NEED HELP Can p0171 be related to sais

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
Hi guys long time since I posted.

History. Had p0171 intermittent issues for over a year now never bothered to fix it have to pass emissions this month so am forced to fix it.

Symptoms. No code will show at first but will be pending with a hike in rpm at idle 900 or so. Clear code rpm drops. O2 bank 1 s. 1 voltage fluctuates as normal b1s2 v pretty much steady.

Intake pressure 21 at idle
Can't find a vacume leak anywhere the cap on intake manifold was off replaced went away for a little longer came back

Have tightened manifold bolts gasket replaced last year.

So only other thing wrong is sais pump failed no longer runs. And the hose not sure which one won't connect on the pump side. My ecu is at pcmofnc getting tuned right now and getting sais tuned out.

Assumption/question. Can air somehow be getting in through sais system causing it to show lean? Should I just remove valve and cap it off. And how would I cap hose on intake hose. Or should I still be hunting a vacume leak or fuel delivery issue. Pressure is good regulator is new along with filter

Any help would be great I have torque app so if need any reading I'll be happy to post

At the point if you help me fix it ill find a way to give a small donation as I'm not rich. Ie. Why I'm not going to a dealer or mechanic


Thanks all have a good day
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
That's what it's all about... stickin' it to the dealer! :thumbsup:

Definitely remove the SAIS and block it off in the head. Get a block off plate from an '02/'03 junker. Not sure what else needs to be blocked off though if someone else could chime in on that.

If still not resolved, check for a vacuum leak using carb cleaner as per this video.

Look at the fuel trims using Torque. If getting a P0171, you'll likely get high trims (adding fuel) as the PCM is trying to control the lean condition.
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
Thanks for the quick reply. As far as fuel trim on torque.. I see long term fuel. Short term fuel. Then there is fuel trim for b1s1 and b1s2. I know if I go into torque and add a gauge then it listes all the pids. The b1s2 fuel trim is highlighted green but not as green as all the other ones that show a reading and there is no reading not sure why


Anyway when I get out of work I will take note of the fuel trims at idle while driving and if the high idle pending code kicks in that too.


I have tried every method I could think of for finding a vacuum leak no such luck. Used carb cleaner propane from my propane torch even tried building a home made smoker which I don't think produced enough smoke. End result no vacuum leaks found.

As far as the plate is there a part number so I can order from dealer as the scrap yard around here have changed management no longer allow me to go in and get what I need and nor will they get me something that small. Can I make one?

I pulled all fuses and what not for entire sais system just not unit itself so I'm assuming in theory the valve could be open allowing extra air to enter exhaust?

Thanks for quick reply.
 

MAY03LT

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Nov 18, 2011
3,412
Delmarva

This video has some good info on the sais and has some o2/fuel trim tidbits.
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
Thanks for video this sort of confirms my thought at first.

I was in torque today on my drive home. Couldn't get code to set or rpm to jump to 900. Figures. I'm going to get my hands on the plate to cap off valve after j remove it see if it fixes the issue.

Only other thought is the bank 1 sensor 2 I'm assuming is after cat sensor is faulty I have voltage readings for it but it doesn't read in the torque app the fuel trim for that sensor. Is it supposed to? B1s1 displays a reading I just need it to pass emissions been driving like this for a year so far still going haha.... Have 233034 miles on her.

I'll attach a torque screen shot show what I'm talking about. I have data logs to but just shows normal I think. If anyone feels like looking at it and see something I don't notice wrong let me know

Screenshot_20160913-132617.png Screenshot_20160913-132753.png Screenshot_20160913-132406.png
 

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jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
Ok an update

I removed sais completely installed block off plate

Pcmofnc programmed out sais code with tune (should have gotten a tune long time ago)

Installed 2 new o2 sensors acdelco brand

Cleaned throttle body

So after all this was done I noticed b1s1 o2 was a little more responsive on graph the after cat sensor basically stays same after warm up

So I drove some waiting to see if p0171 and the rpm jump came back and sure enough with just my luck it did

The actual mil light rarely comes on but Rpms will jump to 900 when that happens most time pending p0171 code will appear sometimes Rpms jump no pending code but if I hit clear codes Rpms drop then immediately jump back up.


