pnewman30

I'm REALLY needing some help here.

Problem:
92 SC400, 150k, runs fantastic, no issues...HOWEVER within the last month I've have a problem that can't be diagnosed by 3 repair shops, including the Toyota dealership. Out of the blue the car won't randomly start every now and then. I've had it towed several times and it's really becoming a pain in the a$$ for my father in law (of whom I got the car for).

We've replaced the battery so far, but literally we have not been able to duplicate the issue after having it towed to any of the shops (it starts right up once they get it off the flatbed)

I'm thinking ignition, starter, a starter wire grounding somewhere...not sure. It never dies when running (not the alternator) and always starts when it starts (new battery).

This is the third SC I've bought and never have I dealt with something like this. No codes come up either.

What could this be?

FatBrian81

iTrader: (2)

Maybe if you didn't try to start it randomly and only started it when you had a purpose this would go away.

Okay, now for the real answer. Have you ever checked for power at the starter when it won't start ? Will it crank but won't turn over or do you not get anything when you turn the key ? Do your other accessories work when it won't start ? I had something like this on my suburban and it was a dirty battery terminal.

1WILLY1

iTrader: (9)

okay i dealth with a similar issue with my sc and it was a total nightmare for me.

I also brought it to 3-4 mechanics including the dealer and they also couldnt diagnose it.

My question is yes it wont start sometimes but has it ever stalled out on you as well?

Im assuming your car isnt throwing any codes as well?

My problem turned out to be a loose cam sensor plug.

Please get your mechanic to check all your sensors including your two cam sensors and your crank sensor.

They can cause the car to not start and they are not expensive to replace.

please get back to me with a little more info i would love to help if i can.

good2go

iTrader: (6)

Need a bit more info. When it acts up, does the engine turn over but just won't start, or does it not turn over at all? If it's the later, does it make any noise from the starter at all? If it clicks or ticks but doesn't turn over, you could just have a flat spot on your starter motor.

1WILLY1

iTrader: (9)

good point we definitely need more info.

in my case the car starter sounded just fine but sometimes it would not fire at all.

please let us know your symptoms

pnewman30

We have not been able to duplicate the problem in order to check for power at the starter yet. It will crank, dash lights come on and then you turn the key and it won't "catch" and turn over.

One of the first things we did was replace the terminals and get a new battery. Still didn't fix it.

pnewman30

It has never stalled out before once it is running. There are no codes coming back either. I actually just informed Toyota Dealer to check cam sensor plugs and crank sensor plugs. We will see what transpires there.

I did get a suggestion that there could be a problem with the security system anti theft system that a sensor in the key is not communicating with a sensor in the ignition and "allowing" the car to turn over???I thought this sounded a bit weird though. Any possibility with this scenario and if so how they hell do we go about fixing that?

pnewman30

No clicking or ticking. Once key goes in, dash lights up and accessories chime on, but once you turn the key it won't turn over. It just keeps eeewewwwwwwewwwewwing, haha. If you can imagine the sound.

FatBrian81

iTrader: (2)

If it turns but won't start you either aren't getting spark or aren't getting fuel. If you crank on it for a while when it won't start do you get a raw gasoline smell ? Since the problem is intermittent you need to start carrying a tool box with you so when this happens you can try to track it down. For this I would want a multi meter, a spark tester that plugs into the plug wire, if your fuel rail has a schrader valve on it a tire pressure gauge you don't care about, and a few hand tools. Problems like this can be a bear but if you're prepared you might be able to find it.

scviolence

iTrader: (17)

bad fuel pump ecu? old plugs and wires??

good2go

iTrader: (6)

I'm sorry, can you clarify this part. As I read it, it can be contradictory:

"It will crank ... then you turn the key and it won't ... turn over."

How does it crank before you turn the key?
Also, cranking = turning over , so which one is it, either it will or won't crank/turn over?

And then in an even later post, you go on to say:

"but once you turn the key it won't turn over."

pnewman30

Geez, reading that makes me feel like an idiot. Sorry, so what I mean is that there is no clicking, the car just won't catch and turn over.

99SC42

iTrader: (44)

I think it's the ECU my SC did the exact samething majority of the SC4 have that issue.
I would start with no issues and then 30min later it will stall by itself lol i replaced the ECU and bingo i was good to go.

Check the codes jump E1 and T1 and check for codes.

FatBrian81

iTrader: (2)

When you turn the key the starter turns and you get the cranking sound but the car doesn't actually run on its own, correct ?

iridebmx

iTrader: (6)

i really hope your joking......


anyway i had the same issues with my sc400 and it turned out to be the ecu. get it rebuilt or do it yourself. all it is, is a capacitor that goes bad, but some will argue this.... (my fix was the caps)...


https://www.clublexus.com/forums/sc-...apacitors.html

i honestly dont see why that thread is not stickied or something just for sc400's