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Discussion Starter #41
I'll be happy to provide vacuum gauge readings soon. I have just driven the car a few miles away, then took an idle reading ...then drove the car home and took an idle reading. I had hoped to have recorded data while driving but it failed to record, so I will post the idle readings and get back in the car.

Regarding WOT, can I do this while the car is in neutral?

OBD2_20200730_Idle1&2.jpg
 

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Discussion Starter #42 (Edited)
I hope this is helpful, and isn't too confusing. I drove the car for a few minutes, and had it above 3000 rpm for a short spurt up a hill. The data also shows the period of time when I was coasting down the hill. There is a throttle position row that should capture what point of the drive the reading is coming from. I'll bet Excel isn't the optimal way to view these readings, but it's all I know. I am linking to a spreadsheet of all the readings, and uploading to this post a jpeg of a select excerpt. You can see which readings made the excerpt by looking at the column headings.

Side note, as I was making my way home, I smelled a faint smell of something burning ...like plastic. Very faint. It came and went, and came.

There are no viruses in this Excel file. If you would like me to manipulate these figures to make them more readable, let me know. FYI, it seems that the OBD2 values are not all taken simultaneously for every sensor. If you look at the "Seconds" column in the "Data" tab you'll see that they are taken very close together, but not at the exact same instant. I have assumed the OBD module voltage reading to kick off each reading#. So, every value falls between one OBD module voltage reading and the subsequent OBD module voltage reading.

******I have updated these files as of 10:26PM on 7/30/2020.


OBD2_20200730_Driving_excerpt_2.jpg
 

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Your post appears to show a WOT run, so that's good. It does not show your engine off MAP, so I'm just going to go with sea-level . I cut out a lot of the extra stuff to make this easier to read the good stuff. At idle, you are showing 37 kpa. If accurate, that's a bit low. Should be between 40-50. Look at what happens to your LTFT on bank 2 at 100% throttle - it cleans up. Go back to idle/decel, and it goes to **** again. Your MAF @ idle is also a bit low at 7.10 g/sec, but without looking at an actual graph of it over time, nobody can be sure. If it is actually low, then that, coupled with the low MAP at idle, and the LTFT's cleaning up at WOT point to a vacuum leak. As soon as your car goes into more of a vacuum state, bank 2 starts dumping in fuel because something on bank 2 is creating a lot more oxygen in the burn. The only way to introduce more oxygen is to add air.
194807

Adding air is only done in a handful of ways: throttle, exhaust leak, intake leak, and dead injector are the top 4. Blown rings or a valvetrain issue would present as an intake leak, too, but a compression test would quickly determine if that were the case. Exhaust leak would cause trims to go to hell on one side, but would not cause a cylinder specific miss, nor lower your intake pressure. Dead injector would read as more 02 in the mix, and would also cause a dead cyl, but it probably would not clean up at WOT. It might, if your PCM is able to toss enough fuel at the other 3 cylinders during WOT to compensate, but I think you'd still see a lean condition in a WOT log.

Edit: you mentioned the burning smell. I initially thought that could be a plug lead grounding out, which would make sense given that this all started after a mechanic worked on the front of the engine. However, were it a bad plug lead, I would think the log would show as a rich condition on bank 2 and not lean. Rich = the PCM is still firing the injector but the fuel isn't burning. Gets dumped into the exhaust, read by the 02 as rich, PCM pulls fuel out. Your PCM isn't pulling fuel, it's adding as much as it can at idle.

Get the compression tester, fuel pressure tester, and a vacuum gauge and see what you see. If those three tests come back as good, then start looking at injectors and spark.
 
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Edit: All three of those devices (compression, fuel, and vac testers) are available at Autozone for either a $0 rental or $15 for the vac gauge.
 
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Discussion Starter #45
Your post appears to show a WOT run, so that's good. It does not show your engine off MAP, so I'm just going to go with sea-level . I cut out a lot of the extra stuff to make this easier to read the good stuff. At idle, you are showing 37 kpa. If accurate, that's a bit low. Should be between 40-50. Look at what happens to your LTFT on bank 2 at 100% throttle - it cleans up. Go back to idle/decel, and it goes to **** again. Your MAF @ idle is also a bit low at 7.10 g/sec, but without looking at an actual graph of it over time, nobody can be sure. If it is actually low, then that, coupled with the low MAP at idle, and the LTFT's cleaning up at WOT point to a vacuum leak. As soon as your car goes into more of a vacuum state, bank 2 starts dumping in fuel because something on bank 2 is creating a lot more oxygen in the burn. The only way to introduce more oxygen is to add air.
View attachment 194807
Adding air is only done in a handful of ways: throttle, exhaust leak, intake leak, and dead injector are the top 4. Blown rings or a valvetrain issue would present as an intake leak, too, but a compression test would quickly determine if that were the case. Exhaust leak would cause trims to go to hell on one side, but would not cause a cylinder specific miss, nor lower your intake pressure. Dead injector would read as more 02 in the mix, and would also cause a dead cyl, but it probably would not clean up at WOT. It might, if your PCM is able to toss enough fuel at the other 3 cylinders during WOT to compensate, but I think you'd still see a lean condition in a WOT log.