So I'm left back at the beginning ruled out for sure sais issue and bad o2 sensors
Checked over and over and over for vacuum leaks if there is one it's tiny and I can't find it and ive tested with gauge it's normal

Last year I had it in a shop for days what they checked and did not 100℅ sure just know they changed intake manifold gasket because I told them too didn't change anything obviously


Car runs fine otherwise if I don't clear code after rpm jump 9 out if ten times it goes away on its own and rpm goes to normal


Should i just deal with it? I had gotten really lucky had to do emissions so I got all emissions checks to show ready go to shop and as I'm waiting to get it done damn light comes on. So I drove next day got emissions ready went to place shut off car he pulls it in it passed I pull out light popped on immediately so got lucky

Could it be fuel related
Things done on that side last year. New fuel pressure regulator and filter and def ran bunch of cleaner through since then I do it every so often

Thanks for any help if anyone has it
 

MAY03LT

Member
Nov 18, 2011
3,412
Delmarva
So SAIS is ruled out. Is the pcm at the latest calibration?

I've yet to see fuel delivery cause a p0171 in these trucks but that doesn't mean it isn't possible. Since it's passed vac leak test multiple times, it might be the next step (assuming pcm cal is the latest and greatest). Testing fuel pressure is DIY friendly, testing injectors is not.
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
What do you mean is pcm latest calibration. It's never been calibrated? But I just sent it to pcmofnc for a tune a week ago. Would they have calibrated it?


Only other thing crosses my mind is when I bout car long time ago they replaced exhaust manifold as old one was cracked. Well they snapped one bolt off but I don't hear a leak there. Would that cause any kind of lean condition if slightly leaking that would be blowing air out though not sucking unmetered air in
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
So since removing sais and adding block plate and replacing both o2 sensors p0171 engine light pops up more then before really damn frustrating lol. So during next week or weekend going to check everything again

Going to check
1. Vacuum
2. Fuel pressure
3. Fuel trims


Anyone has anything else to check please add-on appreciate it
 

AtlWrk

Member
Dec 6, 2011
674
Only other thing crosses my mind is when I bout car long time ago they replaced exhaust manifold as old one was cracked. Well they snapped one bolt off but I don't hear a leak there. Would that cause any kind of lean condition if slightly leaking that would be blowing air out though not sucking unmetered air in

So they didn't fix the stud when they replaced the manifold, they just left one out? An exhaust leak at the manifold gasket or a cracked manifold could definitely allow outside air to be pulled into the exhaust manifold. While you generally think of exhaust being pushed out of an engine this is only true downstream and in general where you don't have the dynamics of individual cylinders and their runners (and that net pressure is very very small to begin with, fractions of a PSI normally). Without getting into unnecessary detail, local pressures inside the manifold can and do go below ambient (vacuum) meaning if there's a leak air will be drawn in leading to a false-lean condition.

It may not be the cause of your P0171 but it definitely warrants further investigating.
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
So they didn't fix the stud when they replaced the manifold, they just left one out? .

Yes they refused to fix it even though I was able to get them to admit they did it it's obvious they did it I reported them to better business bureau and his response was "with this many miles on vehicle something else will go wrong before that snapped stud causes a problem". Basically he was cheap and was mad he had to out 4 brand new tires on it and a new exhaust manifold also stated that the car I was trading in had issues to and he isn't requiring me to fix them. Haha that's why I was trading it in asshole lol


Anyway I am in no way going to pay someone or spend the time myself to get in there and try to drill it out. Bought car over 6 years ago been like that since put 70,000 miles on it like that so yea that's going to stay there.

Just curious how much could it leak from 1 missing stud?

Anyway thanks for the input if that's the cause I'll just deal with it until car dies but I'd like to be sure that's it you know


Today I took some logs on drive home. Check engine light off during this drive towards end will see rpm at idle be 900ish tried clearing code it jumped up then down again. I'll attach it in next post along with a video of me inside car reving engine and i can hear slight high pitched almost whistle maybe it's a vacuum leak maybe it's normal I was just paying attebtion heard it so let y'all listen.

Thanks for reading post more soon
 
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Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
If you don't hear exhaust noise, it should be OK.

