SC400 problem...5k and no further
10-12-15, 08:18 PM
#1
SC400 problem...5k and no further
92 SC400, has been running the same way for 4 years, not perfect, fails emissions, not tuned right. Anyways, I floor it WOT with the pedal all the way to the floor and the RPM's rise to 5k RPM's and go no further. It just stays there. Doesn't shift, doesn't jerk, doesn't slip, just stays at 5k RPMs with the pedal to the floor, it's when you ease off the pedal a little bit and it shifts down. TPS is fine. ECU was rebuilt. I unplugged the MAF and nothing really changed but I never did drive it with it unplugged.
Just looking for input. The difference with driving my 93 or 96 SC400 is night and day, with this 92 being night.
Thanks! Always stuff to learn
Just looking for input. The difference with driving my 93 or 96 SC400 is night and day, with this 92 being night.
Thanks! Always stuff to learn
10-16-15, 07:38 PM
#5
Unless you've had the car for more than 4 years, I read the first post as saying it's run that way since you owned it, so prior history would be a question mark.
10-16-15, 10:00 PM
#6
That's not what I asked, unless you know that a P.O. didn't put in the wrong one. That's why I specifically asked about the part # match. Unless you've had the car for more than 4 years, I read the first post as saying it's run that way since you owned it, so prior history would be a question mark.
Unless you've had the car for more than 4 years, I read the first post as saying it's run that way since you owned it, so prior history would be a question mark.
10-16-15, 10:48 PM
#7
Well sure, repairing the ECU would have solved whatever was wrong with it. But it if were hypothetically the wrong year and wasn't controlling the tranny properly, rebuilding it would have had no effect. It's a long shot, but it seems worth at least ruling out. POs have done dumber things!
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11-08-15, 03:15 PM
#8
^Havent checked the ECU for matching part numbers yet, but will soon.
Still have the issue. Unplugged AFM, no change, swapped it out for a working AFM from my other DD SC400, no change. Unplugged ignition coil, its good.
To be more clear, if I floor the car, it will accelerate fast up to 4k rpms, then just stop at 5k rpms like I'm using the engine to slow down, its not under load nor is it accelerating. Ease of the skinny pedal, it drops to second and flies away. Also, 99% of the time, it will start in 2nd gear. To get into first I have to literally STOMP on it.
Any more ideas?
t2d2, I owe you something if you are right...ill check it once i find the time!
Still have the issue. Unplugged AFM, no change, swapped it out for a working AFM from my other DD SC400, no change. Unplugged ignition coil, its good.
To be more clear, if I floor the car, it will accelerate fast up to 4k rpms, then just stop at 5k rpms like I'm using the engine to slow down, its not under load nor is it accelerating. Ease of the skinny pedal, it drops to second and flies away. Also, 99% of the time, it will start in 2nd gear. To get into first I have to literally STOMP on it.
Any more ideas?
t2d2, I owe you something if you are right...ill check it once i find the time!
12-15-15, 03:49 AM
#11
Answered your PM .
btw , just read that you failed emission . Your exhaust gases may help you determine some of your car problem . You still have the print out ?
Since you have a 1992 and a 1993 SC400 looking at your signature and are at a loss in troubleshooting, do some parts swapping from one to the other , at least the easy to replace ones so you can rule out what is a good or bad part. Those two cars basically has identical parts . Even your ECU should work with one on the other .
btw , just read that you failed emission . Your exhaust gases may help you determine some of your car problem . You still have the print out ?
Since you have a 1992 and a 1993 SC400 looking at your signature and are at a loss in troubleshooting, do some parts swapping from one to the other , at least the easy to replace ones so you can rule out what is a good or bad part. Those two cars basically has identical parts . Even your ECU should work with one on the other .
12-15-15, 08:50 AM
#12
My 6th gearhead sense is telling me you have an overfueling issue and is likely a leaky injector. that would explain emissions and why you hit a ceiling at a certain rpm. basically overfueling and crank sensor issues is what causes a car to hit a wall like that.
