For those going from VEC2 to AEM

[Bob D]

If you have any of the additional suggested grounds for the VEC2 install, you need to disconnect them. They really screw up the AEM. There is one ground near the power steering pump and more importantly, one near the battery. Jason from AEM mentioned this to me when he saw I have a Roe SC. I never knew I had a problem until I disconnected them and my idle RPM went up 200 rpm and my speedo was no longer jumping when I turned the key on. I had to recalibrate the TPS and MAP.

Bob

 

[Larry Macedo]

Anything and everything non-factory installed will cause problems when upgrading to AEM. Speedometer calibrator, CAGS eliminator, added ground wires, Etc.

 

[carl B]

How do you work around the CAGS eliminator??

I just sold my VEC 2 and am about to fit the AEM?

Thanks


Carl

 

[HOdbleFman]

You don't need the CAGS eliminator anymore. The AEM eliminates the skip shift.

 

[carl B]

Thankyou so much!

I love this board!

Carl

 

[Jerome Sparich]

Can anyone tell me how any extra ground/s can screw up the AEM?

I am just trying to understand this.

Thanks

 

[1TONY1]

Can anyone tell me how any extra ground/s can screw up the AEM?

I am just trying to understand this.

Thanks

I have heard that....certainly don't understand it

 

[Jerome Sparich]

Can anyone tell me how any extra ground/s can screw up the AEM?

I am just trying to understand this.

Thanks

I have heard that....certainly don't understand it

After thinking about this and talking it over with some other techs, we are still at a loss for an explanation.

Usually bad grounds are cause for trouble. Never heard of "too many" being bad and causing trouble.

I just have to hear the "logic" behind this. Now is someone going to say it is top secret reasons and to just believe it?

 

[John Reed]

I fought this problem when the AEM first came out for the Viper, and it took a bit to find what was causing the problem. Thankfully now the information is out there so others don't have to do the same.

There is a circuit on the car called "sensor ground". All of the engine sensors use this ground, and it goes through the PCM (or AEM) before going to actual chassis or battery ground. There is circuitry in there to prevent electrical noise from causing erroneous sensor readings.

Well, for some reason people running the VEC2 were being asked to "ground" this sensor ground directly to chassis ground. One of the favorite places (which made it fun to find) is the battery temp sensor back by the battery. Doing this bypasses the filtering ciruits in the PCM (or AEM) and is what created the problem. The AEM just seems to be more sensitive to this, and you will get all sorts of eratic behaviour. I have experienced the car cutting out with the windshield wipers cycle, headlights turn on, etc.

Anyway, hope that answers the question about this "mystery" problem.

 

[Bob D]

Thanks for the explanation John.

 

[Larry Macedo]

I fought this problem when the AEM first came out for the Viper, and it took a bit to find what was causing the problem. Thankfully now the information is out there so others don't have to do the same.

There is a circuit on the car called "sensor ground". All of the engine sensors use this ground, and it goes through the PCM (or AEM) before going to actual chassis or battery ground. There is circuitry in there to prevent electrical noise from causing erroneous sensor readings.

Well, for some reason people running the VEC2 were being asked to "ground" this sensor ground directly to chassis ground. One of the favorite places (which made it fun to find) is the battery temp sensor back by the battery. Doing this bypasses the filtering ciruits in the PCM (or AEM) and is what created the problem. The AEM just seems to be more sensitive to this, and you will get all sorts of eratic behaviour. I have experienced the car cutting out with the windshield wipers cycle, headlights turn on, etc.

Anyway, hope that answers the question about this "mystery" problem.

We encountered the same problem and spent hours searching for the cause. We removed all the extra added grounds, but forgot about the one @ the BTS. Amazing how added resistance works, or doesn't in this case.