My Underground Racing Car

[2MANYTOYS]

As some of you know I've had some horrible drivability issues with my car. A lot of time was spent trying to diagnose the problem. Kevin @ KC (Underground Racing)tuned, retuned, checked, and re-checked the entire system multiple times. They added an AEM thinking this would fix the assumed tuning issues. After adding the AEM the car went from driveable to UN-driveable. It started bucking, surging, stumbling, etc.... I couldn't even drive it to the store a couple miles away. I became very frustrated. I thought about selling the car but realized that I couldn't sell it with it not running, I even thought about getting another tuner to work on it. Fortunately, I decided to give Underground another chance. Turns out that when I had the Roe blower on, my car had the rear "ground" done. We disconnected the ground put the cover back on as well as the rear wheel and fired it up. The car immediately sounded different, and the idle was smooth and steady. We then backed it out of the garage and took it for a ride. The bucking was completely gone and the car accellerated up through the rpm range very smoothly and precise. No missing, bogging, or stumbling was present. We did several highway high speed, high boost runs and the car ran perfect. I couldn't believe it, something so small created so much frustration. Anyway, just wanted to let everyone know the car is fixed. A big THANK YOU to Kevin and KC @ Underground Racing for not giving up and sticking with it until it was fixed.

 

[Casey]

Good news!

Now go drive that B otch!

 

[Joseph Dell]

dang! Glad to hear it is back on the road!

For the less-knowledgable ones here, can you explain the "rear ground"

JD

 

[2MANYTOYS]

All I know is that on the Roe cars at least when my car was having it installed Sean recommended an additional ground located on the frame in the rear near the battery. When the AEM was installed for some reason (I'm not sure why)the AEM didn't like having that additional ground. There is a post out here somewhere either here or on the Alley from John Reid explaining this in detail. Hell JD your an "engineer" why don't you tell us? I'm sure you've heard of this?

 

[Simms]

Glad to hear its running.

I've heard a lot about various/multiple grounds (especially from previous VEC2 cars) affecting the AEM.

 

[GARY J]

Fantastic news Brian!

 

[syclone1157]

What a friggin' relief. I totally understand your frustration. Now it's balls to the wall!!!!

 

[Shelby3]

Brian, I tried to tell you that was your problem all along. Maybe next time you will listen to me.

 

[KenH]

Glad you found your issue. Nothing more frustrating than chasing electrical gremlins around.

The ground in question is the battery temperature sensor gets grounded to the frame where the negative battery termal is grounded.

I could never verify that adding grounds helped with the VEC2 in my installation. Now that the VEC2 software has evolved, I wonder if having these extra grounds could be a liability even with a VEC2?

 

[SUN RA KAT]

I'm so glad you got your car running right, Brian.

Streetablity in a Viper is very important if you want to drive it on the street.

 

[UndergroundRacing.com]

As some of you know I've had some horrible drivability issues with my car. A lot of time was spent trying to diagnose the problem. Kevin @ KC (Underground Racing)tuned, retuned, checked, and re-checked the entire system multiple times. They added an AEM thinking this would fix the assumed tuning issues. After adding the AEM the car went from driveable to UN-driveable. It started bucking, surging, stumbling, etc.... I couldn't even drive it to the store a couple miles away. I became very frustrated. I thought about selling the car but realized that I couldn't sell it with it not running, I even thought about getting another tuner to work on it. Fortunately, I decided to give Underground another chance. Turns out that when I had the Roe blower on, my car had the rear "ground" done. We disconnected the ground put the cover back on as well as the rear wheel and fired it up. The car immediately sounded different, and the idle was smooth and steady. We then backed it out of the garage and took it for a ride. The bucking was completely gone and the car accellerated up through the rpm range very smoothly and precise. No missing, bogging, or stumbling was present. We did several highway high speed, high boost runs and the car ran perfect. I couldn't believe it, something so small created so much frustration. Anyway, just wanted to let everyone know the car is fixed. A big THANK YOU to Kevin and KC @ Underground Racing for not giving up and sticking with it until it was fixed.

This is why top tuners hate to work on a Viper that has been in others hands. Thank GOD the problem was found. I thought I was going to have to buy that car at one point! Enjoy the World Record Supercharged Viper 2 years and counting!!

 

[GARY J]

I'm so glad you got your car running right, Brian.

Streetablity in a Viper is very important if you want to drive it on the street.

Kenny, sounds like you might want to check that ground.

 

[Joseph Dell]

Or add it if it wasn't there...

 

[SUN RA KAT]

I'm so glad you got your car running right, Brian.

Streetablity in a Viper is very important if you want to drive it on the street.

Kenny, sounds like you might want to check that ground.

It's in Larry Macedo's hands right now and I'm sure he's going to be doing whatever it takes to make it right.

 

[99 R/T 10]

Hey Kevin,
can you post more info on this "ground"? Pictures would be great, but also if it affected Brian's car, would it be doing the same thing to Kenny's car. I have always had a slightly surge while driving, but it never really bothered me, I hardly noticed it. But if this a problem, I would like to know how to fix it. TIA,

 

[2MANYTOYS]

Hey Kevin,
can you post more info on this "ground"? Pictures would be great, but also if it affected Brian's car, would it be doing the same thing to Kenny's car. I have always had a slightly surge while driving, but it never really bothered me, I hardly noticed it. But if this a problem, I would like to know how to fix it. TIA,

Mike I think this would be a better question to ask Sean Roe. He knows his system better than anyone. I've heard conflicting reports about whether you need it or not for the Roe.

