Car just accelerates to 110mph! Please Help
09-17-2004, 09:59 AM
#1
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Car just accelerates to 110mph! Please Help Hello,
I have my new cam dyno tuned today.
We had the failuire message "throttle body performance" all the time.
Then when we raised the rev up to 6200 rpm and let it get down the car sounds like running not on all cylinders. They said it perhaps just run on 4.
I drove the car 4 weeks without tuning and I never had a problem or failure message.
After we couldnt find out what we should do we stoped and I drove home.
The Check light went on but I had no problems.
But then when I went up to 110mph the car dont accelerates no more.
And it sounds like its sucking air.
We drilled a hole in the TB. Is it possible that the hole was to big?
Did anyone had the same problem?
Please help me.
My power went up from 340BHP to 420BHP. The only good thing today!
I have my new cam dyno tuned today.
We had the failuire message "throttle body performance" all the time.
Then when we raised the rev up to 6200 rpm and let it get down the car sounds like running not on all cylinders. They said it perhaps just run on 4.
I drove the car 4 weeks without tuning and I never had a problem or failure message.
After we couldnt find out what we should do we stoped and I drove home.
The Check light went on but I had no problems.
But then when I went up to 110mph the car dont accelerates no more.
And it sounds like its sucking air.
We drilled a hole in the TB. Is it possible that the hole was to big?
Did anyone had the same problem?
Please help me.
My power went up from 340BHP to 420BHP. The only good thing today!
09-17-2004, 03:54 PM
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Originally Posted by donscheffler
Hello,
I have my new cam dyno tuned today.
We had the failuire message "throttle body performance" all the time.
Then when we raised the rev up to 6200 rpm and let it get down the car sounds like running not on all cylinders. They said it perhaps just run on 4.
I drove the car 4 weeks without tuning and I never had a problem or failure message.
After we couldnt find out what we should do we stoped and I drove home.
The Check light went on but I had no problems.
But then when I went up to 110mph the car dont accelerates no more.
And it sounds like its sucking air.
We drilled a hole in the TB. Is it possible that the hole was to big?
Did anyone had the same problem?
Please help me.
My power went up from 340BHP to 420BHP. The only good thing today!
I have my new cam dyno tuned today.
We had the failuire message "throttle body performance" all the time.
Then when we raised the rev up to 6200 rpm and let it get down the car sounds like running not on all cylinders. They said it perhaps just run on 4.
I drove the car 4 weeks without tuning and I never had a problem or failure message.
After we couldnt find out what we should do we stoped and I drove home.
The Check light went on but I had no problems.
But then when I went up to 110mph the car dont accelerates no more.
And it sounds like its sucking air.
We drilled a hole in the TB. Is it possible that the hole was to big?
Did anyone had the same problem?
Please help me.
My power went up from 340BHP to 420BHP. The only good thing today!
09-17-2004, 07:50 PM
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It depends on whether or not you've ever hit the limiter before...
I'd guess that if there was something wrong such as ignition, fuel or even something mechanical, he'd have noticed long before 110mph.
I'd guess that if there was something wrong such as ignition, fuel or even something mechanical, he'd have noticed long before 110mph.
09-17-2004, 08:47 PM
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IMHO you NEVER drill a hole in a C5 TB !
Use a pop rivet for a temp fix to fill that hole up
I have tuned 100's of C5s with all types of N/A and boost mods and not once have I had to drill a hole like a F-body has.
Doing so screws up the TAC ( drive by wire)
If exhaust valves did not bend while on the dyno then the tune is super bad.
I would suspect a 80 HP gain if they are saying that is just due to that tune and just a mild CAM
Use a pop rivet for a temp fix to fill that hole up
I have tuned 100's of C5s with all types of N/A and boost mods and not once have I had to drill a hole like a F-body has.
Doing so screws up the TAC ( drive by wire)
If exhaust valves did not bend while on the dyno then the tune is super bad.
I would suspect a 80 HP gain if they are saying that is just due to that tune and just a mild CAM
Originally Posted by donscheffler
Hello,
I have my new cam dyno tuned today.
We had the failuire message "throttle body performance" all the time.
Then when we raised the rev up to 6200 rpm and let it get down the car sounds like running not on all cylinders. They said it perhaps just run on 4.
I drove the car 4 weeks without tuning and I never had a problem or failure message.
After we couldnt find out what we should do we stoped and I drove home.
