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Lexus es300 Engine turns over but doesnt catch

I allowed my '97 Lexus es300 to sit in my front yard from Feb-May of this year.

Obviously the battery died, and my buddy and I went to jump it… It was 11:30 at night, we were both tired and accidentally ran my car through a series.( + to - )( - to +). I went to autozone and got a new battery, hooked it up… and only certain electrical devices worked. I went under the hood and checked the fuses, and of course the main 100A fuse blew. I replaced it, and everything but the radio turns on.

I now try to start the car, the engine cranks, but wont turn over. I put new fuel in the tank, and when my ear is pressed to the tank while the car is cranked I can hear the fuel pump whirring. While cranking the engine, I don’t smell any gas or fumes under the hood. I’ve tried several times to crank while pressing the gas pedal, but to no avail (over the course of a few hours…)

Could it still be an issue with fuel or is something else more sinister at play? My next guess is an electrical relay issue, seeing as I fried the 100A fuse.

Any advice on this issue would be so greatly appreciated.
Thanks in advanced.

Check your fuses, first hope, second hope a mechanic and probably an expensive ecm

I was worried it was an ecm/pcm

Is there any way to self diagnose a bad ECM?

The 100 amp fuse is for the alternator, you will have other blown fuses. I have repaired a few Lexus vehicle that were connected backwards during a jump start and have not had to replace a computer. You may have damaged the ECM but check each fuse box first.

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I just found a busted EFI fuse. Is that the fuel pump fuse? Trying all the small fuses before I pull out the relays.

The fuse labeled “EFI” is probable the ECU fuse.

The one that was busted was the 15A EFI above the horn. I sadly have a breathalyzer and after working on my car for nearly 4 hours today cracked a brew and cant check if its the culprit.

Also, the Rad.01 was busted, so managed to find the culprit behind the broken radio. It functions properly now.

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You can’t crank the engine but if the ECU is dead or has no power the check engine light won’t be on with the ignition in the “Run” position. If the ECU is active you will see a check engine light with the ignition in the run position.

This is my first time dealing with electrical issues with my car. Dumb it down if possible?

Are you saying with the fuse fixed I’ll have a check engine light, and able to use a diagnostics tool?

Edit: After testing, yes. It controls the engine light on the dash.

The absence of a check engine light with the ignition on and the engine not running is generally a telltale sign of an ECU problem.

If you now see the check engine light on with the ignition on, you have probable solved your problem, tomorrow you may be able to start the car.

Will update in the AM. Thanks for your help thus far. Much appreciated.


I LOVE YOU. My sober roommate just arrived home and had him check if it would run.

Heard the beep of the breathalyzer saying he was clear, turned the key… and BOOM. Life.
Thanks for giving me hope instead of turning it over to a mechanic.

Much appreciated and much love, the screams from the garage brought all my roommates out to hear the revving of the engine.

Do not think I can make it, party on :sunglasses:

Thanks to you too Barkydog,

Scared me with the ECM comment. Glad I didnt give up hope.

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Expensive repair at shop averted? Compared to insurance premium due to DUI and breathalyzer? That’s life.

I’m guessing you aren’t getting a spark at the spark plugs. Which you should during cranking. Suggest you test that idea, ask a shop to do the test, are you getting spark at the spark plugs during cranking or not? Once you know that you can begin to narrow down the source of the problem.

One thing you got going for you, the engineers who design cars anticipate this will happen, and design the cars so when it does, it doesn’t damage the ecu for the most part. You probably just have one or two blown fuses, fusible links, or other components like relays still to sus out.

If I read the post correctly the breath analyzer did it’s job and would not let car start until a sober person tried it. Let’s hope lesson learned.