SC400 Multiple issues
03-11-11, 08:49 PM
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SC400 Multiple issues
Hi guys,
I am having multiple issues with my SC4 that I was hoping to get some help resolving.
BACKGROUND INFO:
92 SC400 297K
NO LEAKS
BURNS A LITTLE OIL (NOT MUCH)
Completely stock
14mpg hwy
Everyday driver
Brakes and Suspension
Issue:
>Mushy brakes Air in the line maybe
>Shaking at 55 or above. (Tires are new)
>Rear inner tires wearing prematurely ( have subs/ amps/ box in trunk)
>When I step on the brakes the car shakes / can be felt in steering wheel
Recent corrective actions / Purchased parts:
>Wheel Alignment
>New Tires
>Control arms replaced
>Brake Booster / Master Cyclinder purchased today
>Rotors Cut
>Oem pads purchased
QUESTIONS:
1. What could be causing the wheels to shake at 55+ mph
2. When I install rotors, booster, master cyclinder etc is there anything else I should be do that will aid in complete resolution of the braking issue I am having?
3. I recently had a 4 wheel alignment done, but it seems that the rear tires are wearing prematurely. Could the added weight in my trunk be causing this?
Engine / Drive Train
Issues:
>Code 25 and Code 26 Air fuel ratio fault
>14Mpg Hwy
>When I shift to Drive there is a clunk sound sometimes
>Slight hesitation at low speeds
>Car starts to Jerk at exactly 45mph
>Poor Exaust smell (But passed emmisions with flying colors with check engine >light on)
>Car does not have the same power it had 6 months ago. (I can't even smoke >the wheels anymore)
>Tranmission cable broken where it meets the transmission, (Purchased new transmission cable not installed yet)
Recent corrective actions / Purchased parts:
>Fuel filter (replaced last week)
>Ignition Cap / Ignition Rotor (replaced last week)
>Starter / New Intake Gaskets (Replaced 6 months ago)
>Original MAF meter cleaned (No change)
>Used MAF meter cleaned and swapped (no change)
>Removed the egr and it was really a lot of exhaust build up where it meets >the intake. (Cleaned the hell out of it. (No change)
Additional Note:
>Check engine light sometimes will go off for a day or so but will return!!
>Broken Transmission cable (not completely broken just the outside housing >where it meets the transmission.
>When I am under the car with it running and I have someone shut it off it
sounds like a bolt dropping to the bottom of the transmission pan.
>I took my car to a local mechanic and he had a ODB1 scanner. While the car was running he pushed one end of a tube into a can of Seafoam and the other end into the intake and raised the rpms. while doing so he monitored the
status of the O2 sensors. He said they did not change at all and that was my issue. the sensors look to be original. I have not purchased because I want to make sure that this is def. my issue as they are not cheap you know..
Questions:
1. In regards to the air fuel ration issue I am having where should I start first?
Should I start looking at the egr system or the fuel system first?
2. In regard to the transmission cable could this be related to my issue of the
engine bucking at 45mph?
3. Is the slight hesitation at take off a completely different issue or is it tied
into something else?
thanks everyone, I know this is a lot of reading but any help would be awesome right now. I feel like I am throwing money at this issue and I do not want to do that.
I am having multiple issues with my SC4 that I was hoping to get some help resolving.
BACKGROUND INFO:
92 SC400 297K
NO LEAKS
BURNS A LITTLE OIL (NOT MUCH)
Completely stock
14mpg hwy
Everyday driver
Brakes and Suspension
Issue:
>Mushy brakes Air in the line maybe
>Shaking at 55 or above. (Tires are new)
>Rear inner tires wearing prematurely ( have subs/ amps/ box in trunk)
>When I step on the brakes the car shakes / can be felt in steering wheel
Recent corrective actions / Purchased parts:
>Wheel Alignment
>New Tires
>Control arms replaced
>Brake Booster / Master Cyclinder purchased today
>Rotors Cut
>Oem pads purchased
QUESTIONS:
1. What could be causing the wheels to shake at 55+ mph
2. When I install rotors, booster, master cyclinder etc is there anything else I should be do that will aid in complete resolution of the braking issue I am having?
3. I recently had a 4 wheel alignment done, but it seems that the rear tires are wearing prematurely. Could the added weight in my trunk be causing this?
