jqzhang

I understand what you're saying and I agree. Now I'm going to the full length to have it done, taking your advice. I did have the link that you sent me, which is my guide for the project. I also have the detailed description from TIS (Tech. Information System) so I should be OK. Thank you very much for all your help.

Yes. It makes sense. I'll probably do it during the holidays. One more question for the 1990 one: the one with water pump problem. I am in the process of ripping it apart but one thing surprised me. The timing belt looks quite new. It must be replaced not too long ago (but not me). I guess they changed the belt not the water pump. My question is, can I replace the pump and leave the belt alone? It looks like I have to loose the belt before I have access to the pump. Thanks again.

No, my CEL is not lit yet since I stoppd driving the car after I heard the noise. If I kept driving, it would light up for sure. I agree with you about the re-routing stuff because you cannot beat the design of the car. I have a 96 Lancruiser too. There is slightly leaking in both converters because of rust. I tried welding using flux core wire (MIG welding machine). It is not working well: either burning the steel through or not enough penetration. Someone suggested using gas welding. I'm not sure. Any ideas about that? Of course, for the EGR pipe, I'd probably replace it with a new pipe. Thanks in advance.

Thanks for the quick return, and the tips too. They are going to be helpful. I did not know so many Toyota and Lexus models use the same water pump. Good to know. I read some posts saying that if the the leak is at the EGR pipe, the upper end of the pipe can be blocked or capped. The emission won't be affected so the car can still pass inspection no problem. Sounds hard to believe. What if the CheckEngine light might come on because the oxygen sensors might sense the change first. What would you think? Thanks again.

Hi, Hope you all is well. But bad luck for me. The 1995 one has a broken exhaust, probably EGR pipe but not sure since it's hard to detect. Any suggestions? For the 1991 LS400, coolant is leaking slightly from the bottom of crankshaft pulley. I am afraid the water pump is gone. Any someone confirm that? Because I don't want to go through the pain of replacing water pump, probably timing belt too, but end up with something that doesn't take me that far. I have a used part of water pump taken out from a 95 SC400, which can probably fit my LS400 of 91. If not, have to get a new one. Greatly appreciate it! jqz.

One more question. I changed the plugs about a couple of years ago using Bosch. I heard something negative about those plugs (I was trying to get some NGKs but they were out of stock). So what's so bad about Bosch plugs? Thanks in advance.

You probably right about it. But my question still is if replacement of the converters can make the exhaust smell better. I don't think they are clogged because there is no hesitation as long as the engine warmed up. Thanks.

Thanks Jaswood for the valuble tips. I'll certainly follow what you said and check it out. Have a good one.

Hi, Hope all is well with you guys. My 1991 LS400 cannot pass inspection. I bought a oxy. sensor from Ebay and replaced the old one since I had a trouble code indicating the sensor on the right bank had failed. It did not work: check engine light still on; another code tells me the fuel mixture is lean. I suspect the converters be gone because the exhaust really smells. I'm planning to buy a universal one that is cheap. In case it did not work, I'd only lose about $50. Would you think a bad oxy. sensor can cause bad smell of exhaust? I doubt it. I read some reviews. It looks like people change converters just to quiet down the noise instead of improving the emission. I'm confused. Noises come from bad exhaust pipes or mufflers, not converters. What would you think? BTW, the car has about 159K miles on it; newly rebuilt starter; 2 year old of radiator; another symptom: occasional missing when engine is hot, not very frequent; it may have something to do with lean mixture of the fuel, maybe converters. Thanks in advance.

Thanks. But I clean the throttle body and it did not solve the problem. I have to try something else. Thanks again.

Hi, I have a 1991 Lexus Ls400 with a mileage of over 150k. The problem is the engine misfire especially when it's hot, I mean after warming up. 1) the radiator is 2 or 3 years old, copper or brass; 2) newly changed thermostate valve; 3) newly rebuilt starter (pain in the neck job); 4) Check Engine light has been on for a couple of years: main oxy sensor at the right bank, replaced but the light won't go away; 5) converters are sort very old but doubt they will cause missing; 6) plugs and ignition wires 2 years old; 7) one of the ignition modules a few months old; 8) when doing 40M to 50M per hour, the car starts jerky. It feels like a tranny lock-up failure but at other speed range, it would be fine. Any suggestions? A mechanic told me it's sort of common for early model of LS400. My 95 LS400 behaves similar but not so obvious. When the engine misfires, it will get worse. Thanks in advance John Z.

