Major Power Loss 3.0L SE
09-25-2010, 11:20 PM
#1
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Join Date: Mar 2001
Posts: 1,142
Major Power Loss 3.0L SE
Before anybody decides to tell me to do a search... I have been searching for a solution to my power loss issues for over 6 months. It took serious courage for me to post a thread about this!!! 
I understand that there are a lot of threads out there where 2000 Maxima owners explain having similar problems as I am experiencing, however none of those people ever reports back on the progress or the results of their repair attempts.
I have a 2000 Nissan Maxima SE with just under 100k miles. The car does not throw an engine code. It idles rock solid at 750rpm with no rougness whatsoever. The car does not hesitate throughout the RPM. No ping or knock. However, the car simply does not have any power.
I have the following replaced so far:
- Rear O2 sensor
- Rear bank Coilpacks (3x)
- MAF Sensor
- Spark Plugs
- Cleaned Thottle body and intake system
- Engine oil/air filter are always in tip top shape
I suspected the variable intake valve being a culprit, but I do not experience the symptoms of a broken variable intake valve, and I hear the pitch of the engine changing at over 3500rpm as the valve opens.
I also suspected the fuel pump/filter, but it seems that all the people who reported having these parts replaced do not find any improvement.
Any advice???
I understand that there are a lot of threads out there where 2000 Maxima owners explain having similar problems as I am experiencing, however none of those people ever reports back on the progress or the results of their repair attempts.
I have a 2000 Nissan Maxima SE with just under 100k miles. The car does not throw an engine code. It idles rock solid at 750rpm with no rougness whatsoever. The car does not hesitate throughout the RPM. No ping or knock. However, the car simply does not have any power.
I have the following replaced so far:
- Rear O2 sensor
- Rear bank Coilpacks (3x)
- MAF Sensor
- Spark Plugs
- Cleaned Thottle body and intake system
- Engine oil/air filter are always in tip top shape
I suspected the variable intake valve being a culprit, but I do not experience the symptoms of a broken variable intake valve, and I hear the pitch of the engine changing at over 3500rpm as the valve opens.
I also suspected the fuel pump/filter, but it seems that all the people who reported having these parts replaced do not find any improvement.
Any advice???
09-26-2010, 01:26 PM
#4
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Join Date: Mar 2001
Posts: 1,142
I have suspected knock sensor also. However I am under the impression that a knock sensor failure would triger an engine code, which I don't have. But knock sensor makes sense because my car does not hesitate or have idle issues. It simply lacks power throughout the entire powerband, as if the power is restricted by the computer rather than exhibiting an underlying problem.
Could anybody tell me if a could knock sensor could without a code???
09-26-2010, 01:29 PM
#5
I did a compression test when I replaced the spark plugs. I forgot exactly what the figure was, but all six cylinders had consistent numbers spot on at stock specification. I am sure that quarter mile suffered greatly just from driving the car around town. The engine simply lacks power and response.
I have suspected knock sensor also. However I am under the impression that a knock sensor failure would triger an engine code, which I don't have. But knock sensor makes sense because my car does not hesitate or have idle issues. It simply lacks power throughout the entire powerband, as if the power is restricted by the computer rather than exhibiting an underlying problem.
Could anybody tell me if a could knock sensor could without a code???
I have suspected knock sensor also. However I am under the impression that a knock sensor failure would triger an engine code, which I don't have. But knock sensor makes sense because my car does not hesitate or have idle issues. It simply lacks power throughout the entire powerband, as if the power is restricted by the computer rather than exhibiting an underlying problem.
Could anybody tell me if a could knock sensor could without a code???
There's a bunch of threads...but get a 470K ohm resistor and stick it in the KS connector (on the side of the engine where you can see the wire going into the V under the IM). Fold the leads up to make them thicker so it's a tight fit. Reset the ECU for the fun of it, then go drive.
Last edited by Child_uv_KoRn; 09-26-2010 at 01:34 PM.
09-26-2010, 01:59 PM
#6
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Join Date: Sep 2010
Posts: 24
No acceleration is too broad of a complaint..will it rev fine in park or neutral? Only hold back in gear? Over-revving like a trans slippage issue? Check ECU connector and pins for water-leak damage. Check all grounds (battery,body,engine,trans). Is MAF blocked and/or dirty?
09-26-2010, 05:59 PM
#8
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Join Date: Mar 2001
Posts: 1,142
Thanks for the advice. Based on the feedbacks and further research, I am suspecting knock sensor.
I looked at the FSM regarding the location of the KS. It is on the cylinder block. However I cannot see it from the engine bay. Could you guys give me some pointers on where to look or how to replace it?
Thanks!!!
I looked at the FSM regarding the location of the KS. It is on the cylinder block. However I cannot see it from the engine bay. Could you guys give me some pointers on where to look or how to replace it?
