Cars & Trucks Logo

Related Topics:

Posted on Jun 30, 2011
Answered by a Fixya Expert

Trustworthy Expert Solutions

At Fixya.com, our trusted experts are meticulously vetted and possess extensive experience in their respective fields. Backed by a community of knowledgeable professionals, our platform ensures that the solutions provided are thoroughly researched and validated.

View Our Top Experts

Idle goes up and down when engine is hot .Idle motor changed,electronic temperature sensors both changed new,thermal switch new,thermostat new this is for audi 80 2.6 auto 1994

Answer This Question

1 Answer

Anonymous

Level 2:

An expert who has achieved level 2 by getting 100 points
MVP:

An expert that got 5 achievements.
Governor:

An expert whose answer got voted for 20 times.
New Friend:

An expert that has 1 follower.

  • Expert 188 Answers
  • Posted on Jul 05, 2011
Anonymous
Expert
Level 2:

An expert who has achieved level 2 by getting 100 points
MVP:

An expert that got 5 achievements.
Governor:

An expert whose answer got voted for 20 times.
New Friend:

An expert that has 1 follower.

Joined: Apr 06, 2011
Answers
188
Questions
0
Helped
43482
Points
326

Hi,normally its the throttle valve faulty or not adapted rite or a crack in the pyp going to from airfilter to intake valve.hope this helps

Add Your Answer

×

Uploading: 0%

my-video-file.mp4

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

×

Loading...
Loading...

Related Questions:

0helpful
1answer

2004 Toyota Camry Hester does not warm up. When driven (not when at idle) the temperature gauge pegs out to highest then will slowly come down. Already replaced thermostat and temperature sensor, new fluid...
First, your engine will heat up to the temperature that the thermostat is rated for and when the thermostat opens the coolant will flow through the radiator and start to cool down. In order to have heat in the heater, the coolant must pass through the heater core. To find out if that is happening, locate the heater hoses and when the engine is warm and running touch them to see if they are hot. If they are not hot then there is a blockage in the heating system.
Read full answer
Feb 15, 2019 • Toyota Cars & Trucks
tip

ECT - Engine Coolant Temperature sensor
<p><b><span>2.2) <span> </span><u>ECT - Engine Coolant Temperature </u>(sensor)<u></u></span></b><br /> <p><b><u><span><span> </span></span></u></b><br /> <p><b><span>What is it?</span></b><span> This is small electrical device for measuring the coolant temperature in the engine</span><br /> <p><span> </span><br /> <p><b><span>Where is it located?</span></b><span> It is usually located on the engine near to the thermostat housing.<span> </span>The ECT is sited on the 'hot' side of the thermostat so that it senses the coolant/engine temperature before the thermostat opens and allows coolant to flow through the radiator.</span><br /> <p><span> </span><br /> <p><b><span>How does it work?</span></b><span> Modern temperature sensors consist of a thermistor in a sealed unit.<span> </span>As the temperature rises the electrical resistance varies proportionately; some thermistors increase their resistance with temperature (PTC - positive temperature correlation) whilst others decrease their resistance (NTC - negative temperature correlation).<span> </span>When the engine is cold at start up the coolant sensor sends an appropriate signal to the ECU.<span> </span>The ECU responds by increasing the length of the injection cycles to enrich the combustion mix.<span> </span>This is an electronic equivalent of pulling the 'choke' out on a carburetor.<span> </span>As the engine warms up the signals from the coolant sensor cause the ECU to shorten the injection cycles making the fuel mix progressively leaner.<span> </span>The process of coolant sensor and ECU interaction explains why engines have a slightly faster idle when starting cold than when running hot.</span><br /> <p><span> </span><br /> <p><b><u><span>Symptoms of faulty coolant sensor</span></u></b><br /> <p><b><span>Associated OBD2 error codes DTCs: <span> </span>P0115 - P119; P0125, P0126, P0128</span></b><br /> <p><b><u><span><span> </span></span></u></b><br /> <ul> <li><b><span>Poor starting</span></b><span> - If the coolant sensor reports in error that the engine is warm the ECU will not enrich the fuel mix at ignition.<span> </span>The engine will falter at idle if it is not given additional help by the driver by pressing on the accelerator pedal to maintain speed.<span> </span>Once the engine has warmed up the engine will behave correctly.</span></li> <li><b><span>Fast/erratic idle, Poor fuel economy - </span></b><span>conversely if<b> </b>the coolant sensor reports in error that the engine is permanently 'cold' the ECU will keep the fuel mix rich.<span> </span>This is OK at start up but will become more noticeable when the engine is hot; idle will be fast and lumpy.<span> </span>Fuel consumption will be high due the permanently rich fuel mix set by the ECU.<b></b></span></li> <li><b><span>Excessive emissions - </span></b><span>the enriched fuel mix delivered in response to ECT signal error causes the exhaust to be heavy in un-burnt hydrocarbons.<span> </span>This often results in 'emission test' failure.<b></b></span></li> </ul> <p><b><span> </span></b><br /> <p><b><span>How to check? </span></b><span><span> </span>Most often the <b>coolant sensor</b> is quite separate to the <b>temperature sender</b>, so a correct read-out on the dash board does not necessarily indicate correct sensor function. Using<b> </b>a voltmeter the resistance across the electrical terminals on the sensor can be measured.<span> </span>By removing the device from the car and putting the end of the sensor in a pan of hot water it should be possible to see an immediate change in resistance, it does not matter so much that the resistance goes up or down but that there is a discernable change with change in temperature.<span> </span>Generally high resistance equates to cold temperatures and vice versa. If there is no resistance change commensurate with temperature change then the sensor is at fault.<span> </span>If there is simply no resistance measurable (open circuit) then the sensor is at fault. If the sensor is working correctly check the connector, the wiring and the wiring insulation for faults and possible shorting.</span><br /> <p><b><span> </span></b><br /> <p><b><span>How to fix?<span> </span></span></b><span>Replace if found faulty</span><br /> <p><span><br /></span><br /> <p><span><b>NEXT 3.1) CKP - Crankshaft position sensor</b></span><br />
Read full tip
on Jul 22, 2011 • Mercedes-Benz E-Class Cars & Trucks
0helpful
1answer

