Question about 1991 Ford Mustang

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My check engine light stays on and idles at 500 rpm have replaced the computer, coil packs, oxygen sensor and DIS, what else can be wrong?

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  • Ford Master
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I would make sure that all of the wiring is ok between the coil packs and the DIS, computer, etc. A wiring problem can make changing the parts in between seem easy, to say the least, as the wiring harness has to be torn apart to check for breaks and shorts. This is best left to an 'auto electric' shop that can do this without damaging your engine controls investment.

Posted on Jul 11, 2010

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My 1989 pontiac grand prix keeps stalling once it is warmed up after about 15 minutes of idle.


No, not the oxygen sensor. A couple of things you need to make clear. What light flickers, then stays on? That can't be a sensor light, it would have to be the "check engine light" or an engine temperature light (for like when your cluster has no temperature gauge, but just the "red light").
At any rate, the sensor you changed is not the engine temp. sending unit for the instrument panel. I believe on your '89 there would be two sensors for temp. One is the CTS for the engine computer, and the other is a sending unit for the dash, probably a 1 wire connector. It could be at fault, but it wouldn't cause stalling, I do not think anyway.
If it stalls and won't restart until cooled, this is a symptom of loss of ignition (spark) caused by either a faulty coil, or faulty Ignition Control Module (the coil controller), or last a faulty Crank Position Sensor (this sensor used by computer to determine ignition spark timing). You could test if ignition is lost, by checking for spark right after the engine warms and then stalls. If you have no spark to a spark plug right after it stalls, this is the reason for stalling. Usually it is the crank sensor, rather than the ignition control module or an ignition coil. Your car has 3 coils anyway in a "coil pack", so if one coil went bad, you'd still have two good coils, but engine would only be firing on four of the six cylinders-could easily stall a car.
You should check for trouble codes whenever you have a problem. A code might have been set. Easy to check for codes on your car, just ask if you don't know how-only takes a jumper wire or even a paper clip works. good luck.

Jun 16, 2016 | 1989 Pontiac Grand Prix

1 Answer

2002 escape 3.0 idle fluctuates and misfires when driving


No such thing as a tune-up

All you did was replace spark plugs which should be
done every 3 years

Oxygen Sensors get replaced at 100,000 miles which you
also did

You most likely have an intake gasket leak,smoke test
the entire Evap System & Engine

You also are have bad igniton coils

Jan 18, 2013 | 2002 Ford Escape

1 Answer

Has rough idle, engine light on, codes P0303 and U3FFF. Have had installed new coil pack and new injector on cyclinder 3, same problem persist.


check spark plug and wire
test oxygen sensor
check compression ( valve might be at fault)
have computer checked

Jul 05, 2010 | 2005 Jeep Grand Cherokee

1 Answer

The orange engine warning light is lit and the engine surges between 4,000 and 5,000 rpm


The first step is to delete the fault code:
Disconnect + wire on the battery for one hour. Turn ignition ON but do not start the engine. Leave it on so the throttle resets automatically. Turn ignition OFF and then start the engine as you normally do. Go for a 15 minutes drive, Audi reccomends to not let the engine idle, go for a normal drive so the ECU reads the values from all sensors again and remaps the ignition and fuel timing. If after all this the Engine Service light stays ON the engine needs to be diagnosed by an Audi workshop as it could be a lot of things, from a faulty coil pack, to an oxygen sensor or maybe a coolant/air temp sensor...

Jan 30, 2010 | 2001 Audi TT

1 Answer

Rough Idle trough1500 RPM with trouble


A code P0303 may mean that one or more of the following has happened:
  • Faulty spark plug or wire
  • Faulty coil (pack)
  • Faulty oxygen sensor(s)
  • Faulty fuel injector
  • Burned exhaust valve
  • Faulty catalytic converter(s)
  • Running out of fuel
  • Poor compression
  • Defective computer
Possible Solutions If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

A. P0401 "Exhaust Gas Recirculation Flow Insufficient Detected" that there is not enough exhaust gas being admitted to the engine.
There are a number of things you can check, and others you need a scan tool to check.
What you can do is check for vacuum to the EGR valve. You can remove the EGR valve and see if it is stuck closed. Test it with a hand vacuum pump and see if it opens smoothly. Check the EGR valve orifice and make sure it is free and clear. Check and clean the EGR passages in the going to and from the EGR valve.
If this checks out, then the Differential Pressure Feedback EGR system will need to be scanned to check the EGR sensors and switches

A code P0301 may mean that one or more of the following has happened:
  • Faulty spark plug or wire
  • Faulty coil (pack)
  • Faulty oxygen sensor(s)
  • Faulty fuel injector
  • Burned exhaust valve
  • Faulty catalytic converter(s)
  • Running out of fuel
  • Poor compression
  • Defective computer

Oct 11, 2009 | 1999 Ford Taurus

1 Answer

98 Lincoln Navigator Check Eng light on


fuel pump is going out causing the truck to run lean and miss

Aug 22, 2009 | 1999 Lincoln Navigator

1 Answer

1992 cadillac Deville OBD code read out and what it means.


