SC 400 Starter Motor Removal
05-07-17, 02:18 PM
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Alright, I finally got back to the car yesterday after a long absence (I had a lot of other stuff going on and set this project aside for a while). I finished the job this morning - I was able to rebuild the starter in place. The car starts (yay!), but I have encountered a new issue - a rough idle. The engine shakes and sounds lopey, almost as if I have a higher-lift cam installed. I let the car warm up fully and drove it a bit, but the rough idle remains. The problem only occurs at idle, as the engine runs smoothly if I rev it to 1200-1400 rpm and above. I have double and triple-checked that everything is plugged in. There is no check-engine light. Does anyone have any ideas as to what may be the cause?
It is worth noting that the connection between the PCV hose and the intake resonator broke during the job, which I "repaired" with some high-temperature electrical tape. I do not understand how this could cause a rough idle except maybe through some small vacuum leak.
It is worth noting that the connection between the PCV hose and the intake resonator broke during the job, which I "repaired" with some high-temperature electrical tape. I do not understand how this could cause a rough idle except maybe through some small vacuum leak.
05-07-17, 05:58 PM
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Problem Solved: Starter Removal: What I Learned
Update: The previously mentioned rough-idle problem has disappeared; the car behaves as normal. I can only speculate as to what caused it; perhaps the timing was somehow off after the first post-reassembly start. At any rate, the car is now running faultlessly. Thank you to everyone who assisted me throughout this process.
For future reference by others, here is a list of problems I encountered and things I learned during my starter rebuild process:
1. Be VERY careful of the myriad plastic clips on sensors, connectors, etc. Throughout the many heat cycles over the life of the car, the plastic becomes quite brittle and easily snaps. If you need to use pliers to remove some of the plastic clips (some of them are very stiff and may require more than just your fingers), use wide-mouth pliers to spread out the force as much as possible. If you do break some, I suggest getting some high-temperature electrical tape - regular electrical tape will melt.
2. Be wary of the connection between the right-side PCV hose and the intake resonator. The PCV hose and the plastic nipple on the resonator to which it attaches may be have practically bonded together over time due to heat, and will thus be difficult to separate. If you try to remove the PCV hose from the intake resonator, it is likely that the plastic nipple will break - mine did. I suggest detaching the PCV hose from the bottom (where it connects to the engine) and leaving it attached to the intake resonator at the top, removing both together. This applies only to the VVT-i version.
3. If you do break the plastic nipple on the intake resonator (as I did) and choose to replace it, do NOT use an intake resonator from a GS 400 on the SC 400. I learned this the hard way after I took an intake resonator from a salvaged GS 400 to replace mine. I was previously under the impression that the resonator was the same on all the LS 400/GS 400/SC 400 VVT-i cars, which is not the case. I do not know about the LS 400, but the resonators on the GS 400 and SC 400 are not interchangeable. They may look the same, but they are not.
4. On the left side of the engine above the fuel rails is a large collection of wires which make it very difficult to access the fuel rail bolts and the lower intake bolts. Adjacent to these wires is a large metal thing (I do not know the correct term) which is attached to the cylinder head. I suggest lifting the wires up and over this metal thing and placing them on the other side of it, which keeps them out of the way. Although this is not necessary, it does make accessing the left-side fuel rail and lower intake bolts much easier.
5. Others will disagree, but I recommend leaving the starter mount in place for this job, at least on the VVT-i models (I can't speak to the earlier cars, which have different water/coolant and EGR passages which may or may not make this job more difficult). The rear-access 14mm bolts which hold the mount in place are extremely difficult to remove, and I personally found it easier to just work on it in-place.
6. If you choose to leave the starter mount in place, you will need to remove the starter motor itself in order to access the contacts. Unlike the LS 400 in which the water passage through the valley of the block passes along the right side, the SC 400's water passage zig-zags from left to right, which leaves very little room to pull the motor out. Consequently, you may need to disassemble the starter motor in order to remove it, so be aware of that.
7. If leaving the starter mount in place, the right-side contact is very easy to remove and replace. On the left side, however, there is very little space in which to work. When removing the 12mm nut for the left-side contact, do NOT go from the top - the wire terminal above it (which cannot be removed) requires you to place the wrench at an angle, which prevents you from getting a proper grip and will cause you to round the bolt. Go from the front instead. The same goes for the 14mm nut.
8. Replace both contacts, even if one appears in much better shape than the other. A very close tolerance (1mm) in the thickness of the two contact plates is required for proper functioning, and if you replace just one, you will need to replace the other in short order. The previous owner of my car replaced only one of the contacts, thinking that the other one looked okay, and sure enough I have had to do this just 14,000 miles later. Replace both of them.
9. Last but not least, replace the plunger as well. Some people overlook this, but the plunger wears just like the contact plates do, and replacing the plunger at the same time will help it to last longer.
So that is what I learned in the process of replacing my starter contacts. Hopefully this helps someone.
