Question about 1990 Lexus LS 400

1 Answer

I have a 90 Lexus 400 LS, when engine is cold it idles on regula 1500rpm. When it warms up it drops to normal rpm. But if i turn it off for more than thirty minutes, it idles back to 1500 rpms and it takes 5 minutes to drop to normal. If i dont wait the 5 minutes and i drive off, it runs on 1000 rpms for about 1 mile, and it makes it hard to brake on red lights because it forces the car to go. After that 1 mile it drops to normal.

Posted by on

Ad

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Master
  • 4,803 Answers

You need to test your Engine Control Unit (ECU) for fault codes.
This could be caused by several things:
- Coolant Temperature Sensor or circuit
- Intake Air Temperature Sensor or circuit
- A/C Signal circuit
- Power Steering Pressure sensor or circuit.
- Neutral Start Switch circuit
- Throttle Position Sensor or circuit
- Idle Control Valve or circuits
- ECU

You can check fault codes by placing a jumper between terminals E1 and TE1 in the check connector.
(See pictures below) Turn the ignition switch on and count the flashes of the Check Engine light.

If it flashes 2 times every second, this is normal (No codes present). If a fault code is present, the first group of flashes is the first digit in the 2-digit code. There will then be a 1.5 second delay and the second digit will be output. If there is more than 1 code present, there will be a 2.5 second delay, then the nexy code will begin tobe output.
It is recommended that you read the codes (flashes) several times to make sure you are reading them correctly.




I have a 90 Lexus - dttech_86.gif

dttech_87.gif

Posted on May 21, 2011

Ad

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of.(from cars to computers, handyman, and even drones)
click here to download the app (for users in the US for now) and get all the help you need.
Goodluck!

Posted on Jan 02, 2017

Ad

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Fast idle cold to hot


to fast hot and too fast cold that it?
well here is normal, its a G16 engine, a Vitara with Sidekick badge.
G16 in cold weather, start and race idle at about 1500 rpm
or more if in ALASKA, you never said that or how cold it is.
the IAC valve is thermal, it and opens more colder, a fact.
the 8valve engine (black steel top) is faster. cold idle
then drops in a few seconds, to 1500rpm
at this time, the ECU brain does NOT control idle speeds at all.
the the engine warms up by virtue of the thermostat
as it warms to 150F to on way to 180f stock temp.
the ECU then takes control of the idle speeds.
got that so far?
so at 180f the idle is 800 rpm (800 is hard coded in the ECU,
ad ECU regulates this, unless you turn on the A.C , and if that happens 1000rpm is called up.
if not the ECU cant control it or the ECU is in limphome mode or worse.

if you insert the diagnostic jumper
does the CEL lamp flash 12s
it must.
see this paper clip this is your only scan tool.
it is crude but that is all you get until 1996.

http://www.fixkick.com/CEL/CEL.html#OBD1codes


Jan 04, 2017 | 1993 Suzuki Sidekick

1 Answer

Toyota corolla hatch 2002 idle at 2000 rpm when


All the above is normal , except 2000rpm is a little high at idle . can be adjusted down to 1500rpm. the computer adjusts the engine speed . in drive the transmission loads up the engine idle drops to 1000rpm . in park engine unloaded rpm increase all normal.

Sep 17, 2014 | Cars & Trucks

1 Answer

I have a 2008 mercury Milan with nearly 60k miles on it. When I come to a stop the rpm drops by 1000 then recovers quickly. What should I do to fix the problem? Any suggestions will be greatly appreciated.


Check out related help links to troubleshoot these problem:----Click the link below:---Idles Fine but RPM jumps in drive mode? http://technoanswers.blogspot.in/2012/07/idles-fine-but-rpm-jumps-in-drive-mode.html
---------Mitsubishi Lancer rpm needle bounces? http://technoanswers.blogspot.in/2012/02/mitsubishi-lancer-rpm-needle-bounces.html
--------How to adjust rpm on 2009 dodge charger SRT8?


http://schematicsdiagram.blogspot.com/2011/12/how-to-adjust-rpm-on-2009-dodge-charger.html
---------
Engine cuts out at 3000 RPM? http://schematicsdiagram.blogspot.com/2011/12/engine-cuts-out-at-3000-rpm.html

---------

Cold start problem and vehicle shudder around 2500 to 3500 rpms
http://repairhelpcenter.blogspot.com/2012/10/cold-start-problem-and-vehicle-shudder.html