E13-Oxygen sensor voltage stays between 0.307 and 0.609 volts for 64 seconds. Engine was at normal operating temperature at a speed over 800 RPM.
E44-Right oxygen sensor was lean for more than 50 seconds when engine was warm and at 800 RPM or greater.
E52-PCM has lost primary battery power.
E58-Pass Key fuel enable was not correct.
F47-PCM has received bad data from IPC for 3 seconds while engine speed was 500 RPM or more for 3 seconds.
F48-EGR open command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. Vehicle speed was over 35 MPH and engine was warm.
Good luck and hope this helps, keep me posted be glad to answer any questions you may have. 

Jul 05, 2009 | 1992 Cadillac Seville

1 Answer

Engine light won't go off.


have the EGR valve tested because this will cause the engine light to come on and also check all vacuum lines

Mar 19, 2009 | Ford Windstar Cars & Trucks

3 Answers

1997 DODGE RAM 1500 360 VERY LOW IDLE


I think you have ruled out the engine with all the parts you have replace. The transmission torque convertor is in lock up mode all the time. The engine is having to hard of a time to stay at the normal idle. The over drive clutches and soleniod are most likely damaged in the transmission.
I think you should take the vehicle to a trasnmission shop , The can check the torque convetror soleniods and pressure control soleniod.

The oil light coming on bothers me. I know you have the rebuilt engine in the vehicle but I think the oil pump in the engine is starting to go out or could be weak. The lower bearings connected to the crank shaft might be starting to leak. Have the oil pressure checked .

Mar 19, 2009 | 1998 Dodge Ram 1500 4WD

1 Answer

Xterra repair


Since this is an intermittent problem, first try to determine if the problem arises due to one of these many intermittent problems:

* Vehicle vibration
* Heat sensitive
* Freezing
* Water intrusion
* Electrical load
* Cold or hot start up

If you can't isolate the cause of the intermittent problem, you can try adjusting the Idle Speed/Ignition Timing/Idle Mixture Ratio:

Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment

PREPARATION
1) Make sure that the following parts are in good order.

* Battery
* Ignition system
* Engine oil and coolant levels
* Fuses
* ECM harness connector
* Vacuum hoses
* Air intake system
* (Oil filler cap, oil level gauge, etc.)
* Fuel pressure
* Engine compression
* EGR valve operation (If so equipped)
* Throttle valve
* Evaporative emission system

2) On air conditioner equipped models, checks should be carried out while the air conditioner is OFF.
3) On automatic transmission equipped models, when checking idle rpm, ignition timing and mixture ratio,
checks should be carried out while shift lever is in “N” position.
4) When measuring “CO” percentage, insert probe more than 40 cm (15.7 in) into tail pipe.
5) Turn off headlamps, heater blower, rear defogger.
6) Keep front wheels pointed straight ahead.
7) Make the check after the cooling fan has stopped.

INSPECTION PROCEDURE

1 INSPECTION START
1. Visually check the following:
I Air cleaner clogging
I Hoses and ducts for leaks
I EGR valve operation (If so equipped)
I Electrical connectors
I Gasket
I Throttle valve and throttle position sensor operation
2. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
Ensure engine stays below 1,000 rpm.
3. Open engine hood and run engine at about 2,000 rpm for about 2 minutes under no-load.
4. Perform diagnostic test mode II (Self-diagnostic results).
OK or NG
OK ' GO TO 2.
NG ' 1. Repair or replace components as necessary.
2. GO TO 2.

2 CHECK IGNITION TIMING
1. Run engine at about 2,000 rpm for about 2 minutes under no-load.
2. Rev engine (2,000 to 3,000 rpm) two or three times under no-load, then run engine at idle speed.
3. Turn off engine and disconnect throttle position sensor harness connector.
4. Start and rev engine (2,000 - 3,000 rpm) two or three times under no-load, then run at idle speed.
5. Check ignition timing with a timing light.
15°±2° BTDC (in “P” or “N” position)
OK or NG
OK ' GO TO 4.
NG ' GO TO 3.

3 ADJUST IGNITION TIMING
1. Adjust ignition timing by turning distributor after loosening securing bolts.
2. Turn off engine and connect throttle position sensor harness connector to throttle position sensor.
' GO TO 2.


4 CHECK BASE IDLE SPEED
1. Check idle speed.
700±50 rpm (in “P” or “N” position)
OK or NG
OK ' GO TO 6.
NG ' GO TO 5.

5 ADJUST BASE IDLE SPEED
1. Rev engine (2,000 to 3,000 rpm) 2 or 3 times under no-load then run engine at idle speed.
2. Adjust idle speed by turning idle speed adjusting screw.
700±50 rpm (in “P” or “N” position)
' GO TO 6.

6 CHECK TARGET IDLE SPEED
1. Turn off engine and connect throttle position sensor harness connector.
2. Start and rev engine (2,000 to 3,000 rpm) 2 or 3 times under no-load then run at idle speed.
3. Check idle speed.
750±50 rpm (in “P” or “N” position)
OK or NG
OK ' GO TO 9.
NG ' GO TO 7.