Gerrb is correct the emission numbers would give us clues, as if it was overfueling your HC numbers would be excessive and nox would be low.
I would also blame the ecu but you said it was repaired... however, there is a possibility that the ecu sustained some permanent damage that could not be repaired. try the 93 ecu on the 92 to rule that out, you may get some CEL's but it should run the car properly.
does it take longer to crank up than the other SC4's you have? thats usually a sign of injector issues, and lots of the early year cars like 92, 93 etc are starting to show issues like that I mean its been over 23 years in use.
the 92 also has a cold start injector, if that is gone faulty in some way then that could also be part of the problem, I dont have a lot of experience with those or how they fail but I have seen eough threads of sc400's with a faulty injector causing problems that people cant seem to solve by changing the maf, ecu etc...
Gerrb is correct the emission numbers would give us clues, as if it was overfueling your HC numbers would be excessive and nox would be low.
I would also blame the ecu but you said it was repaired... however, there is a possibility that the ecu sustained some permanent damage that could not be repaired. try the 93 ecu on the 92 to rule that out, you may get some CEL's but it should run the car properly.
does it take longer to crank up than the other SC4's you have? thats usually a sign of injector issues, and lots of the early year cars like 92, 93 etc are starting to show issues like that I mean its been over 23 years in use.
the 92 also has a cold start injector, if that is gone faulty in some way then that could also be part of the problem, I dont have a lot of experience with those or how they fail but I have seen eough threads of sc400's with a faulty injector causing problems that people cant seem to solve by changing the maf, ecu etc...
Last edited by Ali SC3; 12-15-15 at 08:54 AM.
12-15-15, 06:00 PM
#13
Answered your PM .
btw , just read that you failed emission . Your exhaust gases may help you determine some of your car problem . You still have the print out ?
Since you have a 1992 and a 1993 SC400 looking at your signature and are at a loss in troubleshooting, do some parts swapping from one to the other , at least the easy to replace ones so you can rule out what is a good or bad part. Those two cars basically has identical parts . Even your ECU should work with one on the other .
btw , just read that you failed emission . Your exhaust gases may help you determine some of your car problem . You still have the print out ?
Since you have a 1992 and a 1993 SC400 looking at your signature and are at a loss in troubleshooting, do some parts swapping from one to the other , at least the easy to replace ones so you can rule out what is a good or bad part. Those two cars basically has identical parts . Even your ECU should work with one on the other .
Another thing, the CEL doesn't work. The cluster is fully working, however, I'm too chicken to remove it and replace the CEL bulb because a lot of times when removed, some lights go out.
My 6th gearhead sense is telling me you have an overfueling issue and is likely a leaky injector. that would explain emissions and why you hit a ceiling at a certain rpm. basically overfueling and crank sensor issues is what causes a car to hit a wall like that.
Gerrb is correct the emission numbers would give us clues, as if it was overfueling your HC numbers would be excessive and nox would be low.
I would also blame the ecu but you said it was repaired... however, there is a possibility that the ecu sustained some permanent damage that could not be repaired. try the 93 ecu on the 92 to rule that out, you may get some CEL's but it should run the car properly.
does it take longer to crank up than the other SC4's you have? thats usually a sign of injector issues, and lots of the early year cars like 92, 93 etc are starting to show issues like that I mean its been over 23 years in use.
the 92 also has a cold start injector, if that is gone faulty in some way then that could also be part of the problem, I dont have a lot of experience with those or how they fail but I have seen eough threads of sc400's with a faulty injector causing problems that people cant seem to solve by changing the maf, ecu etc...
Gerrb is correct the emission numbers would give us clues, as if it was overfueling your HC numbers would be excessive and nox would be low.