For future reference by others, here is a list of problems I encountered and things I learned during my starter rebuild process:
1. Be VERY careful of the myriad plastic clips on sensors, connectors, etc. Throughout the many heat cycles over the life of the car, the plastic becomes quite brittle and easily snaps. If you need to use pliers to remove some of the plastic clips (some of them are very stiff and may require more than just your fingers), use wide-mouth pliers to spread out the force as much as possible. If you do break some, I suggest getting some high-temperature electrical tape - regular electrical tape will melt.
2. Be wary of the connection between the right-side PCV hose and the intake resonator. The PCV hose and the plastic nipple on the resonator to which it attaches may be have practically bonded together over time due to heat, and will thus be difficult to separate. If you try to remove the PCV hose from the intake resonator, it is likely that the plastic nipple will break - mine did. I suggest detaching the PCV hose from the bottom (where it connects to the engine) and leaving it attached to the intake resonator at the top, removing both together. This applies only to the VVT-i version.
3. If you do break the plastic nipple on the intake resonator (as I did) and choose to replace it, do NOT use an intake resonator from a GS 400 on the SC 400. I learned this the hard way after I took an intake resonator from a salvaged GS 400 to replace mine. I was previously under the impression that the resonator was the same on all the LS 400/GS 400/SC 400 VVT-i cars, which is not the case. I do not know about the LS 400, but the resonators on the GS 400 and SC 400 are not interchangeable. They may look the same, but they are not.
4. On the left side of the engine above the fuel rails is a large collection of wires which make it very difficult to access the fuel rail bolts and the lower intake bolts. Adjacent to these wires is a large metal thing (I do not know the correct term) which is attached to the cylinder head. I suggest lifting the wires up and over this metal thing and placing them on the other side of it, which keeps them out of the way. Although this is not necessary, it does make accessing the left-side fuel rail and lower intake bolts much easier.
5. Others will disagree, but I recommend leaving the starter mount in place for this job, at least on the VVT-i models (I can't speak to the earlier cars, which have different water/coolant and EGR passages which may or may not make this job more difficult). The rear-access 14mm bolts which hold the mount in place are extremely difficult to remove, and I personally found it easier to just work on it in-place.
6. If you choose to leave the starter mount in place, you will need to remove the starter motor itself in order to access the contacts. Unlike the LS 400 in which the water passage through the valley of the block passes along the right side, the SC 400's water passage zig-zags from left to right, which leaves very little room to pull the motor out. Consequently, you may need to disassemble the starter motor in order to remove it, so be aware of that.
7. If leaving the starter mount in place, the right-side contact is very easy to remove and replace. On the left side, however, there is very little space in which to work. When removing the 12mm nut for the left-side contact, do NOT go from the top - the wire terminal above it (which cannot be removed) requires you to place the wrench at an angle, which prevents you from getting a proper grip and will cause you to round the bolt. Go from the front instead. The same goes for the 14mm nut.
8. Replace both contacts, even if one appears in much better shape than the other. A very close tolerance (1mm) in the thickness of the two contact plates is required for proper functioning, and if you replace just one, you will need to replace the other in short order. The previous owner of my car replaced only one of the contacts, thinking that the other one looked okay, and sure enough I have had to do this just 14,000 miles later. Replace both of them.
9. Last but not least, replace the plunger as well. Some people overlook this, but the plunger wears just like the contact plates do, and replacing the plunger at the same time will help it to last longer.
So that is what I learned in the process of replacing my starter contacts. Hopefully this helps someone.
03-04-19, 06:52 PM
#33
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sc400 starter replacement without special tools
This thread is incorrectly titled, you never actually removed the starter motor as a complete unit.
This thread should be titled "How to disassemble SC400 starter without removing it".
Correct, I agree with your statement "Others will disagree", 100%.
I completely disagree with "leaving the starter in place"!.
It is my opinion that in order to properly rebuild and "bench test" a starter, you must, and actually have to remove it. Your not saving anything, specially your back!
I just finished removal of a starter in a 1992 SC400, using the following:
- I accomplished removing starter bolts with a regular 3/8" ratchet
- passenger side used a 14mm deep, and driver side a 14mm short socket
This thread should be titled "How to disassemble SC400 starter without removing it".
5. Others will disagree, but I recommend leaving the starter mount in place for this job, at least on the VVT-i models (I can't speak to the earlier cars, which have different water/coolant and EGR passages which may or may not make this job more difficult). The rear-access 14mm bolts which hold the mount in place are extremely difficult to remove, and I personally found it easier to just work on it in-place.
.
.
I completely disagree with "leaving the starter in place"!.
It is my opinion that in order to properly rebuild and "bench test" a starter, you must, and actually have to remove it. Your not saving anything, specially your back!
I just finished removal of a starter in a 1992 SC400, using the following:
- I accomplished removing starter bolts with a regular 3/8" ratchet
- passenger side used a 14mm deep, and driver side a 14mm short socket
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