coacheddie

So I had some time to work on my GS the last couple of days. It had been throwing codes for random misfire, so I bought new plugs and coil packs and installed. Nothing remarkable happened during installation. Started the car up and the misfires had definitely decreased. Drove the car 10.5 miles and it died while driving. Car will power up but the starter will not engage. Took off the covers and checked my work and it looks like everything was put together properly. Checked the timing belt, still good.Checked Main and ECU fuse, both good. Disconnected the battery for 10 minutes, still no crank. Any suggestions where I should look from this point? Any help is, as always, appreciated.

TrueGS300

Whats the battery voltage at. Maybe your alternator is bad. Drove it on battery power till it died, now not enough juice to power the starter.

coacheddie

Thanks for the suggestion! Just checked voltage, 12.7. When the key is in the on position everything (interior lights, headlights, gauges, steering column lowers, radio) works normally. Engine will not turn over.

sbagdon

12.7v sounds about right, for static. We usually look for 14.4v running, 12.7v static.

Can you her the solenoid click?

Click the starter a few times. Our starter is going... on really cold days this winter (<10F), it would take up to 3-4 clicks, for the starter to engage. You could hear the solenoid click, yet the starter wouldn't engage until after a few tries. Probably have to do the starter this summer... 8hr job, on the GS4. Sigh.

coacheddie

sbagdon, thanks for chipping in! There is no solenoid click. Silent as the grave. I'm in process of jacking up the car and testing the leads at the starter. Checked the motor at the crank pulley to make sure it wasn't locked up and thank God it wasn't.

sbagdon

Glad to help. And yes, thought of that, and glad it's not locked. If the starter isn't engaging, might be some other safety feature, such as the trans lockout.

TrueGS300

Try tapping on the relays and check fuses. I get lucky more than one would think with that. If you get crank you'll know what area to mess with.

HiDef

When this happened to me it ended up being my fuel pump 🤷

coacheddie

Thanks True! I have checked fuses and all appears to be well, just the same I'm going to sub in new fuses today in case my eyes have deceived me.

coacheddie

HiDef that would certainly makes sense. When your pump went would the car crank over at all? Like sbagdon said it may be a safety feature preventing the car from cranking: ECU reads no activity from the pump and shuts everything down. I had a pump go bad on a Chevy Blazer once and it behaved the same way when it died but the motor would still crank. Regardless the car has over 250k on it and I have no evidence the fuel pump was ever changed. Pumps are inexpensive and an easy change. Think I'll try it this afternoon. Thanks!

TrueGS300

I don't think it would stop it from cranking. No manufacturer I know of does this. It would make diagnosing a car very difficult.

coacheddie

True I was thinking the same. Before I start throwing money into a Lexus shaped hole I'm contacting a buddy that has enough scan tools to read the ECU. I'll post more as I find more. I am getting current to the starter so now I'm baffled.

coacheddie

Final post on this thread -
Took the GS to a mechanic friend familiar with the 2JZ. a broken wire from the ECU to the harness was the non start culprit. Still had a random misfire after that repair, so he checked the coil packs and plugs. Plugs had oil pooling and the center coil pack was bad (my fault for using the cheapest coil packs I could find), replaced the valve cover gasket and coil pack with OEM. Alternator was fluctuating output so replaced it as well. Long story short, 500 bucks and my GS runs like new. I see that as a bargain.