MAF sensor replaced but still having issues.
08-13-13, 10:37 AM
#17
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08-16-13, 03:04 AM
#18
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drone...
Have you received the MAF assembly from ebay yet and have you tried it out. Please give a follow up report when you have time.
I am currently running "MAF-less" (unit unplugged ). Bought a replacement unit from ebay but
it was not compatible as advertised for my '93sc400. I plan to run for a week or so with unit
unplugged and if it keeps running good like it does now, I will look for another replacement
MAF.
08-16-13, 09:47 AM
#19
Lexus Champion
'93 SC400 + living in Florida = textbook case for failing ECU capacitors
I couldn't design a more probable scenario
I couldn't design a more probable scenario
08-16-13, 10:21 AM
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'93 SC400 + living in Florida = textbook case for failing ECU capacitors
I couldn't design a more probable scenario
I couldn't design a more probable scenario
If the ECU caps are bad or going bad, would my sc400 run well with the MAF unplugged.
My plan was to run unplugged for a week or so and see if any performance issues might
occur. If they did then ECU would be likely culprit and then I could remove (kind of hard to get
to) and inspect for bad caps. Tempted to just buy a $60 MAF unit(ebay) and give it try and then
if no improvement move on to the ECU. Also, what are chances that it might be the fuel pump
ECU??? I assume you were alluding to the main ECU caps.
08-16-13, 11:03 AM
#21
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LS...your opinion.
If the ECU caps are bad or going bad, would my sc400 run well with the MAF unplugged.
My plan was to run unplugged for a week or so and see if any performance issues might
occur. If they did then ECU would be likely culprit and then I could remove (kind of hard to get
to) and inspect for bad caps. Tempted to just buy a $60 MAF unit(ebay) and give it try and then
if no improvement move on to the ECU. Also, what are chances that it might be the fuel pump
ECU??? I assume you were alluding to the main ECU caps.
If the ECU caps are bad or going bad, would my sc400 run well with the MAF unplugged.
My plan was to run unplugged for a week or so and see if any performance issues might
occur. If they did then ECU would be likely culprit and then I could remove (kind of hard to get
to) and inspect for bad caps. Tempted to just buy a $60 MAF unit(ebay) and give it try and then
if no improvement move on to the ECU. Also, what are chances that it might be the fuel pump
ECU??? I assume you were alluding to the main ECU caps.
I just read your very comprehensive ECU repair tutorial ...nice job... and guess what?
I have several of the problems that you outlined but I think the one that kind of nails
down a cap(s) problem is the speedometer not working properly. Mine either doesn't read at
all or when it does, probably at least 20mph low.
I am pretty much convinced to remove the unit and inspect. Where do I buy the caps if I need
to replace? I am the worlds worst solderer so I will farm out to an electrical tech I know.
Also, any major clue other than what you describe in you tutorial in getting to the unit. The
write ups I have read say that the glove box is a b***h to drop.
Thx for your comments.
08-16-13, 11:04 AM
#22
If toyota ecu's work the same way as my older ford.
If you unplug the MAF the computer will go into "limp"mode. which runs the motor on a preset setting and ignores all the sensors and allows you limp home.
So it is possible that there is another sensor causing your problems but when you unplug the MAF the computer ignores the other sensor.
If you unplug the MAF the computer will go into "limp"mode. which runs the motor on a preset setting and ignores all the sensors and allows you limp home.
So it is possible that there is another sensor causing your problems but when you unplug the MAF the computer ignores the other sensor.
08-16-13, 11:35 AM
#23
Pole Position
If toyota ecu's work the same way as my older ford.
If you unplug the MAF the computer will go into "limp"mode. which runs the motor on a preset setting and ignores all the sensors and allows you limp home.
So it is possible that there is another sensor causing your problems but when you unplug the MAF the computer ignores the other sensor.
If you unplug the MAF the computer will go into "limp"mode. which runs the motor on a preset setting and ignores all the sensors and allows you limp home.
So it is possible that there is another sensor causing your problems but when you unplug the MAF the computer ignores the other sensor.
