My 92 SC400 is bucking/stalling at lights/ studdering under any throttle more than 1/10th.

I took it in to Lexus paid $1500 for them to change the starter, it was running like a top going in and got the car back it didn't even run. They will not fix it. They said it is my problem and they wont touch the car because it will blow up They said because of the high mileage they don't want to diagnose or touch the car. Deuchebags. It stalls at lights, it kills the engine if I give any gas, it hesitates. Lexus said it was a secondary ignition problem whatever that is. It is obviously not that- look below.

REPLACED:
Entire ignition from Spark plug to ecu(plugs, wires, cap, rotor, coils, igniters)
New Fuel pump, Filter and ICV (ordered coming soon)
New Alternator, battery and battery cables


I am running out of things to replace. Super annoying.

Lexus won't touch the car anymore they refused to work on it. I am wondering if it is

A. Fuel ECU.
B. Torque Converter/tranny (long shot but a shot)
C. Ground Faulty somewhere.
D. Catalitic Converter clogged

Please chime in help me out. Thanks Guys!!

 

Plug in another AFM and try that out.

 

Mass airflow sensor?

 

i beleive thats whut he meant. yea i got ur pm... and for me, it seems that the fuel pump ecu fixed the problem. i doubt thats the problem with your car. people bypass the fuel ecu only because they have fuel starvation with bigger fuel pumps and bigger power demands such as turbo which tends to suck alot of fuel at certain rpms depending on the turbo.

ill try and find the thread about the fuel ecu, but yea, you might want to check ur AFM/MAF try borrowing someones

 

Do you have a CEL?

Jonny

 

I’m wondering if they did not replace or miss-install your intake gaskets when the starter was replaced. When the motor is COLD, try to start it and spray “brake cleaner” around the intake and see if the car idles up. If so it’s your intake gaskets. It sounds like the car is sucking air that the computer can not account for. Hence the running ruff condition. Just a thought.

 

Here is the weird thing. I drive the car everyday, and it runs butter smooth at less than 5% throttle. Yesterday, I went home and checked the MAF and cleaned it out, just for giggles left it off. Went for a drive. Even though the check engine light came on, the car cleaned up considerably. Smooth powerful acceleration from 5% to about 50-60% throttle now before it stalls and kills the engine. It will not rev past 4,000 rpm. Connect the MAF and it is back at 5%.

How do you bypass the fuel ecu?

It runs smooth and great unless you put your foot down. I left the MAF off for now. I can at least drive it to work and back.

????

It idles o.k. pretty smooth a little irregular. With the MAF connected, it will stall at idle in (D)drive. With it disconnected it will run fine, no stall in (D), and accelerate up to about 50% throttle before it dies.

Thanks for the ideas guys keep them coming.

Jonny are you talking about a cell phone?

 

LOL - no I mean a Check Engine Light? Are you getting a CEL on your car?

Sounds like your MAF is bad. You can pick up a Reman for $100 at your local parts store. Put it in, reset your ECU and then check it out. If it doesn't work, just return the MAF.

Jonny

 

No check engine light with the MAF plugged in. No auto parts store carries one nor can order one, checked yesterday. Probably buy one online somewhere.

 

To bypass your fuel pump ecu, take a paperclip or piece of wire and jump terminals b+ to fp on your diagnostics port. Get in your car, put the key in the ignition and turn it to the on position. If you hear your fuel pump turn on (humming sound coming from behind the back seat) than you did it correctly. Now start it up and see if it drives better. If that doesn't help anything, your fp ecu is probably fine and you can check that one off the list.

 

Is it normal to have cream colored goop in the terminals? The whole Diagnostics port is crapped up with this grease. Anyway, I bypassed the B+ and FP and the car does not miss at all with the MAF plugged in. I took it for a short drive for a min and could go 100% throttle. The car never warmed up yet, in a hour I'll take it for a longer drive. I pray this fixes it, I hope a Fuel ECU isn't expensive. Sounds like it is.

autozone didn't have any or could order any as of yesterday... Maybe I'll try checker. Thanks.

 

Yeah they do. I got mine at Autozone.

Jonny

 

I think you need to go back to the stealer and talk to the service manager. If you say the car was fine going in make them fix it. It sound like you have a leak around the intake. GL

 

The dealer refused to work on it. They want $500 for diagnostic starting and additional $1300 for stuff that has nothing to do with the stalling issue. I am never going back to the stealer-um I mean dealer again. They just raped me $1500 for the starter.

Bypassing fuel ecu did not fix it. Same problem still. Later today I am getting a fuel pump, filter, oil change and diagnostic. Lets see what they say...

It might be a bad ground somewhere or a sensor going out. It seems possible the gasket is bad...

 

hey man, i just tried to clean my maf earlier in the day because it was dirty.
basically long story short, i didnt do it propery and now my car does the exact same thing your car is doing.

idles mostly ok but over 4k and the car just cuts off immediately.
after that it wont hold idle till i reset the ecu

it is definately the maf if you can drive your car with it disconnected and not when it is connected.
with it disconnected you ecu goes open mode and it basically guesses at how much gas to throw in. it makes a safe guess = runs rich = bad gas milleage = "appears" to be running better = will not want to go high in the revs to avoid engine damage.

im still figuring out how to correctly clean our maf's because they are different than most cars slightly. popular route seems to be electrical parts cleaner, but it didnt help me too much on my first time around. gonna clean it again tonight. why cant toyota just use a map sensor? i might write them an email.