7 DETECT MALFUNCTIONING PART
Check the following.
1. Check IACV-AAC valve and replace if necessary.
2. Check IACV-AAC valve harness and repair if necessary.
3. Check ECM function by substituting another known good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
' GO TO 9.

9 CHECK FRONT HEATED OXYGEN SENSOR LH SIGNAL
1. Run engine at about 2,000 rpm for about 2 minutes under no-load.
2. Set “Left bank front heated oxygen sensor monitor” in the Diagnostic Test Mode II.
3. Make sure that MIL goes on more than 5 times during 10 seconds at 2,000 rpm.
OK or NG
OK ' GO TO 12.
NG (MIL does not blink.) ' GO TO 17.
NG (MIL blinks less than 5 times.)
' 1. Replace front heated oxygen sensor LH.
2. GO TO 10.


10 CHECK FRONT HEATED OXYGEN SENSOR LH SIGNAL
1. Warm engine to normal operating temperature.
2. Run engine at approx. 2000 rpm for approx. 2 minutes under no-load.
3. Set “Left bank front heated oxygen sensor monitor” in the Diagnostic Test Mode II.
4. Make sure that MIL goes on more than 5 times during 10 seconds at 2,000 rpm.
OK or NG
OK ' GO TO 13.
NG ' GO TO 11.

11 DETECT MALFUNCTIONING PART
Check the following.
1. Check fuel pressure regulator.
2. Check mass air flow sensor and its circuit.
3. Check injector and its circuit.
Clean or replace if necessary.
4. Check engine coolant temperature sensor and its circuit.
5. Check ECM function by substituting another known good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
' GO TO 2.


13 CHECK FRONT HEATED OXYGEN SENSOR RH SIGNAL
1. Set “Right bank front heated oxygen sensor monitor” in the Diagnostic Test Mode II.
2. Make sure that MIL goes on more than 5 times during 10 seconds at 2,000 rpm.
OK or NG
OK ' INSPECTION END
NG (MIL does not blink.) ' GO TO 16.
NG (MIL blinks less than 5 times.)
' 1. Replace front heated oxygen sensor RH.
2. GO TO 14.


14 CHECK FRONT HEATED OXYGEN SENSOR RH SIGNAL
1. Warm engine to normal operating temperature.
2. Run engine at approx. 2000 rpm for approx. 2 minutes under no-load.
3. Set “Right bank front heated oxygen sensor monitor” in the Diagnostic Test Mode II.
4. Make sure that MIL goes on more than 5 times during 10 seconds at 2,000 rpm.
OK or NG
OK ' INSPECTION END
NG ' GO TO 15.

15 DETECT MALFUNCTIONING PART
Check the following.
1. Check fuel pressure regulator.
2. Check mass air flow sensor and its circuit.
3. Check injector and its circuit. Clean or replace if necessary.
4. Check engine coolant temperature sensor and its circuit.
5. Check ECM function by substituting another known good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
' GO TO 2.
16 CHECK FRONT HEATED OXYGEN SENSOR RH HARNESS
1. Turn off engine and disconnect battery ground cable.
2. Disconnect ECM harness connector.
3. Disconnect front heated oxygen sensor RH harness connector.
4. Check harness continuity between ECM terminal 50 and front heated oxygen sensor RH harness connector.
Continuity should exist.
OK or NG
OK ' 1. Connect ECM harness connector.
2. GO TO 18.
NG ' 1. Repair or replace harness.
2. GO TO 9.

17 CHECK FRONT HEATED OXYGEN SENSOR LH HARNESS
1. Turn off engine and disconnect battery ground cable.
2. Disconnect ECM harness connector.
3. Disconnect front heated oxygen sensor LH harness connector.
4. Check harness continuity between ECM terminal 51 and front heated oxygen sensor LH harness connector.
Continuity should exist.
OK or NG
OK ' 1. Connect ECM harness connector.
2. GO TO 18.
NG ' 1. Repair or replace harness.
2. GO TO 9.

18 PREPARATION FOR “CO” % CHECK
1. Disconnect engine coolant temperature sensor harness connector.
2. Connect a resistor (4.4 kW) between terminals of engine coolant temperature sensor harness connector.
' GO TO 19.

19 CHECK “CO” %
1. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
2. Rev engine (2,000 to 3,000 rpm) two or three times under no-load, then run engine at idle speed.
3. Check “CO” %.
Idle CO: 1.5 - 9%
After checking CO%,
a. Disconnect the resistor from terminals of engine coolant temperature sensor.
b. Connect engine coolant temperature sensor harness connector to engine coolant temperature sensor.
OK or NG
OK ' 1. Replace front heated oxygen sensor LH.
2. GO TO 10.
NG ' GO TO 20.

20 DETECT MALFUNCTIONING PART
Check the following.
1. Connect front heated oxygen sensor harness connectors to front heated oxygen sensors.
2. Check fuel pressure regulator.
3. Check mass air flow sensor and its circuit.
4. Check injector and its circuit.
Clean or replace if necessary.
5. Check engine coolant temperature sensor and its circuit.
6. Check ECM function by substituting another known good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
' GO TO 2.

Aug 17, 2008 | 2000 Nissan Xterra

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