Engine / Drive Train
Issues:
>Code 25 and Code 26 Air fuel ratio fault
>14Mpg Hwy
>When I shift to Drive there is a clunk sound sometimes
>Slight hesitation at low speeds
>Car starts to Jerk at exactly 45mph
>Poor Exaust smell (But passed emmisions with flying colors with check engine >light on)
>Car does not have the same power it had 6 months ago. (I can't even smoke >the wheels anymore)
>Tranmission cable broken where it meets the transmission, (Purchased new transmission cable not installed yet)
Recent corrective actions / Purchased parts:
>Fuel filter (replaced last week)
>Ignition Cap / Ignition Rotor (replaced last week)
>Starter / New Intake Gaskets (Replaced 6 months ago)
>Original MAF meter cleaned (No change)
>Used MAF meter cleaned and swapped (no change)
>Removed the egr and it was really a lot of exhaust build up where it meets >the intake. (Cleaned the hell out of it. (No change)
Additional Note:
>Check engine light sometimes will go off for a day or so but will return!!
>Broken Transmission cable (not completely broken just the outside housing >where it meets the transmission.
>When I am under the car with it running and I have someone shut it off it
sounds like a bolt dropping to the bottom of the transmission pan.
>I took my car to a local mechanic and he had a ODB1 scanner. While the car was running he pushed one end of a tube into a can of Seafoam and the other end into the intake and raised the rpms. while doing so he monitored the
status of the O2 sensors. He said they did not change at all and that was my issue. the sensors look to be original. I have not purchased because I want to make sure that this is def. my issue as they are not cheap you know..
Questions:
1. In regards to the air fuel ration issue I am having where should I start first?
Should I start looking at the egr system or the fuel system first?
2. In regard to the transmission cable could this be related to my issue of the
engine bucking at 45mph?
3. Is the slight hesitation at take off a completely different issue or is it tied
into something else?
thanks everyone, I know this is a lot of reading but any help would be awesome right now. I feel like I am throwing money at this issue and I do not want to do that.
03-14-11, 07:51 AM
#4
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+1 on the mounts... I had to replace the rear tranny mount as the entire bushing was gone... removed a LOT of noise.. And did the Engine mounts a few months before that.. as for the fuel issues etc.. I would agree probably bad O2's. And jerking at 45... mine does that once in a while if i keep it at a steady spot.. Haven't really figured that one out yet. Mine only does it like... ONCE in a while its not a constant. I was told once that it could have something to do w a loose bearing in the tranny? But have not seen any other problems, my tranny seems to be as good as ever. Hope this helps even a tiny bit.
03-14-11, 08:55 AM
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The shaking at 55+ and the shaking in the brakes, and even the poor gas mileage could very likely all be due to a seized caliper. Does the car pull to one side or the other when you're braking? Or were any of your brake pads worn prematurely more than the others? An easy to way to check is just lifting the wheel off the ground and spinning the tire. The fronts should have no resistance. These calipers are 4 piston, similar to those on a 4Runner and are infamous for seizing. I've seen this many times, and even had it on my own about a month ago
03-14-11, 11:03 AM
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Okay, thank you but that's not the important part. It really doesn't matter, just letting them know that that's a simple fix that accounts for multiple of the concerns. I agree with the mounts going bad for the clunking as well.
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03-14-11, 01:38 PM
#8
1JZ Single SC400
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The bucking could be the driveshaft center bearing.. It could be cracked or loose, or just plain worn out with the mileage. Also could be the mounts, motor and transmission.
The premature wear on tires is bushings or struts with strut mounts. They are a pain in the neck to change, the bushings, but the time is well worth the effort.
Shaking could be several things.. alignment, poor tire pressure, bad tie rod ends, inner or outer, and balljoints... Check all of these for play..
The codes readings are correct. Check the fuel filter again, the main 02 sensors, ignition system, coils, wires, plugs, water temp sensor... There is more to check, but let me know if you need more info..
Sorry so vague, but gives you an idea of what to check or recheck again.
Clean the IAC valve on the front of the motor. Ground it out and check it for a clicking sound, this means its working properly. PM me for more info... If needed..
Good luck
The premature wear on tires is bushings or struts with strut mounts. They are a pain in the neck to change, the bushings, but the time is well worth the effort.
Shaking could be several things.. alignment, poor tire pressure, bad tie rod ends, inner or outer, and balljoints... Check all of these for play..
The codes readings are correct. Check the fuel filter again, the main 02 sensors, ignition system, coils, wires, plugs, water temp sensor... There is more to check, but let me know if you need more info..
Sorry so vague, but gives you an idea of what to check or recheck again.