---------
High rpm in neutral? Inconsistant high RPM in neutral? http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html

-----------
Jetski Sputters and Low RPM? http://whatisbyme.blogspot.in/2012/07/jetski-sputters-and-low-rpm.html

--------
Fuel Injection Problem And RPM suddenly increases http://whatisbyme.blogspot.in/2012/07/fuel-injection-problem-and-rpm-suddenly.html

----------
2005 Toyota Highlander: Engine runs hard RPM below 3000? http://whatisbyme.blogspot.in/2012/05/2005-toyota-highlander-engine-runs-hard.html

---------
1987 Toyota Camry: RPM Drops going Up hills? http://whatisbyme.blogspot.in/2012/05/1987-toyota-camry-rpm-drops-going-up.html

-----------
Cruise Control stops working, Excessive cranks to start the engine and RPM goes max 2500 http://whoisbyme.blogspot.in/2012/07/cruise-control-stops-workingexcessive.html

----------
1990 Toyota 4Runner: Engine cuts off when reaches 2000 RPM?


http://whatisbyme.blogspot.in/2012/05/1990-toyota-4runner-engine-cuts-off.html

------------
1999 Toyota Camry: Erratic stalling and high engine RPM at idle?


http://whatisbyme.blogspot.in/2012/05/1999-toyota-camry-erratic-stalling-and.html

---------
1995 Toyota LS: Misfire at idle or low RPM http://whatisbyme.blogspot.in/2012/04/1995-toyota-ls-misfire-at-idle-or-low.html

-----------
Lexus RX: Tapping noise under Valve Cover At Low RPM? http://technoanswers.blogspot.in/2012/04/lexus-rx-tapping-noise-under-valve.html

----------
These will help.
Thanks.

Nov 22, 2012 | Cars & Trucks

1 Answer

Driving on the road the RPM goes higher wituout speedind


Check out related help links to troubleshoot these problem:----Click the link below:---Idles Fine but RPM jumps in drive mode?http://technoanswers.blogspot.in/2012/07/idles-fine-but-rpm-jumps-in-drive-mode.html
---------Mitsubishi Lancer rpm needle bounces?http://technoanswers.blogspot.in/2012/02/mitsubishi-lancer-rpm-needle-bounces.html
--------How to adjust rpm on 2009 dodge charger SRT8?


http://schematicsdiagram.blogspot.com/2011/12/how-to-adjust-rpm-on-2009-dodge-charger.html
---------
Engine cuts out at 3000 RPM?http://schematicsdiagram.blogspot.com/2011/12/engine-cuts-out-at-3000-rpm.html

---------

Cold start problem and vehicle shudder around 2500 to 3500 rpms
http://repairhelpcenter.blogspot.com/2012/10/cold-start-problem-and-vehicle-shudder.html

---------
High rpm in neutral? Inconsistant high RPM in neutral?http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html

-----------
Jetski Sputters and Low RPM? http://whatisbyme.blogspot.in/2012/07/jetski-sputters-and-low-rpm.html

--------
Fuel Injection Problem And RPM suddenly increaseshttp://whatisbyme.blogspot.in/2012/07/fuel-injection-problem-and-rpm-suddenly.html

----------
2005 Toyota Highlander: Engine runs hard RPM below 3000?http://whatisbyme.blogspot.in/2012/05/2005-toyota-highlander-engine-runs-hard.html

---------
1987 Toyota Camry: RPM Drops going Up hills?http://whatisbyme.blogspot.in/2012/05/1987-toyota-camry-rpm-drops-going-up.html

-----------
Cruise Control stops working, Excessive cranks to start the engine and RPM goes max 2500 http://whoisbyme.blogspot.in/2012/07/cruise-control-stops-workingexcessive.html

----------
1990 Toyota 4Runner: Engine cuts off when reaches 2000 RPM?


http://whatisbyme.blogspot.in/2012/05/1990-toyota-4runner-engine-cuts-off.html

------------
1999 Toyota Camry: Erratic stalling and high engine RPM at idle?


http://whatisbyme.blogspot.in/2012/05/1999-toyota-camry-erratic-stalling-and.html

---------
1995 Toyota LS: Misfire at idle or low RPMhttp://whatisbyme.blogspot.in/2012/04/1995-toyota-ls-misfire-at-idle-or-low.html

-----------
Lexus RX: Tapping noise under Valve Cover At Low RPM?http://technoanswers.blogspot.in/2012/04/lexus-rx-tapping-noise-under-valve.html

----------
These will help.
Thanks.

