Location of O2 Sensor
- Thread starter djk4013
- Start date
O2 Sensor?
Wanted to give a bit more detail on what my problem is:
Everyday my truck starts out good, like this morning, I was driving to work and could feel it "miss" then, start running bad - the Check Engine Light comes on. The truck runs bad, missing , etc. If/When I shut the truck off, the light goes off and the truck runs fine again.
I've had so many problems with my old truck and am at my witts end, if anyone can help me with my issue, I sure would appreciate it.
Thanks, Tony
Wanted to give a bit more detail on what my problem is:
Everyday my truck starts out good, like this morning, I was driving to work and could feel it "miss" then, start running bad - the Check Engine Light comes on. The truck runs bad, missing , etc. If/When I shut the truck off, the light goes off and the truck runs fine again.
I've had so many problems with my old truck and am at my witts end, if anyone can help me with my issue, I sure would appreciate it.
Thanks, Tony
Molson02536
New member
Start with finding out why your check engine light is coming on, this way there is no expensive guessing work. Here is a link for you to retrieve the DTC codes and post me back. Be glad to help you get your Sonoma running 100% again soon.
http://www.troublecodes.net/GM/
Molson.....
Thank you for the information. I will take it to a nearby Auto place to read the code as soon as it comes on again, and re-post. It may be a day or so, the light doesn't come on everyday but, I do appreciate your help.
Thank you for the information. I will take it to a nearby Auto place to read the code as soon as it comes on again, and re-post. It may be a day or so, the light doesn't come on everyday but, I do appreciate your help.
We read the computer codes and got the following codes:
33 - MAP Sensor
34 - Vaccuum Sensor or MAP Sensor
43 - Electronic Spark Timing (EST)
45 - O2 Sensor
We replaced the MAP Sensor & the Oxygen sensor. The truck isn't running "as bad" as it was but now, when I hit 5th gear it seems to lug and feels like it's loosing power.
Could my CLUTCH be slipping? or Could this be a SPARK Plug issue?
The "Check Engine Light" hasn't come back on but, I only replaced the sensors last night and, have reset the computer.
Any ideas what to try next???
33 - MAP Sensor
34 - Vaccuum Sensor or MAP Sensor
43 - Electronic Spark Timing (EST)
45 - O2 Sensor
We replaced the MAP Sensor & the Oxygen sensor. The truck isn't running "as bad" as it was but now, when I hit 5th gear it seems to lug and feels like it's loosing power.
Could my CLUTCH be slipping? or Could this be a SPARK Plug issue?
The "Check Engine Light" hasn't come back on but, I only replaced the sensors last night and, have reset the computer.
Any ideas what to try next???
Molson02536
New member
Simple, just finieh doing your tune up, repalce the fuel filter, spark plugs and spark plug wires, distributor cap and rotor. Also clean out your Throttle body with throttle body cleaner, not carburator cleaner. The carb cleaner is to corrosive to the gaskets used on the throttle body,
Replace any vacuum lines that are damaged and is causing you to loose any vacuum throughout your engine. The sensors as you well have found out by now run of the vacuum of the engine as to manipulate it's performance.
Start with what has been mentioned above and check your engine timing last.
Good luck and please keep us posted and it's not your clutch slipping to make your engine bog down.
Molson,
Check Engine light came on on my way home from work again today.
The computer read a Code: 43 Electronic Spark Control. Going now to buy a ESC Knock Sensor - the chilton book says this will result in sluggish performance so, I'm hoping this is what it is.
Will also check what you stated above and buy the cleaner too and, double check the GAP settings on the Spark Plugs.
Thanks for your help!! Tony
Check Engine light came on on my way home from work again today.
The computer read a Code: 43 Electronic Spark Control. Going now to buy a ESC Knock Sensor - the chilton book says this will result in sluggish performance so, I'm hoping this is what it is.
