Question about 2007 GMC Envoy Denali

1 Answer

Cylinder #4 misfire

Cylinder 4 misfire. Vehicle exhibits misfire after normal operating temperature is reached and vehicle is driving a short distance. Spark plug, spark plug wire, ignition coil and fuel injector have been exchanged all check good. Injector signal has been verified and is good. Ignition coil wiring including: power, ground, reference ground, signal have been verified and are good. Stethoscope placed around #4 cylinder shows a faint knock in that cylinder which is not heard on any other cylinders. What is the probability of the AFM lifters in cylinder 4 unlocking prematurely after the vehicle reaches operating temperature ? Is there a way to check the VLOM solenoid for that cylinder or are they all activated at the same time ? Please Help with this issue. I do not have a scanner capable of actuating the solenoids or performing any of the associated testing of the DOD system.

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  • GMC Master
  • 1,969 Answers

Could be crank or cam sensor

Posted on Mar 12, 2017

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6ya6ya
  • 2 Answers

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Posted on Jan 02, 2017

  • 1 Answer

SOURCE: cylinder 8 dead misfires of and on goes away and comes back

I had the same problem. New injector distributor (spider as he called it) fixed ir. Cost about 800.00

Posted on May 14, 2009

  • 7 Answers

SOURCE: 96 Sonoma-engine misses around 30 mph.

Remove right side front tire, pull up flap by shock and you will see the two ignition coils bolted on right side of engine. Each coil fires 2 plugs, 1&3 and 2&4. Had a similar problem and it was the coil. FYI my fuel pump went out and your dead when you stand.

Posted on Sep 18, 2009

  • 194 Answers

SOURCE: 1990 gmc 6500 topkick with no spark or injector pulse

You are jumping to conclusions. Slow down.
No spark AND no injector pulse indicates none of the desired outputs were triggered. The ignition module makes spark when it receives a crankshaft position sensor signal, and then transfers control of that spark to the computer after it starts. The module takes its crank sensor signal and generates an RPM count that it forwards to the PCM(main computer) which is used for triggering the injectors and controlling timing. SO, if you had a bad crank sensor OR a bad ignition module, you could lose both spark AND fuel. a coil would not disable injector pulse. modules RARELY fail in a manner that disables RPM reference to the computer causing it to not fire the injectors...At this point, I would TEST the crank sensor as the next step. If its easier, 1 of the wires on the module goes directly there so you can test the crank sensor at the module.

Posted on Sep 18, 2009

Testimonial: "great info, thanks!"

  • 880 Answers

SOURCE: i have a 2000 gmc sierra 5.3 with a number 6

I would check the valves for number 6. If one or both are burned, stuck or out of adjustment it would cause your problem. If a cam lobe for that cylinder is burned or badly worn it could be the culprit.

Posted on Jan 10, 2010

duane_wong
  • 6826 Answers

SOURCE: my truck has a #4

Try to check that the fuel injector, using a fuel injector tester, is getting an electrical pulse as indicated by the tester lighting up and blinking periodically.

Also, one can check the injector by putting a stethoscope on the injector and listening for a loud click.

Also, check that antifreeze is not leaking into the cylinder causing the plugs not to fire. How did the plug look that was replaced? It should have had a light brown dry appearance if normal.

Posted on Oct 07, 2010

Testimonial: "answer was very timely, and definately gave a good NEW direction to look. Thanks."

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03 Nissan Altima showing codes P0304,P0102,P0154,P0113 what are they and how do i repair the problems.


Hi Chris.

p0304 = Number 4 Cylinder Misfire Detected

Faulty spark plug 4
Clogged or faulty fuel injector 4
Faulty ignition coil 4
Fuel injector 4 harness is open or shorted
Fuel injector 4 circuit poor electrical connection
Ignition coil 4 harness is open or shorted
Ignition coil 4 circuit poor electrical connection
Insufficient cylinder 4 compression
Incorrect fuel pressure
Intake air leak

The P0304 code means that the cylinder 4 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 4.


p0102 = Mass or Volume Air Flow Circuit Low Input

Faulty mass air flow sensor
Intake air leaks
Dirty mass air flow sensor
Dirty mass air filter
Mass air flow sensor harness is open or shorted
Mass air flow sensor circuit poor electrical connection

