IHADAV8.com - Turbo Buick Tech, and Nonsense
Tech Area => General Buick Tech => Topic started by: daveismissing on May 10 2012, 08:27:17 AM
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Developed a stumble/stutter. No codes. Idle is ok . From stone cold to about ~8 minutes.
Perfect behavior past that point once its hot.
Suggest a starting point?
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is it lean or rich? Does the coolant temp reflect ambient conditions initially? Is the vacuum at normal levels?
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Developed a stumble/stutter.
From stone cold to about ~8 minutes.
Perfect behavior past that point once its hot.
Quit getting stoned, or wait 8 minutes or until you are hot before you start to talk; may take a long time to converse with someone. :atbeer:
AJ___
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Developed a stumble/stutter.
From stone cold to about ~8 minutes.
Perfect behavior past that point once its hot.
Quit getting stoned, or wait 8 minutes or until you are hot before you start to talk; may take a long time to converse with someone. :atbeer:
AJ___
(http://www.opry.com/img/artist-photos/MelTillis1.jpg)
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Mel?? had performance issues.
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Does the coolant temp reflect ambient conditions initially?
Yes
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is it lean or rich?
Dumb this one down for me :(
Is the vacuum at normal levels?
Sh*t - thought I had one, dozens of pressure gauges tho :icon_eyes:
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Or the blms and O2s lower or higher than usual when this is happening...at the point where it is happening
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Can you glean anything from this?
stupid cameras stupid new format stupid operators...
http://youtu.be/T_wiMWe6Ba4 (http://youtu.be/T_wiMWe6Ba4)
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I can glean it is not getting any fuel
What is the fuel pressure?
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FP diaphragm old and brittle...more pliable when warm.
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When was the last time the fuel filter was changed?
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Got the metco mini stuffed under the wiper. Will report after a cold AM run.
That may be the original filter I changed out when I did the lines ~2yrs ago.
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http://youtu.be/MO_RNln_Xfw (http://youtu.be/MO_RNln_Xfw)
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could not tell anything from that...did the pressure drop at the end of the clip? I would guess you let off and were coasting?
Were your O2s dead lean during that run as they were yesterday?
What chip are you using?
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stock reg 233
stock jectors
stock chip
I didn't want to prejudice interpretation by stating anything beforehand.
The pressure seems to follow the rules.
~close to 40 line off.
Drops with vacuum and rises smoothly with throttle. When the stutter is happening the gauge doesn't seem to vary by more than +/- 1 LB? or less Hard to tell exactly on that small gauge.
I'd guess the problem occurs still in the vacuum range vs boost?
It was much warmer overnight and the problem went away quickly and less pronounced so not much opportunity for capture, I was solo and didn't see the o2s.
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You cannot make an interpretation without knowing the basics
stock injectors...wh o knows what might be going on after all these years with regard to gum, etc.
The SM showed it to be extremely lean yesterday...wh en in closed loop, I would expect something like a continual movement between 300 and the 700s.
Factory chip is aiming for stoch.
Okay, next time look at the blms and see what they are reporting while this is going on.
Assuming you were not under boost during the video, then the fuel pressure was probably about right.
In the mean time...try some logger shirt maintenance. Crank it up, let it idle, and rattle each injector by holding an extension against the shoulder and tap it rapidly with a hammer...not hard enuf to break the housing of course...do each one-won't clean them, but, it might free up a sticking pintel
go to the home store, paint store, or whatever, buy a gallon of xylene and pour it in the tank with about ten gals of gas....half a tank, whatever
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Well, I couldn't pronounce xylene so I swapped the injectors ( and ancilliary items).
no change. :(
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so this happens in normal driving, not when in boost?
This happens in both open loop and closed loop?
Your SM showed the car to be very lean. Once the problem goes away, do the O2s get back into a normal range?
What are your blms showing while this is going on? What do they show when it goes away under the same driving conditions?