It's because so many of us have dealt with the exact same problem on our gen 1 LS400's. Sometimes I wake up at night screeming "IT'S THE LEFT TRUNK HINGE WIRES!!! THERE'RE BROKEN!!! AHHHHHH!!!". The remote for opening the trunk is not working for a while. Does that have anything to do with the broken wires? If it does, how come it's still not working after the wires are fixed? thanks in advance.

It's because so many of us have dealt with the exact same problem on our gen 1 LS400's. Sometimes I wake up at night screeming "IT'S THE LEFT TRUNK HINGE WIRES!!! THERE'RE BROKEN!!! AHHHHHH!!!".

Python & fsuguy, I cannot help saying that you guys are incredible. Really, I mean it. Following you guys' comments, I have it fixed, even not completely. I don't know why but mine is slightly diff. from what you mentioned. I saw a picture that CUMan posted (I guess). It was a 12 pin female socket so you have to find out which wire is really broken. Mine is easier. About 5 or 6 wires covered by a black plastic box with the size of a small Bic lighter (too bad I don't have my camera handy). The broken wires are just right there for you to pick: a grey and a white. I said 'not completely' since the remote for trunk opening is still not working. I suspect there be some more broken wires that I haven't found yet. Don't you agree? But at least the weird response of tranny is gone and the shift-lights on the dashboard come back normal, thanks to you guys. I was curious, very much. How the heck you guys found out about the trunk wiring harness was the culprit? I believe most of the dealership won't be able to pin-point the problems either. They may go through the routine that I did: check the trouble code first. Then I would change the TPS for nothing, so would the dealership. Again, you guys are great! I really appreciate your help.

Thanks Python. I checked the trouble code. It's 41: TPS problem (probably ECU, but I'll take my chance of assuming ECU's OK). I guess I have both: the trunk harness and TPS. Don't you think so? Can I have some details about how to fix the trunk harness? Thanks again Python!

Hi, My 1991 LS400 started having problem yesterday, after I changed the drive belt. Here is the symptoms: 1) when driving, as I press brake pedal, the shift light on the dashboard lit up and the rest of the lights on the board are all gone; releasing the brake, all lights back to normal. 2) when shifting from N to D or from R to D or from P to D, it's rough but used to be smooth. But there is no problem accelerating and shifting for now. I'm going to check the code see any code coming up; also check the stop light switch. Hopefully the tranny is not dying. BTW, I checked the fluid too, it's pink and no bad smell. Thanks in advance.

Hi folks, I finally fixed the problem. Just take a wild guess about what really happened. I couldn't believe it until I found that out: one of the ignition coil went bad. I cleaned up all the fuel system like I said before but nothing improved. The next step was to check the electrical system. I was lazy so I started with the easy one: checking the sparks plugs. Before I took them out, I disconnected one of the ignition cable to see how the engine behavior changed with the engine running. As I tried the second one, the engine ran the same way with or without the ignition cable and it meant that cylinder not working I checked the 4 cylinders on the driver side and 2 of them not working, which means 2 of them on the other side also not working. The car has only 4 cylinders working and the other 4 are not. That's exactly why it felt the engine was so weak but running relatively stable. That's why I suspect the fuel might be OK because the engine wouldn't run stable if the fuel had a problem. I bought a coil at Pepboy at $40 and replaced the coil next day. Now the engine runs even better than before the replacement of the starter. But it's not over yet. The car failed emission check at a inspection station. Both HC and CO are too high, especially CO. The funny thing is that CheckEngine light is not always there. I used to have a trouble code 28; I checked again the other day, it turned out a 25: air and fuel mixture too lean. I believe it might partially cause the failure of inspection. I'll keep checking. One more question for you guys. The situation has nothing to do with the replacement of the starter. As I am doing 45 to 50 and trying to speed up, the car feels instant jerky. It feels like the tranny tries to lock up but fails. I don't think it's an engine problem. Does anyone have this kind of experience? Somehow, my 95 LS has slightly the similar feelings but not as obvious as the 91. Thanks again to all.

