Need expert advice.

**hamptonwsk** · 06-14-2008, 06:10 PM

Ok in a nutshell my car is running 9.4s in the 1/8th with a trap of 75mph. I have a 99 z-28 vert a4 w/ 3.23 gears and 56k on the clock. I have a hooker catback and a slp lid and descreened maf. If you want I wrote a more elabrate explaination of my run in the drag racing forum titled PLEASE GOD SOMEONE HELP ME. lol. Well the reason I am posting in here to is that my service engine light came on after the first pass and I was told that makes the computer lower my timing and cuts power. Can I get my computer check at like auto zone to see what codes its throwing? Also I was thinking about sending my computer to Frost to see if he could tune my car up to try and make it wake up. Point is I should not be running 9.40 with a 2.16 60ft! Lt-1s and trucks where beating me. All you computer tuning experts out there please give me a hand and tell me whats wrong with my car? Thanks

**98 Stang Killer** · 06-14-2008, 10:03 PM

yeah they can check your code for free at auto zone

**Mr. Luos** · 06-14-2008, 10:18 PM

Originally Posted by 98 Stang Killer

yeah they can check your code for free at auto zone

Agreed.
Please get the code(s) and report back.

Something isn't right. Are you spinning throught 1st gear??

**Frost** · 06-15-2008, 06:26 AM

Originally Posted by hamptonwsk

Ok in a nutshell my car is running 9.4s in the 1/8th with a trap of 75mph. I have a 99 z-28 vert a4 w/ 3.23 gears and 56k on the clock. I have a hooker catback and a slp lid and descreened maf. If you want I wrote a more elabrate explaination of my run in the drag racing forum titled PLEASE GOD SOMEONE HELP ME. lol. Well the reason I am posting in here to is that my service engine light came on after the first pass and I was told that makes the computer lower my timing and cuts power. Can I get my computer check at like auto zone to see what codes its throwing? Also I was thinking about sending my computer to Frost to see if he could tune my car up to try and make it wake up. Point is I should not be running 9.40 with a 2.16 60ft! Lt-1s and trucks where beating me. All you computer tuning experts out there please give me a hand and tell me whats wrong with my car? Thanks

with your mods, the tune isn't the issue, there is something physically wrong with your car. No one on the net can help you unfortunately, until you do the required work first, which includes pulling a list of codes.

**hamptonwsk** · 06-15-2008, 05:28 PM

Going to get codes checked tomorrow. I wasn't spinning at all through first. I would hold the brake in and rev it until it almost broke lose and then punched it with minimal spin just hook and go. Thats why I am so baffled. There where other Ls1s there to and they where running awful as well. A WS6 trans am sixpeed was running 9.30s at around 77mph and a 2001 SS six speed was running 8.80 at 81 but he said he ran 8.45s two weeks ago. Must be in some part due to the weather but I should be running around 8.70s or better. Car is running fine dosent miss or hesitate. The light in the dash says ars off but the car just seems real sluggish between gears and is shifting really soft. It wont even spin the shift to second at all.

**hamptonwsk** · 06-16-2008, 06:55 PM

Went to autozone tonight and right when I pulled in the parking lot the service engine soon light goes off. I couldnt believe it. It came on at the drag strip friday night and stayed on until monday evening. Anyways we still checked it and it said that 2 of my o2 sensors where reporting low voltage. Could that be whats making the car run weak and making the service engine light come on?

**98 Stang Killer** · 06-16-2008, 06:56 PM

yeah it could

**98 Stang Killer** · 06-16-2008, 06:57 PM

throws the wrong signal and reregulates the timing and air fuel ratio

**Wesman** · 06-16-2008, 07:12 PM

Originally Posted by hamptonwsk

Went to autozone tonight and right when I pulled in the parking lot the service engine soon light goes off. I couldnt believe it. It came on at the drag strip friday night and stayed on until monday evening. Anyways we still checked it and it said that 2 of my o2 sensors where reporting low voltage. Could that be whats making the car run weak and making the service engine light come on?

Yes. Constant low voltage readings will throw off your short and long term fuel trims. The oxygen sensors generate a voltage based on how much oxygen content is present in the exhaust. A low voltage means that there is high oxygen content in the exhaust, so the computer thinks that the engine is running lean and adds more fuel. When adding more fuel doesn't bring the sensor voltage up, it throws a code to let you know something is wrong with the sensor readings.

**axxdet** · 06-16-2008, 08:20 PM

so is the o^2 sensor bad or is there a problem with the alt / batt not supplying enough volts to the system

**Frost** · 06-16-2008, 08:58 PM

what were the numbers you got from the codes?

**hamptonwsk** · 06-19-2008, 04:51 PM

He didnt get me the codes. His hand held unit only said that bank 2 sensor 1 and bank 1 sensor 2 where reporting low voltage. I am going to try and get a friend to hook his computer up to it and he will able to give me the codes. Like I said earlier the service engine light only stayed on for a few days and now its off so I dont know whats going on.

**Hot Black Trans-Am** · 06-19-2008, 05:28 PM

Put a new fuel filter in it and see if it goes any better. When your car is hot pop the hood at night and see if your manifolds are glowing red, could be a clogged cat. A couple of simple things I've already ran into that are easily over looked.

**Wesman** · 06-19-2008, 09:14 PM

Originally Posted by axxdet

so is the o^2 sensor bad or is there a problem with the alt / batt not supplying enough volts to the system

The O2's would be bad. They are zirconda oxygen sensors, which generate their own voltage based on the difference in oxygen content between the outside air and the exhaust. A bad battery would not throw their readings off. The only solution is the replace the oxygen sensors themselves.