My 05 Envoy has no ballz. 0-60 times horrible!

[CaptainXL]

10-15 Bumps on the starter isn't bad, that's prob 4-5 bumps per revolution.

Remember you get compression on every other stroke. your 40 could have been on mid- stroke.

Try it on a few without the extension tube.

Gonna do that. ive decided to just test 2 and 3. I've read a bunch of horrible reviews about compression testers in general and how the peak pressure can be off by as much as 60 psi so I'm not holding my breath. I think my best bet is to get a new one from harbor freight but then those don't have glowing reviews either.

The fact that the engine starts immediately would indicate that my compression must be good. The idle is good as well.

 

[CaptainXL]

Rented out the compression tester again. Gonna hook it up to my compressor and see if it is calibrated correctly before beginning. Can't totally trust these Autozone loan - a -tools. The plan is to do a dry and wet test on as many cylinders as I can. Will report back in time. Wish me luck.

 

[WarGawd]

Rented out the compression tester again. Gonna hook it up to my compressor and see if it is calibrated correctly before beginning. Can't totally trust these Autozone loan - a -tools. The plan is to do a dry and wet test on as many cylinders as I can. Will report back in time. Wish me luck.

Yeah I've been sorta waiting to see what develops....120 seems way low and way too uniform. Guess if it's a rented tool we should see results pretty quick (try to get #6 in there, given previous misfire history)

Oh - I also found something that may be a reasonable candidate for explaining a problem like yours that might not throw codes over the longer term. You had said something before about feeling like it was in 2nd gear. I think I shrugged it off at the time, but there's a possibility you may have been right - if you have time to try a short test, warm it up, and try the 2nd gear start option - put it in D2 from a standstill (design feature, locks tranny in 2nd not first), and floor it. You will (should?) notice an immediate lack of torque off the line (I tried it several times tonite, and definitely noticed the difference but couldn't do any WOT runs to 60 or 90 to see full behavior) . Compare that behavior/performance to your previous sluggish experience and let us know. Be even nicer if you could datalog speed/throttle pos/rpm while you do it.

One last quick question - related to something else I read, do you by any chance have a remote starter installed?

 

[CaptainXL]

I've done the start from second gear many times before and noticed that it downshifts to first if floored if I am not mistaken.

Yes, I have a Viper remote start.

 

[WarGawd]

I've done the start from second gear many times before and noticed that it downshifts to first if floored if I am not mistaken.

Yes, I have a Viper remote start.

Lol it's pretty hard to read between the lines of such a short reply but I'm getting the impression you've known about the D2 start thing for so long that you assume most everyone else knows about it too. OTOH, for as long as I've been driving and as many different vehicles I've owned or driven, I can honestly say I'd never heard of it until a few days ago.

With that in mind I'm guessing your earlier mention of feeling like it was in 2nd gear was meant to give all those in the know an understanding of what the sluggish performance felt like? And therefore the implication is that having tried the D2 start several times before, the sluggish performance feels like starting in 2nd but you would know the difference for sure? Am I on the right track with that?

So when I discovered the D2 start thing, I tried it on mine. Though I didn't do any WOT stuff I never saw any downshift, and the performance understandably felt really sluggish. To me it was obscure enough to have possibly never crossed your radar -, I googled around a bit on the subject, came across some references to TSBs where our vehicles reported problems with getting stuck in 2nd or 3rd that were often associated with improper installation of aftermaket electronics (mainly remote starters) and it all seemed to fit the general picture here (except temp connection, I have no explanation for that yet). But if I understand better now, you're discounting that possibility because while it may feel like it's sometimes starting in 2nd, you're pretty sure it isn't? Correct, or do you think it may be worth pursuing?

 

[CaptainXL]

Sorry for the short replies. Taking care of babies gives you a limited amount of time to do hobbies or fix things. Its gonna be slow goin so please bear with me.

Im pretty sure that it really isn't starting out in second because I can shift into second while starting out in first and it shifts into second. Pretty simple test. Not worth pursuing.

 

[WarGawd]

Sorry for the short replies. Taking care of babies gives you a limited amount of time to do hobbies or fix things. Its gonna be slow goin so please bear with me.

Im pretty sure that it really isn't starting out in second because I can shift into second while starting out in first and it shifts into second. Pretty simple test. Not worth pursuing.