1986 Mercury grand Marquis cutting out when slowing down nearly impossible to start. Oil changed, new air filter, new plugs and wires, new fuel filter...?
I had an experience with a 1984 T-Bird with a 302. The 1986 may have the same system. With that car there was a temperature sensor that affected the idle speed once the car was close to warming up.
With even later models there is a "cold start sequence" which is an electronic way of replacing the ancient choke. The "cold" feature set the fuel mix and the RPM and made starts easier. Now you did not say if the starting problem was when hot or cold or both.

The poor performance when slowing down can be related to the idle rpm being set too low once the thermal switch cuts out. What happens is someone tunes the engine for a rpm that may be correct for the car, but the thermal switch has not dropped the rpm yet. Then when the car really heats up, the idle drops even lower and when you take off your foot from the throttle, the throttle closes too much and the engine cuts out when you are slowing.

Put in a new thermostat. The idle settings can not be set until the thermal switches activate to a run position. Also you may have some vacuum lines crossed which are making the cold and hot cycles reverse. There should be a label with vacuum line routing shown stuck on a part that holds the radiator.
Read full answer
May 31, 2015 • Mercury Cars & Trucks
1helpful
1answer

Po115
The Code P0115 is a coolant sensor error (measures temperature of engine coolant). First make sure that you have enough coolant in the engine. If there is enough coolant and you still get the error then the following explanation should help:-

What is it? This is small electrical device for measuring the coolant temperature in the engine

Where is it located? It is usually located on the engine near to the thermostat housing. The ECT is sited on the 'hot' side of the thermostat so that it senses the coolant/engine temperature before the thermostat opens and allows coolant to flow through the radiator.

How does it work? Modern temperature sensors consist of a thermistor in a sealed unit. As the temperature rises the electrical resistance varies proportionately; some thermistors increase their resistance with temperature (PTC - positive temperature correlation) whilst others decrease their resistance (NTC - negative temperature correlation). When the engine is cold at start up the coolant sensor sends an appropriate signal to the ECU. The ECU responds by increasing the length of the injection cycles to enrich the combustion mix. This is an electronic equivalent of pulling the 'choke' out on a carburetor. As the engine warms up the signals from the coolant sensor cause the ECU to shorten the injection cycles making the fuel mix progressively leaner. The process of coolant sensor and ECU interaction explains why engines have a slightly faster idle when starting cold than when running hot.

Symptoms of faulty coolant sensor
Associated OBD2 error codes DTCs: P0115 - P119; P0125, P0126, P0128

  • 2.2a Poor starting - If the coolant sensor reports in error that the engine is warm the ECU (electronic control unit) will not enrich the fuel mix at ignition. The engine will falter at idle if it is not given additional help by the driver by pressing on the accelerator pedal to maintain speed. Once the engine has warmed up the engine will behave correctly.
  • 2.2b Fast/erratic idle, Poor fuel economy - conversely ifthe coolant sensor reports in error that the engine is permanently 'cold' the ECU (electronic control unit) will keep the fuel mix rich. This is OK at start up but will become more noticeable when the engine is hot; idle will be fast and lumpy. Fuel consumption will be high due the permanently rich fuel mix set by the ECU.
  • 2.2c Excessive emissions - the enriched fuel mix delivered in response to ECT (engine coolant temperature) signal error causes the exhaust to be heavy in un-burnt hydrocarbons. This often results in 'emission test' failure.

