injectors on that bank? maybe pull the plugs on that bank and see if one looks different than the rest.

 

Could it be the injectors? Code 28 says right bank, which side is the right bank? Is it when we're facing the car or in the driver seat? Why couldn't they just have said driver side or passenger side. Will check this tomorrow.

 

Ugh! I'm so stumped, what could be the cause of this... I'm still getting code 28. I listened to each and every fuel injector with a stethoscope, multiple times, and each and every one of them are functioning well.

 

Did you every figure this out I am also getting codes 24, 28 and 31, I am able to unplug the Karmen Vortex sensor completely and the engine running doesnt change at all...Do you think it would be good to replace the MAF sensor to start as well as the o2 sensors?

 

No sir, this is still in progress of getting fixed. I'm running out of ideas at this point. I will check my exhaust for leak, again.

On another note, I've been running for roughly a week without code 24 and 31, until I changed a couple vacuum lines this morning, ran into a speed bump where my undercarriage and exhaust scrapes all the time and the 2 other codes are back. WTF?!?

 

maybe one of the connectors is loose or a pin in the connector is loose on the maf. really just guessing at this point it seems alot of people get these codes now with what seems like working maf's. even starting to suspect the ecu although those aren't the typical symptoms I wouldn't rule it out completely. must be some sort of connection going on here. I want to say those particular sensors share grounds at the least I will check over some diagrams later and see if anything pops out.

so as I understand it the car itself it driving fine Kingphilip? no misfires? anything?
and it changes when you unplug the maf which sounds normal as well...

 

Ali, I really appreciate your help. See, that's what's weird. It would've been a lot easier to diagnose if the engine is acting up somehow someway, but it runs perfectly. No misfires, no idle issues, no hesitation issues, runs perfectly. Only problem I can tell is its running really really rich, and its back to 15MPG.

 

15mpg is really not bad for a 1uz =)
maybe it is that autozone coolant temp sensor, the coolant temp sensor is a major ecu input for fueling. It is odd that its not throwing that code, but the codes on odb1 are only useful half the time anyways.

 

15mpg is not bad? How come I see people here claiming to be getting 20-25, even more in that thread how much mpg's are you getting? Which is exactly why I started replacing parts actually. And yeah, codes for OBD1 cars is useless at times, just like now. Lol

I'll order a new coolant temp sensor from Lexus, and check again for exhaust leak, and check the contact points for the MAF plug. I'll get back here ASAP.

 

I am not sure what they are doing but a odb1 sc400 uses fuel like its going out of style. in the city 12 is probably closer to what it averages. highway is where it starts to get a little better maybe low 20's so I guess it matters alot what kind of driving you do, but I would say averaging 25 is very very good.

 

Is the idle supposed to react when I unplug the MAF? Is it supposed to shudder or something? 'Cause that has never happened on this car on any of the MAF's I've owned. And how much of a bad luck can I have to have 3 non-working MAF's right? That's why I kinda doubt it's the MAF.

I have a buddy with a '94 SC400 said the same thing to me about the mpg. Maybe the people who say they get 20-25 mpg's doesn't really calculate their mpg's or doesn't know how to do it the right way? I don't know. But in some websites, it says 18 city and 25 highway for the SC's.

I have no problem getting this mpg's really, I've owned this car for 3 years now, and its always given me 230-250 miles out of my tank with plain city driving. But it would be better if I get better, and if it doesn't damage anything in my SC. Besides I have modded a lot on this car, which I'm pretty sure can also affect my mpg, like aftermarket mufflers, lowered suspension, cambered wheels, 19" wheels(which are heavier and wider than OEM or stock), I just want to fix this damn CEL 'cause I hate seeing my gauge cluster looking like Xmas lights. LOL

 

[QUOTE=KingPhilip;8076549]Is the idle supposed to react when I unplug the MAF? Is it supposed to shudder or something?

I would also like to find out an answer for this.....my idle is fine but when i get up to 3k in rpm range it is really sluggish and gets stuck in the 3k -4k range....it runs great but when I step on it and it gets up to that range it boggs down..would you suggest getting another MAF and replacing the o2 sensor to start...btw I have owned the car for 2 months and this problem just started to happen...sometimes it even stalls out on me when I fire it up every once in a while I have an SC300....Any ideas??

 

Sorry to jack your thread KingPhillip...im just trying to figure this out as well...I have tried a different ecu on mine as well and it made it worse....checked all vacuum lines are they are good....I can only suspect it has to be the MAF or o2 sensors...

 

So after going through multiple threads and finding similar issues people are having has someone figured out the hesitation issues, idle issues and overall lacking in performance.....I am going to try the 12V ECU fuel mod, another MAF from a member and new o2 sensors...btw I have already replaced cap, rotor, plug wires and spark plugs..and tried a different ECU

What would you guys recommend to start with first?

 

Is it just me but I think there needs to be some sticky made for this topic to cover general hesitation, idle issues.....etc.....There are multiple threads created on these issues and none of them seem to have answers to what to try or if they have been solved

If several others have had these symptoms and have remedied the problem please post up what you have done to solve your issue..

Thanks in Advace

KingPhillip do you think it is fair to say that Mods could re-title this thread to start the sticky

Give your feedback guys!!!