Edit: you mentioned the burning smell. I initially thought that could be a plug lead grounding out, which would make sense given that this all started after a mechanic worked on the front of the engine. However, were it a bad plug lead, I would think the log would show as a rich condition on bank 2 and not lean. Rich = the PCM is still firing the injector but the fuel isn't burning. Gets dumped into the exhaust, read by the 02 as rich, PCM pulls fuel out. Your PCM isn't pulling fuel, it's adding as much as it can at idle.

Get the compression tester, fuel pressure tester, and a vacuum gauge and see what you see. If those three tests come back as good, then start looking at injectors and spark.
I just plugged in the reader and turned the ignition to On, and the kPa was 100. According to Find altitude of an address - AdvancedConverter I am at 787 ft altitude, and I drove up the hill to about 1500. The open throttle was probably in the 1000-1200 range.

Here are a couple of graphs. The first image is the entire drive, and the second one zooms in on the WOT portion and the deceleration. I'll get those other readings soon. Thank you so much for taking the time to help me with this.

Edit: Both mechanics told me the compression was good, and I have on my invoice from mechanic #1 that all cylinders tested at 175psi.

1.jpg 2.jpg
 

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The likelihood of all 8 cylinders testing 175 PSI is exactly nil. Its impossible.
 

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Discussion Starter #47 (Edited)
The likelihood of all 8 cylinders testing 175 PSI is exactly nil. Its impossible.
I've reached out to a family friend who is going to assist me with some tests. It'll be a few days until I'm back with results, but I should have some info soon.

I was taking with a neighbor yesterday who said he once had a similar issue and the cause ended up being a dirty MAF sensor. My K&N was absolutely filthy when this began (it's the full K&N intake system, with the arm). I have since noticed the filth and properly cleaned and oiled the filter, good as new (used the K&N cleaning kit). However, if the sensor inside was dirty, it's still dirty. Any chance that's the cause?
 

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Buy this and use exactly as directed, do not touch the MAF:


"Proven to gain 4 to 10 HP at the wheels" :ROFLMAO::rolleyes::mad:

What other mods have you done? Putting this info in your signature would help us help you.

Those 2 techs you saw should have seen a dirty MAF and cleaned it or done it regardless. Normal PM.

It is easy to over oil a K&N, probably why your MAF is dirty but unlikely the cause of your problem.
 

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Discussion Starter #49
Buy this and use exactly as directed, do not touch the MAF:


"Proven to gain 4 to 10 HP at the wheels" :ROFLMAO::rolleyes::mad:

What other mods have you done? Putting this info in your signature would help us help you.

Those 2 techs you saw should have seen a dirty MAF and cleaned it or done it regardless. Normal PM.

It is easy to over oil a K&N, probably why your MAF is dirty but unlikely the cause of your problem.
I never said the MAF was dirty. Signature updated with info.
 

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Discussion Starter #50
I took the car to a family friend who hooked up the vacuum gauge. I started the car and the gauge looked good in park/idle. Then he had me put the car in drive with the brake engaged and he pulled the throttle, and he noticed the misfire then. That's all I know.

He gave me the card of someone whom he says will be able to solve this riddle. I'll reach out to him next.
 

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Discussion Starter #51
I just spoke with the mechanic my friend referred me to. This shop deals primarily with fleets, but they were able to squeeze me in after some waiting, and they worked on my car yesterday. Here is where things are at the moment:

Turns out there were some swapped spark plug wires. He put them back where they go. That was the main cause of the issue. Now there is an issue with the right-front O2 sensor, which has gone bad, probably due to damage caused by gas flooding it from the misfire. He's going to replace the sensor and see how the other three have held up. He thinks the catalytic converter might be damaged.

This is what I know at the moment. I'll follow up when I have more news.
 
