Spark Question

[craigbx2]

Hello all! I just finished putting a head gasket in my '93. Was running good when I started the gasket, but now, on reassembly I'm not getting spark. Where should I start looking??

 

[inkpot]

Have you tested the coil?

 

[craigbx2]

Have you tested the coil?

No, just tried to start it, found no spark. How do I test the coil?

 

[Tools R Us]

With the key turned to run, is the CEL on?

 

[craigbx2]

With the key turned to run, is the CEL on?

No, A/T Temp, oil level, charge and brake come on

 

[Tools R Us]

No CEL often points to no power to the ECU, and that will cause no spark.

 

[Desert Dino]

@Tools R Us Fusible link?

 

[craigbx2]

No CEL often points to no power to the ECU, and that will cause no spark.

Thanks! Where does the ECU get power from?

 

[LINUS]

No CEL often points to no power to the ECU, and that will cause no spark.

Just thinkimg out loud, is the ECU / CEL the same between early & late 1FZ’s?
IDK, they seem to be different animals, but I just know OBD2’s.

@Tools R Us Fusible link?

Gotta wonder on that too....these thimgs can screw a fuse-link in any situation, even a speedbump can kill one.
But they are all 2 decades old now.

- not in front of that 80.

 

[craigbx2]

I did the head gasket with the engine in the truck. Spent a lot of time standing in the engine compartment. Wondering if I stepped on wiring, pulled apart a connector, etc. Or if I missed a connector on re-assembly....

 

[LINUS]

^^^
that’s the downfall of the 1FZ motor harness.
You had to unplug everything & now we’re talking decades old wires / wire insulation jackets.

If you hit q point where you have resolved you did perfect mechanical work, these wire harnesses are old & getting brittle.

Just my opinion / BTDT where I cut the lower intake now - in future years I bet a ‘certain vendor’ offers lower intakes that are cut.

I did mine in ~’02.
I still have that same 80 & it’s still a great & reliable.
Plus, if I ever need pull the lower intake I cam without any extra work.

No regrets doing it,

 

[Tools R Us]

Knowing where the power is interrupted is helpful. With the key to run, is there battery ish voltage at the B+ term in the diagnostic box on the firewall? If not, is there power at both sides of the EFI fuse? There are little contacts on top of the fuse for testing. If none at the fuse, wiggle the fusible link and see if there is a bad connection, if so they need to be replaced. If the power is good at the fuse, is the EFI relay clicking when the key is cycled off to run?

 

[craigbx2]

Knowing where the power is interrupted is helpful. With the key to run, is there battery ish voltage at the B+ term in the diagnostic box on the firewall? If not, is there power at both sides of the EFI fuse? There are little contacts on top of the fuse for testing. If none at the fuse, wiggle the fusible link and see if there is a bad connection, if so they need to be replaced. If the power is good at the fuse, is the EFI relay clicking when the key is cycled off to run?

Hi! Just got it running! Bad VAF. Yes, my fault...thank you all for the advice and ideas, ver much appreciated!!