JAndersson

Bought a program to my phone that makes it possible to measure the performance on the car with help of the internal GPS. The program is called Tempes GT and you find out more about it here: http://www.tempes.com/index.html

After I installed the program a went of to a abandoned military air field to do some performance test. First a tested the 0-100 kph (0-62mph) time. The best time a got was 10.3 which seems a bit slow. It should be at least 2 seconds faster. The TRC was of and it made no different if the ECT was in the normal or power mode. Even did some 70-130kph (44-81mph) test and the best time a got was 9,8 seconds. My best 1/4 mile time was 17,1 seconds which also seems a bit slow.

So what can be my problem? The car feels strong when I drive it as normal. But it's feels really slow from a standstill. From 3000 rpm and up it feels strong. The spark plugs and wires are recently changed. And I have a K&N replacement air filter that I cleaned and oiled today. Could it be a clogged fuel filter (going to be changed)? Or some problem with the fuel pump? Found a cheap OEM replacement on Ebay (http://cgi.ebay.com/ebaymotors/ws/eB...m=390039930365) , would it be worth it to change the fuel pump just to be sure or is it money just wasted. Or can it be some problem with the engine coolant temp sensor? But my lambda values was good (1.0) last time a tested my car at Swedish Motor Vehicle Inspection Co. in November.
Or worse, could it be some problem with the torque converter? Or something else.

/Joel

bkr300

could it be the system your testing with aswell?

JAndersson

Tested with a stopwatch too and got similar results.

PureDrifter

iTrader: (10)

if you have a first gen ls400 (89-94) then it's not tooo bad, those LS were factory overstated at ~7.9seconds 0-60, iirc it was tested to be ~8.1-8.5 in reality but can't find the link anymore.

JAndersson

Yes, have a -94 LS400 and I have also read that 8.5 second is a more true 0-100 time. Think I'm going to change the engine coolant temp sensor anyway just to see if that makes any difference. Seems that could be a solution to my problem after reading this thread: https://www.clublexus.com/forums/ls4...ange-pics.html

mark98ls40

Higher Altitude can make a big diff. also, although I don't know what altitude you're at.

JAndersson

Was about 100 meters above sea level so don't think thats the problem. Will try to change the fuel filter today. Wish me luck

PureDrifter

iTrader: (10)

check spark plugs and rotors too

JAndersson

The spark plugs was recently replaced so I don't think they are the problem but I guess it will not hurt to check. Have the parts to change the rotors and distributors but it seems to be a lot of work to do it according to lexls.com. How much do you really need to dissmantle to be able to change the rotors and distributors?

PureDrifter

iTrader: (10)

it's not that bad.

JAndersson

Haven't check the rotors yet because I couldn't figure out how do get the last cover of that is in front of the rotors without have to take out the cooler (as stated by Lexls.com)

But today i finally got the fuel filter changed. A long story short, it was hell of a mess and a lot of work. See my fuel filter change tread for more info:
https://www.clublexus.com/forums/ls4...-mistakes.html

But the fuel filter change restored quite a lot of the cars performance. The 0-100 kph time improved with almost one second. The car doesn't feels so slow from a standstill anymore. The next thing on my to do list is to change the engine coolant temp sensor (art. nr. 89422-20010)