1997 LT1 Misfire
01-05-2019, 04:19 PM
#16
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Join Date: Sep 2018
Posts: 12
Re: 1997 LT1 Misfire
Ok thanks everyone for all the help but I found my problem. I cant believe that I overlooked it every time I checked but it was the 5 and 7 plug wires reversed. I looked at those dang wires and traced them 100 times and could have swore that they were on the correct plug. Well at least I found the problem but unfortunately the engine is still tired and needs to be replaced so that is another adventure. Thanks again for all the help and insight to learning the LT1. On a side note the guy on Ebay that rebuilds the Opti's I will now highly recommend as that thing is firing great.
01-05-2019, 09:58 PM
#18
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Join Date: Sep 2018
Posts: 12
Re: 1997 LT1 Misfire
Yeah after searching and reading all the misfire problems and not very many posting the follow ups I thought I should give mine to stop the cycle. Just out of curiosity how hard was it to setup and use the MoTec?
01-06-2019, 01:05 AM
#19
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Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,648
Re: 1997 LT1 Misfire
The engine was built by Second Street Speed in Perkasie, PA. One of the owners, Bill Hunsberger, at the time (2000) was one of only 6 people in the US authorized to do general purpose MoTeC performance tuning. Kenny Duttweiler was one of the others. Bill had been instrumental in getting MoTeC to incorporate Optispark cam position data into the systems accepted by their ECUs.
When I dropped the car off at the shop, with a bunch of parts (CNC Cylinder Heads Inc. ported factory LT4 heads and intake manifold, LT4 Extreme Duty timing set, Holley 58mm throttle body, brand new GM Opti and all parts for vented conversion, AS&M mid-length headers, converted for true duals, etc.) it was my intention to work side by side with the shop on the build. That fell apart when the Callies Stealth crank was back-ordered three months, and then my employer sent me to Italy for the rest of the year on a consulting project. I got to see the progress when I came home for R&R every 6 weeks.
So, Second Street completed the build, did complete tuning on an engine dyno for NA, and two stages of nitrous totaling ~265 HP. I saw a couple pulls and that was it.
https://www.firebirdnation.com/forum...orginal-build/
Then they put the engine in the car, in front of a McLeod Street Twin and the original T56 and verified the tune. Also checked on an emissions dyno to verify met NJ standards. I have data that allowed calculating drivetrain losses for 496, 625,and 762 HP, for both the 6-speed and TH400 setups. The tune was kept simple - speed-density, open loop, no knock sensor (does not play nice w/ solid roller cam). Later we added more nitrous to bring it to 800 HP/800 lb-ft (back calculated from RWHP results. At this point it was tuned to run on a blend of VP Fuels C16 and their Air Race Fuel.
The MoTeC has the optional data logging and diagnostic option. Software unfortunately was still DOS. But it was easy to make a pass, review the data and tweak the fuel, or rarely the timing. Also, unfortunately I changed jobs, and was working 5-1/2 days a week, so Saturday morning events as Englishtown were no longer possible. It has never made a pass with the 300-shot. At this point hasn’t been started in 5 years. Need to clean up the fuel system, get it running and put it up for sale. At this point I'm too old to go out and make 9-second passes.
Second Street also built George Baxter's 30th SS convertible, with a 1,125 flywheel HP 383 LT1/Vortech SC, and also the Gen 1 383 SBC/Vortech SC (Dart Iron Eagle block) making 1,350 HP he eventually put in the 30th SS, running low 8’s and high 160’s MPH in the PRO/Edelbrock Xtreme Street class back in the mid 2000’s. Both using MoTeC ECUs.
When I dropped the car off at the shop, with a bunch of parts (CNC Cylinder Heads Inc. ported factory LT4 heads and intake manifold, LT4 Extreme Duty timing set, Holley 58mm throttle body, brand new GM Opti and all parts for vented conversion, AS&M mid-length headers, converted for true duals, etc.) it was my intention to work side by side with the shop on the build. That fell apart when the Callies Stealth crank was back-ordered three months, and then my employer sent me to Italy for the rest of the year on a consulting project. I got to see the progress when I came home for R&R every 6 weeks.
So, Second Street completed the build, did complete tuning on an engine dyno for NA, and two stages of nitrous totaling ~265 HP. I saw a couple pulls and that was it.
https://www.firebirdnation.com/forum...orginal-build/
Then they put the engine in the car, in front of a McLeod Street Twin and the original T56 and verified the tune. Also checked on an emissions dyno to verify met NJ standards. I have data that allowed calculating drivetrain losses for 496, 625,and 762 HP, for both the 6-speed and TH400 setups. The tune was kept simple - speed-density, open loop, no knock sensor (does not play nice w/ solid roller cam). Later we added more nitrous to bring it to 800 HP/800 lb-ft (back calculated from RWHP results. At this point it was tuned to run on a blend of VP Fuels C16 and their Air Race Fuel.
The MoTeC has the optional data logging and diagnostic option. Software unfortunately was still DOS. But it was easy to make a pass, review the data and tweak the fuel, or rarely the timing. Also, unfortunately I changed jobs, and was working 5-1/2 days a week, so Saturday morning events as Englishtown were no longer possible. It has never made a pass with the 300-shot. At this point hasn’t been started in 5 years. Need to clean up the fuel system, get it running and put it up for sale. At this point I'm too old to go out and make 9-second passes.
Second Street also built George Baxter's 30th SS convertible, with a 1,125 flywheel HP 383 LT1/Vortech SC, and also the Gen 1 383 SBC/Vortech SC (Dart Iron Eagle block) making 1,350 HP he eventually put in the 30th SS, running low 8’s and high 160’s MPH in the PRO/Edelbrock Xtreme Street class back in the mid 2000’s. Both using MoTeC ECUs.
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