clacey

I have a 91 LS 400. The Freon has leaked out. I took it to a shop and they did a quick scan with a UV light under the hood but found no leaks. He said that he could smell freon inside the car and thought it was leaking there.

My Question:

Is there any particular place inside the car that is prone to leaking?

Since the Freon is gone, can I service it myself and take it to someone to refill it with R12? I have done a lot of work on the car so I am very mechanically inclined but don't have the evac equipment. The freon window under the hood has nothing in it.

Thanks for your input.

CL

Thanks again for the post. I checked my wire but it is fine. are there any other gounds that I can check? If so, where might I find them? The issue seems to be linked to the brake lights or brake switch. All of the lights dim when the brake lights come on. It can be running or completely turned off and it still does it.

Thanks,

CL

That would be F A N T A S T I C!

Thanks,

CL

I have a 91 LS400 that does a similar thing. My lights do not go completely out, but they dim when I step on the brake and I hear the same clicking sound in the shifter. I would definately like to know what the problem is as well.

CL

What year is your car and how many miles has it been driven.

I have a 1991 LS400 with 213000 miles that was getting bad mileage like this (about 10 miles per gallon) and here is what I replaced:

air filter

spark plugs

distributor caps and rotors

front oxygen sensors

and cleaned the intake housing

The intake cleaning helped a lot. It was very dirty and I found that the Pipe going into the egr valve from inside the housing was almost completely clogged.

Fuel economy is back to normal.

CL

Have you done anything to the car lately (repairs). If so it may just need to be reset. Mine came on after I did a power steering repair. I had arched a wrench across my alternator terminal and blew the alternator fuse. It somehow afected my airbag light. I reset it and all is well. Check the fuses first. mine is a 91 LS as well. Do a search on it in the forums and you will find the reset proceedure. It's where I figured it out.

CL

Thanks a ton for taking the time to post these.

Am I correct in assuming that the system should stay pressurized when turned off?

Thanks,

CL

I have a 91LS400 with 213000mi. I am wondering how the fuel systems works. My fuel system seems to be loosing pressure as it sits with the engine off.

Is this normal or should the system stay pressurized after the ignition is off?

The car takes about 4 secs to start for the first time, if it has set overnight. Otherwise, it starts immediately.

If it is supposed to stay pressurized, What could be allowing it to disipate? The fuel pressure regulator or the fuel pump?

If it isn't supposed to stay pressurized, could the fuel pump be getting weak or could the fuel pressure regulator be out of spec?

Other than this there are no visible leaks and the car runs great.

Can anyone help? Class? Anyone?

Thanks,

CL

Whseeeew. :D I found it. It blew the 120 fuse under the hood.

Thanks for your responses.

CL

A fuse would be good.

I know it isn't working because I decided to check the voltage at the battery (knowing I sparked it) and it read 9 volts just seconds before it started to die.

Thanks,

CL

I was messing around with my 91 LS400. I forgot to unhook the - cable on the battery. I touched the alternator with the wrench and it sparked. I just cranked the car and the alternator is not working.

Does this thing have a fuse or something or am I going to have to replace the whole thing. I not sure where the wrench touched it.

I guess I wont forget to remove the neg cable next time.

Any input?

Thanks,

CL

I just pulled mine out. Are you talking about the little flat ones on the plunger inside the valve? Those aren't your typical round o-rings. Where would I get those? The plunger in mine just fell out. I suppose it (the o-rings) should be tighter than that?

Thanks,

CL

The throttle body is the top part or layer of the engine. It proudly displays the Lexus badge. The air filter element connect into it. I bought some Carb and choke cleaner and some shop rags. I chose to remove mine. It takes about an hour. There is a post on here somewhere that shows how to clean it without removing it. I only removed mine to check the cold start injector which is in the bottom of the intake assembly.

CL

Mine has the same problem. Where is this pressure switch and it's o-rings?

Thanks,

CL

You might trya good throttle body cleaning. Mine has 213,000 mi and everything was really gunked up, including the cold start injector.