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H
Can you glean anything from this?
stupid cameras stupid new format stupid operators...
http://youtu.be/T_wiMWe6Ba4 (http://youtu.be/T_wiMWe6Ba4)
How are your scanmaster IAC and TPS numbers at warm idle?
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BLMs seem to be 117-119 in the area of interest.
No real change cold to hot.
I want to say it still looks lean but let me confirm again, not really seeing much diff there either hot vs cold.
TPS seems to around 0.8-1.5 when it stutters.
Gotta be in vacuum still, pushing it into boost clears or masks the stutter
Now TT 5.6 installed so I'll look at open/closed loop.
hot park
TPS .38
IAC .19
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so, if O2s are still lean like they were, and the blms say they are pulling fuel instead of adding it, then we seem to have a paradox, eh?
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bad spot on the TPS...
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will the car miss when you bring the gas up in Park?
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Got anyone around that you can borrow an ecm with Powerlogger on it from? God bless Bob Bailey and Scanmaster/Powerlogger!
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Got anyone around that you can borrow an ecm with Powerlogger on it from? God bless Bob Bailey and Scanmaster/Powerlogger!
Hey Dave,
Sent you a PM on the above subject.
Dave
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will the car miss when you bring the gas up in Park?
Yes
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Just like a treasure hunt...one clue at a time
Let's see, O2s seem low indicating it needs more fuel, blms are low indicating it is pulling fuel, fuel pressure might be okay-was hard to coordinate it with unknown driving conditions
Fueling is supposed to be easy on these cars. ECM has a fueling curve that depends upon the maf and the O2 inputs for adjustment. This can be messed up by unmetered air leaks between the maf and the O2 sensor. This could be a leak between the maf and the turbo or anywhere else in the system including vacuum lines, plenum seal to intake, etc. Also, any leaks in the exhaust before the turbo can suck air in.
At this point, we know the stutter goes away when it gets hot, but, we really don't know if the problem goes away, or simply gets covered up to some degree.
Can you tell us if this happens only in open loop operation, or does it happen in closed loop initially as well?
Also, are you running a factory original maf, a rebuilt unit, or a Translator?
What brand and how old O2 sensor?
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Wonder if the egr is hanging up? When it's stumbling at idle pull up on the diaphragm a few times and let it reseat and see if it clears up.
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I appreciate the responses, bear with me as I try to give accurate answers.
New Denso O2 installed with the injectors.
Rebuilt MAF 3yrs in service, tested/bought thru turbofish.
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The egr has been in the back of my mind....
With regard to the maf, we are always leery of the rebuilt ones. In park, when missing, what is the rpm and what is the maf number?
Does this occur in both open and closed loop modes?
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Rigged up a big a*ss analogue meter and tested the TPS- very smooth no dropsies.
Swapped the MAF, no change.
Looks like open and closed loop are the same
( that flashing DP is way slow and being it happens just off idle which is open loop- PITA to tell).
Was cold this AM, took a long time to hit the magic 180deg and go away.
Not fun in traffic.
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Did you check the EGR as I suggested?
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The only reason I have stayed away from the EGR is that the blms usually go high to make up for the leaness that occurs when the egr is open, but I would certainly check it as Ed has suggested to eliminate it. Hate to go 17 pages like I did on someone else's car to find out the egr was stuck open and leaking at the same time.
First, a car that misses when it is cold is often too lean and needs to be "choked" to run right. When the problem is not gigantic, the symptoms can lessen as it warms up. I forget all the conditions for closed loop, but the temp is something like 145F and the O2 has to be warmed up. As it appears to still be missing when it goes closed loop, it would seem to be something more basic.
Is the coolant temp on the SM reading properly?
Once again, see if you can give us the fuel pressure when you first start the car with the hose off and again when it warms up enuf to quit stuttering. Also give us the O2s and blms once it goes into closed loop and again when it stops sputtering.
This would be a lot easier if you had a modern chip that stayed open loop at idle so you could get consistent readings.
