Hello,

My 1995 LS400 has over 130k miles on it (I know, it's old but still too good to throw away). It's been running fine until lately. It's very hard to start when cold. But as long as it's started, everything is fine: fine idling, fine and peppy acceleration and so on. When the engine is turned off, it will be quite easy to start again, since it's already warm. I suspect that the fuel pump or fuel filter be probably the culprit. However, if something wrong with the fuel pump, the acceleration should be sluggish but it's not. This is weird.

When trying to start it cold, I will have a trouble code P0117 but not sure if the water temp sensor has anything to do with it. Some folks said it was obvious that the culprit was with the leaking of injectors. I eyeballed the fuel trail around and didn't see any moisture around the injectors. I guess I will replace the coolant sensor first and see what happens.

I am wondering if what happened to me probably have ever happen to you guys.

Before making further investigation, I need you guys advice about the situation.

Thanks in advance.

 

The coolant temp sensor could very well be the cause. If the car thinks it's colder than it is (or vice versa) fuel trims can be effected. Fuel trims bring off can cause plenty of issues.

Did it only set a p0117? No p0128?

 

Thanks for the quick return! No, I don't see the code of P0128.
It sounds silly but I cannot find the ECT sensor that I may have issues with. Let me send you a pic of the engine bay. One pic is the new sensor; the other is a part of engine bay.
Thanks again.

 

quick search:
https://www.clublexus.com/forums/ls-...ange-pics.html

 

Thanks for your input. I will try to replace the sensor today. It looks like the ECT sensor is hidding under the rail of ignition cables. I tried to find it on the 1995 Lexus LS400 repair manual (PDF file) but failed.

 

I replaced the ECT sensor but still no start. Cranking is fine but not start. Here is some new findings.

I suspect that the culprit might be of electrical. Then I picked one of the plug connected to the corresponding ignition cable. Then told me wife to start the car. Guess what, there was no spark at all. But the plug was pretty wet. It should be covered by fuel.
1) one or both coils might be bad;
2) or the ignition fuse can be bad too.
Please check the pics attached. Let me know what you guys think. I am not sure which fuse is the one that takes care of ignition. Please advise.
Thanks again.

 

Hello guys,

Still working on the issues that haven't been resolved yet. Please do me another favor: I still believe there is something wrong around the fuel pump. But, don't laugh at me please, I am too clumpsy to remove the backseat in order to access the pump. In another word, I need to remove the seat cushion, then seat back, before see the pump cover. Thanks in advance.

 

Your whole post is a guessing game.Why would it be fuse?starts when warm and does not start when cold and it could be fuse?Why are you behind the seat checking the fuel pump when you can test for pressure by the drivers side fuel line?No crank sensor code?When it doesnt start when cold check the ignitor for ohms and compare to the other.