hey everyone,

the 98 sc400 has had it's first big problem... the car wouldn't start... it would crank over but it wouldnt' ignite.

the car's fuel pump did not have any sound when i put the key in ON position. so that led me to think and look into things.

i did some searching on here and read about the fuel pump ecu and or pump failing. so i tried doing the 12v mod and it still wouldn't start.
BUT after trying for a few attempts, i got it to start up but now the car is smoking a TON of white smoke! it seems like a RICH issue... not really a coolant/water issue...

i know something isn't right... it's a fuel issue but i'm not sure what it is... i know the OIL light came on intermittenly a few days ago (but oil is leveled ok). has anyone encountered this issue before???


NOTES:

my car is a 98 (obd-2) so i can't do the Fp and B+ (paper clip mod) to test the fuel pump ecu... ???

but i guess wiring the 12v mod just by-passed the fuel pump ecu?

it seems like as soon as i put the key in now, the fuel pump turns on? so the pump is turned on by the key entering the ignition chamber?

was it always suppose to be like that or was it only turned on when the key was turned to the "ON" position?

 

Does it smell like raw fuel, like all the fuel isnt being burned?? if so its ur ecu

 

yeah it does smell like raw fuel...

but i don't get how it would be ECU???

do you think the oil light has anything to do with it?

 

BumpPpppppp

 

True, I had the same problem that I had a TON of white smoke pouring out on start up. It smelled like pure fuel. Me and many other members deduced it to the fuel injectors being open for much longer then they were supposed to.

I changed up my ecu and the problem went away. No more white smoke and my car drove better as well. But 1 year later and it seems the problem is coming back again. Not nearly as bad as before but definitely some white smoke on start up.

https://www.clublexus.com/forums/per...mely-rich.html

Recently, I've been starting to think that it might a failing mass air flow sensor that is messing up the ecu, or at least causing that white smoke problem.

No way to tell unless you swap it out for a working one. You could try getting some MAF cleaner from the auto store and spraying it onto that sensor. Make sure it is hotwire sensor safe since 96+ maf sensors are hotwire. If it helps that may be the culprit, if not, I might look into an ecu from another 98-00 SC400.

Hope I helped.
David

 

Before you swap out the ecu, I'd at least try resetting yours first. Pull the battery cable for 10-15 minutes and see what happens. Free and it sure can't hurt.

 

coil maybe??

 

try the ecu swap

 

The ECU is not reading properly and is causing the injector to pump more and more fuel into a cylinder and it isnt being burned, that why u get the white smoke and the raw fuel smell

 

exactly! well put my friend.

Did you experience any problems while driving? Like sluggishness?

 

Yes, it was very sluggish when i had this issue...i tried to floor it and the rpm's wouldnt go past 4k like it was limp mode or sumthin

 

thanks guys

well the car was getting a bit under powered also before this for some time now. so i dont know if it is related at all.

i figured i should start with the basic tune up first (spark plugs, fuel pump, clean maf, etc) and i'll definitely look into the ECU.

i've never heard of an ECU 'failing' before, so this would definitely be a surprise to me if it was.

i've had the battery reset, doesn't do much for this case. thanks though

 

well i kinda have the same problem so let me add my .02...

well i have researched all up and dwn hear and found nuttin but what "scdriver" said and i didnt want to beleave it either up till like a week ago. i got 2 ecu's and didnt seem to help any.hence y u also beleave how it cld be the ecu.well the other nite i took it to the corner store and when i came out to start it and take off nuttin...no fuel sound no tick no nuttin...so i called to get towed and said y not try switchin the ecu with another one i had in the car... well i did and it started.. well 3 days later the same thing happin when i went to move it so i switched it one more time and it started but i dnt think the ecu's are good... so i have decided to purchase a new one or a good used one... the reason many say its the ecu is cause the fuel caps in the ecu basically fry and cause it to read incorrectly so it runs sluggish or wont start ..basically the mother board has fried in that area...hope this help as i hope it helps me..i have also done a major tune up

 

wow thanks for the feedback, your similar experiences have definitely helped diagnose my car as well.

i'll look into a new/used ECU... so all you had to do was replace the ECU and that's it? do you know hwat caused the ECU to "fry?" bad MAF?
i'd hate to get an ECU and have it FRY on me later again...

thanks for your guys' inputs

 

Sent you PM bunch of times bro.. whats up? Those clips gone for the headlight? There are also a few things missing like I mentioned on my PM... lmk.. thanks