The Check light went on but I had no problems.
But then when I went up to 110mph the car dont accelerates no more.
And it sounds like its sucking air.
We drilled a hole in the TB. Is it possible that the hole was to big?
Did anyone had the same problem?
Please help me.
My power went up from 340BHP to 420BHP. The only good thing today!
I have my new cam dyno tuned today.
We had the failuire message "throttle body performance" all the time.
Then when we raised the rev up to 6200 rpm and let it get down the car sounds like running not on all cylinders. They said it perhaps just run on 4.
I drove the car 4 weeks without tuning and I never had a problem or failure message.
After we couldnt find out what we should do we stoped and I drove home.
The Check light went on but I had no problems.
But then when I went up to 110mph the car dont accelerates no more.
And it sounds like its sucking air.
We drilled a hole in the TB. Is it possible that the hole was to big?
Did anyone had the same problem?
Please help me.
My power went up from 340BHP to 420BHP. The only good thing today!
09-18-2004, 05:00 AM
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Just to clarify what happened:
We are located in Germany, and there are no professional tuners around for LS1edit. I learned how to do it on my car, so I told Donscheffler I could do it on his car if he wants to. I am not doing this professionally!
Donscheffler got the cam put into his car before I got a new license for Ls1edit, so the car was in the shop, and I could do nothing. By the time I got the new Ls1edit license, it was their holiday break at the shop. Donscheffler didn't want to leave the car there for another week, and the owner agreed to show up during their holidays and let us get the car at least ready to be driven on the road.
The car would start cold and run in "P". Shifting to "D", the engine would die immediately. Then you couldn't even restart without giving it some gas. So far I had only looked at cars with manual transmissions, time was running out, the best I got with tuning was the engine bogging at 400 rpm. I hadn't tuned an automatic before, and the advice on idle tuning I had found on the forums was confused (at least to me), and didn't work.
So, with time running out, we decided to drill a small hole into the throttle body. 3mm at first, which was an improvement, but not quite enough. Then the mechanic drilled a 5 or 6mm hole, and the car was running fine. I think the hole was probably a bit bigger than it would have needed to be.
We took the car on the road, and it drove just fine. I logged some pinging and reduced spark advance. I also did some very quick and dirty adjustments to MAF and VE.
The car was running fine, almost like stock. There were no error messages at all. Good enough to drive it home without worrying.
I told Donscheffler we should meet and tune VE and MAF before we went to the dyno. He didn't have the time.
So we met at the dyno yesterday. There had been no problems or error codes in three weeks of street driving. Before tuning anything, we wanted to do a baseline run. I wasn't sitting in the car, but here is what happened, as far as I understood:
The car was warm, and the owner of the dyno shop made a test run at a fixed speed, going from idle to full throttle. This just gives you the torque at that rpm, and an indication that everything is okay without having to go to very high rpm. He went back to idle and was just about to start the actual dyno run when the check engine light went on and the engine went into a reduced power mode, running on four cylinders.
We got the error code "Throttle body performance". We had a guy with a Tech II come over, and he found that "desired throttle body position" and "actual throttle body position" didn't always match, he thinks the throttle body is slow. We tried another dyno run, and got the "throttle body performance" code again, as well as "MAF performance".
For some reason, we then could do a couple of dyno runs without any problems. First runs was 360hp at the crank. It went up to 380hp and then 405hp at 6000rpm with some very minor changes to spark advance. I didn't do the runs myself, so I had no chance to cheat (if that is what Team ZR1 is implying). I was surprised at the gains myself, on my own car I got gains of 5-6 hp with similar changes.
I had made some crude adjustements to VE, and gotten the LTFTs down from 10% to 5% before. I adjusted VE a bit more, and reduces PE slightly. But we never got to do another dyno run, we got the error code again and time was up.
One thing I noticed: The first LTFT, the one with the lowest pressure and rpm, went to -100% for Bank 1 after turning the engine off and on again. All the other LTFTs were between -2% and 10%. Manifold pressure at idle is around 50kPA, so maybe it just never gets into that trim cell?
The idle in drive was at 750 yesterday, and I reduced it to 725, since the car shakes less at 725. At 750-800 there must be some resonance in the suspension or engine mounts. TPS was around 4.5% with both settings.
I just can't see how the car would run for three weeks with no problems if this was related to the hole in the throttle body. Maybe it got colder, and the PCM tries to close the throttle body further?