Clean the IAC valve on the front of the motor. Ground it out and check it for a clicking sound, this means its working properly. PM me for more info... If needed..
Good luck
03-14-11, 03:03 PM
#10
One of you sparks could be misfiring, causing a cylinder to not work? This would also result in a vibrtion at higher speeds. Maybe check your sparks first? As this is relatively easy and cheap to do. Then start looking at other more expensive fixes..
03-14-11, 05:44 PM
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Holy cow where to start. Ok the one item that jumped out at me. The clunking when you put it into drive. Had the same issue and it is in the transmission throttle cable adjustment. Now you said you have a broken transmission cable. If is is the same cable, the broken piece you were talking about is placing the cable out of adjustment. Ge that fixed and. Bet your engine clunking issue will disappear.
I have been trying to help another member diagnose the lean/rich malfunction. I can tell you that having this condition can point either to bad o2 sensors, a bad coolant temp sensor or both. You should test your o2 sensors with a volt meter. Let me know if you would like for me to post the testing procedure.
I think your bucking at 45 and slight hesitation issues are related. I am sure you have seen references to the fuel ECU modification on here. I can tell you from personal experience that if the fuel pump ECU stops working properly you will have hesitation issues and for some reason your o2 sensors will not read right. I tested my o2 sensors and they were stuck at 5 volts. Thats bad. Yo want to see a steady voltage fluctuation. If they are reading 0 or. 5 volts something is not right. I jumped my fuel pump to constantly run in high speed than checked my o2 sensors and again and found them reading properly.
So with all of that said. Get your transmission cable fixed first. Than jumper your fuel pump in the diagnostic connector and drive around for awhile to see if your hesitation/ bucking issues disappear. You might also find that your engine lean/ rich malfunction might be clear. I would still replace the o2 sensors. They are cheaper on rock auto.com. I jus bought the densos. Also you can replace your coolant temp sensor for under $30.
The shaking above 55 could be attributed to unbalanced wheels. When were your steering rack and sway bar bushings last changed.
I have been trying to help another member diagnose the lean/rich malfunction. I can tell you that having this condition can point either to bad o2 sensors, a bad coolant temp sensor or both. You should test your o2 sensors with a volt meter. Let me know if you would like for me to post the testing procedure.
I think your bucking at 45 and slight hesitation issues are related. I am sure you have seen references to the fuel ECU modification on here. I can tell you from personal experience that if the fuel pump ECU stops working properly you will have hesitation issues and for some reason your o2 sensors will not read right. I tested my o2 sensors and they were stuck at 5 volts. Thats bad. Yo want to see a steady voltage fluctuation. If they are reading 0 or. 5 volts something is not right. I jumped my fuel pump to constantly run in high speed than checked my o2 sensors and again and found them reading properly.
So with all of that said. Get your transmission cable fixed first. Than jumper your fuel pump in the diagnostic connector and drive around for awhile to see if your hesitation/ bucking issues disappear. You might also find that your engine lean/ rich malfunction might be clear. I would still replace the o2 sensors. They are cheaper on rock auto.com. I jus bought the densos. Also you can replace your coolant temp sensor for under $30.
The shaking above 55 could be attributed to unbalanced wheels. When were your steering rack and sway bar bushings last changed.
03-15-11, 10:00 AM
#12
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Do you recommend replacing anything else in conjunction with the mounts?
Holy cow where to start. Ok the one item that jumped out at me. The clunking when you put it into drive. Had the same issue and it is in the transmission throttle cable adjustment. Now you said you have a broken transmission cable. If is is the same cable, the broken piece you were talking about is placing the cable out of adjustment. Ge that fixed and. Bet your engine clunking issue will disappear.
I have been trying to help another member diagnose the lean/rich malfunction. I can tell you that having this condition can point either to bad o2 sensors, a bad coolant temp sensor or both. You should test your o2 sensors with a volt meter. Let me know if you would like for me to post the testing procedure.
I think your bucking at 45 and slight hesitation issues are related. I am sure you have seen references to the fuel ECU modification on here. I can tell you from personal experience that if the fuel pump ECU stops working properly you will have hesitation issues and for some reason your o2 sensors will not read right. I tested my o2 sensors and they were stuck at 5 volts. Thats bad. Yo want to see a steady voltage fluctuation. If they are reading 0 or. 5 volts something is not right. I jumped my fuel pump to constantly run in high speed than checked my o2 sensors and again and found them reading properly.