How to check? Most often the coolant sensor is quite separate to the temperature sender, so a correct read-out on the dash board does not necessarily indicate correct sensor function. Usinga voltmeter the resistance across the electrical terminals on the sensor can be measured. By removing the device from the car and putting the end of the sensor in a pan of hot water it should be possible to see an immediate change in resistance, it does not matter so much that the resistance goes up or down but that there is a discernable change with change in temperature. Generally high resistance equates to cold temperatures and vice versa. If there is no resistance change commensurate with temperature change then the sensor is at fault. If there is simply no resistance measurable (open circuit) then the sensor is at fault. If the sensor is working correctly check the connector, the wiring and the wiring insulation for faults and possible shorting.

How to fix? Replace if found faulty
Read full answer
May 25, 2014 • 2001 Hyundai XG300
0helpful
1answer

Car hiccups and stalls
Although your temperature gauge may show that it works, some models have a second temperature sensor for the engine management system.
That second sensor provides info which sets curb idle and timing advance. The "Cold start" feature is a part of this. The hic-cup is something of a bucking symptom as the engine controls toggle between hot and cold run settings repeatedly as water temperature is not stable.
In the past, I found several 1984 engines having defective thermostats which are tied into "Step-up" solenoids for the curb idle. What happens is idle speed is suppose to drop when the engine is hot.
When someone adjusts the curb idle while the engine is on the "cold setting", the setting(rpm) will be too low once the engine has heated up and the part drops to a hot setting.
So to clearly define your problem, you have 2 stemming from the same defects. The "in motion" problem is caused by timing changes based on temperature and the "idle" problem is caused by improper adjustment of the curb idle solenoid because of unstable operating temperature.
What you want to do is change your thermostat. This will give you a stable temperature. Then let the engine heat up and you should notice a "click" and the engine should idle down. It may stall. Then turn the idle rpm up until the engine will not stall.
The hic-cups should disappear once the operating temp is reached. If you still have problems then look for the water temperature sensors before replacing expensive parts.
Read full answer
May 24, 2013 • 1984 Ford Mustang
6helpful
1answer

Mini Cooper temperature gauge goes to red zone when idle
check coolant level could be too low allowing air in the cooling system causing air pocket in engine around the engine coolant sensor.coolant sensor needs to be in hot coolant so it will cause the cooling fan to come on at a set temperature.make sure coolant correct level and the coolant level in the cooling overflow jug should be at full cold mark.the cooling overflow jug should never be empty,if you see empty cooling overflow jug air got in the cooling system so make sure when engine cold every time raise hood make sure cooling overflow jug coolant level at full cold mark.if jug stay empty you have cooling leak.so replace radiator cap,if coolant level all good,i would replace the engine coolant temperature and thermostat.when your car come to a long stop or driving along long line of slow moving traffic the engine coolant blower motor should running if not have vechicle code scan for faulty coolant fan motor control module.or ecm problems.
Read full answer
Sep 01, 2012 • 2005 Mini Cooper
0helpful
1answer

Temperature gage goes up and down
The breather hose should run to the air cleaner housing or intake tube.
Check your radiator cooling fan. If it isn't working the car will run hot at slow speeds or idle then cool down after you get going faster. A quick check would be to turn the AC on and see if the fan comes on. If not try lightly tapping on the cooling fan motor with a wooden broom handle. If it comes on then you have a bad motor.
If the fan comes on with the AC then check to see if the fan comes on after the engine gets hot. If the engine temp doesn't kick it on then the temperature sensor might be bad.
If the fan is ok please post more info on your problem
Read full answer
May 27, 2012 • 2002 Ford ZX2
1helpful
2answers

Stalls while in drive with foot on brake , changed MAP Sensor, Crank Shaft Sensor , Distributor, Fuel Pump, Fuel Filter , have ran out of ideas
I would check the IAC motor or idle air control motor, heres a little info.about the part.Stratus Sedan, 1999-2005 Idle Air Control Motor

Print


Description & Operation

Not for Dodge Stratus Sedan
The idle air control motor (IAC) attaches to the throttle body. It is an electric stepper motor. The PCM adjusts engine idle speed through the idle air control motor to compensate for engine load, coolant temperature or barometric pressure changes. The throttle body has an air bypass passage that provides air for the engine during closed throttle idle. The idle air control motor pintle protrudes into the air bypass passage and regulates airflow through it.
The PCM adjusts engine idle speed by moving the IAC motor pintle in and out of the bypass passage. The adjustments are based on inputs the PCM receives. The inputs are from the throttle position sensor, crankshaft position sensor, coolant temperature sensor, MAP sensor, vehicle speed sensor and various switch operations (brake, park/neutral, air conditioning).

0996b43f8020234f.jpg enlarge_icon.gifenlarge_tooltip.gif

Fig.