How old is the fuel pump? I am sure you have a reasonably new fuel filter?
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Modern chip:
Now TT 5.6 installed so I'll look at open/closed loop.
Sorry if that wasn't clear -injectors on hand were larger thus TT chip.
Todays observation:
Magic number seems to be 180deg - car stayed at 171-175 in the highway for a stretch and it wasn't behaving.
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I'm trying to get to the EGR thing-- I can access the diaphragm from under the dome?
Bear with me ,4 out of 5 cars in the family fleet are broken/semibroken, ($ :o $)
most of my warmup windows are in rushhour.
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put your fingers...use both hands...under the egr and you can feel the diaphragm. Lift up and you should feel it move against a spring...when you let go, the spring should pop it down. Lift it all the way up and let it pop down a few times. helps to pop the cover off the egr to give more room for your fingers....do it when the engine is cold!
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On the week end, crank it up, drive it around the block, or whatever to warm it up a bit....say to 160 and then read the O2s at idle. then watch them at idle as the car warms up further until it quits missing to see if anything changes.
Except for the blms which are confusing me, I would say the pump is getting tired...of course the fuel pressure did not seem to say this, but, you seemed to be driving so that can add to the confusion a bit.
Did you just change to the TT chip or has it been in during this episode? Do you have an adjustable fuel pressure regulator so you could set fp to 43# or did you tell Eric you have a non adjustable regulator so he could change the chip to make it work properly?
Be sure you are using a proper fuel pressure gauge to measure with as the little mini gauges are often 10% off when new and get worse. Some local expertise to help you look would be nice....:)
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Well, I couldn't pronounce xylene so I swapped the injectors ( and ancilliary items).
no change. :(
As of this (above)date: TT5.6 + 42Lb green stripe + Accufab @43lb aka ancilliary items
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raise the hose off pressure to 48 psi which will be about 6% increase and see what happens
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Not driving the car today, the need to mash the throttle to get past the stutters not compatible with the rain.
Noticed Eric says he disables the EGR, does that mean the plunger can still mess thing up sitting there?
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If the egr is not seated it can cause a problem. Only real cure if your not using it is to take it off and get a blockoff plate. You can pull the hose and plug it. Then move it up and down with your fingers and make sure its seated. Then drive. Its a free easy test and get it off your list as a possible problem.
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Not driving the car today, the need to mash the throttle to get past the stutters not compatible with the rain.
now, you lost me...you said it did it in park...the car is not moving in park :D
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You guys are hard to please, throw out a little anecdotal conversation and you're all over me. :)
"Just the facts 'Mam"
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Found some lost gauges> new "enhanced" directors cut videos-
same settings, car is warming so only slight stutter at 6-9 seconds-
tevestutr05 02 16 (http://www.youtube.com/watch?v=uCX5cHdM7lE#ws)
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tevestutr05_02_13.wmv (http://www.youtube.com/watch?v=KIwxvZZGdkk#ws)
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boost
tevestutr05 02 boost (http://www.youtube.com/watch?v=t64o8cmjMe0#ws)
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this is with the additional fuel pressure I asked you for?
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this is with the additionsal fuel pressure I asked you for?
No, I wanted to see if the small metco was/wasn't fibbing as baseline.
Thats next- rain delay encore.
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Again, if it will do it in park, you don't have to drive the car. Let it get cold, add the fuel pressure, and rev it in park....does it stutter, or not? :)
What is your vacuum reading in Park at idle? Is the idle steady when it is missing in park?
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Put down the labatts and listen to Steve.....
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That's CC please.
Beer is only for public buick events :)
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LOL
Do it this way. With the fuel pressure where it is, and the car warmed up so that it does not sputter in Park:
give me the scanmaster readings for all parameters in Park at idle and at the rpm where it normally would sputter when cold.
Then give me the same at idle and at that rpm with +5# added to the fp.