Thanks!!!
09-28-2010, 03:37 AM
#10
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Join Date: Mar 2001
Posts: 1,142
- Use Redline fuel injector cleaner once a month.
- Used seafoam in engine oil before previous oil change about 1 month ago.
- Used seafoam in engine intake (induced through brake booster hose) before changing spark plugs 2 months ago.
- I only use brand new OEM parts.
- Been experiencing a gradual loss of power for the past 7 months. It has gotten unbearable about 3 months ago.
- I do NOT experience hesitation or idle roughness. The car idles fine and revs smoothly to redline, but significantly slower than before.
Again, the problem I experience is not a slight loss of power due to lack of maintenance. There is definitely a problem with some of the sensors or ignition/fuel system. The lack of engine hesitation or idle problem makes pin-pointing the problem extremely hard. The problem I am experiencing is too broad to diagnose precisely.
I am believing the problem to be the knock sensor, but it is a part that is too time consuing to replace.
09-28-2010, 02:46 PM
#11
KS can be replaced in 15 mins with a small ratchet and the socket taped on. You just have to take your time getting your hands in there (I have huge hands). A girl will be able to do it in no time flat. Loosen the bolt for her, then have her unscrew it and take it out, then vice versa.
Or you can just use 93 ocatane and sim it with the resistor. I've been using a resistor for over year on my current car just so the ECU can't be a ****.
Or you can just use 93 ocatane and sim it with the resistor. I've been using a resistor for over year on my current car just so the ECU can't be a ****.
09-29-2010, 12:40 PM
#12
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Join Date: Mar 2001
Posts: 1,142
KS can be replaced in 15 mins with a small ratchet and the socket taped on. You just have to take your time getting your hands in there (I have huge hands). A girl will be able to do it in no time flat. Loosen the bolt for her, then have her unscrew it and take it out, then vice versa.
Or you can just use 93 ocatane and sim it with the resistor. I've been using a resistor for over year on my current car just so the ECU can't be a ****.
Or you can just use 93 ocatane and sim it with the resistor. I've been using a resistor for over year on my current car just so the ECU can't be a ****.
I find it very hard to replace the KS on the 5th gen. It's virtually impossible to reach it
09-29-2010, 12:50 PM
#13
The 95-99 was fairly tight, but from what I recall the 00-01 is the most difficult in terms of space, with the 02-03 being the easiest, again in terms of space without removing the IM.
09-29-2010, 06:59 PM
#14
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Join Date: Aug 2010
Location: Twin Cities
Posts: 67
Sounds like the OP has the same problem as I do. Think I'll replace my KS then.
Any recommendations on which one to buy? I see Delphi and Bosch knock sensors selling for about $150 online, with cheapo MTC knock sensors for dirt cheap. Naturally I assume the Delphi and Bosch parts would be superior, but are the cheapo parts decent or just a waste of money? I'm not averse to spending money on a good quality part, but I also don't want to spend it needlessly.
thanks in advance
Any recommendations on which one to buy? I see Delphi and Bosch knock sensors selling for about $150 online, with cheapo MTC knock sensors for dirt cheap. Naturally I assume the Delphi and Bosch parts would be superior, but are the cheapo parts decent or just a waste of money? I'm not averse to spending money on a good quality part, but I also don't want to spend it needlessly.
thanks in advance
09-30-2010, 07:20 AM
#17
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Join Date: Mar 2004
Posts: 497
Can you put a live scanner on it and watch the timing? The big question though, what are the "correct" values of timing advance? On my 2000 5-speed GXE, it goes as high as 47 at part throttle. At idle it is around 15-16. This is with 87 octane.
If you hook up a live scanner and watch various parameters such as MAF readings, TPS reading, fuel trims, timing advance and publish those numbers, others might be able to compare and spot any abnormal readings.
Your symptoms indicate that you might have clogged exhaust system. I believe if you hook up vacuum gauge to intake manifold, you might be able to verify that.
Given that you have done most of the research already, I believe you will be able to nail this down with few more tests.
- Vikas
If you hook up a live scanner and watch various parameters such as MAF readings, TPS reading, fuel trims, timing advance and publish those numbers, others might be able to compare and spot any abnormal readings.
Your symptoms indicate that you might have clogged exhaust system. I believe if you hook up vacuum gauge to intake manifold, you might be able to verify that.
Given that you have done most of the research already, I believe you will be able to nail this down with few more tests.
- Vikas
Last edited by sontakke; 09-30-2010 at 07:22 AM.
09-30-2010, 09:52 AM
#18
Can you put a live scanner on it and watch the timing? The big question though, what are the "correct" values of timing advance? On my 2000 5-speed GXE, it goes as high as 47 at part throttle. At idle it is around 15-16. This is with 87 octane.
