1998 Tacoma Intermittent Crank No Start Issue

I didn’t read thru my entire thread
But
Did remember electrical guru told me to use paper clip on CTS pigtail(jump/bypass the sensor)
Immediately, 80% easier to start
(Not perfect but got/installed new sensor….then was good to go)

 

Gotcha. I'll keep that in mind next time it won't start. But right now, it starts up without issue like nothing ever happened... Maybe I'll pull that sensor and see if I can get it to act the same way.

 

Check that the EFI and Circuit Opening relays are functioning properly.

 

I’m not amazing when it comes to diagnosis sensors or anything electrical but I am getting both of those relays to click when powering them on or off. That’s the only way I know how to check them, but I’m not sure if it’s the best way to do it.

 

The last crank no start issue the guy checked everything with no luck. The last thing he did was take the PCM out and took the back off and found an obviuosly bad/flaky PC board.

 

I have looked at the front of the PCM, while it’s sitting in the car, and it doesn’t look damaged. Besides pulling it out and visually inspecting it is there anyway to verify the functionality of your ECU?

 

Crack the alum case open
Look for any burn marks on the green board
Lots of pix posted here for exact thing to look for

 

Pulled the ECU and opened it up. Didn’t find any obvious damage to the unit. It was dirty from dust and some other gunk that I cleaned off with isopropyl alcohol and let dry for a day. Reinstalled it and had the truck throw P0100 and do 3 cranks where it started then stalled followed by the 4th where it ran perfectly. Cleared the code and couldn’t get it to pop back up or act the same tonight.

I’m wondering if maybe my new MAF sensor isn’t functioning properly? Anyone know the best way to test the sensor or what it ohms at?

Side note, my temperature gauge is now an on or off switch with full cold and hot. Hoping that my gauge sensor has gone bad and it’s not something I did to the ECU. The actual engine temperature from the ECT sensor is reading normally.

 

Top side of ECU

 

I really don’t see any catastrophic/burn marks

here lil dirt/dust build up :
Easy clean
But I wonder what pin out signals are in that dirty area.

 

Ah, I forgot to take a picture of the pins. But I didn't find any broken or damaged pins, and I cleaned them and the connectors. These photos are before cleaning.

Nothing about the ECU screamed damaged to me.

 

Assuming that you blew/brushed away that dirt/dust build up

but I wonder what signals are sent from ECM where was dirty thru this pins

 

Sometimes just exercising the connector plug "fixes" an intermittant.