I have 5 including triplets, I know allllllll about it, no worries.

 

[CaptainXL]

Did a dry test on each cylinder again and got the same 120 psi on all cylinders as before. I didn't use the extension this time which apparently didn't make any difference in reading.

I then did a wet test with a few squirts of 10W and then all cylinders tested at 175 psi.

So I guess my piston rings or cylinders are worn. The question I have is this fixable using anything in can?

 

[Phantom]

Did a dry test on each cylinder again and got the same 120 psi on all cylinders as before. I didn't use the extension this time which apparently didn't make any difference in reading.

I then did a wet test with a few squirts of 10W and then all cylinders tested at 175 psi.

So I guess my piston rings or cylinders are worn. The question I have is this fixable using anything in can?

Do not use the Engine restore which is in the silver can! I found that out the hard way. I had always used it in other vehicles and it worked the way it was supposed to. But upon putting it in the envoy, after ten minutes it threw a code for the CPAS and we had to clean that along with a double oil change to get the crap out.

 

[C-ya]

Edited.

Had a brain fart.

 

[gmcman]

How long is the extension tube?

Did you test a cold or hot motor?

 

[CaptainXL]

How long is the extension tube?

Did you test a cold or hot motor?

The extension tube is about 2 inches long. I was told it's for ohc engines due to long reach. I have always done the compression tests when engine is warm.

I'm thinking the rings are stuck. Just got to find something to unstick them with.

 

[WarGawd]

...
Also you've made no prior mention of any observed plug fouling on 6, nor of noticing any odor from the tailpipe (both would speak to the relative longterm condition of a consistent misfire that would be dumping unburned fuel, and which probably would have affected the cat converter by now & more or less eliminated by the backpressure test). You've never mentioned any excessive oil consumption or any bluish exhaust, and the fact that you experience a return to decent performance practically rules out compression issues (bad rings --> oil in cylinder --> misfire or burned valve --> low compression on 6 --> misfire), because compression issues won't come and go.

There should be a P0306 but weather or not that gets stored for any amount of misfires or if the PCM waits until a set amount (say 24000) misfires occurs...your guess is as good as mine. Either way, it's minimal and I don't think I have a real issue here. If nothing gets stored in the HISTORY I am satisfied nothing is wrong.

Did a compression test today. Got 120 psi on 1 thru 5 cylinders and 110 psi on 6.

According to Alldata my compression should be 150 psi minimum and 215 psi typical. So this looks like I have major problems.

So 2nd test yielded same results. No variation cylinder to cylinder at all?? You surely must be rounding off to the nearest 5 psi or something like that no?

And #6 came up to 120 dry perfectly in line with all the others I presume. Assuming 120 is accurate and is actually indicative of "major problems" where are all the other symptoms? Where are all the misfires on other cylinders and the corresponding P0300 thru P0305? Where's the rough idle? Quoting another source,

Low usually means anything under 120 PSI (although the service manual says 100 PSI is the minimum). If your Engine has reached this point... it's also smoking from the quart of oil it's burning every few days.​

After the 2nd test where wet was 175 you make the logical leap to stuck/bad rings....stuck uniformly in all 6 cylinders? really? How in all this are you accounting for stuck rings to all come unstuck and give you good performance for a while, then all get stuck again?

I'm not disputing the test result, but none of ^^ that stuff fits. Don't you agree?

I've tried searching for actual published test results with no success...I suspect MAY03LT must have done this more than a few times on various I6's, I suggest you send him a PM and see what kind of numbers he's seen in practice.

 

[CaptainXL]

So 2nd test yielded same results. No variation cylinder to cylinder at all?? You surely must be rounding off to the nearest 5 psi or something like that no?

The difference between the lowest and highest of the cylinders wet was about 5 psi. For instance #3 dry was 117 and #4 dry was 120 but they are both very close to 175 wet.

Edit: Forgot to mention # 6 which was 110 psi dry and also ended up being 175 +-2 psi.

Also noted that the amount of 30 weight oil added to each cylinder didn't really make much of a difference in reading. In one cylinder I added 2 tbsp of oil and then ran the engine with the plug in. I then added 3 tbsp of oil and the PSI was the same.