Before replacing the mass air flow sensor, try replacing the air filter and cleaning the air flow sensor with low compress air or mass air flow sensor cleaner.
Reset code and drive vehicle.
If the code comes back, it may be necessary to replaced the mass air flow sensor.


p0154 = O2 Sensor Circuit No Activity Detected Sensor 1 Bank 2

Faulty Front Heated Oxygen Sensor Bank 2
Front Heated Oxygen Sensor Bank 2 harness is open or shorted
Front Heated Oxygen Sensor Bank 2 circuit poor electrical connection
Inappropriate fuel pressure
Faulty fuel injectors
Intake air leaks may be faulty
Exhaust gas leaks

Replacing the Front Heated Oxygen Sensor Bank 2 usually takes care of the problem.


p0113 = Intake Air Temperature Sensor Circuit High

Faulty Intake Air Temperature (IAT) sensor
Dirty air filter
Intake Air Temperature (IAT) sensor harness is open or shorted
Intake Air Temperature (IAT) sensor circuit poor electrical connection

The Intake Air Temperature (IAT) sensor is built into mass air flow sensor or in some vehicles mounted to the air filter duct housing. The sensor detects intake air temperature and transmits a signal to the Engine Control Module (ECM).The temperature sensing unit uses a thermistor which is sensitive to the change in temperature. Electrical resistance of the thermistor decreases in response to the temperature rise. The Intake Air Temperature signal is used as an input for various systems in the vehicle.



Hope this helps
FYT

http://www.autocodes.com/make/nissan

Mar 26, 2017 | Nissan Cars & Trucks

2 Answers

I went to change the thermostat. on 98 Olds Sillouet When I removed the throttle body I found oil and water in the upper intake manifold Also I did not find any water on the dipstick. Any ideas?


If your thermostat is sticking open, the vehicle never reaches operating temperature. Moisture in the engine is never vaporized and burned off. This is also normal if you only drive short distances. Take your vehicle for about an hour drive and the moisture should be gone.

Feb 11, 2017 | 1998 Oldsmobile Silhouette

1 Answer

Oil sludge found in Air Cleaner, replaced PCV and filter and cleaned and had to replace filter in 6 months due to yellow oil sludge


Oil sludge can be caused by a few different things. I don't think you have head gasket/head problems as you say you've been using the vehicle for 6 months.

However, do check your oil dipstick and see if the same sludge (also known as 'mayonnaise') is on it. Mayonnaise on a dipstick is a symptom of a defective head gasket that is allowing coolant into the oil system.

If your vehicle looses/uses coolant this may be a sign of a faulty head gasket/head.

Very short- repeated - journeys can allow sludge to form, simply because on short journeys the engine does not reach its normal operating temperature. The engine is 'cool'.

It can also be caused by a faulty thermostat. If the thermostat is jammed in the open position it can take a long time for the engine to reach normal operating temperature. Other than changing the thermostat (maybe for one that opens at a higher temperature - a 'winter' thermostat) there's no practical way of checking it. Replacement is the easiest and cheapest option. It's not a difficult job.

It's not unknown for a thermostat to have been removed by a previous owner (for various reasons..). If you're going to check if there's a thermostat there - replace it anyway.

If you're not losing/using coolant and there's no mayonnaise on the dipstick it may well be due to repeated short journeys where the engine doesn't reach normal operating temperature - or the thermostat.

Feb 05, 2016 | Cars & Trucks

2 Answers

99 ford taurus starts up but doesnt drive more than 10 miles per hour and temperature starts to rise


maybe a coolant thermostat that is faulty, a collapsed or perished hose..

It could also indicate cylinder head gasket/cylinder head problems.

Ten miles is about the correct distance for a car engine to reach normal operating temperature. If your temperature gauge continues to rise beyond normal ..ie. overheating .. you risk causing a lot of damage to your engine.

If you're not sure what to do or look for - get somebody to check it out for you

Jan 27, 2016 | 1999 Ford Taurus

1 Answer

96 acura tl 2.5 liter,short term fuel trim at negative 20 percent


Do a cylinder leak down test,for bad valves on #3
or head gasket,misfires for a reason

(Cam Worn ?)

Have to get rid of any misfires

If your taking out 20% your correcting for a rich condition,maybe

Some injector issues,old,need to be sent away for cleaning & flow
testing or replaced?

Drive it for 30 miles & add short & long term & see what you get

Exhaust Converter any good ?