So with all of that said. Get your transmission cable fixed first. Than jumper your fuel pump in the diagnostic connector and drive around for awhile to see if your hesitation/ bucking issues disappear. You might also find that your engine lean/ rich malfunction might be clear. I would still replace the o2 sensors. They are cheaper on rock auto.com. I jus bought the densos. Also you can replace your coolant temp sensor for under $30.
The shaking above 55 could be attributed to unbalanced wheels. When were your steering rack and sway bar bushings last changed.
I have been trying to help another member diagnose the lean/rich malfunction. I can tell you that having this condition can point either to bad o2 sensors, a bad coolant temp sensor or both. You should test your o2 sensors with a volt meter. Let me know if you would like for me to post the testing procedure.
I think your bucking at 45 and slight hesitation issues are related. I am sure you have seen references to the fuel ECU modification on here. I can tell you from personal experience that if the fuel pump ECU stops working properly you will have hesitation issues and for some reason your o2 sensors will not read right. I tested my o2 sensors and they were stuck at 5 volts. Thats bad. Yo want to see a steady voltage fluctuation. If they are reading 0 or. 5 volts something is not right. I jumped my fuel pump to constantly run in high speed than checked my o2 sensors and again and found them reading properly.
So with all of that said. Get your transmission cable fixed first. Than jumper your fuel pump in the diagnostic connector and drive around for awhile to see if your hesitation/ bucking issues disappear. You might also find that your engine lean/ rich malfunction might be clear. I would still replace the o2 sensors. They are cheaper on rock auto.com. I jus bought the densos. Also you can replace your coolant temp sensor for under $30.
The shaking above 55 could be attributed to unbalanced wheels. When were your steering rack and sway bar bushings last changed.
I will follow you advice. As for the sway and rack bushings I am under the car now and the bushing is shot to hell... Good Call Brad !!!!!!!!
thanks a million
I will let you know how it goes..
thanks man...
Who are you telling!!!!!
The bucking could be the driveshaft center bearing.. It could be cracked or loose, or just plain worn out with the mileage. Also could be the mounts, motor and transmission.
The premature wear on tires is bushings or struts with strut mounts. They are a pain in the neck to change, the bushings, but the time is well worth the effort.
Shaking could be several things.. alignment, poor tire pressure, bad tie rod ends, inner or outer, and balljoints... Check all of these for play..
The codes readings are correct. Check the fuel filter again, the main 02 sensors, ignition system, coils, wires, plugs, water temp sensor... There is more to check, but let me know if you need more info..
Sorry so vague, but gives you an idea of what to check or recheck again.
Clean the IAC valve on the front of the motor. Ground it out and check it for a clicking sound, this means its working properly. PM me for more info... If needed..
Good luck
The premature wear on tires is bushings or struts with strut mounts. They are a pain in the neck to change, the bushings, but the time is well worth the effort.
Shaking could be several things.. alignment, poor tire pressure, bad tie rod ends, inner or outer, and balljoints... Check all of these for play..
The codes readings are correct. Check the fuel filter again, the main 02 sensors, ignition system, coils, wires, plugs, water temp sensor... There is more to check, but let me know if you need more info..
Sorry so vague, but gives you an idea of what to check or recheck again.
Clean the IAC valve on the front of the motor. Ground it out and check it for a clicking sound, this means its working properly. PM me for more info... If needed..
Good luck
thanks for the help!!
If you could would you tell me how to ground out the IAC. That would help tremendously....
Thanks for the offer to help...
The shaking at 55+ and the shaking in the brakes, and even the poor gas mileage could very likely all be due to a seized caliper. Does the car pull to one side or the other when you're braking? Or were any of your brake pads worn prematurely more than the others? An easy to way to check is just lifting the wheel off the ground and spinning the tire. The fronts should have no resistance. These calipers are 4 piston, similar to those on a 4Runner and are infamous for seizing. I've seen this many times, and even had it on my own about a month ago
+1 on the mounts... I had to replace the rear tranny mount as the entire bushing was gone... removed a LOT of noise.. And did the Engine mounts a few months before that.. as for the fuel issues etc.. I would agree probably bad O2's. And jerking at 45... mine does that once in a while if i keep it at a steady spot.. Haven't really figured that one out yet. Mine only does it like... ONCE in a while its not a constant. I was told once that it could have something to do w a loose bearing in the tranny? But have not seen any other problems, my tranny seems to be as good as ever. Hope this helps even a tiny bit.
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