"By having it unplugged the ECU just goes to factory settings and the car will run great. But....I dont recommend you do that for too long. It kills the O2 sensors, and I get really bad MPG"
SC93; Same thing, You say you read all of LScowboyLS's tutorial https://www.clublexus.com/forums/ls4...capacitor.html but then you ask: "Where do I buy the caps if I need
to replace?" It says right in the first post where to buy them. IIRC he mentions 4 places.
Also gives you a diagram how to remove the ECU.
Everything you need to know is in post #1.
08-16-13, 12:19 PM
#24
Lexus Champion
I am not saying that it is 100% sure it is your ECU caps, but I am saying you have the perfect storm of the right state and the right car for this to be a very common issue, and as it is a known defect, if it is not the problem now, it soon will be a huge problem!
removing the lower glove box is a less than 10 minute job as long as you realize there is a hidden fastener behind a secret panel inside the glove box itself, so if the glove box does not want to come out, don't force it, use my diagram in post #1 and find the fastener you have missed!
once the glove box is out, the ECU takes another 5 minutes
make sure you have disconnected the negative battery cable before disconnecting ECU, then, while wearing all cotton clothing and bare feet (for static protection), take the ECU inside to a clean work area, and carefully open it up and take high resolution pics and post them in my main ECU thread and me or Yamae will have a look and we can usually spot bad capacitors a mile away!
removing the lower glove box is a less than 10 minute job as long as you realize there is a hidden fastener behind a secret panel inside the glove box itself, so if the glove box does not want to come out, don't force it, use my diagram in post #1 and find the fastener you have missed!
once the glove box is out, the ECU takes another 5 minutes
make sure you have disconnected the negative battery cable before disconnecting ECU, then, while wearing all cotton clothing and bare feet (for static protection), take the ECU inside to a clean work area, and carefully open it up and take high resolution pics and post them in my main ECU thread and me or Yamae will have a look and we can usually spot bad capacitors a mile away!
08-16-13, 12:32 PM
#25
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I guess you, as alot of people do, just skimmed through this thread. In post #6 I say;
"By having it unplugged the ECU just goes to factory settings and the car will run great. But....I dont recommend you do that for too long. It kills the O2 sensors, and I get really bad MPG"
SC93; Same thing, You say you read all of LScowboyLS's tutorial https://www.clublexus.com/forums/ls4...capacitor.html but then you ask: "Where do I buy the caps if I need
to replace?" It says right in the first post where to buy them. IIRC he mentions 4 places.
Also gives you a diagram how to remove the ECU. Everything you need to know is in post #1.
"By having it unplugged the ECU just goes to factory settings and the car will run great. But....I dont recommend you do that for too long. It kills the O2 sensors, and I get really bad MPG"
SC93; Same thing, You say you read all of LScowboyLS's tutorial https://www.clublexus.com/forums/ls4...capacitor.html but then you ask: "Where do I buy the caps if I need
to replace?" It says right in the first post where to buy them. IIRC he mentions 4 places.
Also gives you a diagram how to remove the ECU.
Everything you need to know is in post #1.Question:
Would I be just as well of by buying a refurbished ECU off ebay vs buying replacement caps
and paying a tech to install. Are the refurbed units reliable??? Do they have all new capacitors
installed??? What would you guys do?? Around $125-$150 for a unit seems reasonable.
All opinions would be appreciated.
08-16-13, 01:04 PM
#26
Lexus Champion
an ECU off of ebay is only necessary if the caps in your ECU have been leaking so bad that the corrosive effects have ruined the main circuit boards, because an ebay ECU will still have to have the correct caps installed
there is no seller, ebay or anywhere else, who is currently refurbishing these and doing a good job and using the correct caps! - you would not believe the shoddy repairs I have uncovered from every well known place under the sun!
in fact, you specifically do not want a refurbished one, it is very hard to repair someone's hack job, the only ebay ECU you want is a virgin that has never been repaired, and then have it professionally soldered using the caps YOU have ordered via my ECU thread links.
there is also a huge problem of counterfeit caps out there!
there is no seller, ebay or anywhere else, who is currently refurbishing these and doing a good job and using the correct caps! - you would not believe the shoddy repairs I have uncovered from every well known place under the sun!
in fact, you specifically do not want a refurbished one, it is very hard to repair someone's hack job, the only ebay ECU you want is a virgin that has never been repaired, and then have it professionally soldered using the caps YOU have ordered via my ECU thread links.
there is also a huge problem of counterfeit caps out there!