Mar 25, 2014 | 1996 Acura TL Series

1 Answer

Engine temperature suddenly too high when driving


if the car in the process of operation, coolant temperature gauge indicatorquickly reached 100 degree, or launch in the cold car, engine coolanttemperature rises rapidly to boiling, to make up for the coolant to normal, but the engine power output decreased significantly, the mechanical system of engine system failure. The cause of the fault of cooling system are: seriousWater Leakage; cylinder pad insulation jacket and cylinder impact; the thermostat main valve off; fan belt loosening or fracture; pump shaft and impeller loose; fan clutch side. Use obd2 for automotive diagnostics , you can improve vehicle safety performance and driving more safer.

Dec 09, 2013 | Ford Cars & Trucks

1 Answer

While driving or idling when motor hits 3000 rpm's exactly it cuts out.


Hi,

DO NOT replace any more compoents until you have checked your vehicle's OBD computer for fault codes.

1) Run engine until it reaches operating temperature. Turn off engine.

2) Locate the 2-pin connector (BLUE I think it is) under the passenger dashboard, or behind passenger kick panel - this connector could also be mounted into an unused socket ( DO NOT use the 3-pin connector). Using a suitable jumper wire, short these 2 pins together.

3) Turn ignition to ON (but do not start)

4) The Check Engine light will flash the appropriate codes - long flash represents the 1st digit of the code, short flashes represent the 2nd digit of the code, followed by a long pause between codes. e.g. LONG, LONG, SHORT, SHORT, SHORT (long pause) = Code 23 etc.

These are the Honda codes and their meanings:

Code 0 Electronic Control Module (ECM)
Code1 Heated oxygen sensor A
Code 2 Oxygen content B
Code 3 and 5 Manifold Absolute Pressure
Code 4 Crank position sensor
Code 6 Engine coolant temperature
Code 7 Throttle position sensor
Code 8 Top dead center sensor
Code 9 No.1 cylinder position sensor
Code 10 Intake air temperature sensor
Code 11 Electronic Control Module (ECM)
Code 12 Exhaust recirculation system
Code 13 Barometric pressure sensor
Code 14 Idle air control valve or bad ECM
Code 15 Ignition output signal
Code 16 Fuel Injector
Code 17 Vehicle speed sensor
Code 19 A/T lock-up control solenoid
Code 20 Electric load detector
Code 21 V-TEC control solenoid
Code 22 V-TEC pressure solenoid
Code 23 Knock sensor
Code 30 A/T FI signal A
Code 30 A/T FI signal B
Code 41 Heated oxygen sensor heater
Code 43 Fuel supply system
Code 45 Fuel supply metering
Code 48 Heated oxygen sensor
Code 61 Front heated oxygen sensor
Code 63 Rear heated oxygen sensor
Code 65 Rear heated oxygen sensor heater
Code 67 Catalytic converter system
Code 70 Automatic transaxle
Code 71 Misfire detected cylinder 1
Code 72 Misfire detected cylinder 2
Code 73 Misfire detected cylinder 3
Code 74 Misfire detected cylinder 4
Code 75 Misfire detected cylinder 5
Code 76 Misfire detected cylinder 6
Code 80 Exhaust recirculation system
Code 86 Coolant temperature
Code 92 Evaporative emission control system


Hope this helps........

Oct 28, 2011 | 1993 Honda Prelude

1 Answer

The Drive light flashes and the car loses power and sometimes won't start.


It is either your Vehicle Speed Sensor (easy to change) or your Automatic Transmission Computer (capacitors burn out on these boards, there is a fix for this too, the picture is at the bottom of this page). You need to diagnose by removing the lower right plastic kick panel on the passenger side. There you will find a blue plug. With the car OFF stick a paper clip, wire or stuff the plug with foil to make electrical connection so that the two terminals are touching. Then, turn the ignition to ON (not enough to start it though, just power it up). When you do this, count the blinks in the "D Light" or count your blinking Check Engine Light. Both are different but can refer to different things wrong with your car. A long blink is the first number and the short blinks that follow are the second number.
So imagine this as being 14 : ___ _ _ _ _

Below is a decoding chart:

The first section will be the check engine light codes, the next one is the Transmission Control Unit Codes read from the D Light;