Nov 22, 2012 | 2008 Toyota Avalon

1 Answer

Idle drops form 900 to 300 rpm at stops & hesitation at speeds over 2000 rpm


Could be a throttle position sensor, or a myriad of other things related to the ignition, timing, spark plugs ... maybe the engine needs a complete tune up.

Dec 23, 2010 | 1992 Lexus Ls 400

1 Answer

Error code po0117. Vw beetle


16501/P0117 - Engine Coolant Temperature Sensor (G62): Signal too Low Possible Symptoms
  • Difficulties with starting a cold engine.
  • Starting the engine when engine is warmish or warm, idle rpm immediately is 1200 - 3000 rpm.
  • RPM at idle is irregular.
  • With all engine temperatures seldom idle rpm will vary between 900 - 1000 rpm.
  • With engine warm (90 °C) the engine temperature suddenly drops (70 °C) and slowly comes back to 90 °C.
  • Bad acceleration during warming up.
    • Diesel: an indication is extreme long time burning time of the glow indication light.
Possible Causes
  • The electrical signal coming from G62 is too low
  • Wiring and/or connections faulty (short circuit?)
  • Engine Coolant Temperature Sensor (G62) faulty
Possible Solutions
  • Check wiring and connections
  • Check / Replace Engine Coolant Temperature Sensor (G62)
Special Notes
  • In MY 1995-2002 (?) in Europe at VW-cars the G2/G62 had the bad reputation of breaking down often. The default G2/G62 is black and all replacements are green.

Mar 21, 2010 | 1999 Volkswagen Beetle

1 Answer

The check engine light on a 2001 beetle read code PO118 engine coolant temperature circuit high input. what do i do?


16502/P0118/000280 From Ross-Tech Wiki Jump to: navigation, search Contents [hide] if (window.showTocToggle) { var tocShowText = "show"; var tocHideText = "hide"; showTocToggle(); } 16502/P0118/000280 - Engine Coolant Temperature Sensor (G62): Signal too High Possible Symptoms
  • Difficulties with starting a cold engine.
  • Starting the engine when engine is warmish or warm, idle rpm immediately is 1200 - 3000 rpm.
  • RPM at idle is irregular.
  • With all engine temperatures idle rpm will often vary between 900 - 1000 rpm.
  • With engine warm (90 °C) the engine temperature suddenly drops (70 °C) and slowly comes back to 90 °C.
  • Bad acceleration during warm-up.
  • Diesel Engines: Glow plug indicator may be on for a longer than normal time or at ambient temperatures where it shouldn't come on at all.
Possible Causes
  • The electrical signal coming from G62 is too low
  • Wiring and/or connections faulty (short circuit?)
  • Engine Coolant Temperature Sensor (G62) faulty
Possible Solutions
  • Check wiring and connections
  • Check / Replace Engine Coolant Temperature Sensor (G62)
Special Notes
  • In many cars between MY 1995-2002 the G2/G62 had a bad reputation for failing often. The original G2/G62 sensor is black and the improved replacements are green.

Jan 26, 2010 | 2000 Volkswagen Beetle

1 Answer

My 1992 lexus ls 400 keeps stalling and idleis very low


Look for a small electric motor near the accelerator cable and near the top of the valve cover.

It's call IDLE AIR CONTROL (IAC) motor.

It's job is to increase the idle when load is added.
Example: turning on headlight,turning on AC.

Testing it is simple.

Warm up you car for 10 minutes.

Locate the IAC motor

turn on loads.....AC,headlights,etc


The motor should move the idle up


If the motor does not increase the RPM then it can be stick.

Try to give it few gentle taps to free up the gears.

It can be clean if your are up to it.


This electrical motor is very expensive. Please handle it with care.

====

The other trouble spot are

old accelerator cable

TPS Throttle position sensor

====

I will do a simple tune up and gas treatment before starting to replace any parts.


Please post reply on the comment window.


Oct 27, 2009 | 1992 Lexus Ls 400

Not finding what you are looking for?
1990 Lexus LS 400 Logo

293 people viewed this question

Ask a Question

Usually answered in minutes!

Top Lexus Experts

yadayada
yadayada

Level 3 Expert

76846 Answers

ROBERT GARCIA
ROBERT GARCIA

Level 3 Expert

907 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22246 Answers

Are you a Lexus Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...