2007 Base, manual - Hesitation on acceleration - Need help
04-09-2014, 10:57 AM
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2007 Base, manual - Hesitation on acceleration - Need help
I need some help/advice on my car. I do not know a lot about cars or terminology. Also don't know a lot about my car. I have posted on here about this problem months ago; hoping to get some new/updated perspective. My story is lengthy.
I bought my car used out of tamps, Fl. The car had been hit in the front wrecked and rebuilt. All it needed was paint. Drove well, no issues. Brought it home. Has it painted, happy with it except for an issue on idle. The car idles really rough and, at some points, it would actually lie when stopped at a redlight. When the air was off, it wasn't as bad, but with the air on, the idle was really rough. I took it to a local mechanic to check it out and scan it on the computer. The codes it threw were an 02 sensor and the mass airflow. So, he got a new mass airflow (I think from autozone or advance) and put it in the car. Did not help. He checked out the wiring and found nothing. He doesn't really work on or isn't familiar with corvettes, so he recommended someone else. Called him (who owns his own 2002 ZO6 and is familiar) and he looked at it and said it probably needed a tune. He informed me the car has no cats or 02 sensors. I do not know what else has been done to the car. Looking back, I probably shouldn't have bought it given the situation, but I did drive strong, and I've always wanted one. I made an appointment with a tune shop fairly locally and they did an HP Tuners tune. The fixed the idle. It idled fine. The problem was on the way home, when I would accelerate, the car had a terrible hesitation, especially around 2000-2500 RPMs. But it is a consistent problem and is bad enough that the passenger can feel it. So, I turned directly around and took it back to the tuner to address the problem. He drove it and said it was noticeable. The hesitation was not there before the tune. The idle was bad before, but it did not have the miss/hesitation. He kept the car for nearly two moths trying to figure it out. He even took of the tune and did it again and said it didn't help. He, too, checked a lot of the wiring and found nothing. He also tried another MAF and it did not help. He tuned to bypass the 02 sensors if I understood correctly. Eventually I got fed up with the fact that he did not seem to be finding anything, and him being about an hour away, I did not know how much time he was actually spending on it. He did say he thinks the problem is either electrical or in the wiring. So, I took it back to the second mechanic (the one with the Z06) and had him go through the wiring. He found one small portion or wiring that looked burnt up and replaced it, but it did not help and was not the problem. He also got the MAF code, which we told him about. He wanted to try to replace it (a third time) as well, as he said some of the aftermarket ones are junk, He did that, and it did not work. The MAF is the only code the car puts off. So, he found nothing as well. He thought the problem was probably in the original tune. So, I got another recommendation about another tuner fairly local and took him the car. He drove it and said he couldn't be 100% sure, but by driving it, he was fairly certain that the problem was in the tune. He said he could fix it. Well, after the weekend, he called me back and said he tuned it (HP Tuners) and it did not fix the problem. He wanted to look at it and check some things. It has been almost two months. I call and he updates me weekly, but he has found nothing. The only code it shows is MAF, which he wants to try as well. I told him it's had three already. He has additionally been through the wiring and found nothing. I am waiting on a call back from him this week to see if he has made any progress or has any news. I fear for the worst. I really need some advice. The only thing I bought for the car and put on it are two aftermarket air filters (Spectre) that are like the K&N. I also changed the oil with the recommended synthetic Mobil 1. Can someone give me some advice other than that I'm stupid for buying the car and spending all this money on repairs? I have had some advice, so tell me if any of it is logical... 1. Fuel filter, 2. Air filters (something about the oil can mess up the MAF), 3. MAF, 4. Have torque management disabled, 5. A possible crack in the radiator support, 6. A crack or hole in fuel pump or water pump. Can someone who has some experience let me know where I should go from here. I don't want to spend a lot more money on this thing, but I love it when it runs right. It's fun. I want it fixed. Not to mention, no one is going to buy it with the problems it's having. Additionally, could the original tuner have messed something up within the car during the first tune? Does that happen? If so, what could be the issue(s)?
The bad thing is I don't know anything else about the car and what it has and doesn't have.
I would appreciate any and all advice on the matter. Be honest with me. I want this fixed! I will also take recommendations for people who work on these things (East Tennessee area).
