# '89 Kingcab (VG30i) no-start... suspect computer? Wiring diagram, anyone?



## GordonW (Jun 25, 2010)

Well, this is a first. 

Went out to start up my '89 D21 (king-cab, VG30i throttle-body-injected V6, 5-speed)... no fire.  

Started checking things out- there's no spark from the coil (held the coil wire near a grounded bolt, no spark at all when the engine is turned over), and the fuel pump does not seem to be cycling at all. If you turn the key to start, you can hear a relay click as you engage and release the starter (it's one of the relays near the battery- fuel pump, main, etc). 

Checked for power at the coil assembly- 12v there. No fuses blown, all fusible links OK at the battery. 

Coil also checks OK for continuity (when you unplug the power transistor plug from it, it reads 1 ohm across the coil primary winding). Nothing obvious wrong anywhere else, that I can see.

I suspect the problem is NOT something like the crank sensor/timing sensor in the distributor- as the fuel pump does not even seem to initially cycle as I turn the key on, before turning over the engine, as it normally does. Acts like something has shut the whole kit and kaboodle down, wholesale... computer? 

Anyone got a copy of the wiring diagram for this truck, that would show the connectors going to and from the computer to the sensors, relays, ignition, and such? I think I could get a lot further, if I had a few more clues as to what and where I should be looking for stuff. There's a small control box under the drivers seat, and what looks like the main engine computer under the passenger seat... I have a good Fluke multimeter, and a frequency counter meter, so I could probably figure out if what is supposed to be going on, IS going on, if I knew what the color codes were...

Thanks in advance- and if anyone wants to contact me by email (which might be good- I am going to be only briefly online for the next half a week), it's [email protected]. Any help greatly appreciated, since I got some stuff I need to haul in the truck as soon as I can get it up and going again!

Regards,
Gordon.


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## CMax03 (Jan 17, 2009)

Dizzy cam sensor


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## GordonW (Jun 25, 2010)

Found the problem. Actually, it was stupid simple. 

I printed out the "how to read your computer code" instructions (from the sticky at the top of the message board section here), and went to it... pulled the seat, turned on the ignition, flipped the diagnostic switch... and NO LED activity whatsoever. That told me that there was probably no power TO the computer! 

I then traced the power line, back to the fusible link under the hood. Funny thing- the fusible link was showing 12V at the receiving end, under no-load (which is why I didn't suspect it before), but dropped to about 1V, as soon as the ignition was turned on (a load applied). It's almost like the stereotypical "high-impedance ground"... only on the POWER side, instead. 

Replaced the connector for the fusible link to the battery terminal... voila, life restored! It's almost like magic! 

Regards,
Gordon.


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