If you hook up a live scanner and watch various parameters such as MAF readings, TPS reading, fuel trims, timing advance and publish those numbers, others might be able to compare and spot any abnormal readings.
Your symptoms indicate that you might have clogged exhaust system. I believe if you hook up vacuum gauge to intake manifold, you might be able to verify that.
Given that you have done most of the research already, I believe you will be able to nail this down with few more tests.
- Vikas
If you hook up a live scanner and watch various parameters such as MAF readings, TPS reading, fuel trims, timing advance and publish those numbers, others might be able to compare and spot any abnormal readings.
Your symptoms indicate that you might have clogged exhaust system. I believe if you hook up vacuum gauge to intake manifold, you might be able to verify that.
Given that you have done most of the research already, I believe you will be able to nail this down with few more tests.
- Vikas
09-30-2010, 02:28 PM
#20
As in I approve this message, as in I think this is the answer, as in this reflects my opinion.
09-30-2010, 02:32 PM
#21
10-01-2010, 06:45 AM
#22
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Join Date: Mar 2004
Posts: 497
Sorry about that! Let us hope OP comes back and tells us what is going on.
To OP,
If you are willing to put put some money, go for ultra-gauge. I highly recommend it. It costs peanuts and has the live data scanner functionality built in. Google it using my user id/name and ultra-gauge. This will tell you all the engine parameters as you are driving. Unfortunately, there is no way to save it in a file for later analysis. For that you will need an expensive hand held scanner or cheap laptop based dongle. Given that you are mechanically inclined and use logic to diagnosis your vehicle, you have to invest in a tool which will help you.
- Vikas
To OP,
If you are willing to put put some money, go for ultra-gauge. I highly recommend it. It costs peanuts and has the live data scanner functionality built in. Google it using my user id/name and ultra-gauge. This will tell you all the engine parameters as you are driving. Unfortunately, there is no way to save it in a file for later analysis. For that you will need an expensive hand held scanner or cheap laptop based dongle. Given that you are mechanically inclined and use logic to diagnosis your vehicle, you have to invest in a tool which will help you.
- Vikas
11-05-2010, 03:50 AM
#25
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Thread Starter
Join Date: Mar 2001
Posts: 1,142
Sorry for the lack of update! During late summer I stopped the insurance on the Maxima and put my G35 and M45 back on the road. I was unable to drive or test the Maxima; it sat in my garage for over two months.
Today, as Fall is approaching, I renewed the insurance on the Maxima for winter driving. I drove it on the freeway for 3hrs straight and hit speeds of over 120mph. The car felt fine and the power loss seems to have disappeared. Gear shifts (auto) are no longer rough or jerky compared to when the car was losing power.
I suspect the summer heat had a great effect on the power of the car. The Maxima seems have regained all the lost power in colder weather. Although I admit that this is NOT normal and that there is probably an underlying problem, I think I will leave the car the way it is for now.
I have contemplated changing the KS, but it involves more work than I would like to perform.
I will update this thread as things change. For now, the car is no longer experiencing power loss and the 3.0VQ definitely feels more like 220hp than before.
11-05-2010, 04:03 AM
#26
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Join Date: Feb 2006
Location: East Granby, Connecticut
Posts: 945
Sorry for the lack of update! During late summer I stopped the insurance on the Maxima and put my G35 and M45 back on the road. I was unable to drive or test the Maxima; it sat in my garage for over two months.
Today, as Fall is approaching, I renewed the insurance on the Maxima for winter driving. I drove it on the freeway for 3hrs straight and hit speeds of over 120mph. The car felt fine and the power loss seems to have disappeared. Gear shifts (auto) are no longer rough or jerky compared to when the car was losing power.
I suspect the summer heat had a great effect on the power of the car. The Maxima seems have regained all the lost power in colder weather. Although I admit that this is NOT normal and that there is probably an underlying problem, I think I will leave the car the way it is for now.
I have contemplated changing the KS, but it involves more work than I would like to perform.
I will update this thread as things change. For now, the car is no longer experiencing power loss and the 3.0VQ definitely feels more like 220hp than before.
Today, as Fall is approaching, I renewed the insurance on the Maxima for winter driving. I drove it on the freeway for 3hrs straight and hit speeds of over 120mph. The car felt fine and the power loss seems to have disappeared. Gear shifts (auto) are no longer rough or jerky compared to when the car was losing power.
I suspect the summer heat had a great effect on the power of the car. The Maxima seems have regained all the lost power in colder weather. Although I admit that this is NOT normal and that there is probably an underlying problem, I think I will leave the car the way it is for now.
I have contemplated changing the KS, but it involves more work than I would like to perform.
I will update this thread as things change. For now, the car is no longer experiencing power loss and the 3.0VQ definitely feels more like 220hp than before.
Ya sure you didn't just have your butt-dyno recalibrated?
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