I bought my car used out of tamps, Fl. The car had been hit in the front wrecked and rebuilt. All it needed was paint. Drove well, no issues. Brought it home. Has it painted, happy with it except for an issue on idle. The car idles really rough and, at some points, it would actually lie when stopped at a redlight. When the air was off, it wasn't as bad, but with the air on, the idle was really rough. I took it to a local mechanic to check it out and scan it on the computer. The codes it threw were an 02 sensor and the mass airflow. So, he got a new mass airflow (I think from autozone or advance) and put it in the car. Did not help. He checked out the wiring and found nothing. He doesn't really work on or isn't familiar with corvettes, so he recommended someone else. Called him (who owns his own 2002 ZO6 and is familiar) and he looked at it and said it probably needed a tune. He informed me the car has no cats or 02 sensors. I do not know what else has been done to the car. Looking back, I probably shouldn't have bought it given the situation, but I did drive strong, and I've always wanted one. I made an appointment with a tune shop fairly locally and they did an HP Tuners tune. The fixed the idle. It idled fine. The problem was on the way home, when I would accelerate, the car had a terrible hesitation, especially around 2000-2500 RPMs. But it is a consistent problem and is bad enough that the passenger can feel it. So, I turned directly around and took it back to the tuner to address the problem. He drove it and said it was noticeable. The hesitation was not there before the tune. The idle was bad before, but it did not have the miss/hesitation. He kept the car for nearly two moths trying to figure it out. He even took of the tune and did it again and said it didn't help. He, too, checked a lot of the wiring and found nothing. He also tried another MAF and it did not help. He tuned to bypass the 02 sensors if I understood correctly. Eventually I got fed up with the fact that he did not seem to be finding anything, and him being about an hour away, I did not know how much time he was actually spending on it. He did say he thinks the problem is either electrical or in the wiring. So, I took it back to the second mechanic (the one with the Z06) and had him go through the wiring. He found one small portion or wiring that looked burnt up and replaced it, but it did not help and was not the problem. He also got the MAF code, which we told him about. He wanted to try to replace it (a third time) as well, as he said some of the aftermarket ones are junk, He did that, and it did not work. The MAF is the only code the car puts off. So, he found nothing as well. He thought the problem was probably in the original tune. So, I got another recommendation about another tuner fairly local and took him the car. He drove it and said he couldn't be 100% sure, but by driving it, he was fairly certain that the problem was in the tune. He said he could fix it. Well, after the weekend, he called me back and said he tuned it (HP Tuners) and it did not fix the problem. He wanted to look at it and check some things. It has been almost two months. I call and he updates me weekly, but he has found nothing. The only code it shows is MAF, which he wants to try as well. I told him it's had three already. He has additionally been through the wiring and found nothing. I am waiting on a call back from him this week to see if he has made any progress or has any news. I fear for the worst. I really need some advice. The only thing I bought for the car and put on it are two aftermarket air filters (Spectre) that are like the K&N. I also changed the oil with the recommended synthetic Mobil 1. Can someone give me some advice other than that I'm stupid for buying the car and spending all this money on repairs? I have had some advice, so tell me if any of it is logical... 1. Fuel filter, 2. Air filters (something about the oil can mess up the MAF), 3. MAF, 4. Have torque management disabled, 5. A possible crack in the radiator support, 6. A crack or hole in fuel pump or water pump. Can someone who has some experience let me know where I should go from here. I don't want to spend a lot more money on this thing, but I love it when it runs right. It's fun. I want it fixed. Not to mention, no one is going to buy it with the problems it's having. Additionally, could the original tuner have messed something up within the car during the first tune? Does that happen? If so, what could be the issue(s)?
The bad thing is I don't know anything else about the car and what it has and doesn't have.
I would appreciate any and all advice on the matter. Be honest with me. I want this fixed! I will also take recommendations for people who work on these things (East Tennessee area).
04-10-2014, 04:23 PM
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Update: talked to the tuner/garage last night. After going through wiring and everything else, he believes it may be a problem or a bad ECM. Any thoughts on this? Ideas? He said he knows a tech who is going to come in and check it out this weekend. I would appreciate any other or additional input...
04-11-2014, 01:43 PM
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Take it to GM and for $80 they hook it up to their scanner, instead of guessing, or a shop that has a good machine, less then $100 for a GOOD scan or have GM reflash it and see if that fixes it and then go to a tuner that KNOWS what he's doing.
04-11-2014, 01:58 PM
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Well, I actually thought of that a few months ago, and I called a Chevrolet dealership around an hour away from my house and asked them about that. Basically, what the guy told me is that since it had been tuned and was not stock, they would not even touch it. He said the only thing he could recommend would be to put cats back on it and the original exhaust and have a tuner tune it back to stock. He said unless that was done, they wouldn't do anything to it. Considering it was a dealership, I just figured that was standard procedure for all dealerships. Does anyone know if that is true or not? Maybe he just didn't want to fool with it?
04-11-2014, 04:04 PM
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St. Jude Donor '15
"In honor of jpee"
To an extent, I'd say what the dealer/service told you about not wanting to fool with your car is correct. They can't by Federal EPA rules work on an altered car and thus alter it some more. Or, at least that's the theory. The actual practice is that some dealers will work on them.
Still, what you have is a form of puzzle and so far, you have not found anyone with the needed skills to figure out the puzzle. You have so many things potentially wrong with the car from the start of your purchase, including what other things may have been involved (maybe not and maybe a LOT more than just paint and bodywork), that it would take, in my opinion a really good "diagnostician" or analyst. Time to figure it out is money.
Maybe I'm being harsh but if it were me, I'd get the car in as good running shape as possible, stumble included, and sell it for whatever I can get out of it and move on to another car. That is, unless you have an unlimited wallet. This will take a shop and technician who isn't just guessing, but knowing what to do, what to try and how to tune it. So, in my opinion, it is BOTH mechanical and technical (computer, tuning, electrical) skills required as well as actual familiarity with a C6 Corvette. And that will still take time, and dollars out of your pocket.
