gtolds

I have experience with two LS400 cars - a 1990 that ran perfect and a 1996 that idles too high when cold.

I know that they are similar but they do have differences.

I'm going to try to solve the 1996 problem and want your opinion before I touch anything.

I know there are atleast three temp sending units: one for the ecu, one for the guage, and one for the radiator fan.

I have measured the functionality of the sending unit for the ECU as follows:

4 ohms resistance at 43 degrees
3.8 at 47
2.75 at 61
1.83 at 81
1.37 at 98
1.05 at 110
.88 at 120
.57 at 145
.45 at 160
.30 at 195

I have only had the 1996 during this winter so the outside air temp has never been over 60 degrees.

Even at 60 degrees however, the cold idle is still 1500 rpm - too high for me - I would rather have 1000 or 1100.

How to get there s the question. Do I just jump the wires leading to my temp sender for the ecu with a 2 ohm or so resister?

I don't even know if that would work. I'm a simple man. Do I have to go after my Idle air control valve?

Do I have to do something else? I checked my TPS and it was tripping at just the right spot. The TRAC position sender was OK too - not that it has squat to do with the problem.

Let me know what you think of jumping the temp sending wires with a 1.5 ohm resister to make the car think it is never colder than 88 degrees or so and thus idle lower.

Thanks

PureDrifter

iTrader: (10)

it's supposed to idle higher when cold....pretty much all 95-97 LS i've seen do that.

MEANDAFAKA

^agree, i believe that all car would idle higher at cold wheather.

gtolds

I agree, it should idle higher when cold but 1500 rpm is too high. Question is what is causing this?

thanks

link13

The ECU is causing it. That's the correct cold idle speed. The 2JZ-E's cold idle is also about 1500 rpm, but in CA, it comes down pretty quickly.

MEANDAFAKA

then case is closed, lol.

PureDrifter

iTrader: (10)

what are you basing off to say that it's "too high"?

my old 95 idled cold between 1300-1500rpm too, here in socal, it just never lasted longer than 5minutes or so