1 O2A - Oxygen sensor #1
2 O2B - Oxygen sensor #2
3 MAP - manifold absolute pressure sensor
4 CKP - crank position sensor
5 MAP - manifold absolute pressure sensor
6 ECT - water temperature sensor
7 TPS - throttle position sensor
8 TDC - top dead centre sensor
9 CYP - cylinder sensor
10 IAT - intake air temperature sensor
12 EGR - exhaust gas recirculation lift valve
13 BARO - atmospheric pressure sensor
14 IAC (EACV) - idle air control valve
15 Ignition output signal
16 Fuel injectors
17 VSS - speed sensor
19 Automatic transmission lockup control valve
20 Electrical load detector
21 VTEC spool solenoid valve
22 VTEC pressure valve
23 Knock sensor
30 Automatic transmission A signal
31 Automatic transmission B signal
36 traction control found on JDM ecu's
41 Primary oxygen sensor heater
43 Fuel supply system
45 Fuel system too rich or lean
48 LAF - lean air fuel sensor
54 CKF - crank fluctuation sensor
58 TDC sensor #2
61 Primary oxygen sensor
63 Secondary oxygen sensor
65 Secondary oxygen sensor heater
71 random misfire cylinder 1
72 random misfire cylinder 2
73 random misfire cylinder 3
74 random misfire cylinder 4
80 Exhaust Gas Recirculation insufficient flow detected
86 ECT Sensor (Engine Coolant Temperature) circuit range / performance problem
90 Evaporative Emission Control System leak detected in the fuel tank area
91 Fuel Tank Pressure Sensor low input
92 Evaporative Emission Control System insufficient purge flow

TCU Codes:

CODE LIST:

1-Lock-up solenoid 'A' circuit open or shorted.
2-Lock-up solenoid 'B' circuit open or shorted.
3-Throttle Position Sensor circuit open or shorted.
4-Vehicle Speed Sensor open or shorted - No signal from speedometer.
5-Shift Lever Position Switch circuit shorted.
6-Shift Lever Position Switch circuit open.
7-Shift Solenoid 'A' circuit open or shorted.
8-Shift Solenoid 'B' circuit open or shorted.
9-Counter shaft or transmission speed pulse generator open or shorted.
10-Coolant Temperature Sensor open or shorted.
11-Engine RPM (Ignition coil signal) open or shorted.
12-(No code 12 used)
13-Main shaft speed pulse generator open or shorted.
14-Linear (line pressure control) solenoid open or shorted.
15-Kick down switch circuit shorted.

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Feb 14, 2010 | 1992 Honda Accord

1 Answer

1991 accord, auto trans: green sport light is flashing. WHY???


It is either your Vehicle Speed Sensor (easy to change) or your Automatic Transmission Computer (capacitors burn out on these boards, there is a fix for this too, the picture is at the bottom of this page). You need to diagnose by removing the lower right plastic kick panel on the passenger side. There you will find a blue plug. With the car OFF stick a paper clip, wire or stuff the plug with foil to make electrical connection so that the two terminals are touching. Then, turn the ignition to ON (not enough to start it though, just power it up). When you do this, count the blinks in the "S Light" or count your blinking Check Engine Light. Both are different but can refer to different things wrong with your car. A long blink is the first number and the short blinks that follow are the second number.
So imagine this as being 14 : ___ _ _ _ _

Below is a decoding chart:

The first section will be the check engine light codes2_bing.gif, the next one is the Transmission Control Unit Codes read from the S Light;

1 O2A - Oxygen sensor #1
2 O2B - Oxygen sensor #2
3 MAP - manifold absolute pressure sensor
4 CKP - crank position sensor
5 MAP - manifold absolute pressure sensor
6 ECT - water temperature sensor
7 TPS - throttle position sensor
8 TDC - top dead centre sensor
9 CYP - cylinder sensor
10 IAT - intake air temperature sensor
12 EGR - exhaust gas recirculation lift valve
13 BARO - atmospheric pressure sensor
14 IAC (EACV) - idle air control valve
15 Ignition output signal
16 Fuel injectors
17 VSS - speed sensor
19 Automatic transmission lockup control valve
20 Electrical load detector
21 VTEC spool solenoid valve
22 VTEC pressure valve
23 Knock sensor
30 Automatic transmission A signal
31 Automatic transmission B signal
36 traction control found on JDM ecu's
41 Primary oxygen sensor heater
43 Fuel supply system
45 Fuel system too rich or lean
48 LAF - lean air fuel sensor
54 CKF - crank fluctuation sensor
58 TDC sensor #2
61 Primary oxygen sensor
63 Secondary oxygen sensor
65 Secondary oxygen sensor heater
71 random misfire cylinder 1
72 random misfire cylinder 2
73 random misfire cylinder 3
74 random misfire cylinder 4
80 Exhaust Gas Recirculation insufficient flow detected
86 ECT Sensor (Engine Coolant Temperature) circuit range / performance problem
90 Evaporative Emission Control System leak detected in the fuel tank area
91 Fuel Tank Pressure Sensor low input
92 Evaporative Emission Control System insufficient purge flow