You still getting the same codes?
 

stickypoop

Member
Oct 14, 2014
872
For reference, my manifold is missing at least one stud and also has a very nasty crack.. very noticeable leak... and this has not set any codes
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
Attached is a excel in a zip of my log on 20 min trip home shoes engine temp rpm speed o2 voltages fuel trims

Highest long term fuel trim goes is 14.7 I think for short time under acceleration once I release gas to coast it drops back down

Some pictures at idle
Screenshot_20161010-182209.png
Screenshot_20161010-182242.png
Then I think I revved it up here Screenshot_20161010-182235.png

Just another shot dunno if helps Screenshot_20161010-182330.png

Yea that's it idling high. Also my temps rarely get above 200 always between 195 and 200.
 

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Mooseman

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jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
Your LTFT seem a bit high to me showing it's on the lean side and adding fuel. The majority of the time it's above 6 and it hits above 10 a lot.

For some reading on fuel trims:
http://www.aa1car.com/library/what_is_fuel_trim.htm


Hey mooseman thanks for that info I read that over plus a few similar articles.

It says if it's a vacuum leak that ltft should return to normal at higher rpm and there

I tested this theory and ltft. First I did it when I left work but engine was cold so nothing warmed up etc. At idle ltft was 4.6 steady. If I hit gas to 2k it jumped 10 or more.

Realized was cold so I started driving home with torque open and at one point I stomped on gas to pass an idiot and noticed when I did that ltft immediately dropped to 0 stft also. So I kept doing it lol and notice basically anything more then like 55-60℅ throttle ltft hit 0. Don't know if this means anything if it's supposed to do that.

I got home shut car off (forgot I wanted to test at idle warmed up). Started back up and at idle ltft was 5-8ish if I revved to 2k it jumped to 10-14 so I went past 3k and as soon as I did that ltft dropped and held at or near 0. Slowly went under 3k and jumped back to 11-14

Really don't know what this explains reading that link if it was a vacuum leak it would should go back down with faster engine speed unless I have a huge vacuum leak somewhere and it takes 3k engine speed and 60℅ throttle under load for the vacuum not to make a difference I dunno

Other hunch is fuel pressure not enough at idle and stomping on gas causes more pressure so it's not a lean condition anymore.

Just wish my car was smart enough to tell me what's wrong comon gm start making smart pcms that diagnose themselves for us wonderful customers

Anyway here's a log showing what I attempted to explain.

Thanks for the link moose alot easier to fix things when you know how they work I had general idea but still helped.

I think in my head I am biased that it's something small and stupid and no way my buicka has leaky exhaust valves or some other major issue haha so any input outside my box is awesome thanks guys

Trying to get my hands in fuel pressure gauge and vacuum gauge again. Can check all that all over again.
 

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jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
Also quick question tried searching via Google on here for how to actually remove and clean injectors manually not by adding fuel additives? Or is that something easier done paying a shop to do? Not sure if special tools or what not is involved
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
When it drops to 0, that means it's not using the O2 sensor to adjust fuel. I knew that at WOT it did this but not sure about when it does in neutral. Could be because of the rev limiter.

A proper injector cleaning requires a machine that is plumbed into the fuel line and feeds a mix of fuel and cleaner directly. I don't believe in additives to clean them but apparently using top tier gas works. I have heard good things about BG44K cleaner although I have never used it myself.
 

AtlWrk

Member
Dec 6, 2011
674
There's an applet in Torque called Fuel Status (add displays-> and scroll down to "Fuel Status". it's not a PID but a standalone display) that will tell you whether you're in closed or open loop operation. You can use this to confirm that anytime your ltft drops to zero is because of going into open-loop (99% sure that's the case). Doesn't add much to this diagnosis but a little FYI.

Have you gotten under the hood while someone revved it and tracked down that whistle? Hard to tell if it's just normal intake noise or some sort of leak (intake or exhaust). Have you checked your exhaust manifold bolts? They can/do loosen over time--and you already have one missing.

Another potential culprit is the MAP sensor. These rarely fail but bad info from this sensor would definitely throw off fuel trims.