And #6 came up to 120 dry perfectly in line with all the others I presume. Assuming 120 is accurate and is actually indicative of "major problems" where are all the other symptoms? Where are all the misfires on other cylinders and the corresponding P0300 thru P0305? Where's the rough idle? Quoting another source,

You got me. Perhaps because the pressures are so even across the board is the reason it runs so smooth?

Low usually means anything under 120 PSI (although the service manual says 100 PSI is the minimum). If your Engine has reached this point... it's also smoking from the quart of oil it's burning every few days.​

You hit the nail on the head here. These things have me scratching my head the most. I am not burning any significant amount of oil and the dipstick reads the same even after 6K miles.

After the 2nd test where wet was 175 you make the logical leap to stuck/bad rings....stuck uniformly in all 6 cylinders? really? How in all this are you accounting for stuck rings to all come unstuck and give you good performance for a while, then all get stuck again?

I am just making an educated guess from reading issues others have had with low compression. My guess is that the previous owner coked up the piston rings using the wrong type of oil or something. I could be wrong. But I am researching the possibility of stuck rings among other possibilities.

I'm not disputing the test result, but none of ^^ that stuff fits. Don't you agree?

The dry vs wet test most definitely fits worn cylinders and/or piston rings. Its really the only plausible explanation from all the documentation I have read on the internet. It's not timing chain slipped, it's not valves... Only so many parts in an engine you can blame.

I've tried searching for actual published test results with no success...I suspect MAY03LT must have done this more than a few times on various I6's, I suggest you send him a PM and see what kind of numbers he's seen in practice.

Are you referring to the published cylinder pressure numbers? 215 psi as indicated in Alldata? Not 100% following you here.

Do not use the Engine restore which is in the silver can! I found that out the hard way. I had always used it in other vehicles and it worked the way it was supposed to. But upon putting it in the envoy, after ten minutes it threw a code for the CPAS and we had to clean that along with a double oil change to get the crap out.

I was thinking of trying BG 109

View attachment 23392

 

[WarGawd]

Hey Cap'n - thanx for the effort at supplying details - helps us get in your head and the situation better.

My thinking is that the variability should be higher. The rings rotate around the piston over time, and eventually you will have two rings whose end gaps are much closer together than in the other cylinders. While the gaps aren't huge they do get bigger over time as they wear. Imagine for a second having built an engine without any rings. Assume we found a way to keep the piston from banging against the cylinder wall. Crank it over and do a compression test. Yeah I could imagine they would all be pretty uniform measurements, but the difference in area between the piston and the cylinder amounts to something of the order of 2%. I looked up a bunch of ring specs, and at 93mm bore allowing 1mm (0.040") clearance that's the difference in area. It's not exact but should be close enough to illustrate my point here. I would expect pumping that piston up and down in the cylinder at ~400rpm would get you reasonable pressures without rings! Put the rings back in and even allow for them to be stuck in the groove by heavy carbon buildup, and they'd still probably protrude somewhat, reducing the compression blowby by some amount. I'm only guessing at what the ringless engine loss of compression would be, but my gut feel is it would still run. Misfiring like crazy though, burning oil, throwing codes...bear with me, I know I'm being a little silly but I'm trying to get somewhere with this

...then ran the engine with the plug in​

Not to play dumb here but you meant cranked it right?

You got me. Perhaps because the pressures are so even across the board is the reason it runs so smooth?​

I can see how you might think that, but smooth running isn't coming so much from equal power being produced by each cylinder so much as it comes from one or more cylinders NOT firing inconsistently. The cylinder to cylinder difference in power output when all are firing vs the difference when one fires only say 80% is minor in comparison.

The dry vs wet test most definitely fits worn cylinders and/or piston rings. Its really the only plausible explanation from all the documentation I have read on the internet. It's not timing chain slipped, it's not valves... Only so many parts in an engine you can blame​

Agreed, and I can only say that at this point I don't have a good feel for what the difference (of a healthy engine) would be wet vs dry. Just going on intuition I hadn't expected that much delta personally, but haven't found any info to really quantify it. It will always go up some amount wet vs dry, I just don't have any clue what's "normal" and what would be considered drastic enough to lead to a conclusion of (really) bad rings.