The cam is the Thunder Racing 224/224 .563/.563, and I don't know if the got the 112 or 114 LSA. If anyone could just tell me to make this thing idle with an automatic and stock torque converter, without drilling a hole into the throttle body, I would appreciate that.
Maybe the throttle body was damaged, and there is a mechanical problem? We didn't get a chance to have a look at it yet.
Any input appreciated. Thanks, Till
We are located in Germany, and there are no professional tuners around for LS1edit. I learned how to do it on my car, so I told Donscheffler I could do it on his car if he wants to. I am not doing this professionally!
Donscheffler got the cam put into his car before I got a new license for Ls1edit, so the car was in the shop, and I could do nothing. By the time I got the new Ls1edit license, it was their holiday break at the shop. Donscheffler didn't want to leave the car there for another week, and the owner agreed to show up during their holidays and let us get the car at least ready to be driven on the road.
The car would start cold and run in "P". Shifting to "D", the engine would die immediately. Then you couldn't even restart without giving it some gas. So far I had only looked at cars with manual transmissions, time was running out, the best I got with tuning was the engine bogging at 400 rpm. I hadn't tuned an automatic before, and the advice on idle tuning I had found on the forums was confused (at least to me), and didn't work.
So, with time running out, we decided to drill a small hole into the throttle body. 3mm at first, which was an improvement, but not quite enough. Then the mechanic drilled a 5 or 6mm hole, and the car was running fine. I think the hole was probably a bit bigger than it would have needed to be.
We took the car on the road, and it drove just fine. I logged some pinging and reduced spark advance. I also did some very quick and dirty adjustments to MAF and VE.
The car was running fine, almost like stock. There were no error messages at all. Good enough to drive it home without worrying.
I told Donscheffler we should meet and tune VE and MAF before we went to the dyno. He didn't have the time.
So we met at the dyno yesterday. There had been no problems or error codes in three weeks of street driving. Before tuning anything, we wanted to do a baseline run. I wasn't sitting in the car, but here is what happened, as far as I understood:
The car was warm, and the owner of the dyno shop made a test run at a fixed speed, going from idle to full throttle. This just gives you the torque at that rpm, and an indication that everything is okay without having to go to very high rpm. He went back to idle and was just about to start the actual dyno run when the check engine light went on and the engine went into a reduced power mode, running on four cylinders.
We got the error code "Throttle body performance". We had a guy with a Tech II come over, and he found that "desired throttle body position" and "actual throttle body position" didn't always match, he thinks the throttle body is slow. We tried another dyno run, and got the "throttle body performance" code again, as well as "MAF performance".
For some reason, we then could do a couple of dyno runs without any problems. First runs was 360hp at the crank. It went up to 380hp and then 405hp at 6000rpm with some very minor changes to spark advance. I didn't do the runs myself, so I had no chance to cheat (if that is what Team ZR1 is implying). I was surprised at the gains myself, on my own car I got gains of 5-6 hp with similar changes.
I had made some crude adjustements to VE, and gotten the LTFTs down from 10% to 5% before. I adjusted VE a bit more, and reduces PE slightly. But we never got to do another dyno run, we got the error code again and time was up.
One thing I noticed: The first LTFT, the one with the lowest pressure and rpm, went to -100% for Bank 1 after turning the engine off and on again. All the other LTFTs were between -2% and 10%. Manifold pressure at idle is around 50kPA, so maybe it just never gets into that trim cell?
The idle in drive was at 750 yesterday, and I reduced it to 725, since the car shakes less at 725. At 750-800 there must be some resonance in the suspension or engine mounts. TPS was around 4.5% with both settings.
I just can't see how the car would run for three weeks with no problems if this was related to the hole in the throttle body. Maybe it got colder, and the PCM tries to close the throttle body further?
The cam is the Thunder Racing 224/224 .563/.563, and I don't know if the got the 112 or 114 LSA. If anyone could just tell me to make this thing idle with an automatic and stock torque converter, without drilling a hole into the throttle body, I would appreciate that.
Maybe the throttle body was damaged, and there is a mechanical problem? We didn't get a chance to have a look at it yet.
Any input appreciated. Thanks, Till
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09-18-2004, 05:52 AM
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Electronic TB - no IAC motor, idle air is controlled by throttle blade position. My idle is around 6.5%tps at 560 rpms with stock internals on a 6.0L HO. Sounds like your 4.5%tps at 725rpms is on the low side - which makes sense with a hole in the blade.
