2017 Z06 choppy acceleration below 4k
05-16-2017, 01:21 PM
#41
Instructor
Thread Starter
Drive home was awesome! The car felt great, like I remember my ZL1 after I got it tuned, nice and smooth.
I'm used to giving it throttle because it was so bogged down, now it spins the tires just a hair when tires are cold teeheehee
Only quirk I noticed is a nanosecond hesitation between cruising along and sudden wot, though I'm pretty sure this is just VVT and I'm fine with it.
So now the question is, what will happen on my next tank fill.
Should I:
A) Rock the boat and try 91 + 100 again to see if it goes back?
B) Stick with 91 + Torco and hope I remain problem free and potentially never know the original cause.
hmmmm
I'm used to giving it throttle because it was so bogged down, now it spins the tires just a hair when tires are cold teeheehee
Only quirk I noticed is a nanosecond hesitation between cruising along and sudden wot, though I'm pretty sure this is just VVT and I'm fine with it.
So now the question is, what will happen on my next tank fill.
Should I:
A) Rock the boat and try 91 + 100 again to see if it goes back?
B) Stick with 91 + Torco and hope I remain problem free and potentially never know the original cause.
hmmmm
05-16-2017, 01:42 PM
#42
Melting Slicks
Go to the same out of town gas station and run only 91. I think it's either your normal gas station or the race fuel. Even though you said it happened from day 1, that's what I think. I would see how it does without Torco for the heck of it. Also, because I want to know for myself what is going to happen if I get the Z and use 91. LOL.
Last edited by djnice; 05-16-2017 at 01:43 PM.
05-16-2017, 03:49 PM
#43
Instructor
Thread Starter
Go to the same out of town gas station and run only 91. I think it's either your normal gas station or the race fuel. Even though you said it happened from day 1, that's what I think. I would see how it does without Torco for the heck of it. Also, because I want to know for myself what is going to happen if I get the Z and use 91. LOL.
So lets consider the following scenarios:
I fill up at my usual gas station with 91 + torco:
- 1) Problem returns -- I know it was my local gas.
- 2) Problem does not return -- 91 wasn't the issue.
Either way I have an answer about the gas.
What I don't know is if the 100 octane was bad or Torco is just better, or maybe it just took 966 miles to computer - autocorrect.
I think I'm okay with stopping there. Ultimately the rest of the answer doesn't matter. Torco is cheaper, easier and it works well. I have no need for the race gas anymore. I don't want to run plain 91 since I drive hard.
So if I end up end scenario 2, then you know that 91 + torco works great and we don't need to worry about race gas.
EDIT: I have about 1/2 a tank left -- so I'll have more data in a day or two when I fill up. I'm driving to Google I/O today to pick up my tickets, then again Weds, Thurs and Fri for the event. Its a 75 mile round trip for me, so I have a lot of driving time ahead of me
Last edited by angryBits; 05-16-2017 at 03:52 PM.
05-16-2017, 04:59 PM
#44
Melting Slicks
Good strategy.
05-17-2017, 04:17 PM
#46
Melting Slicks
Because he lives in California where you can't get 93 octane, only 91. Z06's have a different octane requirement than the 91 recommendations of the other engine configs. For them, 93 Octane is more important.
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angryBits (05-17-2017)
05-17-2017, 04:45 PM
#47
Instructor
Thread Starter
It always surprises me how many people don't realize that not everyone gets 93.
Of course it also surprises me that a car comes to 91-only-areas tuned for 93
Last edited by angryBits; 05-17-2017 at 04:46 PM.
05-17-2017, 04:55 PM
#48
Ok, but slapping in 100 octane race gas with a goal of "creating 93 octane" isn't exactly as simple as you guys seem to think. There's a lot more to race gas than the octane rating.
http://www.superchevy.com/how-to/car...-about-octane/
http://www.superchevy.com/how-to/car...-about-octane/
Last edited by slythetove; 05-17-2017 at 04:56 PM.
05-18-2017, 01:29 PM
#50
I'd say run 91 for 2 full tanks without any of the added stuff and see if you ever experience the below 4k stumble during that time.
