.

New wires (as I should have done in the first place) solved that problem.

 

Grounding the coil seems to have resolved the problem. I simply ran a grounding cable from the block to the coil. Note.... I had my coil mounted to a piece of thin guage stainless steel, then to the firewall. It made sense that the ground wasn't being made. OK, so now I still have a spark issue. I am convinced it is something simple as everything seems so nice and tight.

Any suggestions will help tremendously.

Thanks

 

NoCal91Convert, a few basic questions.
does the coil have power to it when the key is on?
with 1 end of a test light hooked to ground, does the dist side of the coil light the test light?
with the test light still hooked up to ground & the dist side of the coil, does it flash when the engine is cranked?
the only things i can think of that would cause an ignition coil to smoke would be a 1, a bad ignition coil, 2, the dist side wire grounded, 3 a bad ignition module.
a bad coil could have taken out the module.


S10Wildside, im not sure if you are interested in this, but maybe on the VATS bypass modules your building, you may want to also set it up so it can be wired into an alarm system with a relay. i have the painless bypass module & have the ground side of it wired through a relay, if the alarm is trigged the relay is turned on & opens the ground side, along with disabling the starter, fuel is also disabled by the alarm through the ECM.

 

I have ignition power going into the coil as well as coming out. I also checked the "sparkplug" type wire going to the center distributor contact and it has power (exact same reading as the pink wire coming out of the coil).

If all of my conncetions are not made (O2 sensor, etc) would that prevent the system from sending spark?

 

where you have power sounds right.

you should have spark when cranking even with the ECM disconnected.
try it with the ECM disconnected & see if you have spark, if you don't then look at your wiring from the coil to the distributor. also check your pickup coil & its wiring.
if everything checks ok, your down to a problem with your module.
have you tried the test light hooked up between ground & the distributor side of the coil?

 

Good idea about disconnection the ECM, I'll give that a try when I get back next week.

Yes, the light comes on when I unplug the connection between the coil and dist. and touch the pink wire going into the dist. In fact, it also lights when I touch the white one.

Do you think that it would have anything to do with the altenator? I was looking at the wiring and had some concerns.

Thanks for responding... it's nice to run a few things past someone.

I have a mechanic coming over a week from this Monday. I was hoping I could get spark by then so he could focus on other matters, but I should at least have an answer then. I'll let you know what I find out.

Ken

 

with the connector between the coil and dist plugged in, the light should flash when cranking with the test light hooked from ground to the white wire.

the alternator won't make any difference on spark.

no problem