The car is a '98 C5 vert, automatic trans, has 68,000 miles, i changed heads, cam, longtubes, injectors, ud pulley, updated valve train, Z06 mufflers, and a nos plate kit, rest of car is stock.

The service act. handling, service trac. control comes on for no reason, reguardless of driving it hard or easy, and the button will not work, then even after i clear it with EFI Live, it will show "active handling warming up" and the button works. But the problem still persists, it has a terrible "bogging" when launching the car, like traction control is on. Then at other times the car will easily blow the tires off from a stop or from a roll. It does not seem to have a pattern to acting up. I have checked and cleaned the grounds on both frame rails in the engine bay, ground strap from motor to frame rail, ground and plug for the EBCM, ground on back of head, the battery is about 1 year old (and seems to hold charge well). The only codes in the DIC were C1283 & C1288 (steering column codes, both history, i assume from when i took the steering rack out during the cam install), but i cleared all modules and no codes have come back since on any modules. I have even zero'd out the timing retard tables for the TCS, increased the max torque and it makes no difference, still sluggish on bottomend, but always pulls hard on topend.
The car ran fine before the H/C install, from a dig, it spun hard and wheel hopped on the nitrous. But now its "hit and miss" on motor, making about the same power as the stock motor was on spray. I pulled TCS/ABS fuses and it made no difference.

What have i missed???
Are there any other grounds??
Any way to check wheel sensors, or EBCM??

Any help is greatly appreciated.

 

ok.... today i unplugged the the EBCM, and tied the plug-in to the radiator hose. as would be expected it set off the ABS and service lights, BUT it made a huge improvement in the "bogging" problem. there is still a very slight hesitation, which i believe to be in the tune, may even be due to having DBW, but when the car starts to move it just keeps pulling. so the EBCM will be the starting point to see if it fixes it.

thanks for all the help from everybody.

 

I know this is an old post but possibly your still around.

My car, 2000 c5 FRC, 500+ rwhp, stroked with an A@A SC, just had a new transmission installed with a 2500 stall. The stall is probably to small for most but my last 3200 stall i thought was bad as i had the same problems with it. Starting from 15 mph or so i can roast my tires (Nitto Extreme 305/35zr18's) untill 3rd gear no problem.

The service act. handling, service trac. control comes on just like your's did.

I bog down at take off's. I cant even power break above 1500 rpm for a launch and that is with both stalls.

I removed the EBCM plug but it didnt seem to help for me.

Did you replace the EBCM and if so was that the problem?

Thanks

 

wondering the same things!!

 

[QUOTE=chris66leo;15978130]I know this is an old post but possibly your still around.

My car, 2000 c5 FRC, 500+ rwhp, stroked with an A@A SC, just had a new transmission installed with a 2500 stall. The stall is probably to small for most but my last 3200 stall i thought was bad as i had the same problems with it. Starting from 15 mph or so i can roast my tires (Nitto Extreme 305/35zr18's) untill 3rd gear no problem.

The service act. handling, service trac. control comes on just like your's did.

I bog down at take off's. I cant even power break above 1500 rpm for a launch and that is with both stalls.

I removed the EBCM plug but it didnt seem to help for me.

Did you replace the EBCM and if so was

Im having the same bogging problem .... what ended up being the problem