Hi folks, I finally fixed the problem. Just take a wild guess about what really happened. I couldn't believe it until I found that out: one of the ignition coil went bad. I cleaned up all the fuel system like I said before but nothing improved. The next step was to check the electrical system. I was lazy so I started with the easy one: checking the sparks plugs. Before I took them out, I disconnected one of the ignition cable to see how the engine behavior changed with the engine running. As I tried the second one, the engine ran the same way with or without the ignition cable and it meant that cylinder not working I checked the 4 cylinders on the driver side and 2 of them not working, which means 2 of them on the other side also not working. The car has only 4 cylinders working and the other 4 are not. That's exactly why it felt the engine was so weak but running relatively stable. That's why I suspect the fuel might be OK because the engine wouldn't run stable if the fuel had a problem. I bought a coil at Pepboy at $40 and replaced the coil next day. Now the engine runs even better than before the replacement of the starter. But it's not over yet. The car failed emission check at a inspection station. Both HC and CO are too high, especially CO. The funny thing is that CheckEngine light is not always there. I used to have a trouble code 28; I checked again the other day, it turned out a 25: air and fuel mixture too lean. I believe it might partially cause the failure of inspection. I'll keep checking. One more question for you guys. The situation has nothing to do with the replacement of the starter. As I am doing 45 to 50 and trying to speed up, the car feels instant jerky. It feels like the tranny tries to lock up but fails. I don't think it's an engine problem. Does anyone have this kind of experience? Somehow, my 95 LS has slightly the similar feelings but not as obvious as the 91. Thanks again to all.

Hi guys, Frankly, I'm almost on the verge of giving up. As a last resort, I might probably drive the car to the dealer and ask them to check it out using their computers. Let me tell what I did today. 1) I used a propane torch (as CuriousB suggested) to move around the areas of intake manifold, vaccum hoses, with the engine running. But the engine idle did not change a thing; 2) I filled the tank with 93 octane gas, with 1.5 bottles of Gas Treatment and dry gas, more than enough to dilute the water and other foreign stuff in the tank but it did not improve anything; 3) I tried OTC 4000 but the hand-held computer couldn't read the ECUs of the car; 4) what's even worse, I can tell there must be some coolant leaking somewhere because I saw some coolant in the front part of the engine valley. I checked the rear by-pass bolts but they were tight enough. As the engine is hot , there's some smoke coming out of the rear of the engine but it didn't smell coolant; Let me tell you more about the symptoms: as the engine idling, it's not quite precise to say 'rough' since it's quite stable but weak; I put my hand at the tailpipe and I can feel a quite stable and strong 'puff,puff,puff'; but normally I should feel the puff but not as strong as it is now. I'll keep checking, especially the fuel lines. Thanks again.

I did change Intake Chamber and Manifold gaskets ($40 for both bought from Pepboy) and re-tightened the bolts and nuts. About 1) yes, I did not hear any hiss but I'll use soap water to check it out; 2) I did not take out the ignition wires since I did not have to. I only removed the intakes, to change the starter; 3) yes, I'll double check even they were OK before changing the starter; 4) How? It's a 1991 LS400, and OBDII cannot be used... Right, you remind me. I have a OTC 4000 and it can do most of the cars older than 1994; 5) make sense; let me dump all the old gas first. Yesterday, I added one more bottle of Gas Treatment and it did not help; 6) I've done that. BTW, as I took apart of the intakes, I broke one of the filters of EGR VSV. I think it's just a filter and it won't cost this kind of engine problems. Thanks again.

Thank you all for replying. No, the error code has not come back yet. Looks like you folks argue it's more like a EFI problem. I'm not sure if I agree but I don't have evidence it's not. I suspect something wrong with ECU, maybe caused by the faulty oxy sensor. I have no problem starting the engine at all, either use the old battery or the newly bought one. But as the engine's running, you can feel it's weak. At the first time it started after the replacement, the engine ran very well. It speeded up as good as before. But it did not last long. Another possibility is the catalyst converters. Because as I tried to smell the exhaust from the tail-pipe, it did not smell the same as before but it's not like rotton eggs either. OK, I'll take you guys' advice and replace the rest gas and fill the tank with new, at the weekend. Thank you all again for involvement.