Will also check what you stated above and buy the cleaner too and, double check the GAP settings on the Spark Plugs.
Thanks for your help!! Tony
1993 GMC Sonoma
Molson,
I was on my way home from work today and that darn check engine light came on again.
Read the code: 43 - Electronic Spark Control Unit.
Should I check the spark plugs before I go buy another part or, should I go buy a new ESC Knock Sensor?
Thank you for all your help. Tony
Molson,
I was on my way home from work today and that darn check engine light came on again.
Read the code: 43 - Electronic Spark Control Unit.
Should I check the spark plugs before I go buy another part or, should I go buy a new ESC Knock Sensor?
Thank you for all your help. Tony
Molson02536
New member
Before you by a new knock sensor (code 43) try disconecting the wire lead to the sensor. It's located on the passneger side I believe on the 4.3, there is going to be one wire lead to it. When you do go to replace the knock sensor, make sure the engine is cold since it's screwes in to the watrer jackets.
There are two timing system on your 4.3, one is the elsectronic timing (EST) which controls the actual timing of the ignition system according to the throttle position and MAP, speed sensors ECT...
The other is the knock sensor (ESC) electronic spark control which will retard the timing if the engine encounters detonation (know as knock or ping). Cheap fuel or badly tuned engine full of carbon will cause the detonation which will put your engine in a reduced power as the timing will be retarded to stop tge detonation.
A faulty Knock sensor that is overly sensitive will pick up the vibration from the lifters and gice the ecm faulty signals to reduce the timing which will give you the low power issues your having.
Start with that and keep me psted and be safe, well get your Sonoma running like a dream yet.
Molson02536
New member
You have to squeeze the side of the wire clip to remove it from the knock sensor. Here is a picture of the wire lead clips. http://www.rmsautoparts.com/prodimages/PT727.gif
Good luck and take your time, as you can see from the picture that there are two clips that hold the harness to the sensor. You need to squeeze the opposite side of where the locking clips are to have them push out from the sensor.
1993 GMC Sonoma
Molson,
We have changed the spark knock detector, throughly cleaned out the throttle body, replaced spark plug - GAP correct, replaced MAP sensor, O2 Sensor, bought new air filter , set timing however, under a load, at the top end of a gear, if I hold it there, the truck feels like it loads up and fouls and the The Check Engine light comes on.
This is where I'm at now.....
The computer pulled a : 43 (Electronic Spark Control)
I'm wondering if there could be a problem with the Catalytic Converter? I'm not sure what to replace or look at next?
Thank you for your time and help, I'm at my witts end and don't know what to do or check next?
Molson,
We have changed the spark knock detector, throughly cleaned out the throttle body, replaced spark plug - GAP correct, replaced MAP sensor, O2 Sensor, bought new air filter , set timing however, under a load, at the top end of a gear, if I hold it there, the truck feels like it loads up and fouls and the The Check Engine light comes on.
This is where I'm at now.....
The computer pulled a : 43 (Electronic Spark Control)
I'm wondering if there could be a problem with the Catalytic Converter? I'm not sure what to replace or look at next?
Thank you for your time and help, I'm at my witts end and don't know what to do or check next?
Molson02536
New member
As mentioned on my previous post, try running the truck with the knock sensor disconnected and see if the engine runs better. If it does, then we need to desensitize the knock sensor. Also check for any signs of a vacuum leak or any signs of bad fuel pressure regulator.
No worries, keep up the great work and we'll get your Sonoma running like a charm soon. It's most likely going to be something simple that we may have over looked. Keep me posted
1993 GMC Sonoma
Molson,
I disconnected the knock sensor, the truck runs rough.
After this happens, once I turn the key off and start it back up, it runs smooth again.
The truck seems to sound "muzzled" from the cabin area when I accelerate.
tony
Molson,
I disconnected the knock sensor, the truck runs rough.
After this happens, once I turn the key off and start it back up, it runs smooth again.