Thanks to all who posted, I'm thrilled to know that my car is running as it should. Just in time for some good fall driving here in the mountains. Thanks again to Kevin & KC.

 

[99 R/T 10]

Yeah, but I've never heard of this rear "ground" and wanted to get some pictures of what we are talking about.

 

[HIBOOST]

Glad they found it. Peske grounds!


Garth W

 

[Batboy]

I'm not a tuner but I'll take a stab. It sounds like a ground loop issue. This is very similar for those that install stereos and get noise. It basically creates a magnetic field which in turn creates "noise" (actually reactance, probably more inductive which is 120 degrees out of phase from pure resistance). Anyway, my guess is the noise was affecting the computer but again I have no idea since I have never worked on car computer.

A good ground is always important in electrical systems. The reason people probably suggest a ground near the battery is to minimize the path the ground takes. But having multiple grounds is more potential for loops. I have had so many grounding problems in my day I now run heavy gauge wire directly to my battery and avoid as much metal and low voltage stuff as possible.

Just my $.02

 

[Tom Sessions]

The ground in question was at he battery temp sensor on the sensor ground circuit.When the roe was installed the car would hardly run.It was found that on stock pcm cars that there is a few hundred milli volts on the sensor ground circuit when the car is running.This can drive the car nuts.With the installation of a AEM it fixes the problem internally so there is no need for the external ground.On stock cars this ground can greatly improve driveabilty,bucking surging idle hang,I always install it right by the PCM where it is easy to see and seems to do the most good.

 

[UndergroundRacing.com]

The ground in question was at he battery temp sensor on the sensor ground circuit.When the roe was installed the car would hardly run.It was found that on stock pcm cars that there is a few hundred milli volts on the sensor ground circuit when the car is running.This can drive the car nuts.With the installation of a AEM it fixes the problem internally so there is no need for the external ground.On stock cars this ground can greatly improve driveabilty,bucking surging idle hang,I always install it right by the PCM where it is easy to see and seems to do the most good.

As bad is that Vec 2 is they still cause problems even after they are removed....lol That is some ***** [******] that we will NEVER use again!!!!! Thank God for AEM!

 

[1BADSNK]

As some of you know I've had some horrible drivability issues with my car. A lot of time was spent trying to diagnose the problem. Kevin @ KC (Underground Racing)tuned, retuned, checked, and re-checked the entire system multiple times. They added an AEM thinking this would fix the assumed tuning issues. After adding the AEM the car went from driveable to UN-driveable. It started bucking, surging, stumbling, etc.... I couldn't even drive it to the store a couple miles away. I became very frustrated. I thought about selling the car but realized that I couldn't sell it with it not running, I even thought about getting another tuner to work on it. Fortunately, I decided to give Underground another chance. Turns out that when I had the Roe blower on, my car had the rear "ground" done. We disconnected the ground put the cover back on as well as the rear wheel and fired it up. The car immediately sounded different, and the idle was smooth and steady. We then backed it out of the garage and took it for a ride. The bucking was completely gone and the car accellerated up through the rpm range very smoothly and precise. No missing, bogging, or stumbling was present. We did several highway high speed, high boost runs and the car ran perfect. I couldn't believe it, something so small created so much frustration. Anyway, just wanted to let everyone know the car is fixed. A big THANK YOU to Kevin and KC @ Underground Racing for not giving up and sticking with it until it was fixed.

Brian
It sounds like we are both benefiting from Kevin and KC finding that ground. What great timing for me at least. Maybe that's why the Roe always acted up so much on my car. Either way I'm glad all that crap is off like it was suppose to have been a long time ago. Way to go UGR! Congrat's Brian on your ride.

 

[UndergroundRacing.com]

As some of you know I've had some horrible drivability issues with my car. A lot of time was spent trying to diagnose the problem. Kevin @ KC (Underground Racing)tuned, retuned, checked, and re-checked the entire system multiple times. They added an AEM thinking this would fix the assumed tuning issues. After adding the AEM the car went from driveable to UN-driveable. It started bucking, surging, stumbling, etc.... I couldn't even drive it to the store a couple miles away. I became very frustrated. I thought about selling the car but realized that I couldn't sell it with it not running, I even thought about getting another tuner to work on it. Fortunately, I decided to give Underground another chance. Turns out that when I had the Roe blower on, my car had the rear "ground" done. We disconnected the ground put the cover back on as well as the rear wheel and fired it up. The car immediately sounded different, and the idle was smooth and steady. We then backed it out of the garage and took it for a ride. The bucking was completely gone and the car accellerated up through the rpm range very smoothly and precise. No missing, bogging, or stumbling was present. We did several highway high speed, high boost runs and the car ran perfect. I couldn't believe it, something so small created so much frustration. Anyway, just wanted to let everyone know the car is fixed. A big THANK YOU to Kevin and KC @ Underground Racing for not giving up and sticking with it until it was fixed.

Brian
It sounds like we are both benefiting from Kevin and KC finding that ground. What great timing for me at least. Maybe that's why the Roe always acted up so much on my car. Either way I'm glad all that crap is off like it was suppose to have been a long time ago. Way to go UGR! Congrat's Brian on your ride.

Mike your car has also been cured of the VEC VIRUS!! See you Friday!!