I've been looking into injector cleaning recently too and there are a few options:

Most expensive is going to be giving it to a shop to do the removal, cleaning and reinstallation.
Next you have removing them yourself, sending them to a shop to be cleaned and reinstalling yourself.
If you youtube DIY injector cleaning you can see some backyard mechanic ways to do a fairly cursory cleaning but to really do it right you need an ultrasonic cleaner and flow test machine to confirm they are spraying evenly and near their rated volume.

Then you have "on-rail" cleaning like Mooseman mentioned where you don't remove them at all but basically attach compressed concentrated cleaner to the fuel pressure port, disable the vehicle fuel pump, and run the engine on the cleaner. There are DIY versions of this setup ($$) or a shop can do it. The effectiveness of all these options is in the details. You might want to call around and price out your options.

All that being said, I'd say it's a last resort. You could try some in-tank additives for a few tanks in the meantime but I'm not convinced they do much either.

I would also consider pulling the spark plugs and comparing their condition. If any one plug looks significantly different than the rest you might narrow it down to a problem with that cylinder. Along those lines, have you checked Torque for individual cylinder misfires? It takes a fairly substantial and prolonged misfire to trigger a misfire DTC or MIL. If one is regularly misfiring it will be dumping unburned oxygen (and fuel) into the exhaust.

Unfortunately since your lean condition is marginal (comes and goes) it might be difficult to find a smoking gun.
 
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jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
hey thanks for info you are correct about it going into open loop when rvved over 3k grr.

going to check spark plugs this weekend

ive replaced map back when first tried fixing this

ill have gf rev engine listen for that whistling
local shop charges 110 for fuel injection cleaning they disconnect fuel line hook up there thing run car off there cleaning mixture. have to wait to get money to do that.

ive been having this same issue since 2014 on and off just keep clearing code.. not sure how much life this truck has drove like this for like 30,000 miles mind as well keep driving
 

mrrsm

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Jeff... DEJA VU... @MAY03LT ...Please have a look at this (ONE MORE TIME) very detailed video that might pin down the problem very well and explains why it is such a mysterious problem to solve... If it works... GMT Nation always appreciates Donations to "Keep The Lights On"...Thanks!

 
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jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
Jeff... DEJA VU... @MAY03LT ...Please have a look at this (ONE MORE TIME) very detailed video that might pin down the problem very well and explains why it is such a mysterious problem to solve... If it works... GMT Nation always appreciates Donations to "Keep The Lights On"...Thanks!

Hey thanks for video. Not sure if I stated before or if that's wrong video but my sais system has been deleted. As in completely removed air pump hoses and valve and a block off plate from dealer installed and pcmofnc deleted code from pcm. Truly wish it was that I'd have it fixed by now
 
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mrrsm

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Thanks for The Update... Jeff... @Mooseman ... His Information on How To Do Things ... Is Always without any "Clutter" and is just about as Good as You can Get... :>)

The only other question left to answer is, "Did You Pass your Vehicle Inspection?"
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
First time I went for emissions was in lot waiting to get it done light came on.

So I cleared it went home went to work came on again. Cleared it drove home and didn't come on emissions were showing complete so I went to the place shut car off.

I had to go back there with guy because I had a DUI last year so have breathalyzer in car so had to be there to start and what not so when he started noticed Rpms were high

In my head thought I was screwed. He hooked his computer up and did w.e. it is they do and it passed. I pull out of garage and bam light comes on before i even left the lot. Whew lol so registration was able to be renewed

Looks like next year they want emissions done again seems to soon but that's what paper said so looks like I'll be doing same thing again.

I don't have money to pay a mechanic to spend days trying to figure it out last shop I went to had it for a week and didn't fix it oh well.

I guess thanks for all the suggestions. If anything comes up I will update

Today I filled up with shell 93 vpower or w.e. it is been driving. Ltft coasting are around 4 if I lightly hit gas to like 15k it jumps to 10+ if I go to like a heavier acceleration 2k it drops to 7 and holds no rpm jumping or pending code or code

Not sure if 02 sensors have to be learned or worn in but notice the graph on that seems a lot more responsive then when first installed though that was odd

So just going to keep driving her till she dies got 234844 miles on her and to be honest I'm surprised engine wise there's not more issues now just need new upper control arms those are shot to shit whole wheel wiggles every which way I replaced ball joints as those were falling apart too figured I'm safer with failing control arms then ball joints.