The truck seems to sound "muzzled" from the cabin area when I accelerate.
tony
Molson02536
New member
The distributor is controlled by the computer and springs, I can't recall but I don't remember seeing springs in there. Regardless, check anyways to see if there is any binding to your counter weights in the distributor.
Recheck your timing and you'd notice more difference if you increased your static timing advance from the stock setting of 10 Deg BTDC to 15 deg BTDC or so. Be sure when you adjust timing to disable the ESC circuit according to the manual. Otherwise the timing will be off scale and you won't even be able to see where it is with a timing lite.
The connector you're looking for is located in the passenger footwell, sometimes covered by the carpet/floor mat. It is a black connector, that has a tan/black wire in each side. Disconnect this wire and you will be able to see the base timing.
The ECM will control the timing with that wire connected. When it is disconnected the timing advance is controled strictly by the ICM (Ignition Control Module) located on the base of the dizzy.
How to set:
The vehicle emission control information label, which is found underhood, will often contain specifications or procedures for checking and adjusting timing that have been updated during production.
Set the parking brake and block the drive wheels, then warm the engine to normal operating temperature. Shut the engine OFF and connect the a timing light to the No. 1 spark plug (right front 2.8L engine, left front 4.3L engine or front plug on in-line engines):
If using a non-inductive type, connect an adapter between the No. 1 spark plug and the spark plug wire; DO NOT puncture the spark plug wire, for this will allow a voltage arc.
If using an inductive type, clamp it around the No. 1 spark plug wire.
If using a magnetic type, place the probe in the connector located near the damper pulley; this type must be used with special electronic timing equipment. Do not under any circumstances pierce the insulation of a spark plug wire in order to connect the timing light.
Clean off the timing marks, then label the pulley or damper notch and the timing scale with white chalk or paint for better visibility. If the timing notch on the damper or pulley is not visible from the top, the crankshaft should be bumped around using the starter or turned using a wrench on the front pulley bolt, in order to bring the mark to an accessible position.
Model vehicles equipped with EST, the electronic spark timing must be disabled or bypassed to prevent the control module from advancing timing while you are attempting to set it. This would obviously lead to an incorrect base timing setting.
There are 2 possible methods of disabling the EST system, depending on the type of engine:
On 2.5L engines, ground the "A" and "B" terminals on the ALDL connector under the dash before adjusting the timing.
On all other engines using the EST distributor, disengage the timing connector wire. On a few of the earlier model vehicles, the 4-terminal EST connector must be disengaged from the distributor, but most later model vehicles are equipped with a single wire timing bypass connector.
On these later model vehicles the bypass wire is usually a tan wire with a black stripe. This wire usually breaks out of the wiring harness conduit adjacent to the distributor, but on some vehicles it may break out of a taped section just below the heater case in the passenger compartment.
Start the engine, then check and adjust the idle speed, as necessary. The idle speed must be properly set to prevent any centrifugal advance of timing in the distributor.
Aim the timing light at the timing marks. Be careful not to touch the fan, which may appear to be standing still. Keep your clothes and hair along with the timing light's wires clear of the fan, belts and pulleys. If the pulley or damper notch isn't aligned with the proper timing mark, the timing will have to be adjusted.
TDC or Top Dead Center corresponds to 0° mark on the scale. Either B, BTDC, or Before Top Dead Center, may be shown as BEFORE on the scale, while A, ATDC or After Top Dead Center, may be shown as AFTER.
Loosen the distributor base clamp locknut. You can buy special wrenches which make this task a lot easier on certain models. Turn the distributor slowly to adjust the timing, holding it by the body and not the cap. Turn the distributor in the direction of rotor rotation to retard, and against the direction to advance.
Once the timing is properly set, hold the distributor to keep it from the turning and tighten the locknut. Check the timing again after finishing with the nut in case the distributor moved as you tightened it.
If applicable, remove the plug and connect the distributor vacuum hose.