Are you referring to the published cylinder pressure numbers? 215 psi as indicated in Alldata? Not 100% following you here​

Yeah that's what I was referring to. I know the 215 is on Alldata, I can confirm I read the same figure in an '04 Trailblazer manual...but from reading some info on compression test methodologies, there are different ways of reporting it (eg dynamic vs static). For example, let's have a perfect world & we have rings that allow absolutely zero compression loss. We go slow, piston at BDC we open the intake valve manually let the cylinder equalize to atmospheric pressure (14.7psia). Then we close the valve and slowly push that piston to TDC in the 100% lossless cylinder. At 10:1 compression you'd expect the pressure to be somewhere around 150psia (135psig). But life gets a little complicated in real world compression tests because when you compress it very quickly, the temperature doesn't stay constant (pV=nRT) and the pressures will be higher. now add back in some rings which have imperfect sealing and the result changes a bit again. In an operating engine when you add fuel that evaporates the pressure is even higher (And it's also compressing faster, adding pressure).

So what I was trying to get at was that the 215 publicized by Alldata (& probably merely repeated from some other source) might be correct for a certain methodology - but if you're not doing that you may get different results. That's why I suggested the PM to MAY03LT. So since I have been unable to find real world results anywhere, and since you have none of the other important symptoms, for the moment I am suspicious that we're trying to compare apples to watermelons. Also, not to insult you, but can we verify that you did the test with all plugs removed, as opposed to one at a time?

Cheers

 

[gmcman]

Capt, It's too much of a pain to go back through all the pages on this phone......I need you to let me know what the vacuum is.

We need to know the reading and how steady the needle is. The needle must be absolutely positively rock steady, it cannot move or fluctuate.....unless of course the rpm changes bit I'm referring to idle and part throttle, steady rpms .


man I hate this phone.

 

[gmcman]

Also, run some BG quick clean through the crankcase then change the oil out.

I would advise against any compression renewers right now.

 

[CaptainXL]

I need you to let me know what the vacuum is.

We need to know the reading and how steady the needle is. The needle must be absolutely positively rock steady, it cannot move or fluctuate.....

Vacuum is 18 in Hg at idle and the needle is not moving at all. Tested this many times.

 

[CaptainXL]

can we verify that you did the test with all plugs removed, as opposed to one at a time?

Yes, I tried it both ways doing one spark plug removed vs all of them removed. Wanted to see if there was a difference. I got roughly the same numbers (120 dry / 175 wet).

I'm 100% sure the test was done correctly. I think its time to sell it. Got my eye on a nice 2006 Envoy Denali for 12K. More payments yes but at least I have money to put down. This truck is payed for. Looking to get about 7-8K for it.

 

[The_Roadie]

Looking to get about 7-8K for it.

You might have better luck finding a sucker on trailvoy who doesn't already know its history.

 

[Denali n DOO]

Yes, I tried it both ways doing one spark plug removed vs all of them removed. Wanted to see if there was a difference. I got roughly the same numbers (120 dry / 175 wet).

I'm 100% sure the test was done correctly. I think its time to sell it. Got my eye on a nice 2006 Envoy Denali for 12K. More payments yes but at least I have money to put down. This truck is payed for. Looking to get about 7-8K for it.

Good idea on the Denali, thats one way to get better 0-60 times....and maybe save money on gas too!

 

[gmcman]

I'm 100% sure the test was done correctly. I think its time to sell it. Got my eye on a nice 2006 Envoy Denali for 12K. More payments yes but at least I have money to put down. This truck is payed for. Looking to get about 7-8K for it.

Yeah, there's not much left to check and even if you do, there's no hiding the fact it has ridiculously low compression. Last thing I would do if I was keeping it would be to verify there is no carbon built up on the rings. Not much else to do before you start pulling the motor down and obviously that's where you are going to draw the line......I don't blame you.

Some quick clean could open some oil passages and maybe clean up the rings but I don't think you are going to get the compression you are looking for.



The Denali you are looking at, is it a XL? I can tell you for certain that with a family that extra room is paramount. The second row of the XL reclines as the SWB models are fixed.


If the Denali is a SWB.......you could also get a van.

 

[CaptainXL]

Good idea on the Denali, thats one way to get better 0-60 times....and maybe save money on gas too!

Exactly my thought. Doesn't seem to be many here complaining about compression issues with the 5.3 engine. If you have heard of anything let me know.

I tow a 5K lb trailer as well so it would be nice to have some additional torque.

