Tapping, knocking noise 02 TB 93k

81turboguy

Original poster
Member
Nov 13, 2012
48
Started this thread not to hijack the other any further than I did :smile:

Here is my mysterious engine sound.

[video=youtube;G3KD_0zqo74]http://www.youtube.com/watch?v=G3KD_0zqo74[/video]

2002, 93k, Mobil 1 change about 1k ago. Recently drove to Columbus OH and back and got ~18mpg on the highway. Used Exxon gas for the past few months with Lucas in it on the way out and a bit of MMO on the was back to see any change.

New plugs last year, the AC Delcos recommended in the forum.
New belt
New idler pulley
New tensioner
Air filter is clean was changed last spring.
TB cleaned last spring

The PS pump does make a bit of noise but it is not the loud one as in the video.

Would a bad water pump cause this? My temp reads right around 210 once warmed up.

Thanks in advance for any input!
 

81turboguy

Original poster
Member
Nov 13, 2012
48
I can see it now.

I'm going to try what Captain suggested and see if there is any change. Yours sound quieter, maybe closer to Zx2ner88,
Is it much louder with the hood open?
 

81turboguy

Original poster
Member
Nov 13, 2012
48
I also have a slight hesitation I have in park, not sure if it is related or not.

After driving and then parking, I can leave the car run and then hit the gas. There's a stumble or hesitation before it finally revs up.

There is a new inline fuel filter.
 

81turboguy

Original poster
Member
Nov 13, 2012
48
CaptainXL said:
Easy enough to check. Take the belt off and run it for a few seconds. See if the noise goes away.

I tried this over the weekend and the noise is still prevalent. I'm going to flush the synthetic oil out and go back to dino to see if there is any change in the noise. Currently there is Mobil 5w30 and a Mobil 1 filter on there. Before I do that I'll do the seafoam treatment in the crankcase.

With my hesitation issue, I was reading up on the fuel trims and how to read them on torque. Here are two shots, with the car warmed up, in park/neutral. I gun it a little bit and it hesitates at first then revs up. In the second shot, the dip in the secondary o2 is right when it happened.

I believe the fuel trims were within spec? Do they look ok?

Many thanks.

View attachment 27827
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CaptainXL

Member
Dec 4, 2011
2,445
At 100k miles or when the plugs are first changed the O2 sensor should be replaced as well. Also I would replace the CPAS. For the STFT and ltft you need to choose a graph view in order to see if the STFT is staying around 0.
 

gmcman

Member
Dec 12, 2011
4,656
81....when I try to diagnose a pronounced knock like yours, I pull each coil pack connector one at a time and see if the knock changes. Just disconnect the harness for a few seconds and you will know if and when you get to the troubled cylinder.

I would not use anything oil related right now and try the coil pack test. Could be valvetrain but doesn't sound like it from these speakers. I have ventured from M1 and my motor is quieter, YMMV, I am currently using Pennzoil Platinum.

A few treatments I would try first is Auto Rx or Rislone.
 

tblazerdude

Member
Dec 4, 2011
321
CaptainXL said:
At 100k miles or when the plugs are first changed the O2 sensor should be replaced as well. Also I would replace the CPAS. For the STFT and ltft you need to choose a graph view in order to see if the STFT is staying around 0.

O2 sensors, yes. They are a 100k replacement item. CPAS should not have to be replaced if regular oil changes have been done. There is nothing that can "wear out" on them, they can only get "gunked up" by using cheap oil and long interval oil changes. Improper weight oil and oil contamination (operating w/o air filter, or coolant seepage) can also damage the CPAS.
 

81turboguy

Original poster
Member
Nov 13, 2012
48
Thanks gents.

The CPAS is the one behind the steering pump correct? I pulled that this past weekend and cleaned it with TB cleaner I had left over and compressed air, it was in pretty good shape with very minimal grit on the screens.

Also pulled 3 and 4 plugs to take a quick look and they appeared to be normal (changed them last year with the delcos recommended here).

Thanks for the Torque tip, I'll change that today and grab another shot.

I'll try the coil packs also. The o2 sensor is due for a change since I'm almost at 100k. After reading around here and the OS, I'm wondering if I have a manifold issue that's causing this noise. Planning on checking when I do the o2 sensor since I'll be there and can take the shield off.