Also thing my power steering rack is shot leaking fluid driver side boot

Not sure if any of it is worth fixing I dunno guess it's all cheaper then a new car but in back of my head I know I'f I fix one thing something else bigger is going to brake.



Thanks gmtnation you guys have been helping me trouble shoot and fix my truck since day 1 7 years ago 1476465988382-519023844.jpg
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
One last question. At idle does everyone rpms fluctuate or are they steady close to one number


Not sure what this means if anything but mine does this goes to 630 then surges kind of down to 592 then slowly goes back to 630 then 592 I'll posts video of sound (edit I lied cant hear it too noisy in video :sadcry:. Anyone live in Ct wanna be my cheap mechanic haha)
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Normal warm idle is ~650, a little faster during warmup but should be fairly steady around that.

With those fuel trims, code and weird idle, I still think there is a vacuum leak somewhere.

I know it's frustrating trying to track this thing down but it's there somewhere.
 

mrrsm

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At first blush... This sound like a" Dirty Throttle Body". This does not require any Master Mechanic Chops to repair and there are abundant Youtube Videos that will walk you through the process. If you look over three or four of these you will get familiar enough to do this job without any serious fanfare. Here are a few to be mindful of::

(1) Don't Monkey around too much with the Electric Motor Controlled Throttle Body Butterfly by pushing it in too fast...or pulling on it. Careful not to Drop it...

(2) Don't Booger Up the Connector and Wire Harness where it plugs into the Throttle Body or lose the Small Retention Clip that will fall out and get lost very easily when you take it loose.

(3) Use the appropriate Throttle Body Cleaning Spray.

(4) Clean around inside of the circular groove for the Throttle Body "O" Ring and make sure that it is seated correctly before tightening up the Four Mount Bolts. DON'T USE TOO MUCH TORQUE... Snugemupnurdunn!

(5) Opinions vary about the need to remove the Ground Cable from the Battery for 30 Minutes after doing this.... Others here with experience can offer ideas for either Pro...or Con.

This search will bring a raft of the videos up to watch and choose from but @MAY03LT has the Right One from the GiTGo:



https://duckduckgo.com/?q=youtube+T...dy&t=h_&atb=v32-7a_&ia=videos&iai=XWNlP5FFZ-A
 
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Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
If you clean the throttle body, you MUST either disconnect the battery or pull the PCM fuses for 30 minutes.

In post #6, he said he cleaned it and I have NEVER heard of a dirty TB throwing a code. Rough idle and stalling, yes, but no codes.
 
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mrrsm

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Whoops...

I searched the post Dyslycallxee (Dyslexically... My Bad)... Thanks for the "Battery Disconnect" clarification.

I know the possibility and tactics for Fuel Injector Cleaning have been discussed above already... This GM Dealership PDF has all their procedural data and instructions from GM and lists the "Spent-More" Speciality Tools that might be out there on eBay for the taking... if Testing and Cleaning them is still being considered over Buying a Set of 6 Re-Manned EFIs from an "ASNU Shop" on eBay:

http://www.autocodes.com/uploads/gmc/03-06-04-030F.pdf

Wow... Somebody on eBay is selling the Entire Dealer CH-47976 EFI Tool Test Kit for $280.00 !

http://www.ebay.com/itm/OEM-CH-4797...:g:dHAAAOSwYIxX4Z7T&item=401193041620&vxp=mtr

As per @MAY03LT ...

"Testing fuel pressure is DIY friendly, Testing Injectors is NOT..."

Active Fuel Injector Tester (AFIT CH-47976)

s-l500.jpg


This one is listed there for MUCH more...

http://www.ebay.com/itm/KENT-MOORE-GM-TOOL-CH-47976-ACTIVE-FUEL-INJECTOR-TESTER-KIT/141968145202?_trksid=p2047675.c100623.m-1&_trkparms=aid=222007&algo=SIC.MBE&ao=1&asc=37115&meid=f32329740a104234a41fa75913f7a850&pid=100623&rk=3&rkt=6&sd=401193041620

s-l1600.jpg
 
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jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
Yea I think I'd most likely pay a shop 2 hours labor to find issue before I bought that thing haha. Thanks for the info. If I win lottery I'll be sure to buy that


So I'm thinking I missed a vacuum leak

What are all things that vacuum could leak out of ?