CL

I checked my injectors yesterday and they were not leaking. I wonder if it could be the fuel pressure regulator.

CL

I have had, what I thought was a "cold start" issue with my 91 LS400. I've tested many of those components and all is well.

I now believe it is a fuel issue. Here is the deal:

The time it takes to crank seems to be related to the amount of time the car has been sitting.

Example:

If the car sets overnight, it takes about 3-4 secs to start in the morning.

If the car sets several days, it might take 6 secs to start the next time.

Once you start it, for the first time in the morning, you can immediatly kill the engine and it will start immediately all subsequent times.

It seems as though the fuel system, very slowly looses pressure over time, as the car sits. There is no gas visibly leaking under the car. The only other thing I noticed is that the evap canister is rusting and it smell like gas. I'm not sure if that could have anything to do with it.

Anyone have a clue? I don't think the injectors are leaking. Is this something I can test? Does the fuel system stay pressurized when the engine is off?

Thanks,

CL

I'm Curious. What does the evap canister do? I have a 91 LS400 and the canister is rusting on the bottom and it smells like gas. What's up?

Thanks,

CL

The cold start injector is attached into the under side of the intake assembly. You can see it by opening the throttle and looking into the intake. it looks like a 2" long 1/4 " rod comming up from the bottom of the housing. It sprays fuel in two directions (front and back) to add extra fuel upon cold startup. It should spray 2 perfect cones of fuel and not leak when it is disengaged.

Now go forth and be enlightened. :D

CL

Yeah. I don't have a lift so I had no manuverability from the bottom. If you could get it off the ground, I suspect it would be easier to come from below. Coming from the top isn't fun but it is possible.

CL

I don't think that there is a major issue. They might be just sticking a little (judging by the gunky condition of the intake) but I hear that #5 & #7 are prone to need some shimming with time and mileage. It's not really loud I'm just being anal. If I were not going to replace the valve cover gaskets, I probably wouldn't worry about it.

CL

Yeah, it's not very thick there. That's why I used a small torch and brazed it. Of course, both of my cracks were located in the recesses of the "accordian" area, which makes it a little more challenging. Even with the torch, I did blow a small hole in it but I was able to fill it in. Just be careful with the heat. I don't think that I would weld it with a regular welding machine. It would probably blow a hole in it. Unless you are better at welding than I, which isn't saying much.

My logic to braze it rather than replace it was this:

I suspect that they crack due to the fact that they stay under constant stress and tension when bent into place and bolted along with vibration. when they finally crack, the stress and tension is relieved. By brazing it, it stays in the relaxed state and you just fill in the holes. Less likely to break again because it has already relieved the stress. With a new one, you would bend it which would add tension and it will crack again with some time.

Any input or comments regarding this logic? Does it seem solid?

I guess if the braze doesn't hold, I can just replace it. It wont be the end of the world.

CL

It took about 30-45 min. The whole process took about 3 hrs but most of that was cleaning. My fuel economy has really gone way up. Which is a good thing since the cost super unleaded is like buying jet fuel these days. My fuel exonomy was way down to about 12 mpg if I were to guess. I'm going to test everything else that the book says test over the weekend. Since the EGR system was essentially clogged, I need to check the valve to see if it is operating correctly. I also suspect that my #5 & 7 valves are off as well (tapping). I need to change a couple of valve cover gaskets so I'll check those valves (adjust if needed) and clean that out before too long as well.

This repair was definately worth the time as well as the $5.00 spent on spray cleaner and shop rags.

I'll update the post as I do things and let everyone know what helps.

CL

My EGR (92 year mod) is not stainless. It's regular steel. It took the weld with no problems.

Pipe Wall Thickness: I'd say that the pipes wall thickness is about 1/16" it thins to about 1/32" in the bendable area which is, of course, where they break.

CL

I believe that you are correct and I think that you could but it seemed to work a little better for me to go at it from the top. I might try to re-install the center bolt from the bottom as JPI mentioned. I'll let everyone know if it works better.

CL