TCU Codes:

CODE LIST:

1-Lock-up solenoid 'A' circuit open or shorted.
2-Lock-up solenoid 'B' circuit open or shorted.
3-Throttle Position Sensor circuit open or shorted.
4-Vehicle Speed Sensor open or shorted - No signal from speedometer.
5-Shift Lever Position Switch circuit shorted.
6-Shift Lever Position Switch circuit open.
7-Shift Solenoid 'A' circuit open or shorted.
8-Shift Solenoid 'B' circuit open or shorted.
9-Counter shaft or transmission speed pulse generator open or shorted.
10-Coolant Temperature Sensor open or shorted.
11-Engine RPM (Ignition coil signal) open or shorted.
12-(No code 12 used)
13-Main shaft speed pulse generator open or shorted.
14-Linear (line pressure control) solenoid open or shorted.
15-Kick down switch circuit shorted.
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Feb 14, 2010 | 1991 Honda Accord

1 Answer

2003 Ford Taurus will not rev above 3000 RPM


you have a rev limiter in neutral. Is that when this happens?

Engine RPM/Vehicle Speed Limiter The powertrain control module (PCM) will disable some or all of the fuel injectors whenever an engine rpm or vehicle overspeed condition is detected. The purpose of the engine rpm or vehicle speed limiter is to prevent damage to the powertrain. The vehicle will exhibit a rough running engine condition, and the PCM will store a Continuous Memory DTC P1270. Once the driver reduces the excessive speed, the engine will return to the normal operating mode. No repair is required. However, the technician should clear the PCM and inform the customer of the reason for the DTC.
--------------------------------------------------------------------------------------

Fail-Safe Cooling Strategy The fail-safe cooling strategy is activated by the PCM only in the event that an overheating condition has been identified. This strategy provides engine temperature control when the cylinder head temperature exceeds certain limits. The cylinder head temperature is measured by the Cylinder Head Temperature (CHT) sensor. For additional information about the CHT sensor, refer to PCM Inputs for a description of the CHT sensor. Note: Not all vehicles equip with a CHT sensor will have the fail-safe cooling strategy.
A cooling system failure such as low coolant or coolant loss could cause an overheating condition. As a result, damage to major engine components could occur. Along with a CHT sensor, the fail-safe cooling strategy is used to prevent damage by allowing air cooling of the engine. This strategy allows the vehicle to be driven safely for a short time with some loss of performance when a overheat condition exist.
Engine temperature is controlled by varying and alternating the number of disabled fuel injectors. This allows all cylinders to cool. When the fuel injectors are disabled, their respective cylinders work as air pumps, and this air is used to cool the cylinders. The more fuel injectors that are disabled, the cooler the engine runs, but the engine has less power.
Note: A wide open throttle (WOT) delay is incorporated if the CHT temperature is exceeded during WOT operation. At WOT, the injectors will function for a limited amount of time allowing the customer to complete a passing maneuver.
Before injectors are disabled, the fail-safe cooling strategy alerts the customer to a cooling system problem by moving the instrument cluster temperature gauge to the hot zone and a PCM DTC P1285 is set. Depending on the vehicle, other indicators, such as an audible chime or warning lamp, can be used to alert the customer of fail-safe cooling. If overheating continues, the strategy begins to disable the fuel injectors, a DTC P1299 is stored in the PCM memory, and a malfunction indicator light (MIL) (either CHECK ENGINE or SERVICE ENGINE SOON), comes on. If the overheating condition continues and a critical temperature is reached, all fuel injectors are turned off and the engine is disabled.

Mar 15, 2009 | 2003 Ford Taurus

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