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I’ve got a 2000 Chevy Malibu with a 3100 that has a drive ability problem. Vehicle starts and idles fine. I step on the gas 3/4 of the way, no problem. I floor it (wide open throttle) and the engine just bogs down, a complete loss of power pretty much. The tach only reads at about 4000-4200 rpm’s at wide open throttle. When driving and flooring it to pass on the highway I get the same effect as mentioned above. Another issue is when driving occasionally the engine surges and the rpm’s fluctuate a bit, not a lot, but it’s noticeable. Any ideas on where to even start on resolving this or what could be causing these problems?
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p0122-throttle position sensor switch A circuit low
http://engine-codes.com/p0122.html
p0440 http://engine-codes.com/p0440.html
p0141-http://engine-codes.com/p0141_chevrolet.html
start with the p0141 o2 sensor heater circuit
here is a video on checking the o2 sensor
The nylon vacuum line in the wiring harness goes to the HVAC damper doors. These lines are prone to breakage with age.
Check the ERLS fuse in the under hood relay/fuse panel to see if it is blown. This fuse powers the O2 sensor heaters and the EVAP system solenoids.
Also clear the engine codes because the P0440 can disable many of the trouble code tests that the PCM normally runs. Note the GM did not check the heater amperage on these engines but checked the time required for the rear O2 sensor to start switching.
The nylon vacuum line in the wiring harness goes to the HVAC damper doors. These lines are prone to breakage with age.
Check the ERLS fuse in the under hood relay/fuse panel to see if it is blown. This fuse powers the O2 sensor heaters and the EVAP system solenoids.
Also clear the engine codes because the P0440 can disable many of the trouble code tests that the PCM normally runs. Note the GM did not check the heater amperage on these engines but checked the time required for the rear O2 sensor to start switching.
[quote=”killman” post=35546]The nylon vacuum line in the wiring harness goes to the HVAC damper doors. These lines are prone to breakage with age.
Check the ERLS fuse in the under hood relay/fuse panel to see if it is blown. This fuse powers the O2 sensor heaters and the EVAP system solenoids.
Also clear the engine codes because the P0440 can disable many of the trouble code tests that the PCM normally runs. Note the GM did not check the heater amperage on these engines but checked the time required for the rear O2 sensor to start switching.
GM 2000 3400 Engine Diagnostic Parameters[/quote]
Nice post!
[quote=”killman” post=35546]The nylon vacuum line in the wiring harness goes to the HVAC damper doors. These lines are prone to breakage with age.
Check the ERLS fuse in the under hood relay/fuse panel to see if it is blown. This fuse powers the O2 sensor heaters and the EVAP system solenoids.
Also clear the engine codes because the P0440 can disable many of the trouble code tests that the PCM normally runs. Note the GM did not check the heater amperage on these engines but checked the time required for the rear O2 sensor to start switching.
GM 2000 3400 Engine Diagnostic Parameters[/quote]
Nice post!
I finally got the plugs replaced and I’ve noticed a big difference but I’m still having some problems. First off is fuel milage is horrible. I’m getting about 200 miles if that on a full tank of gas. Usually averages around 180 miles on a full tank. Secondly when driving with either cruise on or holding steady on the accelerator the rpms sometimes jump around. The best way to describe it is its like someone is quickly hitting the gas and letting off. Also I have yet to replace the o2 sensor that’s throwing a p0141 code, o2 heater circuit bank 1 sensor 2. Is it possible that o2 sensor could be a factor in fuel milage? I was also thinking maybe the other o2 sensor could be lazy and just not throwing a code yet is this possible? If I were to analyze live engine data is there anything particular I should be looking at as far as voltages or whatever on the first o2 sensor (before the cat) to see if its ok?
I finally got the plugs replaced and I’ve noticed a big difference but I’m still having some problems. First off is fuel milage is horrible. I’m getting about 200 miles if that on a full tank of gas. Usually averages around 180 miles on a full tank. Secondly when driving with either cruise on or holding steady on the accelerator the rpms sometimes jump around. The best way to describe it is its like someone is quickly hitting the gas and letting off. Also I have yet to replace the o2 sensor that’s throwing a p0141 code, o2 heater circuit bank 1 sensor 2. Is it possible that o2 sensor could be a factor in fuel milage? I was also thinking maybe the other o2 sensor could be lazy and just not throwing a code yet is this possible? If I were to analyze live engine data is there anything particular I should be looking at as far as voltages or whatever on the first o2 sensor (before the cat) to see if its ok?
