Bartman Posted October 11, 2006 Author Share Posted October 11, 2006 I work at a performance shop where 75% of our work is LT1s. I have seen many failed MSD optis. I don't think their product is superior by any means. We put Accel optis in all of our custoers cars. They seem to be working the best, next to Dynaspark. But Dynaspark is a little pricy for the average LT1 customer. The timing feature on the msd is useless as timing can be more precisely adjust for each rpm cell in the computer. Glad to hear a recommendation for the Accel since that's what I ordered. The Dynaspark does seem to be the best solution, but for my application I can't justify the price. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 11, 2006 Share Posted October 11, 2006 Bart, The opti on that engine was brand new from GM. When you got the engine, it had about 500 miles on it. I installed new coil, coil module, and wires at the same time. The knock sensor, MAP sensor, and O2 sensors were also new genuine GM units. My bet is on fuel. Tim Quote Link to comment Share on other sites More sharing options...
that240guy Posted October 11, 2006 Share Posted October 11, 2006 He just put in an older opti with 50,000 miles on it. He converted to the vented design. Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 11, 2006 Author Share Posted October 11, 2006 Bart,The opti on that engine was brand new from GM. When you got the engine, it had about 500 miles on it. I installed new coil, coil module, and wires at the same time. The knock sensor, MAP sensor, and O2 sensors were also new genuine GM units. My bet is on fuel. Tim Hey Tim, long time no hear. Like that240guy stated I put in an older unit when I switched everything over to the later vented style (I wanted to go with a double roller when I upgraded the top end). Now I'm getting a new opti and to make sure fuel isn't the problem I'm installing a fuel pressure gauge as well. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 11, 2006 Share Posted October 11, 2006 Sorry for not keeping up on your progress, Bart! If you still have the 'old' opti, you could swap them and see if your problem remains. IMHO, the opti is always blamed, but is rarely the actual problem..... Tim Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 11, 2006 Author Share Posted October 11, 2006 Sorry for not keeping up on your progress, Bart!If you still have the 'old' opti, you could swap them and see if your problem remains. IMHO, the opti is always blamed, but is rarely the actual problem..... Tim I would, but with the double roller it won't go back on. I'd have to change the height of the cam dowel and the cam gear doesn't have the spline shaft for the old opti drive pin. I was hesitant to replace the opti, but everything else seems to check out okay and with over 50,000 miles on the old unit it can't hurt. I should sell my genuine GM low mileage non-vented opti to help offset the cost. Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted October 12, 2006 Share Posted October 12, 2006 Bart, To help out a LT1 buddy I have a spare 1995 computer that I can loan you. The computer is from a Camaro with an automatic transmission but I don't think it would be an issue preventing the engine to start. It still has VATS enabled but I don't know if you have a VATS delete module or if it was disabled in the computer. Let me know and I will send it out to you. Danno74Z Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 12, 2006 Author Share Posted October 12, 2006 Bart, To help out a LT1 buddy I have a spare 1995 computer that I can loan you. The computer is from a Camaro with an automatic transmission but I don't think it would be an issue preventing the engine to start. It still has VATS enabled but I don't know if you have a VATS delete module or if it was disabled in the computer. Let me know and I will send it out to you. Danno74Z Thanks for the offer Danno. I have the VATS disabled in the computer, but I think it would still start and then die shortly afterwards. I'll let you know if I want to give that a go, but I'll give the opti a try first and see how that goes. I've also got the fuel pressure gauge yesterday, so I'll hook that up and see if I'm in range. Quote Link to comment Share on other sites More sharing options...
that240guy Posted October 15, 2006 Share Posted October 15, 2006 If you want a hand let me know. I just got my datsun running with the ls1 this week and I am in LA. I would love to see your q45 diff as mine is making tons of noise. Quote Link to comment Share on other sites More sharing options...
love-my-V8-280Z Posted October 15, 2006 Share Posted October 15, 2006 Bart, Hope you let us know what you find.. Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 16, 2006 Author Share Posted October 16, 2006 I found a direct fit replacement fuel pump from Full Throttle Speed for $139.99. Anyone have any experience with them? The pump assembly uses a Walbro pump. They have them on eBay as well as from their website. http://cgi.ebay.com/ebaymotors/1999-2002-LS1-F-Body-DIRECT-FIT-Fuel-Pump-Kit-WALBRO_W0QQcmdZViewItemQQcategoryZ33555QQihZ006QQitemZ160039422166QQrdZ1QQsspagenameZWDVW I've got the fuel bucket from my 2001 Trans Am fuel tank removed already, so now I just need to get a new pump and put everything back together. that240guy, Congrats an completing your LS1 swap, and your offer for help. I hope I've got this problem figured out, but we'll have to see. Quote Link to comment Share on other sites More sharing options...