Bit of history: been running Exxon gas for a few weeks now with an occasional seafom. It doesn't sound like a big difference but I'll keep at it since it was suggested here. The Risoline would be for the crankcase or the gas tank?

Thanks again!
 

ConeKilrAutoX

Member
Dec 8, 2011
1,179
81turboguy said:
Has anyone had an issue with the bosch o2 sensor?

YES I just took mine out! they could have been causing the flooding with the 80lb injector swap and my voy ran so rich before the swap it threw up black debris alll over the back of the vehicle. Never had that happen with ac delco
 

dfc739

Member
Jul 29, 2012
170
Des Moines, IA
81turboguy said:
Has anyone had an issue with the bosch o2 sensor?

I've been running a Bosch O2 sensor for 10k miles without any issues. I know there are several others here that haven't had the same experience with Bosch as me though.
 

ConeKilrAutoX

Member
Dec 8, 2011
1,179
dfc739 said:
I've been running a Bosch O2 sensor for 10k miles without any issues. I know there are several others here that haven't had the same experience with Bosch as me though.

agreed. my friends has been fine also but his wifes was not. guess its hit or miss with bosch sensors.
 

Harpo

Member
Dec 4, 2011
411
Sweden
ShadowClutch said:
Sounds a bit like mine.

[video=youtube_share;L5SQjJm_ofs]http://youtu.be/L5SQjJm_ofs[/video]


Yours is more a valve or lifter noise
 

Sparky

Member
Dec 4, 2011
12,927
My Bosch O2 has been fine for like 60k miles now. Surprised me actually. I would normally stick with AC Delco or a Denso just to be safe however (read on the OS those were good too, I think Denso may have made the OEM AC Delco sensor).

I still have a new Denso sensor on my shelf as I was expecting the Bosch to be crap and need swapped out again.
 

81turboguy

Original poster
Member
Nov 13, 2012
48
Sparky said:
My Bosch O2 has been fine for like 60k miles now. Surprised me actually. I would normally stick with AC Delco or a Denso just to be safe however (read on the OS those were good too, I think Denso may have made the OEM AC Delco sensor).

I still have a new Denso sensor on my shelf as I was expecting the Bosch to be crap and need swapped out again.

Thanks. It looks like Amazon has a good price on it.

ACDelco 213-1551 OE Service Oxygen Sensor
ACDelco 213-1551 OE Service Oxygen Sensor : Amazon.com : Automotive
 

CaptainXL

Member
Dec 4, 2011
2,445
Give Advance Auto a shot. Usually they have $20 off a $50 or $75 order with free ship to store with their BIGXXX codes at checkout. Otherwise try the usual RETAILMENOT123 or VISA code at checkout. They always have some deal going.
 

81turboguy

Original poster
Member
Nov 13, 2012
48
Reconfigured my Torque App.

Here is after driving 5 miles yesterday, outside temp appx 70 degrees.
View attachment 27871

Here are the results while in park and the rpm, hesitation drop occurs. I'll get on ordering the o2 sensor today since that is about due anyway.
View attachment 27872
 

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gmcman

Member
Dec 12, 2011
4,656
81 Turbo....is that a 301?

Hey, it looks like you are chasing an oxygen sensor looking for a rod knock. That knock is nasty and I would focus my attention on that first and foremost. The upstream O2 sensor dances all around, perfectly normal..the hesitation without driving it could be an O2 issue or dirty injectors, etc. When you step on the gas the upstream sensor will spike momentarily and the same when you coast. The values may not be accurate not being a Delco but looks like it is working.

There is a vacuum port at the front of the intake on the right side facing the intake resonator. Use that port and check the vacuum, if a steady needle then we can rule out a stuck valve removing the zero-lash from the cam lobe. Could be a lash adjuster but I don't think it is.

You really need to pull a coil pack harness on each coil when it's running and see if the knock goes away. A knock that pronounced is either a bad exhaust leak at the manifold or a rod, or possibly a wristpin but noy likely a pin.
 

81turboguy

Original poster
Member
Nov 13, 2012
48
gmcman said:
81 Turbo....is that a 301?