Not for Dodge Stratus Sedan
When engine rpm is above idle speed, the IAC is used for the following functions:


Off-idle dashpot Deceleration air flow control A/C compressor load control (also opens the passage slightly before the compressor is engaged so that the engine rpm does not dip down when the compressor engages)
The idle air control motor (IAC) attaches to the throttle body. It is an electric stepper motor. The PCM adjusts engine idle speed through the idle air control motor to compensate for engine load, coolant temperature or barometric pressure changes. The throttle body has an air bypass passage that provides air for the engine during closed throttle idle. The idle air control motor pintle protrudes into the air bypass passage and regulates airflow through it.
The PCM adjusts engine idle speed by moving the IAC motor pintle in and out of the bypass passage. The adjustments are based on inputs the PCM receives. The inputs are from the throttle position sensor, crankshaft position sensor, coolant temperature sensor, MAP sensor, vehicle speed sensor and various switch operations (brake, park/neutral, air conditioning).

21180_cdia_g257.jpg enlarge_icon.gifenlarge_tooltip.gif

Fig.

When engine rpm is above idle speed, the IAC is used for the following functions:


Off-idle dashpot Deceleration air flow control A/C compressor load control (also opens the passage slightly before the compressor is engaged so that the engine rpm does not dip down when the compressor engages)
Target Idle
Target idle is determined by the following inputs:


Gear position ECT Sensor Battery voltage Ambient/Battery Temperature Sensor VSS TPS MAP Sensor
Target idle is determined by the following inputs:


Gear position ECT Sensor Battery voltage Ambient/Battery Temperature Sensor VSS TPS MAP Sensor


Removal & Installation

  1. Disconnect the negative battery cable.
  2. Disconnect the IAC electrical connector.
  3. Remove the IAC mounting screws.
  4. Remove the IAC.

To Install:
  1. Install the IAC to the throttle body.
  2. Tighten mounting screws to 5.1 Nm (45 inch lbs.) torque.
  3. Attach electrical connector to the IAC.
  4. Connect the negative battery cable.

    0996b43f80202350.jpg enlarge_icon.gifenlarge_tooltip.gif

    Fig.


  1. Disconnect the negative battery cable.
  2. Disconnect the IAC electrical connector.
  3. Remove the IAC mounting screws.
  4. Remove the IAC.

To Install:
  1. Install the IAC to the throttle body.
  2. Tighten mounting screws to 5.1 Nm (45 inch lbs.) torque.
  3. Attach electrical connector to the IAC.
  4. Connect the negative battery cable.
Read full answer
May 11, 2012 • 2000 Chrysler Cirrus
1helpful
2answers

Need to revise my previous question...91 Explorer temp going up and down...top and bottom hoses are hot and the radiator IS hot. I have heat (inlet and outlet hoses are hot), new thermostat and serp belt...
definatly sounds like a thermostat not opening early enough it would pay you to check and see the temp setting on the one you put in ,should be 170_180 degrees but put it in hot water and see when it opens. you dont have an electric fan do you?because that could have the same effect if it is switching in late
Read full answer
Oct 09, 2009 • 1991 Ford Explorer
0helpful
1answer

My 1988 f150 does the same thing..idling problem!
Having the proper thermostat in fuel injected vehicles is very important.They have a engine coolant sensor to tell the computer the temp of the coolant. If the engine is running too cold,(or cold all the time), the computer is going to tell the idle motor to raise the idle and to give it more fuel, which can damage the cat converter. These vehicles need a 192-195 degree thermostat. Also check the TP sensor (throttle position sensor for proper voltage) the green wire should read .7 to 1.00 volts.
Read full answer
Sep 30, 2009 • 1990 Ford F250
Not finding what you are looking for?

View Most Popular

Cars & Trucks

Related Question

2004 Toyota Camry Hester does not warm up. When driven (not when at idle) the temperature gauge pegs out to highest then will slowly come down. Already replaced thermostat and temperature sensor, new fluid...

  • Toyota Cars & Trucks

236 views

Ask a Question

Usually answered in minutes!

Popular Questions

Audi 80 oil pressure light

1989 Audi 80

Where is fuel pump relay in audi 80 ?

1992 Audi 80

REPLACING AUDI 80 FUEL PUMP

1992 Audi 80

Hard to start on cold mornings but starts fine when warm

1992 Audi 80

Noisy Fuel Pump?

1992 Audi 80

Check Out the Latest Top Trucks Report!
Check Out the Latest Top Trucks Report!

View all Fixya Reports

Top Audi Experts

ZJ Limited
ZJ Limited

Level 3 Expert

17989 Answers

Thomas Perkins
Thomas Perkins

Level 3 Expert

15088 Answers

Ronny Bennett Sr.
Ronny Bennett Sr.

Level 3 Expert

6988 Answers

Are you an Audi Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...