Yeah, there's not much left to check and even if you do, there's no hiding the fact it has ridiculously low compression. Last thing I would do if I was keeping it would be to verify there is no carbon built up on the rings.

Some quick clean could open some oil passages and maybe clean up the rings but I don't think you are going to get the compression you are looking for.

I'm still considering keeping it IF I can increase the compression to say...150. Gonna try a handful of ancient secret flushing techniques to cleanup the interior of the engine. Are you suggesting I borescope the plug holes and such? Wouldn't it be hard to tell if the rings were coked up?

The Denali you are looking at, is it a XL? I can tell you for certain that with a family that extra room is paramount. The second row of the XL reclines as the SWB models are fixed.


If the Denali is a SWB.......you could also get a van.

Actually, I would be looking for a SLT XL or Denali XL with the 5.3. The Denali adds auto air, premium nav and leather but those aren't my priorities at the moment. My wife did actually ask me how much it would be to have headrest DVD players installed. So I might use that to my advantage as an excuse to upgrade.

She has reservations though and says "we have it payed off, so why have more payments?" If you have any tips on how to reel her in now would be the time.

You might have better luck finding a sucker on trailvoy who doesn't already know its history.

Karma's a bitch. With my luck I might end up with a more expensive truck with similar issues. Double whammy. Thanks for the tip though. Might come in handy.

 

[gmcman]

Are you suggesting I borescope the plug holes and such? Wouldn't it be hard to tell if the rings were coked up?

You read my mind....I was going to add that in to my last post on Thurs but my phone was being a PITA. Wouldn't hurt to take a peek in there, if it's just fouled up that can tell a story but there's only so much more to do with the motor still intact.


Did you wring it out like I mentioned in my PM?

Mine was acting goofy with an occasional rough idle. I ran the 44K the same time you did and can say the motors manners are much more improved, idle is very smooth now.

 

[CaptainXL]

You read my mind....I was going to add that in to my last post on Thurs but my phone was being a PITA. Wouldn't hurt to take a peek in there, if it's just fouled up that can tell a story but there's only so much more to do with the motor still intact.

Looking into a couple borescope options. Harbor Freight has one that fits inside a spark plug hole but it's a bit pricey ($130). The cheaper one won't fit down in there because its too big on the end.

Did you wring it out like I mentioned in my PM?

Mine was acting goofy with an occasional rough idle. I ran the 44K the same time you did and can say the motors manners are much more improved, idle is very smooth now.

I've floored it a few times getting on the highway. Don't get me wrong, I don't baby this truck. It's driven to get me from point A -> B as fast as legally possible. Overall the engine seems smoother having added the 44K. Haven't driven much over the past few days. Will have to see. Currently running some MMO and with do an engine flush tomorrow. I think I am going to buy an engine compression tester given so much is at stake. Not willing give up using a possible bad rental tester. Stay tuned.

 

[WarGawd]

... I think I am going to buy an engine compression tester given so much is at stake. Not willing give up using a possible bad rental tester. Stay tuned.

Did you get the exact same rental tool both times? You had said before you were going to calibrate it against your compressor - I assume it checked out?

I have managed to find a few hard results published in other threads and posts seeking advice - they ranged pretty widely and I don't really understand why. Ranged from 130 to over 200. In each case there was one and only one cylinder misfiring, and all of which had one or more other symptoms - rough idle, CEL, severely fouled plug, high oil consumption. Probably prudent to double check unless you're reallly set on the Denali - and I couldn't fault you for that.

Keep us updated....

 

[CaptainXL]

Did you get the exact same rental tool both times?

Yes. I think it was the same.

You had said before you were going to calibrate it against your compressor - I assume it checked out?

No. I didn't have an adapter that would connect female to female hoses.

I have managed to find a few hard results published in other threads and posts seeking advice - they ranged pretty widely and I don't really understand why. Ranged from 130 to over 200. In each case there was one and only one cylinder misfiring, and all of which had one or more other symptoms - rough idle, CEL, severely fouled plug, high oil consumption. Probably prudent to double check unless you're reallly set on the Denali - and I couldn't fault you for that.

Keep us updated....

Last night I dumped some Gunk engine flush in each of the cylinders and then cranked the engine a few times to spread out the liquid then let it sit until this evening. I ran the engine for about 15 minutes and took another compression reading and it's up 10 psi in cylinders 1-5. 6 is unchanged. Starting to think it's a carbon issue.

