No spark,tested every every thing.

[steve]

They are 0.1uf SMD caps in most cases.
If the old caps leaked just changing them doesn't usually work for long, if at all. The leaking electrolyte corrodes the copper traces it comes in contact with and often creates microscopic breaks between the solder pads and the circuit traces.

 

[74runner]

They are 0.1uf SMD caps in most cases.
If the old caps leaked just changing them doesn't usually work for long, if at all. The leaking electrolyte corrodes the copper traces it comes in contact with and often creates microscopic breaks between the solder pads and the circuit traces.

Thanks Steve, I'll have a closer look at the traces. I think I got to the caps in time as there doesn't seem to be too much damage but, I do suspect the surface mount cap pointed out in another thread due to the build up of crud around it.I'll remove it and install another cap and if that doesn't help I'll send it off for repairs...Pm Me if your interested in working on it.

 

[steve]

I'm going to check pin 64 with the key on to see if it sends the signal for the cel, don't know why I didn't before ?

Just checked it, no voltage coming out at all.

The ECU doesn't generally provide voltage, it sinks current for control functions.
If you look at the FSM wiring diagrams the pins have triangles pointing in the direction of input or output for that pin.

In the case of the CEL the ECU pulls pin 64 to ground. The bulb gets power from the ignition switch via fuse 11 in the junction box.So pin 64 should vary between battery voltage and ground depending if the CEL is off or on.

I'm done fixing ECU's, send it to the guys at ECMTuning.

 

[74runner]

The ECU doesn't generally provide voltage, it sinks current for control functions.
If you look at the FSM wiring diagrams the pins have triangles pointing in the direction of input or output for that pin.

In the case of the CEL the ECU pulls pin 64 to ground. The bulb gets power from the ignition switch via fuse 11 in the junction box.So pin 64 should vary between battery voltage and ground depending if the CEL is off or on.

I'm done fixing ECU's, send it to the guys at ECMTuning.

Thanks Steve that's very well explained, I'll play with it some more and then send it off if I don't burn it up by mistake .

Good news guys!
Steve pointed out that the cel light can be grounded on pin 64 with the key on and the cel should light up.Mine didn't, long story short I found a loose connection and now have both boost gauge movement and a working cel...The bad news is my coolant light is back on ! I've already fixed the coolant wires but I now wonder if the light going out was just the bad connection that caused the cel to go out too Once I figure out the coolant light I'll check for spark again.

Ok another update:
I pulled apart my previous temp sensor/s rewire job and every thing was good. I cut the Sheathing back another 6" and found that someone had done an earlier repair, well they added a new plug and just twisted the wires together and called it good. I cleaned up the wires, soldered and shrink wrapped them....But I still have the coolant light on so I unplugged all of the connectors and swapped out all of the sensors and I still have the coolant light on.

 

[steve]

What coolant light?

The one is the cluster is for the float switch in the overflow bottle. There isn't a hot light.

 

[74runner]

What coolant light?

The one is the cluster is for the float switch in the overflow bottle. There isn't a hot light.

Thanks, I realized that after I redid the temp sensor plugs !
I cleaned out and topped up the over flow bottle but it's still on, I have one in my '90 that I'll try....

Ok boys and girls! The moment we have all been waiting for!!!

It's running.

The cause/fix was well, every thing! The car had many issues starting with the ecu, coolant sensor wiring/plugs, loose connection to the cel, bad wire to the oil light switch, split hose on the fuel pump it just go's on and on, I'd fix one thing and another would pop up but, through the process of elimination and your help I got it!


https://www.youtube.com/watch?v=WLBMXYyyCe0

Watch the link above

 

[steve]

Good work!

 

[74runner]

Good work!

Thanks for the help!

 

[74runner]

A member on here saw my posts about the bad ecu and is sending me a working 91 ecu for $20.00 What great guy! Now I can put the 90 ecu back into my 90 Talon .