1. Intake manifold
2. Fuel pressure regulator hose thing
3. The little hose under vortex resonator thing
4. The plugged off port on inside intake manifold
5. Brake booster line
6. Sais system ( I no longer have )

So where else could it leak from I tried spraying carb cleaner everywhere. Was windy and engine fan blowing so it blew everywhere. But I didn't notice a change in idle

Not sure how much idle will change using that method but my regular idle jumps from 590 to 630 stays mostly around 620-630 surging to 590 every like 10 seconds. So hard to tell if carb cleaner was doing anything

I rechecked 3 of intake manifold bolts I could find towards the windshield side of things they were tight couldn't find my way to others.

So last question is if my exhaust manifold is leaking spraying carb cleaner on that will have absolutely no effect since that's the exhaust correct? So how do I test that for leaks.

I seafoamed yesterday just to do it using the can with hose that goes to throttle body and I figured maybe if it's smokey enough I'd see it leaking from manifold but nothing

So what else can I do to 100℅ rule out vacuum leak
 

mrrsm

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Oct 22, 2015
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Both of these Tests are RISKY...and need to be done OUTSIDE of the Garage...away from the House and your Family...and have an ABC Fire Extinguisher nearby:



Also... A Small... but "On Topic" Sidebar here...

This may seem unusual... But I have some considerable experience with cleaning Electronic Fuel Injectors with the help of a Home Made "Off The Vehicle" EFI Cleaning Machine I designed and built through four generations of development. I called this "Frankenstein Monster" I cobbled together years ago "The FrankInjector Machine"... and it was very successful when being used on both the Multech I and Multech II EFIs.

But strangely enough ... I've never seen the GM Dealer-Tech PDF mentioned above... before yesterday ...and so I neither used the SPECIFIC GM Top Engine-Fuel Injector Cleaner combined with High Test Gasoline they recommended ... nor did I use that elaborate EFI Tester listed above... Hmmmm... In the future... I might have to try out their "EFI Cleaner Recipe" on the Damned Thing (sans gas) and since I don't have to run the engine with the EFIs installed and BURN the stuff to get it to work... I'll be able to observe any performance improvements during the Flow Balance Tests in Graduated Cylinders.

Comparing the results of this stuff will be easy versus what I usually use as a "Chemical Cocktail" that doe NOT include Gasoline. The best part is that all of their Warnings and EFI Cleaner to Fuel Ratios for using the stuff mentioned in the PDF would not apply... since these activities neither take place inside the Engine nor expose the Catalytic Converter to them as as well.

If you are curious..."The Monster" can be seen in action...here...

http://s557.photobucket.com/user/60dgrzbelow0/library/HOMEMADEEFICLEANER?sort=3&page=1
DSC02999.jpg



DSC02994.jpg
 
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jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
Ok so bad news guys while using carb cleaner to find a vacuum leak I was spraying couldn't hear a change so I unplugged that cap off intake manifold and badically caused a vacuum leak so I can. See what carb cleaner does. I sprayed and it really didn't do anything I mean as soon as I unplugged the cap rpms jumped and held. So I sprayed it stayed. Then I went to put cap back on then engine stalled so I'm like wtf.

I start truck back up seemed a little harder to start and now I get a misfire on cylinder 1 so I said Ok recently had 2 coils go maybe just coincidence coil went bad. Switched 1 with 6 and misfire stayed at 1. So I said Ok it's been a while since I changed plugs. So remove six and looked looked like a normal spark plug used. So I put cylinder 1 spark plug into 3 and misfire stayed at 1

So now I have no fucking idea wtf to do grr sure as hell ain't driving around like this


So there's some possibilities in my head no idea how to test any of it.

