So my friend use to own my 95’ SC400 about 5 months ago, barely gets driven now that it’s my spare vehicle, battery had died from sitting, tried to keep it running every week but now just bad battery, had finally got a replacement today, me and my friend had replaced the battery it had as well as the start about the week before I got it (wasn’t gonna pay 2k for a clean car that was tooken apart engine wise lol) so I helped him put the new one in, worked perfectly because his old one wouldn’t engage, now when I connected the new battery, tried to start, the car starts but then dies right away and the starter still stays engaged but as soon as I give gas, it starts immediately but only when constantly being fed gas (since starter is still engaged, Will still turn over duh) anyways when I let off it just stays engaged and so I turn off the car and remove the key and is still engaged, forced to remove positive terminal

 

Anyone???? I replaced the starter relay and no change, I do not get why the car dies though after being started, and starter getting stuck on being engaged. Am so close to ordering a new starter but don’t want to if I’m not sure what is the real problem, it ran PERFECT about 2 weeks ago and now won’t even start without it getting stuck or dying

 

Hmm.

Well an SC400's starter is actually in the middle of the 1UZ-FE engine in the valley between the cylinder heads and under the intake manifold. If it ever needs replacing then it's a doable but very involved and tedious job to get to it. They tend to last a LONG time though.

This sounds more like a fuel delivery issue possibly. You are getting it to start and so that means you have initial fuel pressure and spark to ignite it but it just dies right after.

So my thoughts are:

1) Do you see any Check Engine CEL light right before it dies? If so, do you know how to pull the CEL trouble code by reading the number of flashes?

2) Since it does always initially start I assume you will not have a CEL Code 14 (bad IGF signal). If you did it increasingly wouldn't start at all and that would either be a bad Igniter or bad engine ECU. None of those would seem to be your issue.

3) You could have a fuel delivery issue. This could be related to a worn out Denso fuel pump or an issue with the OEM Fuel ECU. Remove the key from the ignition. Try taking a thick bare metal paper clip and find the under-hood port marked "DIAGNOSTIC". Insert the paperclip ONLY into terminals "FP" and "+B". Make sure it is only those terminals. Then try starting the car again. If the engine stays running now it means there is likely an issue with the OEM Fuel ECU. If there is no change in the engine's dying behavior then at least that has been ruled out.

4) The starter staying engaged when you've started the vehicle bothers me. That's not normal. If the gear on the shaft that contacts the flywheel is not retracting once the engine has been started (and the key is released from the START position back to the ON position once the engine is running) then there would be an issue with that starter.

 

i pulled the starter relay and tried to have a friend start it and I heard the fuel pump and the injectors were spraying, so the fuel pump or ecu would cut power after? And would it be possible that the battery could have low voltage to where it can start it but dies immediately but then that would be a dead alternator.. no? I replaced it with my friend and had to tear it all apart so I know some little tricks on how to get around the egr pipe and get to the bolts in the back for the start, was even thinking about drilling out the threaded holes in the block and rethreading them from the inside of the block versus the back side where you have to reach between the firewall but seems to risky as it’s part of the block and if i f*** up then it’ll never start lol, I’ll try the diagnostic trick when I get home today, thanks

 

If I were to buy one, I know me and my friend when we replaced it the first time, he had got the wrong starter from a different year, I want to buy one from autozone but all 3 for my 95’ SC400 are different and say they are made for a particular month of 95 “before 05/95, up to 06/95, past etc.”

 

There may be some by-year differences in the starters. I'm more familiar with the JZ engines than the 1UZ engines to know but if that's what you're seeing in the parts catalog then I would call up a Lexus dealer, give them your SC400's VIN and have them tell you which starter P/N to reference.

Also, I'm not sure if if can be done with 1UZ starters but the is a kit you can buy for the 2JZ starters to rebuild them yourself. It's maybe... $30? I did this with my original 1993 2JZ starter and it was made good as new. Might be something to look into.

Personally I wouldn't trust an AutoZone starter. I'd get a Denso remanufactured starter from the DensoProducts website or Rockauto.

...

With a suspected alternator you would likely get starting with a GOOD battery but immediately you'd see the charging light CEL come on in your instrument cluster if the charge is too low.

Now the opposite could happen too if an alternator has failed: overcharging. And then your Battery/Charge CEL light would not come on... but you would notice it if you have a voltmeter gauge installed in your car. In that instance you'd want to shut the car off and get the alternator out and replaced with a new Denso Reman alternator to as to not risk any possible damage to your Igniter or main engine ECU.

Right now though I still think you should rule out any fuel system issue.

In theory the only things that should stop your car from staying running are:

--fuel system or fuel electronic control issue
--spark issue or spark control issue
--main engine ECU issue