 

[gmcman]

I can say for certain that my cold starts have quieted down considerably after using both the 44K and the Quick Clean. What I assume was piston-slap is almost non-existent, my cold start tick loudness has been reduced to more than half and the duration is significantly lower.

Time will tell but they are working. Capt you may need a second dose but try the Quick Clean or maybe even some GM Top engine cleaner or Seafoam.

 

[CaptainXL]

I can say for certain that my cold starts have quieted down considerably after using both the 44K and the Quick Clean. What I assume was piston-slap is almost non-existent, my cold start tick loudness has been reduced to more than half and the duration is significantly lower.

Time will tell but they are working. Capt you may need a second dose but try the Quick Clean or maybe even some GM Top engine cleaner or Seafoam.

Excellent results. Your engine noises sounds like what I have. Will go to dealer and get some top engine clean today.

 

[gmcman]

Just wanted to reiterate that my results are from the two BG products alone, I haven't used the top engine cleaner or Seafoam in this motor.

However in your case it likely wouldn't hurt.

I wanted to add I was going to get a comparison video this morning however the Pratt and Whitney kicked in and muffled any internal noise.

 

[gmcman]

Capt, I went back and went over the previous posts.....what air filter did you use and I believe the 05 has a MAF correct?

Just a thought but what does the MAF look like inside?

I'm curious if the previous owner used a K&N and maybe the MAF is covered in oil.

Just something else to check, I'm not sure what the best cleaner is to clean them.

 

[CaptainXL]

Capt, I went back and went over the previous posts.....what air filter did you use and I believe the 05 has a MAF correct?

Just a thought but what does the MAF look like inside?

I'm curious if the previous owner used a K&N and maybe the MAF is covered in oil.

Just something else to check, I'm not sure what the best cleaner is to clean them.

No maf on 02-05's I run a purolator air filter.

 

[gmcman]

No maf on 02-05's I run a purolator air filter.

Ok, I thought they started in 05.

 

[GS_Geoff]

A couple of thoughts...

Higher octane won't cure misfires. It might help drown out knock and prevent the computer from commanding knock retard (pulling timing), but that shouldn't be a problem in these trucks, and it doesn't address the real problem. There is more potential energy in 87 ocatane than 94 octane, so all other things being equal, you will make less power with higher octane. The way race engines take advantage of high octane is through high compression and advanced timing, utilizing the slower burn of higher octane fuel. So on the misfire thing, GM coils are also definitely subject to corrosion, but I am not as familiar with the coils on these trucks. Weak spark can definitely cost you power.

Also, I don't see anywhere here where you mention trying a different throttle body. My truck had acceleration issues from shortly after I bought it, but did not start setting codes for the throttle position sensor until maybe 6 months ago. I installed a new throttle body ($138 from RockAuto and 15 minutes of work), and now it accelerates smoothly. Obviously you don't want to keep throwing random parts at the car, but maybe you could find a spare to try, especially since it only takes a few minutes to replace. On the 5.3L the gaskets are re-usable, so hopefully the same is true on the 4.2L.

Just a few thoughts I didn't really see covered, but I may have missed something - it's a long thread.

 

[WarGawd]

@ Geoff - well done if you actually read through all that. It seems you did, because you seem to have put forth some things that haven't been mentioned. Kudos.


@ CapnXL - LOL I'm confused - two weeks later you go back and like post #213 - did you recently find something of extra value in that?

 

[Harpo]

Oh and lastly @ Harpo - you deleted your post just as I was trying to reference it. Thought I spotted that you had Torque app as well, maybe you can track down that same HP measurement that CapXL has done before and throw it in to the mix.



HAGD all

This took a while before i got it done, but here it is.

A screenshot from Torque app with 0-60mph 0-100kph , calculated hp at rear wheels, and the throttle is not showing in this "after run" screenshot but was at 100%.

The truck has a big rooftop box and is full of kiddy seats, stroller and other kidstuff. It was raining so i had a little wheelspin at first, tried mutiple runs but alway got a little spinning wheel at first. It sucks not to have a G80.
Gears are 3:73


View attachment 23669

 

[CaptainXL]

Hey guys just wanted to update you all on progress.