I would also blame the ecu but you said it was repaired... however, there is a possibility that the ecu sustained some permanent damage that could not be repaired. try the 93 ecu on the 92 to rule that out, you may get some CEL's but it should run the car properly.
does it take longer to crank up than the other SC4's you have? thats usually a sign of injector issues, and lots of the early year cars like 92, 93 etc are starting to show issues like that I mean its been over 23 years in use.
the 92 also has a cold start injector, if that is gone faulty in some way then that could also be part of the problem, I dont have a lot of experience with those or how they fail but I have seen eough threads of sc400's with a faulty injector causing problems that people cant seem to solve by changing the maf, ecu etc...
It doesn't take longer than normal to crank up, however, the starter does grind which is pretty annoying. :roll eyes:
I will rule out the ECU, thanks for the assistance! Picture of the emissions test below.
12-15-15, 06:26 PM
#14
Johnny - go and fix that CEL bulb.. getting error codes if there are any , helps you better isolate the real problem part otherwise you will be on a guessing game which part is the real culprit . For any problem there maybe different parts that can cause it but with an error code , it will pinpoint or give you a better idea which part. May not always be foolproof but close to it.
Your Hydrocarbon and Carbon Monoxide exhaust gases are so high which is as Ali said is a sign of very rich mixture . Leaky injectors can be one cause. That explains why your gas mileage is bad . You are throwing away fuel uselessly. Not everything is being burnt . Can also be a bad O2 sensor . The ECU injecting more fuel through the injectors because it is not receiving a good feedback from the O2 sensor if it is bad. There are a lot of other possible causes but it becomes a guessing game if you don't know the error code... so fix that damn CEL light .
I will PM you some info that can help you diagnose better why you have High HC and CO . A good number of causes but you don't want to be playing the guessing game . It can be an expensive game.
Your Hydrocarbon and Carbon Monoxide exhaust gases are so high which is as Ali said is a sign of very rich mixture . Leaky injectors can be one cause. That explains why your gas mileage is bad . You are throwing away fuel uselessly. Not everything is being burnt . Can also be a bad O2 sensor . The ECU injecting more fuel through the injectors because it is not receiving a good feedback from the O2 sensor if it is bad. There are a lot of other possible causes but it becomes a guessing game if you don't know the error code... so fix that damn CEL light
.I will PM you some info that can help you diagnose better why you have High HC and CO . A good number of causes but you don't want to be playing the guessing game . It can be an expensive game.
Last edited by gerrb; 12-16-15 at 04:51 AM.
12-16-15, 07:02 AM
#15
Johnny - go and fix that CEL bulb.. getting error codes if there are any , helps you better isolate the real problem part otherwise you will be on a guessing game which part is the real culprit . For any problem there maybe different parts that can cause it but with an error code , it will pinpoint or give you a better idea which part. May not always be foolproof but close to it.
Your Hydrocarbon and Carbon Monoxide exhaust gases are so high which is as Ali said is a sign of very rich mixture . Leaky injectors can be one cause. That explains why your gas mileage is bad . You are throwing away fuel uselessly. Not everything is being burnt . Can also be a bad O2 sensor . The ECU injecting more fuel through the injectors because it is not receiving a good feedback from the O2 sensor if it is bad. There are a lot of other possible causes but it becomes a guessing game if you don't know the error code... so fix that damn CEL light .
I will PM you some info that can help you diagnose better why you have High HC and CO . A good number of causes but you don't want to be playing the guessing game . It can be an expensive game.
Your Hydrocarbon and Carbon Monoxide exhaust gases are so high which is as Ali said is a sign of very rich mixture . Leaky injectors can be one cause. That explains why your gas mileage is bad . You are throwing away fuel uselessly. Not everything is being burnt . Can also be a bad O2 sensor . The ECU injecting more fuel through the injectors because it is not receiving a good feedback from the O2 sensor if it is bad. There are a lot of other possible causes but it becomes a guessing game if you don't know the error code... so fix that damn CEL light
.I will PM you some info that can help you diagnose better why you have High HC and CO . A good number of causes but you don't want to be playing the guessing game . It can be an expensive game.
Thanks!