Take a pad and pencil with you-Leave it in Park for all four readings
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| 49Lb | 43Lb | | 49Lb | 43Lb |
| hot | hot | | hot | hot |
| r | 1600 | 1600 | | 1225 | 1225 |
| Ats | 112 | 111 | | | |
| Clt | 178 | 179 | | 178 | 178 |
| BL | 117 | 119 | | 115 | 118 |
| Int | 131 | 121 | | 123 | 123 |
| L8 | 34 | 33 | | 34 | 32 |
| AF | 10 | 10 | | 8 | 8 |
| O2 | 797 | 765 | | 796 | 792 |
| IAC | 32 | 35 | | 14 | 22 |
| TPS | 0.58 | 0.56 | | 0.54 | 0.54 |
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Your car idles at 1225 rpm?
There seems to be something wrong with the tps
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Those are rpms where the stutters happen.
I missed the idle bit (eek), let me go see how warm it still is....
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And, tell me what the vacuum is at idle in park and in drive (at idle)
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| 49Lb | 43Lb |
| hot | hot |
| r | 800 | 800 |
| Ats | 105 | 103 |
| Clt | 176 | 178 |
| BL | 118 | 118 |
| Int | 128 | 128 |
| L8 | 33 | 34 |
| AF | 4 | 5 |
| O2 | 824.179 | 890.089 |
| IAC | 27 | 30 |
| TPS | 0.38 | 0.38 |
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And, tell me what the vacuum is at idle in park and in drive (at idle)
-18 park
-14 drive
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Okay, I admit to being lost. Car is rich at idle and ecm is pulling fuel. It does not seem so rich on the first two sets of data...maybe a little, and the ecm is still pulling a lot of fuel to get it to where it is. Adding 5-6% more flow, I would have expected a greater increase of fuel being pulled as evidenced by the blm numbers.
I also don't understand the 8 in the maf reading at idle in one of the above. It should have stayed on 5.
Vacuum is good...I might have guessed a little more in Drive, but....I think it is okay.
With the engine off, if you very slowly ease down on the gas pedal, does the tps increment smoothly between .50-.60 v? I guess I need to check one of mine to see if there is so little change between 1200-1600 rpm.
Do you have another o2 to stick in it to see if it does the same thing?
On a cold start, does it stutter with the extra added fuel pressure?
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Thats a new Denso O2 sensor , co-incident with the new injectors in post whatever.
I don't think we saw any change. Try a third?
I put a large analogue meter on the TPS to check it, very smooth. Could change it for fun.
Drove the car a little at 49Lbs, still had stutters, possible less and disappeared faster- I need more driving to confirm. Want the video?
That's not an 8 thats a 4 smarten up Dave
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I put a large analogue meter on the TPS to check it, very smooth. Could change it for fun.
You really need a scope to check it.
If this is all for fun why bother Steve, Ed etc?
AJ___
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On a cold start bring up the rpm's until it starts to miss. Shut off and pull all the sparkplugs. Report the condition. I also assume you checked the plugs before all this happened and they are fairly new and correct.
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If you saw no dead spots, or places where the output was stationary for a small increment, then it seems okay. If this is a new sensor and it did it prior, scrub that.
have you tried the egr as Ed suggested? After that, remove the egr hose and plug it just in case the egr solenoid is leaking
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I tried to manipulate the EGR, it seemed to move smoothly.
Pulling on the diaphragm made the car run worse.
It was likely cold when I did that, I'd likely remember if it was hot.
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It's suppose to run bad when you move it. That's good and should seal. Now how about the sparkplugs?
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I see TPS at .38....thought .42-.45 was for Idle
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I see TPS at .38....thought .42-.45 was for Idle
More like .36-.46
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So I think I've pinned it down, whether by intelligent analysis or dumb luck? you can choose.
I was listening to the car on startup and thinking it sounded really good for the first few seconds.
Unplugged the cam sensor and the problem was not manifesting.
