Doner TBI install, no spark. (1 Viewer)

[Heron]

Hi Buds,

Just completed a TBI install and have no spark at the plugs.
The check engine light does come on with the ignition.
There is power to the coil.
The dizzy is from a 78 to 87 FJ40 modified per post by cruiserbrett. (Thanks Brett, great post very helpful.)
I suspect the Dizzy because of the condition when procured from the wrecking yard. It was cleaned and modified, the shaft and bearings appear to be good, but because of its age I would like to test the exciter.
Can any one provide the method and specifications for testing the exciter, or a lead to where I might find this info.
I may be overlooking some other checks so please feel free to jump in.

Al

 

[cruiserbrett]

not sure where to start. could be any number of things. for example, do you get 2 seconds of fuel pump prime when ign is keyed on?

Is the reluctor wheel very close to the small metal tab protruding from the mag pickup? It needs something like a .009" air gap. more=bad.

wiring harness? new or used and modified?

are you getting a rapid flash check engine light?

are you using the gm ignitor from a small cap HEI? is it the 7 pin EFI one?

 

[Heron]

Hi Brett
I do get the two second fuel pump prime.
At this point I failed to notice if I was getting a rapid flashing check engine light or not.
However I found there is no 12 volts to the ignition during cranking.
I was unable to find a circuit from the ignition switch that provided power for run and cranking.
Made a temporary fix by installing a relay to provide 12 volts during cranking.
It appears that the original starter had a tap to power the ignition system when cranking.
I now have a hot blue spark at the plugs.
Redoing the timing using the b/b for the base timing instead of TDC. ( dont know why )
Almost ready to give it another try when the Grand kids arrived.
I will recheck the air gap. The harness along with almost everything else is from a 1990 Astro Van
I removed the ignitor from the dizzy that was on the EFI Astro.

Thanks for your help Brett.
Al

 

[Downey]

You must have a good Signal Generator (which I think you are calling an Igniter) inside the dizzy. Then you should be using GM #10482827 Ignition Module and GM #1115315 Coil mounted externally (outside dizzy). All of this must be wired per our instruction sheet. If any of this seems foreign to you, PM me!!!!