If not - pretty likely mixing 100 octane race gas is creating your unintended consequence.
05-18-2017, 01:56 PM
#51
Instructor
Thread Starter
Yep - that's my working theory at least based on what the OP has described. Running 91 octane the motor will pull a little timing etc so not optimal power but it won't cause damage.
I'd say run 91 for 2 full tanks without any of the added stuff and see if you ever experience the below 4k stumble during that time.
If not - pretty likely mixing 100 octane race gas is creating your unintended consequence.
I'd say run 91 for 2 full tanks without any of the added stuff and see if you ever experience the below 4k stumble during that time.
If not - pretty likely mixing 100 octane race gas is creating your unintended consequence.
Turns out the problem was my local 91 gas station and Torco vs Race Gas was the same. Actually the problem is considerably worse with Torco.
05-18-2017, 02:05 PM
#52
Instructor
Thread Starter
UPDATE
This morning I filled up with 91 from my local gas station as usual + 16oz of Torco. I still had a few gallons of the last mix in, so I'm probably mixed slightly over 93.
Expecting no problems, I head down the road to Google I/O 40 miles away and about 30 miles into the trip, like a switch, BOOM the problem returns. I recognized it immediately, did a few quick tests to be doubly sure and sure enough, Torco vs Race Gas was not the issue. The issue was my local gas. Last time I filled up I was at a foreign gas station and had no issues, returning to my local gas, issues returned.
Whats more... IT'S WORSE
Now I have an error code: P0121
So why do I have an error code on Torco + 91, and didn't get an error code on Race Gas + 91 ? Because of the amount of 91. With Race Gas I put 4 gallons in, leaving only 14 gallons of 91. With Torco I put in all 18 gallons of 91. So Torco isn't the issue, its just concentrated which means it takes up less room, leaving more room for more bad gas.
Recap:
91 + Torco = 18 gallons of bad gas + 16 oz of good gas == really bad
91 + Race Gas = 14 gallons of bad gas + 4 gal of good gas == bad
EDIT: While the symptoms feel more pronounced on this mix, I'm thinking the error code may not be from the gas, but rather from the Tony Mamo Ported Throttle Body I have installed (my only mod) -- an unsuccessful earlier attempt to solve this issue. I'll do more tests and see how it goes.
This morning I filled up with 91 from my local gas station as usual + 16oz of Torco. I still had a few gallons of the last mix in, so I'm probably mixed slightly over 93.
Expecting no problems, I head down the road to Google I/O 40 miles away and about 30 miles into the trip, like a switch, BOOM the problem returns. I recognized it immediately, did a few quick tests to be doubly sure and sure enough, Torco vs Race Gas was not the issue. The issue was my local gas. Last time I filled up I was at a foreign gas station and had no issues, returning to my local gas, issues returned.
Whats more... IT'S WORSE
Now I have an error code: P0121
So why do I have an error code on Torco + 91, and didn't get an error code on Race Gas + 91 ? Because of the amount of 91. With Race Gas I put 4 gallons in, leaving only 14 gallons of 91. With Torco I put in all 18 gallons of 91. So Torco isn't the issue, its just concentrated which means it takes up less room, leaving more room for more bad gas.
Recap:
91 + Torco = 18 gallons of bad gas + 16 oz of good gas == really bad
91 + Race Gas = 14 gallons of bad gas + 4 gal of good gas == bad
EDIT: While the symptoms feel more pronounced on this mix, I'm thinking the error code may not be from the gas, but rather from the Tony Mamo Ported Throttle Body I have installed (my only mod) -- an unsuccessful earlier attempt to solve this issue. I'll do more tests and see how it goes.
Last edited by angryBits; 05-18-2017 at 02:32 PM.
05-18-2017, 06:41 PM
#53
Instructor
Thread Starter
Anyone know what this message means:
0x7E8: P0121 - Throttle/Pedal Position Sensor A Circuit Range/Performance (Permanent)
The word "Permanent" scares me a little.
0x7E8: P0121 - Throttle/Pedal Position Sensor A Circuit Range/Performance (Permanent)
The word "Permanent" scares me a little.