Hey, it looks like you are chasing an oxygen sensor looking for a rod knock. That knock is nasty and I would focus my attention on that first and foremost. The upstream O2 sensor dances all around, perfectly normal..the hesitation without driving it could be an O2 issue or dirty injectors, etc. When you step on the gas the upstream sensor will spike momentarily and the same when you coast. The values may not be accurate not being a Delco but looks like it is working.

There is a vacuum port at the front of the intake on the right side facing the intake resonator. Use that port and check the vacuum, if a steady needle then we can rule out a stuck valve removing the zero-lash from the cam lobe. Could be a lash adjuster but I don't think it is.

You really need to pull a coil pack harness on each coil when it's running and see if the knock goes away. A knock that pronounced is either a bad exhaust leak at the manifold or a rod, or possibly a wristpin but noy likely a pin.

Indeed it is! 1981 Pontiac Turbo Trans Am 301 4.9L 73k original miles. She's getting jealous that the TB is getting all the attention :wink:

Thanks for the additional input. I did order the o2 since I'm almost at the maintenance interval, plugs were done when I bought it last year. I'll hold off installing it though.

Are you referring to the nipple that sticks out and points to the left, passenger side? The port by the FPR? I tried using that with my vac gauge and got nothing. Put a small pick in there and it ended up hitting something. I was able to use the brake booster line and the gauge read normally and returned normally when I gave it gas. Pretty close to the torque reading actually.

Coil pack is my next test. I'm really hoping it's not a rod. The sound doesn't get louder as I drive, it's just noticeable at idle. 5w30 Mobil 1 is in there now with a Mobil filter and the oil didn't appear sludgy to me. I still have the old oil, maybe I'll dip a magnet in there just to be sure of any metal.

Thanks again.
 

CaptainXL

Member
Dec 4, 2011
2,445
Dont use the fpr line. Remove the large evap line at the throttle and use that. To take it off you press the little tab over to the right and pull gently. A good Actron or similar vacuum gauge should have the neccesary adapters. Otherwise MacGuiver it.
 

81turboguy

Original poster
Member
Nov 13, 2012
48
Roger. I've taken it off before to clean the TB.

So, should there be a vac line on that nipple? I don't believe the routing diagram shows one. The Chilton manual I have also showed to use that as a vac source.
 

gmcman

Member
Dec 12, 2011
4,656
This is this is not the fuel pressure regulator line this is on the passenger side of the intake manifold in the front.

I would check to make sure it is the rod before you possibly beat the rod journal out of round if you do that then you will need to pull the crank if it is just a rod bearing if the journal is still round you could probably get by with just replacing with standard size bearings
 

81turboguy

Original poster
Member
Nov 13, 2012
48
Pulled every coil and no change. While I had the resonator off I took a piece of hose and held it up to different areas of the top end. There was noticeable chatter on the drivers side between the intake and block.

The vac gauge on the TB gave me 21 deg Hg at a steady rate. If I gunned it up to 2500 or so, it would jump down to about 6degHg and then up to 25-26 when the rpms came back down. About 3 seconds later it returned to 21. I used the port Captain illustrated.

GMC, the only way to do that is to pull the pan correct?

Thanks again guys.
 

CaptainXL

Member
Dec 4, 2011
2,445
I would drain the oil and check for glitter if you think its a wear problem. But even that probably isn't conclusive.
 

gmcman

Member
Dec 12, 2011
4,656
81turboguy said:
Pulled every coil and no change. While I had the resonator off I took a piece of hose and held it up to different areas of the top end. There was noticeable chatter on the drivers side between the intake and block.

The vac gauge on the TB gave me 21 deg Hg at a steady rate. If I gunned it up to 2500 or so, it would jump down to about 6degHg and then up to 25-26 when the rpms came back down. About 3 seconds later it returned to 21. I used the port Captain illustrated.

GMC, the only way to do that is to pull the pan correct?

Thanks again guys.

Did you rev the engine up to about 1500 ish when you pulled the coil leads?

The racket around the intake could be the injectors
 

81turboguy

Original poster
Member
Nov 13, 2012
48
gmcman said:
Did you rev the engine up to about 1500 ish when you pulled the coil leads?

The racket around the intake could be the injectors

It sounded like a roller coaster would sound being pulled up the hill. I'm assuming one of the cams with a noisey chain.