When you first tuned the car and drilled the TB hole, did you get in several good WOT runs? If not, this may explain why the code never showed up before. Also consider that some codes take a while to appear. How much was the car driven over the few weeks in between?
The TB code makes sense with the hole drilled. The MAF code may be related to the calculated airflow tables that check for bad MAF sensor. There is a table of airflow vs. %tps which could be messed up by the hole in the blade. Or the MAF wires could be dirty?
good luck
When you first tuned the car and drilled the TB hole, did you get in several good WOT runs? If not, this may explain why the code never showed up before. Also consider that some codes take a while to appear. How much was the car driven over the few weeks in between?
The TB code makes sense with the hole drilled. The MAF code may be related to the calculated airflow tables that check for bad MAF sensor. There is a table of airflow vs. %tps which could be messed up by the hole in the blade. Or the MAF wires could be dirty?
good luck
09-18-2004, 08:36 AM
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I drove the car for about 200miles in the three weeks.
I also drove it on the Highway with 130mph and even more but just a few times with WOT and always just a few seconds at low speeds.
My cam is 114LSA.
I also drove it on the Highway with 130mph and even more but just a few times with WOT and always just a few seconds at low speeds.
My cam is 114LSA.
09-19-2004, 10:10 AM
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Originally Posted by deezel
When you first tuned the car and drilled the TB hole, did you get in several good WOT runs?
There is a table of airflow vs. %tps which could be messed up by the hole in the blade.
But I could imagine there being such a table, or at least some expectations what this looks like.
Or the MAF wires could be dirty?
Thanks, Till
09-21-2004, 04:33 AM
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Originally Posted by SmokingWS6
Don't think you mentioned an aftermarket converter for the transmission. That cam will never idle correctly with a stock torque converter.
Maybe a smaller hole and some idle tuning will yield the same result without throwing any codes?
I will try to get it to idle without the hole on friday.
Till
09-21-2004, 01:23 PM
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I would not be surprised that if the GM engineers ever detect an error with the "drive by wire" system that they would put it in a very conservative "limp home mode", at least I would if I were them. If the throttle plate angle Vs MAF air flow Vs RPM do not compute, due to a hole in the throttle body, this could cause such condition as described. I have not researched this but doesn't it make sense?
EJ
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09-28-2004, 04:21 AM
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Problem fixed I called Jeff at Thunder Racing. He was very helpfull.
Jeff told me about the table Deezel mentioned. With this, the error codes could have been turned off without closing the hole in the throttle blade.
Instead, trying to do it properly, we closed the hole in the throttle blade. I increased running airflow by 50%, and the idle was fine right away. Some more fine tuning, and reducing the idle to 625rpm in drive. The idle is now very, very close to stock.
During an extensive test drive, and lot's of starting the car cold or hot, there were no problems at all. I wanted to do a top speed run on the autobahn, to check how well the vararam works, and how fast the car now gets. Engine wise the car has the potential to go over 190mph, but the suspension felt pretty scary, and I didn't go above 160mph. Next mods should be brakes and suspenion!
Yesterday Donscheffler had an error code about manifold pressure. I wasn't there, so I can't say too much about it. If this happens more often, I may have to increase idle again, or find a way to shut that error code off. Maybe I could reduce running airflow a bit to get better vacuum? I doubt this would help a lot.
Thanks, Till
Jeff told me about the table Deezel mentioned. With this, the error codes could have been turned off without closing the hole in the throttle blade.
Instead, trying to do it properly, we closed the hole in the throttle blade. I increased running airflow by 50%, and the idle was fine right away. Some more fine tuning, and reducing the idle to 625rpm in drive. The idle is now very, very close to stock.
During an extensive test drive, and lot's of starting the car cold or hot, there were no problems at all. I wanted to do a top speed run on the autobahn, to check how well the vararam works, and how fast the car now gets. Engine wise the car has the potential to go over 190mph, but the suspension felt pretty scary, and I didn't go above 160mph. Next mods should be brakes and suspenion!
Yesterday Donscheffler had an error code about manifold pressure. I wasn't there, so I can't say too much about it. If this happens more often, I may have to increase idle again, or find a way to shut that error code off. Maybe I could reduce running airflow a bit to get better vacuum? I doubt this would help a lot.
Thanks, Till