1 exhaust valve is totally shot
2 that cylinder fuel injector isn't injecting
3. That cylinder piston and or ring is worn out

So I think if I'm correct to see if it's a valve or ring you do a compression leak down test and then do a wet one and if compression holds more when wet it's the piston

Any other ideas guys and also is this some odd coincidence if happened after the carb cleaner spraying ? I can't make the connection really but when I was spraying engine was idling like it was the 5 min before hand then when I removed the little rubber cap on intake manifold rpms jumped due to extra air coming in I sprayed carb cleaner near hole and nothing happened and when I reinserted cap it stalled restarted truck and misfire

Ugh time for new car? Anyone selling a tb cheap near ct

Edit: while searching here for issues about misfires cane across mooseman post I think when he switched wrong coil. So to be correct are the numbers listed near front of engine near coil packs just a firing order or is that correct layout of cylinder numbers ? So if I'm looking for cylinder 1 according to those number it goes 153624. So cylinder 1 is all the way back last one towards windshield ?

1476549672316336738220.jpg 1476549718302888389943.jpg

Edit number 2:. So read mooseman post little closer and decided that the cylinder goes 123456 front bumper to windshield. So I switched the one closest to front of car with 3 and sure enough misfire followed another coil down the drain.. I just don't get why it would fail the way it did when it did grrr. There werent any misfire prior to that
 
Last edited:

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Could be just a coincidence or you just disturbed it enough to make it fail. replace that coil and re-assess.

While you're there, do a compression test on all the cylinders to rule that out.
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
Could be just a coincidence or you just disturbed it enough to make it fail. replace that coil and re-assess.

While you're there, do a compression test on all the cylinders to rule that out.

Well I went to AutoZone got cheapest coil they had valucraft I know i know horrible idea. (I'm broke sorry) get it home go to plug harness in it wouldn't clip on returned it to AutoZone got next one up duralast I replaced 2 others in past with that one no known issues. Ac delco were 99$ and special order no time for that. Have to go to work tomorrow

So I put the duralast in and now that cylinder is misfiring like wtf so I move coil and same cylinder misfires. Go get all new 41-103 plugs install them. Now newer coil cylinder one misfiring I go check it out coil looks a little crooked I undo it and then put it back and start truck felt smooth drove around block.

On torque I set up 6 gauges for the current misfire reading. I drove around a couple blocks enough time to get to operating temps and then some. Probably a ten minute drive and torque registered a max value of between 2-4 misfires on all cylinders I don't know how often it misfired just know that the max number popping up was 4.

Wasn't able to do compression test don't have gauge nor money to buy one nor the time (my son turned 6 today had his bday party). So I do know that the 3 middle plugs had some oil on them 4 looking the worst no idea what that means haven't gotten to googling that yet.

I was able to shine a light Into cylinder one spark plug whole and saw what looked like alot of carbon buildup on cylinder apparently seafoam doesn't clean that up too good

I'll see on way to and from work tomorrow how it drives I did notice rpms weren't surging as low before staying between 608-625 ish.

Don't know if it matters but I'll post s pictures of my plugs maybe that will tell something and also before I had this misfire pop up I had recorded my screen with torque open on my drive home from work all the way until I stalled it putting the stupid rubber cover on intake port I'll upload and post that asap.
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,642
Tampa Bay Area
You have probably already thought to do this...but look inside each of the three Metripack Connectors for any Rust or Corrosion or Pieces of Dirt or Plastic or OIL that might be getting wedged in between the Coil on Plug Connection Points. Then... LIGHTLY pull on both wires leading from ALL of the COP Connectors in the COP Wiring Harness and see if they have any Cuts, Frays, Shorts or Separations. The TORQUE Analysis Tool is fine under most diagnostic issues... but these OBDII Devices often can NOT DETECT PHYSICAL DAMAGE TO SOME COMPONENTS.
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct

Kinda of a long video or what I thought would be useful torque gauges

Can skim through at the end is when I starting spraying carb cleaner then inducing a vacuum leak by taking that plug off the intake manifold stalled when putting back on restarted to misfire

Sorry bout music. Didn't think audio was getting recorded haha
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Those fuel trims are definitely not good. At least it has smoothed out with the new coil. You probably initially installed the coil crooked and not on the plug.

Anyway, drive it a bit and see if it throws a code.
 

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