If you have access to live data, please post your fuel trim numbers at idle, 1500 and 2500 rpm, thank you.
If you have access to live data, please post your fuel trim numbers at idle, 1500 and 2500 rpm, thank you.
I actually had captured a screen shot with my friends scanner after replacing the plugs. Here’s what I got: (these values are at idle)
HO2 snsr -1 (mv) 993 (my camera had a hard time getting the proper value because it was fluctuating) ill check again and report back
HO2 snsr -2 (mv) 422
O2 S1 ready – yes
O2 cross counts – 0
Open/Closed loop – Open
Hot Open loop – NoST Trim (%) 0
LT Trim (%) 13MAF (Gm/sec) 4.32
Remember these values are at idle. Like I said I’ll repost back with the 1500 and 2500 values and any more information that’s needed
I actually had captured a screen shot with my friends scanner after replacing the plugs. Here’s what I got: (these values are at idle)
HO2 snsr -1 (mv) 993 (my camera had a hard time getting the proper value because it was fluctuating) ill check again and report back
HO2 snsr -2 (mv) 422
O2 S1 ready – yes
O2 cross counts – 0
Open/Closed loop – Open
Hot Open loop – NoST Trim (%) 0
LT Trim (%) 13MAF (Gm/sec) 4.32
Remember these values are at idle. Like I said I’ll repost back with the 1500 and 2500 values and any more information that’s needed
Thank you for posting your numbers @ idle.
In order to diagnose performance, you have to start with a baseline engine and today that means that you have to make sure regular maintenance has been applied and the engine will not fail for neglect, such as a clogged air filter messing with fuel trim.
Please keep this in mind.HO2 snsr -1 (mv) 993
HO2 snsr -2 (mv) 422
O2 S1 ready – yes this may means that it has reached operating temperature and the output signal would be considered reliable by the ECM
O2 cross counts – 0 this means it is stuck unless you have an A/F sensor. When stuck on lean it will cause the fuel system to enrich
Open/Closed loop – Open this means that the ECM is not controlling the engine’s fuel injection for emission purposes
Hot Open loop – No this one is new for me, I am not sure that the engine is in operating temperature and ready for closed loop controlST Trim (%) 0 no modifications can be made or need to be done at this moment, is this always 0 or it fluctuates ?
LT Trim (%) 13 this means that the computer is adding fuel for a perceived lean condition, is this always 13 or it fluctuates ?MAF (Gm/sec) 4.32
What is missing here is the engine and air intake temperature, this will tell what enrichment will apply here. The code will apply for the post cat, it is not used for fuel control, only as a comparator for cat efficiency.
The hesitation you fuel comes from an unbalanced ration of fuel and air, remember you adding more fuel than you need.
Thank you for posting your results.Thank you for posting your numbers @ idle.
In order to diagnose performance, you have to start with a baseline engine and today that means that you have to make sure regular maintenance has been applied and the engine will not fail for neglect, such as a clogged air filter messing with fuel trim.
Please keep this in mind.HO2 snsr -1 (mv) 993
HO2 snsr -2 (mv) 422
O2 S1 ready – yes this may means that it has reached operating temperature and the output signal would be considered reliable by the ECM
O2 cross counts – 0 this means it is stuck unless you have an A/F sensor. When stuck on lean it will cause the fuel system to enrich
Open/Closed loop – Open this means that the ECM is not controlling the engine’s fuel injection for emission purposes
Hot Open loop – No this one is new for me, I am not sure that the engine is in operating temperature and ready for closed loop controlST Trim (%) 0 no modifications can be made or need to be done at this moment, is this always 0 or it fluctuates ?
LT Trim (%) 13 this means that the computer is adding fuel for a perceived lean condition, is this always 13 or it fluctuates ?MAF (Gm/sec) 4.32
What is missing here is the engine and air intake temperature, this will tell what enrichment will apply here. The code will apply for the post cat, it is not used for fuel control, only as a comparator for cat efficiency.
The hesitation you fuel comes from an unbalanced ration of fuel and air, remember you adding more fuel than you need.
Thank you for posting your results.With the O2 heater out it won’t go into closed loop. You can see this based on what you posted. If the engine doesn’t go into closed loop your milage will suffer. If you’re trying to address a performance issue you need to address ALL known issues before you can call it fixed.
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