Last edited by LScowboyLS; 08-16-13 at 01:08 PM.
08-16-13, 01:06 PM
#27
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I am not saying that it is 100% sure it is your ECU caps, but I am saying you have the perfect storm of the right state and the right car for this to be a very common issue, and as it is a known defect, if it is not the problem now, it soon will be a huge problem!
removing the lower glove box is a less than 10 minute job as long as you realize there is a hidden fastener behind a secret panel inside the glove box itself, so if the glove box does not want to come out, don't force it, use my diagram in post #1 and find the fastener you have missed!
once the glove box is out, the ECU takes another 5 minutes
make sure you have disconnected the negative battery cable before disconnecting ECU, then, while wearing all cotton clothing and bare feet (for static protection), take the ECU inside to a clean work area, and carefully open it up and take high resolution pics and post them in my main ECU thread and me or Yamae will have a look and we can usually spot bad capacitors a mile away!
removing the lower glove box is a less than 10 minute job as long as you realize there is a hidden fastener behind a secret panel inside the glove box itself, so if the glove box does not want to come out, don't force it, use my diagram in post #1 and find the fastener you have missed!
once the glove box is out, the ECU takes another 5 minutes
make sure you have disconnected the negative battery cable before disconnecting ECU, then, while wearing all cotton clothing and bare feet (for static protection), take the ECU inside to a clean work area, and carefully open it up and take high resolution pics and post them in my main ECU thread and me or Yamae will have a look and we can usually spot bad capacitors a mile away!
Thx cowboy for the reply. If you would, see my post 25. Assuming the caps are bad which
approach would you recommend for me. I know you would repair but maybe in my case
a refurb would be better/easier overall.
I guess since I was able to repaired my dash cluster, I should be able to get to the ECU unit w/o a great deal of hassle
08-16-13, 01:25 PM
#28
Lexus Champion
the ECU is 100 times easier to remove that the cluster, in my opinion, I can have an ECU out in 10 minutes, and that is with a lot of time goofing off!
and you do not want a refurbished ECU, you would be far better off ordering the correct caps and then taking it and the caps to a place that is not even in the car business, but like an electronics repair shop where they solder all of the time, and you need to carefully inspect their work, making sure the soldering is done well, and the correct caps that YOU supplied are in the correct locations and of the correct polarity (remember to make a complete diagram)
I do not have a listing of the exact caps to order for the 93 SC400 in my thread, but I can get you a listing of what they are, will post here later or PM me - but in any case, although the quantities in yours may be different, all of the caps that are inside your ECU are in my links to Digi-Key in post #1, and that is the only smart place to order them, due to so many counterfeits out there!
did you read my post #26?
and you do not want a refurbished ECU, you would be far better off ordering the correct caps and then taking it and the caps to a place that is not even in the car business, but like an electronics repair shop where they solder all of the time, and you need to carefully inspect their work, making sure the soldering is done well, and the correct caps that YOU supplied are in the correct locations and of the correct polarity (remember to make a complete diagram)
I do not have a listing of the exact caps to order for the 93 SC400 in my thread, but I can get you a listing of what they are, will post here later or PM me - but in any case, although the quantities in yours may be different, all of the caps that are inside your ECU are in my links to Digi-Key in post #1, and that is the only smart place to order them, due to so many counterfeits out there!
did you read my post #26?
Last edited by LScowboyLS; 08-16-13 at 01:33 PM.
08-16-13, 01:53 PM
#29
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Thx for the comments. I will try to get to the ECU unit next week and will take pics of the
mother board. As I had mentioned in some earlier posts my bad back sometimes prevents
me from tackling projects as I would like but at least I am above ground at 77
mother board. As I had mentioned in some earlier posts my bad back sometimes prevents
me from tackling projects as I would like but at least I am above ground at 77
08-16-13, 02:39 PM
#30
Lexus Champion
- as it is upside down work in the passenger side foot area, with 2 or 3 fasteners way up high near the top of the dash - got any sons/grandsons/nephews, etc that are good with a wrench that you could supervise doing that part?