I didn't rev the engine but I can try that again this weekend. Going to to an oil change too back to Penzoil dino just to see if there is any change. Might do half a bottle of seafoam in the crankcase before changing it out.
 

gmcman

Member
Dec 12, 2011
4,656
Have you considered 1qt of Rislone instead of Seafoam? Maybe others can chime in but the Rislone might be the berrer cleaner. Definately check the knock first.
 

81turboguy

Original poster
Member
Nov 13, 2012
48
gmcman said:
Have you considered 1qt of Rislone instead of Seafoam? Maybe others can chime in but the Rislone might be the berrer cleaner. Definately check the knock first.

I'll check it out.

What should I listen for with a coil off and increased rpm, the knock to become worse? Just trying to understand what I should hear if it is a rod.

Thanks.
 

gmcman

Member
Dec 12, 2011
4,656
Get the engine warm and listen to the pattern of the knock, in CASH's situation the bearing was obviously toast and removing the power stroke didn't make too much of a difference. Since the 6cyl fires every 120 deg of crank rotation and also since the compression ratio is high, you may hear knock from the previous cyliner firing forcing the bad cyl up on the compression stroke.

Raise the RPM's and listen for the knock, also the pattern of the knock. As the cylinder leans and richens the intensity changes so when you pull the coil, the knock should change as well as the pattern. I don't think they will all sound the same so hopefully it will be easy to detect.

When you disconnect the coil, observe the pattern change and when you reattach the lead, allow the cyl to catch up with the fuel burn. I don't know exactly what the ECM does but it may pull the injector out of the loop if the coil is disconnected...dunno but give it a few seconds to catch back up if the fuel keeps flowing.
 

gmcman

Member
Dec 12, 2011
4,656
81turboguy said:
Indeed it is! 1981 Pontiac Turbo Trans Am 301 4.9L 73k original miles. She's getting jealous that the TB is getting all the attention :wink:

Sweet! I have a 78 and needs some restoration around the frame rails, doors... was my high school car. A co-worker of mine has a 81 Turbo as well and it's his wife's car, she bought it new. Here's the kicker.....his 81 has about 25K miles and gets driven on a few weekends of the month....:crazy: When he sends me some pics I will share them.
 

81turboguy

Original poster
Member
Nov 13, 2012
48
gmcman said:
Sweet! I have a 78 and needs some restoration around the frame rails, doors... was my high school car. A co-worker of mine has a 81 Turbo as well and it's his wife's car, she bought it new. Here's the kicker.....his 81 has about 25K miles and gets driven on a few weekends of the month....:crazy: When he sends me some pics I will share them.

Nice! Is that the 6.6L? I am the 3rd owner, bought it when I was 15, before I had a license ;-). I just really fell in love with the style for some reason. Just had my carb rebuilt but I'm having a secondary issue that I'm tracking down. I'd love to get the turbo rebuilt this year but we'll see how it goes. There is an excellent site I belong to that specializes in the 301 if they're ever looking for help. That's really amazing with 25k. Some orig engine bay pics would be awesome! :thumbsup:
 

81turboguy

Original poster
Member
Nov 13, 2012
48
As for my knock/noise...I drained the Mobil 1 and filled it with one quart Amsoil, and the remaining with high mileage Penzoil 5w30 with an ACDelco filter. The old oil didn't appear to have any glitter in it that I could see.

No noticeable change but I'm going to lightly drive it around for a few days to see if it improves. If not, I'll probably send it to the shop for their opinion. The exhaust cover will be coming off to check for cracks and I'm going to try and get a socket on the intake bolts to make sure they're tightened, read it from another post.
Thanks.
 

seanpooh

Member
Jan 24, 2012
461
I just seen a thread who had a really bad noise as yours and the members here had the assumption of a thrown rod, spun bearing or lost valve. Turns out it was the water pump and fan clutch. The removing the spark one coil at a time is the power balance test to find a bad cylinder. To conclusively find a bad cylinder, I think the next test would be checking the compression in psi.

But then again, you didn't mention getting a misfire code... Pulling out the spark plugs and inspecting is a good step also. We just need more clues.

As for 02 sensor, there has been speculation about the Bosch sensors. And ACDelco is supplied from Denso.
 

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