Well as it turns out my Envoy is idling 100% better now after adding that BG 44K that gmcman gave me. I no longer have ANY vibrations at idle. Smooth as silk.

Thanks gmcman!

 

[WarGawd]

This took a while before i got it done, but here it is.

A screenshot from Torque app with 0-60mph 0-100kph , calculated hp at rear wheels, and the throttle is not showing in this "after run" screenshot but was at 100%.

The truck has a big rooftop box and is full of kiddy seats, stroller and other kidstuff. It was raining so i had a little wheelspin at first, tried mutiple runs but alway got a little spinning wheel at first. It sucks not to have a G80.
Gears are 3:73


View attachment 10285

I think that 1/4 mile is right bang on the same # I posted for my XL with 3.42 rears earlier in the thread....so you lost a little ground due to early tire slippage of say, what? 20 to 30 feet? Out of 1320 ft/qtr mi it's a pretty small proportion. I'm saying that the wheelspin essentially negates the advantage of the higher {lower? I always fk that up!} gearing, and the additional roofbox weight only adds a small penalty...does that make sense? IE that's pretty much what you'd expect to run.

Interesting info re: Torque - 100% throttle indication...has me wondering which PID it's referencing - and that HP indication seems to add yet another datapoint that would suggest Torque is looking like it may not be all that accurate regardless of the reason (bad calculation or bad input/setup) that potential for inaccuracy seems to have been demonstrated. I can recall three of the numbers posted previously: 46, 137, 190, possibly more - seems fair to say it might be inaccurate.

 

[WarGawd]

Hey guys just wanted to update you all on progress.

Well as it turns out my Envoy is idling 100% better now after adding that BG 44K that gmcman gave me. I no longer have ANY vibrations at idle. Smooth as silk.

Thanks gmcman!

That's really good to hear - I thought gmcman was gonna post a video of the after treatment sound difference, I've been looking forward to that - both his and your description sound very much like what I hear from mine so I am encouraged. I may consider using it myself - mine sounds so much better after it warms up - It'd be much easier to deal with if I knew I had to accept it, but I suspect it has lots of room for improvement.

Sorry though, I rescanned thread briefly and I don't recall where you said it was idling poorly??? I either missed it or somehow didn't register it....

SOOoooo - are you saying you think you've reached a conclusion to the problem that initiated this thread? I mean on balance it seems to me you've been chasing down a series of side-issues and searching for evidence by measuring other performance parameters. You've (re)solved some of those without really getting to the root of the original problem. I don't think you mean to suggest that the conclusion to "My vehicle has HUGE performance variations", is "stuck rings, now freed due to BG44K"? What are you expecting will happen next May-ish? If BG44K is now required to free the rings, what accounts for their previous (apparently spontaneous & simultaneous) freedom during the most recent episode of performance improvement before getting stuck/sticky more recently?

Don't get me wrong, I'm always glad for anything that makes an improvement NOW, but I'm somehow less than fully convinced that your main problem isn't still lurking.

 

[CaptainXL]

A little Background. My engine has had this slight vibration since I bought it. If you put your hand on the top of the resonator you could feel it. If you were in the truck you could fee it. Felt like a misfire. I knew something was amiss and up until now I just chalked it up as being normal.

Over the last two years I have used various fuel system cleaners with slightly better and better results. When I first got the vehicle I almost shook in the seat the vibration was so bad. It was a low frequency drone not unlike a boomy exhaust but less noisy. It would make a weak person dizzy or maybe even sick. That type of noise. Low frequency in nature and about every 3/4 to 1 second intervals.

A bunch of theories including Roadies infamous 1hz resonation had me thinking among other things that my engine mounts were bad. There are a couple other sounds under the hood I need to see if they are still there. I have this metallic sounding on top of the valve cover. Hard to describe it but I hope the bg fixed it. I may do another treatment soon just to be sure I got whatever it was that caused the rough idle.

In regards to your question if this is related to my compression issues.... I don't think so. I just had dirty injectors more than likely.

But this bg 44k stuff sure did fix one annoyance that kept me wondering if something was mechanically wrong with the engine . I mean the rough idle had me checking things on the side that really had nothing to do with the rough idle. I'm glad it's solved.

Now that it solved. Onward to my original goal of trying to find out why I have low compression.