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URGENT '92 SC400 no crank, no start after starter replaced & more
Hi everyone. I figured this would be a good post to introduce myself. I'm new here but I'm hoping someone can help me. I’ll include some pictures below and the story behind my 1992 Lexus SC400. It won't crank and won't start. I've done all the things recommended to get it to start. I replaced all of the following things on my own with Youtube and from reading threads here- I replaced the starter (this was horrendous) and the starter relay, I replaced the battery, I replaced the throttle body, the fuses, etc. I don't know what else I could do to get it to even crank. I filled it up with gas and some new oil because it has been sitting for 1 ½ to 2 years. There is a small noise that happens when I twist the key but then nothing. It sounds like it wants to start but nothing. I also tried taking a paper clip and taking off the cover of the “diagnosis” box (OBD I) in the engine. I put a paper clip in the B+ and FP to see if that would work. That is a fuel pump and ECU trick to get it running. I did that, turned the key and still nothing and then it started to leak fuel. One thing I also tried was putting a paper clip in the starter relay fuse and connected it to 5 and 3 without the key in the car. The car immediately turned “on” and the fluids started to run but when I put the key back in the car to crank, as you would expect, nothing. I’m not sure if it could be the fuel pump, ignition, a wire that isn’t connected, etc. I checked the fuses in the engine and the driver’s side kick panel. I’m not a mechanic but I’ve worked too hard on this to not see it start and not be able to drive. I hope the community here can help me diagnose the problem and help me fix it so that I can get it back on the road again and restore it to its former glory. Thank you so much...
The story behind the car:
I bought my SC400 for only $1000. It was supposed to be repaired by the mechanic hired to fix it but he never got to it and the owner never responded on the invoice so it sat for more than a year in an automobile graveyard. The shop is family owned and honest and the guy needed to sell it for so low because the city would otherwise charge him $500 a day to keep it on the land so he needed it gone. That’s when I bought it. He told me all it needed was a new starter and throttle body. The electronics in the car worked perfectly and as a Toyota/Lexus enthusiast, I trust the reliability of the 1uz enough to buy it (I own a 2uz 4runner). The starter DEFINITELY needed replacement as well as the throttle body. SC400 in the graveyard Brought her home and restored the headlights, pressure washed dirt and grime Engine bay before I cleaned it After cleaning up the engine bay. Much better Removed the throttle body Removed the throttle body A nest in the starter Removed the old starter Put in the new starter Put the engine back together and still no crank no start... :/
This one has me lost... I'm no expert, but assuming a few things
1. Tap/push the gear selector forward, also try starting it from the Neutral position/gear. Additionally place the key in 'ON' and jump the relay as you previously did. See if it stays on.
2. Battery may be dying, get it recharged. I drained my battery and got nothing out of it. Also see about changing your key's battery.
3. Ground cable or power cable may be loose.
4. The transponder is not recognizing the key and enabling the immobilizer, not sure if these cars have these.
Since you can jump start it from the relay, there may be an issue with wiring from the key to the ignition to the wiring to the relay, to thw relay itself. My Celica does something similar when it gets too hot and I have to jump start it from the relay as you stated and have no issue from there. I've replaced that relay but no change, so maybe the ignition switch, but this may be different all together.
This one has me lost... I'm no expert, but assuming a few things
1. Tap/push the gear selector forward, also try starting it from the Neutral position/gear. Additionally place the key in 'ON' and jump the relay as you previously did. See if it stays on.
2. Battery may be dying, get it recharged. I drained my battery and got nothing out of it. Also see about changing your key's battery.
3. Ground cable or power cable may be loose.
4. The transponder is not recognizing the key and enabling the immobilizer, not sure if these cars have these.
Since you can jump start it from the relay, there may be an issue with wiring from the key to the ignition to the wiring to the relay, to thw relay itself. My Celica does something similar when it gets too hot and I have to jump start it from the relay as you stated and have no issue from there. I've replaced that relay but no change, so maybe the ignition switch, but this may be different all together.