Good luck.
Still, what you have is a form of puzzle and so far, you have not found anyone with the needed skills to figure out the puzzle. You have so many things potentially wrong with the car from the start of your purchase, including what other things may have been involved (maybe not and maybe a LOT more than just paint and bodywork), that it would take, in my opinion a really good "diagnostician" or analyst. Time to figure it out is money.
Maybe I'm being harsh but if it were me, I'd get the car in as good running shape as possible, stumble included, and sell it for whatever I can get out of it and move on to another car. That is, unless you have an unlimited wallet. This will take a shop and technician who isn't just guessing, but knowing what to do, what to try and how to tune it. So, in my opinion, it is BOTH mechanical and technical (computer, tuning, electrical) skills required as well as actual familiarity with a C6 Corvette. And that will still take time, and dollars out of your pocket.
Good luck.
04-14-2014, 09:22 AM
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To an extent, I'd say what the dealer/service told you about not wanting to fool with your car is correct. They can't by Federal EPA rules work on an altered car and thus alter it some more. Or, at least that's the theory. The actual practice is that some dealers will work on them.
Still, what you have is a form of puzzle and so far, you have not found anyone with the needed skills to figure out the puzzle. You have so many things potentially wrong with the car from the start of your purchase, including what other things may have been involved (maybe not and maybe a LOT more than just paint and bodywork), that it would take, in my opinion a really good "diagnostician" or analyst. Time to figure it out is money.
Maybe I'm being harsh but if it were me, I'd get the car in as good running shape as possible, stumble included, and sell it for whatever I can get out of it and move on to another car. That is, unless you have an unlimited wallet. This will take a shop and technician who isn't just guessing, but knowing what to do, what to try and how to tune it. So, in my opinion, it is BOTH mechanical and technical (computer, tuning, electrical) skills required as well as actual familiarity with a C6 Corvette. And that will still take time, and dollars out of your pocket.
Good luck.
Still, what you have is a form of puzzle and so far, you have not found anyone with the needed skills to figure out the puzzle. You have so many things potentially wrong with the car from the start of your purchase, including what other things may have been involved (maybe not and maybe a LOT more than just paint and bodywork), that it would take, in my opinion a really good "diagnostician" or analyst. Time to figure it out is money.
Maybe I'm being harsh but if it were me, I'd get the car in as good running shape as possible, stumble included, and sell it for whatever I can get out of it and move on to another car. That is, unless you have an unlimited wallet. This will take a shop and technician who isn't just guessing, but knowing what to do, what to try and how to tune it. So, in my opinion, it is BOTH mechanical and technical (computer, tuning, electrical) skills required as well as actual familiarity with a C6 Corvette. And that will still take time, and dollars out of your pocket.
Good luck.
I certainly do not have an unlimited wallet, but I also have a lot of money and time already invested.
I am supposed to find out this week the outcome on the EMC test. I will more than likely go from there.
Thanks for your input.
04-16-2014, 12:44 PM
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Update: the tuner/mechanic contacted me yesterday and said he "thinks" he may have found the problem. He said they did a check on the ECM and it is functioning properly. However, he believes there is a short in the wiring running to the MAF. The issue is that he thinks the short is actually inside the wiring harness. He was trying to decide whether to find issue and re-wire, or just replace the whole harness. He is not 100% positive this is the problem, but he has a pretty good idea. I'll keep you updated. He said if everything goes right and that is the problem, it may be corrected by this weekend or early next week. Fingers are crossed!
05-05-2014, 02:51 PM
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Update: problem is completely fixed! I'm so relieved. Wanted to update the post in case anyone else has the same problem. Although the symptoms my car had can be a number of different problems (as I was told), at least this can maybe help someone or give them another idea to look at.
The problem did end up being a short in the wiring to my MAF. The short was down in the wiring harness. From what I understand, one of the prongs where it plugged in had broken and caused the short. He fixed the wiring and now everything runs great. The car is doing great. I picked it up Friday and have been enjoying it over the weekend! Additionally, he re-tuned and got some extra HP as well. So, overall, really happy.
Although it was a long process to figure it out (about 2 1/2 months at this place (and about 4 months total), I am happy with the outcome because it wasn't too expensive to fix, and the car is running great.
Maybe my experience can help someone else before they have to spend money they don't have to.
Thanks for everyone's help and suggestions.
The problem did end up being a short in the wiring to my MAF. The short was down in the wiring harness. From what I understand, one of the prongs where it plugged in had broken and caused the short. He fixed the wiring and now everything runs great. The car is doing great. I picked it up Friday and have been enjoying it over the weekend! Additionally, he re-tuned and got some extra HP as well. So, overall, really happy.
Although it was a long process to figure it out (about 2 1/2 months at this place (and about 4 months total), I am happy with the outcome because it wasn't too expensive to fix, and the car is running great.
Maybe my experience can help someone else before they have to spend money they don't have to.
Thanks for everyone's help and suggestions.