05-18-2017, 11:57 PM
#54
IS THIS POSSIBLE??
CAN IT BE??
AM I CRAZY??
I've been putting about 4 to 5 gallons of 100 Octane gas mixed in with 91 Octane gas to get about 93-94 Octane. I've si measured with my HP Tuners and there is ZERO KR.
Well... I happened to be away from home and needing to fill up, so I decided to use my emergency can of Torco in the trunk. I put a 1/2 can in mixed with 91 Octane which I believe gives me a little over 93 Octane.
On the drive home, no real difference -- makes sense right? Same octane, car shouldn't really care. However now about 50-70 miles into this tank of Torco/91, the car seems to have done its last fart/cough/hiccup and now it's running fantastic!
My commute is about 17 miles each way. Today for the first 1/2 it behaved as badly as it normally does, coughing and choking at low RPM and moderate throttle, but often I need to change lanes quickly from 5mph and so I suffer and cringe though it. Then suddenly IT STOPPED. The last 8 miles of my commute were pure bliss, no hesitation and the car took off like a bat outta hell at any gear any rpm.
What could it be?
A: 16 oz of Torco works better than 4-5 gallons of 100 Octane race gas and it took 50-70 miles for the computer to relearn?
B: Torco vs Race Gas didn't matter -- It took the computer 966 miles to "relearn" whatever it learned at the dealership running 91?
C: I'm counting my chickens before they hatch, this bliss is temporary and I'm going to experience the fart/cough/hiccup again on the way home?
D: God decided I learned my lesson
E: I am truly crazy
CAN IT BE??
AM I CRAZY??
I've been putting about 4 to 5 gallons of 100 Octane gas mixed in with 91 Octane gas to get about 93-94 Octane. I've si measured with my HP Tuners and there is ZERO KR.
Well... I happened to be away from home and needing to fill up, so I decided to use my emergency can of Torco in the trunk. I put a 1/2 can in mixed with 91 Octane which I believe gives me a little over 93 Octane.
On the drive home, no real difference -- makes sense right? Same octane, car shouldn't really care. However now about 50-70 miles into this tank of Torco/91, the car seems to have done its last fart/cough/hiccup and now it's running fantastic!
My commute is about 17 miles each way. Today for the first 1/2 it behaved as badly as it normally does, coughing and choking at low RPM and moderate throttle, but often I need to change lanes quickly from 5mph and so I suffer and cringe though it. Then suddenly IT STOPPED. The last 8 miles of my commute were pure bliss, no hesitation and the car took off like a bat outta hell at any gear any rpm.
What could it be?
A: 16 oz of Torco works better than 4-5 gallons of 100 Octane race gas and it took 50-70 miles for the computer to relearn?
B: Torco vs Race Gas didn't matter -- It took the computer 966 miles to "relearn" whatever it learned at the dealership running 91?
C: I'm counting my chickens before they hatch, this bliss is temporary and I'm going to experience the fart/cough/hiccup again on the way home?
D: God decided I learned my lesson
E: I am truly crazy
i have had several instances of picking up a tank of fuel that turned out to be 50% dirty water, and, believe me, they don't run very well on water.
05-22-2017, 01:17 AM
#55
Instructor
Thread Starter
Question for anyone that is still listening:
I had a CEL P0121 which is caused by a faulty TPS Sensor -- I cleared it and the light has gone away but the computer still shows the code. The symptoms described sound very much like my choppy acceleration issue. I'd say we have a winner except... If that has been the problem all along, why did the car work great for 1 tank of gas that filled up at a different gas station, then when switching back to my usual gas station (believed to be bad gas) cause the issue to return?
So now I wonder
Do I actually have a faulty TPS sensor and that has been the issue?
OR
Could it be that a really bad tank of gas caused some funk that threw a P0121?
OR
Could it be both bad gas and P0121 (one hell of a coincidence)?
Any advice is appreciated
EDIT: The next question you'll ask me is: "Why don't you try another tank of gas from a different vendor and see if it goes away" and my answer is, I've called everyone -- the nearest appt I can get to drain the tank is 5/30. I can't drain it myself because I have no way to dispose of it.