So I realized I have a grounding issue- stater isn't getting enough power so it won't crank although I need to find how I can replace the wire so that I can ground it and get it cranking properly. I'll try and include an attachment
I think Tally is guiding you in the right direction. I'd be a bit concerned with the nest you found under that manifold. Did you check for any chewed or frayed wires while you were in there? It's possible something is damaged and perhaps you're missing a ground or a signal wire to the starter? I know it's a huge job and a pain to take back apart, but it may be worth looking into if you haven't already.
Tally also brought up a good point about the battery and key. If it doesn't have a new battery go ahead and swap it - you won't save one that sat in a junk yard for ever a year (new batteries are just trashy like that these days). You may have to look into re-programming the key as well which isn't a bad task on those cars.
Best of luck - love to see one of these pulled out of a junkyard and brought back to life!
So in the picture on the left, the circle on the left is the grounding wire that was attached to the frayed wire in the other circle. When those two wires are connected to the upper ground near the windshield wiper, the car cranks. However, because they are so old, they started to catch on fire while the car was cranking previously. I hope these aren't directly to the starter. Otherwise, I'll have to take it all apart again but I wanted to follow up and see if yourself or anyone else knew where these wires grounded to so I could try and take it out and replace it with a new connection/wire altogether
So in the picture on the left, the circle on the left is the grounding wire that was attached to the frayed wire in the other circle. When those two wires are connected to the upper ground near the windshield wiper, the car cranks. However, because they are so old, they started to catch on fire while the car was cranking previously. I hope these aren't directly to the starter. Otherwise, I'll have to take it all apart again but I wanted to follow up and see if yourself or anyone else knew where these wires grounded to so I could try and take it out and replace it with a new connection/wire altogether
Could that be the transmission ground strap? I'm questioning myself over it catching fire. May make sense, since its channeling static electricity to a grounded. So you will need to trace that wire down to see where it goes. The last electrical fire I caught, was accidentally putting 2 wires together in my MR2 while driving in traffic a quick spark, followed by a fire... Imagine my panic, can't jump out, but can't pull over either... It snuffed itself out though.. I did pull over about a mile later when I managed to pull over and all was good. LOL...
Omg that is SCARY! Not sure if it could be the transmission ground... I'm guessing it has something to do with the starter because the only time it was cranking was when it was connected. It might've also been cranking because I had the key in "on" while I had a paper clip attached to 5 & 3 on the starter relay. I had read some other forums and watched some other videos and when people did that, it cranked and started. Originally, I had tried that and still nothing until I found that mangled wire that was burned off or wasn't attached or grounded where it was supposed to be
Well I took apart the engine again to find that wire... so frustrating but I did it in literally 45 minutes. I'll post some more pics on where I can locate that wire and were it goes to tomorrow
Update: I have a fuel leak after losing a banjo bolt from the upper intake manifold. I was able to replace a new heat sensor wire (shown above) and that was why it wasn't cranking. Wasn't getting enough power from the battery to the starter through that wire. That combined with a leaky fuel injector after replacing with new fuel injectors, new spark plugs and more. I narrowed down my problem to (hopefully) a faulty crankshaft position sensor so I bought a new one and I will be installing that on Thursday. Fuel pump is engaging and I am getting fuel, I'm getting air and I should be getting the correct amount of spark. That's why I believe the final culprit is the crankshaft sensor preventing it from fully turning over. Keeping my fingers crossed.
Even after all of that, it still cranks but doesn't start. I really don't know what to do and I hope it isn't timing. I want to save this car because they are so rare and hard to find but I don't have the money to send it to a shop to have them fix it. What else might the issue be? I'm devasted knowing that if I can't fix it soon then I am going to end up selling it because I am going back to college and won't have any time for it.
Have you tried pumping the gas while trying to start it?? If you're still jumping it, try tugging on the throttle cable and see if it kicks on and sorta stays on
07-23-23, 11:59 AM
URGENT '92 SC400 no crank, no start after starter replaced & more
