Hell everyone, I been having trouble with my 92 sc300. The car was running perfect I go to shut it off then try to start back up and nothing it was just cranking. I asked the previous owner what he thought could be going on ,he said to check the fuel pump ecu. He came over the next day took a look at it and just tapped the fuel pump ecu and it started. But the motor was shaking bad. Eventually I got a new fuel pump ecu and nothing still . He then told me it could be my spark plugs . He changed them the next day for me and still nothing. He starts to look at the distributor and noticed it wasn’t getting enough spark. He then asked on of his buddy’s to barrow one to see if that was the problem. He talked to the guy about everything going and he suggested it was the ecu. He ended up getting the ecu looked at for me and they people he took it so said it’s completely fried beyond the point of repair. I ended up contacting the guy I got the fuel pump ecu from to see if he had any extra. He told be he’ll get back to me .a few day ago he came around with 2 good ecu and we tried them but but no Cel light came on.
ive seen lots of people saying it’s not the ecu,distributor ,ignition switch or the fuel pump ecu and anyone experience something similar or know what I should do

 

I meant. It is one of those causing problems

 

Did You say it cranks but won't start ??? Just to be on safe side have you checked the timing belt for any missing tooth or brittle?

 

if you turn the key from off to on and the cel light does not come on for a second or two, the ecu is no good. it must come off and then go off on key on, assuming the light bulb on the cluster works.
alot of times the ecus that are going bad will work when sitting as in cold, but once they warm up they will start acting up. honestly sounds like could be more issues with the car though.

 

I Haven’t checked that. My motor on got around 50k I’m pretty sure it not that

 

The other day I was messing around with the old one I have and hooked it up. I screwed it down all the way and the cel came on. So I contacted the guy who brought me two to try them out again because I think that was the reason the cel didn’t show the first time. I didn’t screw it down all the way. The next day he told me he was gonna stop by but never did. It’s been about two weeks now since that.

 

you're talking about the ecu connector? if you don't screw that screw in on the big plug the pins won't even be close to seated.
I wouldn't count on the the guy who sold it to you to come back. Is the CEL staying lit? if so look up how to pull the code and let us know what it is unless you just want to replace everything.
sc300 ecus aren't as hard to find as 400's. you can even use a similar year non turbo supra ecu but probably would cost more.

 

So I got a new ecu this past Friday. I plugged it up nothing. It wouldn’t crank or anything. The next day I change my battery where I work and gave the new one to my mom to put in the car. The car started up perfect. No shaking from the motor or anything. Only thing was it was making a squeaking nose from the belt. My dad called his buddy who was the previous own over to check it out . He put a bit of water on it and it went away. I had went home on break to look at it and nothing again. The next day dude came over again to see what was going on. He tested the ignition switch. That came out good along with the starter. Any other suggestions on what to do. It’s been about 2 months since the problem started occurring. I’ve been getting desperate on tryna fix it I’ve been ready to buy whatever I need to get it back up and running. I just need someone to point me in the right direction to find the problem

 

I had intermittent no starting. It turned out to be the fuel pump relay (its in the left front fuse box.)
The relay is too complicated to fix.
Bought a new one.
No problems since (over a year ago)

 

I wanted to make an update for this problem. I had resolved it back in March of this year I change the ecu, spark plugs, starter and the fuel pump ecu and I had no response from the car still . I took it to a shop and all it was, was a loose connector on the body the dude took like a hour to figure it out. It was the most simplest thing. I wanted to put this out there for anyone who might be going thru the same problem and for the people who might possibly experience it in the future. I know this won’t be the case for everyone’s car but it could help