I've switched the sensor cap now and not had any stutter for a few days.
Now the fuel pressure is still up so I should bring that back down?
You guys were suspicious of the numbers, I'll try to get a logger once the budget allows.
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yeah, try bringing it down to where it should be. A cam sensor can do things like that, but, usually, it keeps doing it...have to file this one away in my limited memory banks.
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Put the fuel pressure back to what your chip spec requires. Then jump for joy if the new sensor cap fixed the problem. I doubt it but I've seen spells removed by witches that worked :icon_eyes:
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I'm interested in the colored dots on the caps. I wonder i the mfg "binned" then according to some parameter- rise time etc.
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You line up the dots on the cam sensor cap with the red dot on the boost solenoid :rofl:
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So BLMs are supposed to go up and down as you change fuel pressure?
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You might try reading some of this when you are bored. http://www.vortexbuicks-etc.com/Scantool_Readings.htm (http://www.vortexbuicks-etc.com/Scantool_Readings.htm)
Dave's write up on blms is as good as I have seen. I link it on my page above, but here it is http://www.gnttype.org/techarea/faq/BLMINT.html (http://www.gnttype.org/techarea/faq/BLMINT.html)
When the ecm thinks the fueling is right for current conditions, it will read 128 on the blms. If it thinks the car is on the lean side, it will add fuel and blms will rise showing that the ecm is adding fuel at that point. Vice versa if it thinks rich and the blms will drop showing it is pulling fuel to get back to stoch.
If all things are even, if you add fuel, you would expect to see the blms drop...and vice versa. The ecm does have learning capabilities so if all things remain constant, the blms may approach 128 with time.
remember that fuel FLOW changes by the square root of (new pressure/old pressure) so a five psi change is not a massive change.
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Thanks for the links - sometimes its the "remembering" that the problem.
inner loop and outer loop....
remember that fuel FLOW changes by the square root of (new pressure/oldpressure) so a five psi change is not a massive change.
Excellent - to the heart of the matter
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Gents, I have a log from last weekend have a look and see what you think...
http://www.turbotweak.com/forum/attachment.php?attachmentid=657&d=1340674766 (http://www.turbotweak.com/forum/attachment.php?attachmentid=657&d=1340674766)
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to add to what Eric told you, check for even clearances on the crank sensor as well as no wobble in the damper.
If that does not fix it, try wiggling the the PL connector around a bit to see if that cleans up the contact and gets rid of the problem
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Sufficient road time now:
I think we can say this is solved- root cause crank sensor/connection.
Post-mortem review suggests more so the corroded connection, had the sensor survived the arduous
removal we may have had opportunity to verify. The symptom's disappearance for a few days
when the cam cap was changed and harness being pulled around plus the condition of the connections
kinda fits.
My thanks to ALL for the support.
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Glad it is good now...I hate the problems I fixed without being 100% sure I knew why it got fixed...happen ed many a time, tho
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Update:
this problem came back with a vengance late in the year and the car just got put away, too pissed to post about it. :096:
Following the original hypothesis I rewired the crank sens back to the CCCI- same
Replaced the CCCI and pack with a type II I had-same
:chin:
I then swapped the Cam cap for a third new one and the TPS-
from the moment I started the car I could feel it was different( ie "right")
goes like stink :055:
So its gotta be one of the two or the wiring to the cam sensor
And AJ has a 33.3% percent chance to say "I told you so"
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Dave...put one of those many glasses you have hanging around your neck on and check the wires that go into the weather pack TPS connector. You may find one that has a slight break in it. Had the same stuttering problem with Dans car a while back. Drove us nuts. Swapped every electrical part on the car before we stumbled on it.
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Hey- I'm trifocalized now!
Definitely worth noting , tho my car has so little fixed/modded that I want to believe the harness is fine.
Sure could use another 4 inches of slack in the harness at the CCCI.
I'm not sized for engine sprawling.
[insert Charlie's smart assed comment here]