Thanks for replying. After a few times of trying, the engine finally started. It ran pretty well, at least as well as before replacing the starter, after adding 2 bottles of injector cleaner and one dry gas. However, after driving a few miles, the car started hesitating when speeding up. It will start fine but still hesitate as accelerate, not stalling. As it idles, it's kind of rough: I kept the door open putting my hand on top of the door, I can feel slightly shaking. One more symptom, before the starter change, it had error code of 28, the main oxygen sensor at the right bank. After the changing the starter, the check engine light is gone. I don't think the sensor back to normal without fixing. I suspect the ECU got confused which leads to the rough idling. What do you think? Thanks again.

I have a 1991 Lexus LS400 that won't start after replacing the starter. Say more about the car: the starter stopped working in Jan. 2009 because of the contact points are worn. BTW, it has 142,000 miles on it. The car was parked at a open space and it was too cold to work on changing a starter for a LS400. I guess you know how much pain to take to get the job done. Finally the starter was fixed (only changed the contact points) and re-installed. As I turn the ignition on, the starter will spin because you can see the cooling fan is turning and so is the timing belt (moving). But the problem is 1) it won't start; 2) I can hear the starter spinning but not cranking. I checked the plugs. Most of them are dirty so I cleaned them. They were wet too maybe because of the fuel dumped in the cylinders as I tried to start the car. So I removed the injection fuse. Still, not luck. I'm going to check the diagnosis code tomorrow see if any error code comes up. Any suggestions and hints are welcome. I am stuck here. Thanks in advance.

Its the length of the job compared to what you would normally expect. Most starters in other engine layouts are easily accessable, so to have to strip the whole intake system (which are very complicated, but thats why we love them) on these cars just to get to the starter motor, is very frustrating. Thats why I class it as hell. But if you are doing other work like cleaning the throttle body, check valves, replacing valve cover gaskets etc, and you were not pushed for time I am sure it could be a pleasant experience. You just need patience and time. I know it's been a while but I do need your help with removing the starter. I've taken off the Air Chamber, but I have a problem taking off the Manifold, which is under the Chamber and above the starter. It must be off before I can reach the starter. The problem is it won't come off. It feels like something is in the way but I cannot figure out what. BTW, the By Pass Join is on and I don't think it has much to do with the Manifold. So are the Injection Rails which are on the Manifold so I think I can leave them on. All 6 bolts and 4 nuts are off. I can lift the front of the Manifold about 1 inch from the Cylinder Head. But the rear only a one-tenth of a inch. Would you folks remember as you worked on the starter removal what's at the back, behind the Manifold but in front of the firewall? Would you think there may be an extra bolt that prevents me from taking the Manifold out? Thanks in advance. Have you removed the EGR pipe at the rear, the fuel pipe unions, the injector connectors and the two bolts which hold the black plastic loom cover to the inlet manifold ( see picture). Once you have the inlet manifold off the next problem is the rear coolant bridge as there is very little room to lift it off the studs as yet another plastic wiring loom cover sits above it but the loom cover is held in place with 4 bolts 2 at the rear of it near to the heater hoses and then 2 more going down on the driver's side, removing these bolts gives you a little more clearance to remove the bypass bridge. Ensure that the coolant is fully drained or you will fill the rear cylinders with coolant when you lift up the bypass bridge ( plug the holes as seen in the picture just in case) Thanks for replying. Yes, I disconnected the EGR pipe from the Instake, not removal since it's on one of the exhaust pipes; also the fuel pipe union and injector connectors; also the 2 bolts holding the engine wire (but still, the engine harness feels like secure. I didn't know it had 4 bolts). From the picture attached, I don't need to take off the bridge, do I? Because in the picture, you will have access to the starter with the bridge on the cylinder head. I'll try on the weekend and see what happens. Thanks again for your help.

Thanks a lot, AzHotLS, especially the pictures. I'll let you know if I make it. Take care.