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"swapped spark plug wires"

Your car would have such screwed up timing and firing order it would run so poorly if it would even start at all. (n):mad::cry:

I wish I could be more helpful and tell you what is wrong. But one thing I do know.................... find an HONEST qualified shop. You are again the victim of an incorrect diagnosis. A bad 02 sensor and cat are likely suspects, but not the switched wires being the cause.

What ever happened with your fuel trims and data logs?
 

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Discussion Starter #53 (Edited)
"swapped spark plug wires"

Your car would have such screwed up timing and firing order it would run so poorly if it would even start at all. (n):mad::cry:

I wish I could be more helpful and tell you what is wrong. But one thing I do know.................... find an HONEST qualified shop. You are again the victim of an incorrect diagnosis. A bad 02 sensor and cat are likely suspects, but not the switched wires being the cause.

What ever happened with your fuel trims and data logs?
The family friend who recommended me to this shop had the owner as one of his students when he was the auto mechanics teacher at the local high school. ...and now this teacher/family friend goes to this shop exclusively for his own mechanic needs (he's 80 now). I appreciate your concern and your involvement in this thread, but I'm very comfortable at this current shop. It took them over two weeks to squeeze me in because their bread and butter is servicing Kaiser Permanente vehicles.

For now, the diagnosis is (in my own words): swapped wires, which resulted in fuel leaking onto at least one of the O2 sensors and a damaged catalytic converter. Fingers crossed that upon addressing these three issues the car will be back in proper shape.

I have no doubt that this mechanic is honest. As to whether swapped wires were indeed the cause of the problem, I will let everyone know when I have more news.
 

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See FSM page 6D4-4 and see diagrams. Perhaps it is a matter of word usage or terminology. Improper wire routing vs swapped wires.

"Failure to route the wires harnesses properly can lead to radio ignition noise and cross- firing of the spark plugs, or shorting of the leads to ground"

Because NO WAY would the wrong wire on the wrong plug fire an engine properly. Try it if you dare 🤪
 

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Grandpas wagon, are you saying you have never seen an engine running with a couple wires mixed up ?????? REALLY ?

Depending which two wires you mix up, you certainly can have a running engine .
Two holes will be dead , sure but some people are not aware enough to notice.

As long as you don't mix up 2 consecutive cylinders , like 5-7 where 7 would be firing 90 degrees early, trying to drive the piston back down the hole, an engine will run.

If , say 4 and 6 were swapped
6 plug would fire at 20 -30 before BDC intake . That could happen without drama.

4 plug plug would spark 20-30 before BDC firing.
If it did anything, it might contribute.

Is this what happened here , I have no idea.

But I have over the years mixed up wires when not paying attention and , as I said depending on which wires , no drama other that 2 cylinders not firing.
 

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See FSM page 6D4-4 and see diagrams. Perhaps it is a matter of word usage or terminology. Improper wire routing vs swapped wires.

"Failure to route the wires harnesses properly can lead to radio ignition noise and cross- firing of the spark plugs, or shorting of the leads to ground"

Because NO WAY would the wrong wire on the wrong plug fire an engine properly. Try it if you dare 🤪
When did you swap heads? Maybe it happened then. Or when new wires were installed?
 

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I said it would not fire properly. With all the diagnostics he has done, this would surely be evident.

Read the thread.
 

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Discussion Starter #58
When did you swap heads? Maybe it happened then. Or when new wires were installed?
I bought the car used. Mechanic #1 has been telling me for years that the heads were aluminum. I asked the current mechanic to double check. He said they appeared to be iron, and checked with a magnet, which stuck. So, aluminum heads = debunked. I've removed it from my signature.
 

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" read the thread"

No witty comeback sorry.

What I read is
-He has a dead hole , or more than one.
(Of coarse, you must have two dead cylinders with misconnected wires)
-He is not great at communicating his issue
-He is relying on second hand info from people looking at the car and charging him , apparently not all reliable.
-He has been driving the car a long while with this misfire.
-The last mech has made it much better without parts.


"find an HONEST qualified shop. You are again the victim of an incorrect diagnosis. A bad 02 sensor and cat are likely suspects, but not the switched wires being the cause"

You have pegged the last shop as dishonest.
Not mistaken, not dumb, but disonest.

While I agree, just mixed up wires is not the most likely,

If he has been driving around for 2 months with a couple dead holes, the cat could certainly be molten rubble.

Back pressure check at the upstream O2 bung would be telling.

Again, I am not saying I know what the issue is or was for certain.
What I read was you dismissing the idea that plug wires could have been the issue and the shop that said it is dishonest.
 
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