I had a CEL P0121 which is caused by a faulty TPS Sensor -- I cleared it and the light has gone away but the computer still shows the code. The symptoms described sound very much like my choppy acceleration issue. I'd say we have a winner except... If that has been the problem all along, why did the car work great for 1 tank of gas that filled up at a different gas station, then when switching back to my usual gas station (believed to be bad gas) cause the issue to return?
So now I wonder
Do I actually have a faulty TPS sensor and that has been the issue?
OR
Could it be that a really bad tank of gas caused some funk that threw a P0121?
OR
Could it be both bad gas and P0121 (one hell of a coincidence)?
Any advice is appreciated
EDIT: The next question you'll ask me is: "Why don't you try another tank of gas from a different vendor and see if it goes away" and my answer is, I've called everyone -- the nearest appt I can get to drain the tank is 5/30. I can't drain it myself because I have no way to dispose of it.
Last edited by angryBits; 05-22-2017 at 01:19 AM.
05-22-2017, 07:34 AM
#56
With this code the best advice is to get it to the dealer and let them analyze it with their scan tool. P0121 basically means the indicated throttle (NOT accelerator pedal) position is out of the expected range for operating conditions based upon inputs from other sensors. Either the TPS itself is defective or there is an operating condition causing the throttle plate to be either open or closed beyond the expected range for the given operating conditions. So it can be either a sensor issue or an engine performance issue.
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angryBits (05-22-2017)
05-22-2017, 12:09 PM
#57
Instructor
Thread Starter
With this code the best advice is to get it to the dealer and let them analyze it with their scan tool. P0121 basically means the indicated throttle (NOT accelerator pedal) position is out of the expected range for operating conditions based upon inputs from other sensors. Either the TPS itself is defective or there is an operating condition causing the throttle plate to be either open or closed beyond the expected range for the given operating conditions. So it can be either a sensor issue or an engine performance issue.
05-23-2017, 04:44 AM
#58
Safety Car
Did you email Tony about the P0121 code? I believe that is what happens when any particular car can't handle his porting. His solution is to port a TB for you a little less aggressively if your car continues to throw the code.
If it were me, I would run a few tanks of retail premium gasoline through the car from various sources. There are many of us in California running 91 with no apparent issues.
And if the code is from the TB, I certainly wouldn't take it to any GM dealer, even Abel, to diagnose it. You are exposing them to something they don't want to officially know about.
If it were me, I would run a few tanks of retail premium gasoline through the car from various sources. There are many of us in California running 91 with no apparent issues.
And if the code is from the TB, I certainly wouldn't take it to any GM dealer, even Abel, to diagnose it. You are exposing them to something they don't want to officially know about.
Last edited by pkincy; 05-23-2017 at 04:57 AM.
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angryBits (05-24-2017)
05-23-2017, 07:29 AM
#59
I missed the part where the TB has been modified and I agree you don't want to go to the dealer since this was done. It is probably the cause of your issues since a common reason for the DTC set in your C7 is a mismatch between expected and actual throttle position which can easily be caused by the throttle body modification or installation.
05-24-2017, 11:44 AM
#60
Instructor
Thread Starter
Ah, so you guys think the P0121 is from the TB ?
If thats the case, then I'm experiencing 2 problems that exhibit similar symptoms.
I think for now, I'll revert the TB back to stock.
I couldn't find anyone to suck the gas out for me, so I've been driving on it carefully.
So far I've got 1/2 tank left, once its burned up I'll try a different source.
One of those two things will hopefully resolve my issues. Considering I had the throttle issues before the TB, I suspect the gas is still the bigger issue.
If thats the case, then I'm experiencing 2 problems that exhibit similar symptoms.
I think for now, I'll revert the TB back to stock.
I couldn't find anyone to suck the gas out for me, so I've been driving on it carefully.
So far I've got 1/2 tank left, once its burned up I'll try a different source.
One of those two things will hopefully resolve my issues. Considering I had the throttle issues before the TB, I suspect the gas is still the bigger issue.