Hello all,

I need some advice regarding my 1993 ES300. It currently won't start. It turns over just fine, starter rebuilt and new battery. The coil and ignition control module tested good, but I still don't have any spark at the plugs nor does the coil arc to the frame when grounded.

My troubles started when the RPMs began to fluctuate, going from idle to 2000 constantly, as if I was sitting there revving the engine. I could see the small booted part directly below the intake inlet moving as it surged. I apologize about not knowing the exact name of the booted part (it slips my mind right now, piston something, will take picture when I get a chance). If I shut it off and start it right back up, the surging would go away. Moving on, it eventually got worse to where it would either surge or not run at all unless I was giving it some slight throttle as I idled. This led me to believe that the Idle Air Control Valve wasn't working. I replaced it and it ran perfect for roughly 30 minutes.

I then tried to take it for a test drive around the block before getting far from home at which time it completely died. Times before it would die if I didn't keep it idling and if it died it would start right back up. Now it no longer starts, just continually turns over. Again, I've tested for spark at the plug and at the coil. The coil is getting 5V confirmed, but still doesn't spark.

I've been racking my brain to what it might be, but I can't think of anything else (other than the ECM.) I thought the timing belt broke or got out of alignment. I would think it would run but run like garbage regardless. Please guys, I need some help. I've been chasing this for over a week now. Any advice is appreciated. Don't ask about starter or alternator, both are fine and have nothing to do with ignition of the fuel/air mixture.

P.S. Does the 93 ES300 have some sort of anti-theft or security that might be preventing spark? Some Lexus thing I'm missing. I familiar with Toyotas but this is my first Lexus.

P.S. Does the 93 ES300 have some sort of anti-theft or security that might be preventing spark? Some Lexus thing I'm missing. I familiar with Toyotas but this is my first Lexus.

Thanks,

plosey68

 

Could be a bad coil, how did you test?
Did you check for codes?

 

Your car has a "theft deterrent" system but I don't know how extensive it is, meaning if it can stop the car from running. Is there a security light in the dash? Check out the wiring diagram it might help you.

 

I checked both primary and secondary windings and they were within spec. I also put in a known working coil and srill nothing. Same with the ignitor/ignition control module. Also, it's OBD I so there's no real "codes". Even when it was running the check engine light never came on. Now it won't start for me to even pull codes. There's probably a way to jump two terminals in the diagnostic port and count the flashes. I'll give that a try....

 

Also to add to your list- check the distributor cap, rotor and wire from the cap to coil.

 

All new. Cap, rotor, wires.... I'm stumped.

 

Unhook the negative lead to your battery for about ten minutes.

 

I've had the terminals removed for more than that a couple times.

 

Download this section of the service manual near the end it shows how to test the distributor for a signal and how to find it at the ECU

https://www.sendspace.com/file/woffxu

 

Awesome. Thanks Lexus2000 for that and the wiring diagram.