Bradster

I have a 90 LS400 that i recently inherited and i'm working to get it in tip-top shape.I recently cleaned the throttle body (it needed it badly) and i'm not quite sure if i need to replace the TPS sensor (i'm not even sure what it is) can someone educate me on this and how do i know mine is functioning properly? I'm sure it's never been replaced.TIA to all!

Lextreme

Are you experiencing any problems? If not, dont worry about it.

bokomba

I can't really explain the function of the TPS but I'm sure about two things:
- firstly, the Check Engine light would come on if the TPS malfunctioned
- secondly, the car would hesitate when you accelerate as if the supply of gas is being restricted or being cut off / on, off / on.
The TPS would be very costly and is not a part that has a reputation of going bad anyhow.

Bradster

Thanks boko-i now know the symptoms of a malfunctioning TPS sensor and can happily report that mine seems to be fine @ 232K miles the A/C evaporator was another story but getting a new one from Steve at Carson Toyota along with an expansion valve assembly and receiver/drier (total of 400.00 about 20% off list) and local installation with a conversion to R-134 (275.00) i can now once again hang meat in my LS400!

97LS400

Bradster... you should be aware that when you change your R12 system to R134 it will lose about 10% efficiency. Your shop should have warned you about that up front. Your AC will still work just fine but you can feel the difference losing 10% of the cooling ability.

This occurs because R134 is less efficient than R12. The new (R134) systems were designed for R134 specifically and the normal manufacturer fix was to increase the size of the condensor and evaporator to make up the difference.

That said, I would still make the change. R134 is a lot cheaper to repair in the future and now (when you are replacing major AC parts) is the best time to make the change.

Bradster

I went back and forth with myself as to whether make the conversion.The shop said either going to R-134 or staying with R-12 would be the same price and of course people i asked were on both sides of this debate.The shop did say they've converted several LS400's and have had no complaints.I'm not really a big A/C fan as i do prefer fresh air (living close to the ocean helps out in that respect-nice cool breezes) and i personally (most likely) would not be affected by the 10% decrease in efficiancy (sp) of the 134 system.