mark Posted October 16, 2006 Share Posted October 16, 2006 What did the fuel pressure read? Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 16, 2006 Author Share Posted October 16, 2006 What did the fuel pressure read? My fuel pressure read around 23 PSI when the pump was running and then went to zero within a few seconds of it stopping. The PCM only turns on the pump for a couple of seconds when the ignition is turned on, but it shouldn't lose the pressure when it shuts off. I read that if the pressure drops quickly then it's most likely the check valve in the pump. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted October 17, 2006 Share Posted October 17, 2006 Not to mention the LT1 needs more like 45-50psi. Sounds like you found your problem! I wonder what the check engine light was for though??? Guy Quote Link to comment Share on other sites More sharing options...
Guest 73LT1Z Posted October 19, 2006 Share Posted October 19, 2006 Bart, This sounds similar to what has happened to my '95 LT1 in my 280. When I first did the conversion, it fired up & ran fine. I have a new cap & rotor setup in the Opti that was installed the same time as the motor swap. After a few weeks, it would start and then after I shut it off it would not re-start. Pulling the coil wire showed a strong spark. I installed a set of newer injectors from a low mile LS1 with no difference. Fuel pressure seemed a little low on a mechanical gauge at 39-40, so I replaced the MSD external fuel pump with a Walbro 392 (high pressure external). Pressure is about the same. I got sidelined by an oil pan leak (as well as another swap ) & after fixing this I found that if I disconnect the battery and wait a couple of minutes it starts OK. I talked to the guy that wrote my PCM program and he suggested a power or ground issue, and that possibly the memory in the PCM is bad (see checksum error below). I tested the four plugs and all have battery/ign/ground at the proper place and at the proper time. After hooking the laptop to it and running the PCM Comm program, it is now showing an injector fault. My SES/CEL seems to work OK and all the other wiring I've tested seems OK. The PCM will also give a checksum memory error while running PCM Comm, so at this point I'm planning on buying another one and writing my custom program into it. It is interesting to note that I had two late model GM cars with the 3.8L V6, a 1996 Bonneville SSEi w/ supercharger & 100K miles and a 2003 Impala with the base 3.8L bought new. The Bonneville blew the Impala away not only in performance but also starting ability. The Bonneville only needed to have the starter bumped and it would fire. The Impala cranks over & over and finally starts. If I let the key on for a few seconds it seems to crank less. It had the fuel pump replaced once at 40K miles and this didn't really help, so I think it is a fuel pressure issue with the later motors since both are "Series 2" model motors. Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted October 25, 2006 Share Posted October 25, 2006 Bart, Did you solve your LT1 problem yet? Danno74Z Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 25, 2006 Author Share Posted October 25, 2006 Bart, Did you solve your LT1 problem yet? Danno74Z I got the new fuel pump on Monday and completed the installation last night. I have good fuel pressure, but it's still not starting. I haven't installed the new opti yet, so that's what I'm going to do next. Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 26, 2006 Author Share Posted October 26, 2006 I got the Accel Opti installed tonight and I gave it a quick test before I put everything back together to see if it would fire up. Well it barely cranked (battery is still low), but that was all it needed and she breathed fire again. I shut her down almost immediately because I don't even have the water pump and accessories reinstalled (it ran just the way it is in the attached pic). The old Opti didn't feel right when I removed it, so I was pretty confident that the new one would do the trick...and it did. I may have to pull the old one apart to check it out. I just need to get everything buttoned back up and give her a test run. Thanks to everyone for their advice. Quote Link to comment Share on other sites More sharing options...
Turbo Meister Posted October 26, 2006 Share Posted October 26, 2006 Bart, Glad to hear your starting problems are over. But you don't know how hard it has been for me to read this thread and not make a snide comment. Since you got er fixed I guess I now can say, "Get a Carb.":biggrin: Hanns Quote Link to comment Share on other sites More sharing options...
mark Posted October 26, 2006 Share Posted October 26, 2006 Glad it runs!! Go have fun now. Quote Link to comment Share on other sites More sharing options...
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