Shut off the engine and reconnect the EST wire (if equipped), then disconnect the timing light and tachometer.
Also you may want to inspect the EGR to see if it's stuck, which may be causing our issue when the engine is under load.
Molson....
Thank you, Thank you, Thank you....
The CONNECTOR in the passenger side foot well was the issue with the timing. My truck seems to be running GREAT now!!!
thank you for hanging in there with me and giving me all the detailed information I needed to get my truck running again!!!
Thank you, Thank you, Thank you....
The CONNECTOR in the passenger side foot well was the issue with the timing. My truck seems to be running GREAT now!!!
thank you for hanging in there with me and giving me all the detailed information I needed to get my truck running again!!!
Molson02536
New member
Glad to hear you got your Sonoma running 100% again and think of all the Money you saved if you had sent it to the garage. Keep me posted and be safe.
1993 GMC Sonoma
Molson!
You're not going to believe this. I was on my way home today and my CHECK ENGINE light came one again!!!
The truck was running bad, really bad...couldn't even get it to go 30!! Then, there was a bad odor and sounded muzzled - this is all while under a load - pulling my mowing equipment/trailer.
I got a code: 45 02 Sensor Indicates Rich Exhaust.
I just replaced the Oxygen Sensor this week.
Any ideas??
Thanks, Tony
Molson!
You're not going to believe this. I was on my way home today and my CHECK ENGINE light came one again!!!
The truck was running bad, really bad...couldn't even get it to go 30!! Then, there was a bad odor and sounded muzzled - this is all while under a load - pulling my mowing equipment/trailer.
I got a code: 45 02 Sensor Indicates Rich Exhaust.
I just replaced the Oxygen Sensor this week.
Any ideas??
Thanks, Tony
Molson02536
New member
Molson!
You're not going to believe this. I was on my way home today and my CHECK ENGINE light came one again!!!
The truck was running bad, really bad...couldn't even get it to go 30!! Then, there was a bad odor and sounded muzzled - this is all while under a load - pulling my mowing equipment/trailer.
I got a code: 45 02 Sensor Indicates Rich Exhaust.
I just replaced the Oxygen Sensor this week.
Any ideas??
Thanks, Tony
Check your vacuum line to your fuel pressure regulator, if the line is good. You may have a bad fuel pressure regulator. If I can remember, the 2.8 runs a fuel pressure of 11-13 psi.
Start with that and hope it's that simple
good luck and keep me posted.Gmc.....
Molson,
The other day - Thursday, I pulled a code and replaced the vapor canister. It took until today to get the part in. We now have a new canister in as well.
The truck is running bad - very bad. The fastest it will go is 20 mph.
Now, we just pulled the codes again and here's what I have:
Code 24 - Vechcile speed sensor
and
Code 42 - EST (Electronic Spark Timing)
At this point, I have no idea what to replace next and/or what to try. It was running like a brand new truck for two days.
Just to give you a bit more information, a few weeks ago we put throttle body cleaner and put Chemtrol B-12 in the gas and, as I said, it ran great but, on the way back home from working (and hauling a load) is when it started running bad and we ordered the canister.
Thank you for all your help - it is much appreciated. Tony
Molson,
The other day - Thursday, I pulled a code and replaced the vapor canister. It took until today to get the part in. We now have a new canister in as well.
The truck is running bad - very bad. The fastest it will go is 20 mph.
Now, we just pulled the codes again and here's what I have:
Code 24 - Vechcile speed sensor
and
Code 42 - EST (Electronic Spark Timing)
At this point, I have no idea what to replace next and/or what to try. It was running like a brand new truck for two days.
Just to give you a bit more information, a few weeks ago we put throttle body cleaner and put Chemtrol B-12 in the gas and, as I said, it ran great but, on the way back home from working (and hauling a load) is when it started running bad and we ordered the canister.
Thank you for all your help - it is much appreciated. Tony