DRAGZ Posted October 6, 2006 Share Posted October 6, 2006 i know its not a lt1 but it is gm my vn ss commodore v8 is delco injected and theres no dam way that thing will fire if the batery is crap you could wire up a dam welder to that batery for a jump no cigar its worth a try at least surly you have someone that can lone you one for a test after that ive got no idea because ive not played with a lt good luck Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 6, 2006 Author Share Posted October 6, 2006 Okay I put on a good battery from one of my other cars last night and gave it another go with no luck. The engine turned over quicker, but still won't start. I also tried to disconnect the MAF with no luck as well. I didn't have a hard fault so I have no way to figure out what code(s) were being thrown previously and I don't have a crank sensor. I do need to check my injectors and proper fuel pressure (I've got a fuel pressure gauge on the way). obd1 lt1 ecus don't store codes unless it is a continuous problem (hard fault). The opti can't throw hard faults when the engine isn't running because the computer can't check the opti during cranking or at KOEO. At this point I would put an Opti and a module in the car if you have communication with the PCM, have fuel pressure, injectors are pulsing and there are no mechanical problems. Backfiring is also an opti issue. Double check to make sure all of your Pids are normal with the koeo. Make sure coolant temp is not reading -40, make sure the tps goes through its 5 volt range, pull the map off and suck on it and see if you can get a reaction. If everything looks good, IMO replace the opti. And get a new one this time. Summit has their own brand opti now that is only 249.99. But I have a friend running the accel opti and he has a custom grind isky cam and his motor frequently sees 6800 rpm. The accel is holding up good and is only 299.99.I'm getting close to buying a new Opti (you can get a brand new Accel on eBay for $232.66 http://cgi.ebay.com/ebaymotors/ACCEL-GM-94-97-LT-1-LT1-OPTI-SPARK-DISTRIBUTOR-59125_W0QQcmdZViewItemQQcategoryZ33690QQihZ004QQitemZ140036836451QQrdZ1QQsspagenameZWDVW) but what else, like ICM and coil. This will add up, so I'd like to check everything else first. A couple of things I'm not sure of from this post. on the tps check to you just hook up DataMaster while moving the throttle, or is this with a multimeter. On the MAP what kind of reaction are you looking for? Thanks again to everyone for their help and input. Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted October 6, 2006 Share Posted October 6, 2006 Bart, This is to see if you have a bad Module and we are assuming you have little or no spark because you mentioned you had a weak spark: Where did you see this? At the spark plug wire, coil, or distributor? ---------------------------------------------------------------- No Spark - Go to ignition coil wire and disconnect ignition coil module connector. ignition on. "with dvm check voltage from *harness terminals* A & D to ground". Three possible scenarios: Both Terminals 10 volts or more, Both terminals under 10 volts, Either Terminal under 10 volts. Let me know what you find out and we can go from there. Danno74Z Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted October 6, 2006 Share Posted October 6, 2006 You need to go a little further in testing the module to rule it out as the culprit. Both Terminals 10 volts or more: With DVM on AC scale, connected from ignition coil module connector terminal "B" to ground, crank engine and observe voltage. is the voltage between 1 and 4 volts? Both Terminals Under 10 Volts: Either Terminal Under 10 Volts: Danno74Z Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted October 6, 2006 Share Posted October 6, 2006 Bart, Here is a little more info: http://www.z28.com/forum/archive/index.php/t-6622.html http://shbox.com/1/coil_testing.jpg Danno74Z NAPA: Ignition Control Module Item#: ECHTP12 Price: $96.49 tax and shipping not included Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 6, 2006 Author Share Posted October 6, 2006 Bart, This is to see if you have a bad Module and we are assuming you have little or no spark because you mentioned you had a weak spark: Where did you see this? At the spark plug wire, coil, or distributor? ---------------------------------------------------------------- No Spark - Go to ignition coil wire and disconnect ignition coil module connector. ignition on. "with dvm check voltage from *harness terminals* A & D to ground". Three possible scenarios: Both Terminals 10 volts or more, Both terminals under 10 volts, Either Terminal under 10 volts. Let me know what you find out and we can go from there. Danno74Z I got spark at both a spark plug wire and the coil. I don't have a good reference to use, but it looked a little weak to me. When I tested the spark with my test light at the coil it was able to arc from about an inch away (which I think is normal) I did the voltage checks as part of the shbox opti and spark test and I got over 10 volts DC at both terminals. I also got between 1 and 4 volts ac from terminal B while cranking the engine. Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 6, 2006 Author Share Posted October 6, 2006 One more thing. The last thing I did before the car show was put on a dress top plate which required me to move the MAP sensor. It is now connected to a vacuum port (that was previously capped) on the intake and the old hole is sealed with a plastic cap that came with the top plate. How can I test the MAP and could anything related to this cause this problem? I could move this back for testing purposes. Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted October 6, 2006 Share Posted October 6, 2006 Bart, If it's not a big deal I would put the MAP sensor back in it original location just to eliminate that as being the problem. If you had a failure of the MAP circuit you should of got a DTC33 or DTC34. Testing - Key "ON" engine stopped (no vacuum), MAP will display high voltage or pressure, while at idle (high vacuum), map will display low voltage or pressure. 4.6 volts with engine stopped. Danno74Z Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 7, 2006 Author Share Posted October 7, 2006 I put the MAP Sensor back in it's original location with no change. I've also checked the continuity of the coil and it checked out fine. In addition I checked that one of the injectors is getting power on one side and the negative is pulsing properly on the other. Nothing is pointing to any type of electrical problem at this point. I know my injector is getting the proper signal, how do I know it's actually working properly? I'm also waiting for my presure gauge to make sure that the pressure is in range, otherwise I'm kinda running out of ideas. Any more ideas? Quote Link to comment Share on other sites More sharing options...
gexgexgexgex Posted October 7, 2006 Share Posted October 7, 2006 try some starting fluid, that will tell you if your injectors are opening or not. Just spray a buch into the throttle body, you may fluid it as well so do not forget to hold it at WOT if it does not start at first Quote Link to comment Share on other sites More sharing options...
mark Posted October 8, 2006 Share Posted October 8, 2006 spray some contact cleaner in the vacume port of the opti and crank away. I bet it is corroded inside. I've take my last two apart and it is amazing how bad they looked. This is on a car that is only driven in good weather and stays inside the rest of the time. Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 8, 2006 Author Share Posted October 8, 2006 Could the opti be bad even though it passed all the opti and spark tests? Quote Link to comment Share on other sites More sharing options...
love-my-V8-280Z Posted October 8, 2006 Share Posted October 8, 2006 Bart, When I installed my opti I did not line up the cam pin correctly. It would not start and once in a while back fire. Is there a way you can make sure the correct cyclinder is getting spark when it should? also I had a problem with old gas.. It just would not start. If you have spark and fuel it should at least try to run. If you get any back firing I would think you were out of time. Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted October 9, 2006 Share Posted October 9, 2006 Bart, I might be asking the same question again - sorry. Did you check the spark with a pulled spark plug? Pull a plug, attach the plug wire and ground the plug on the block. You should hear a snap and see a bright flash every time that cylinder fires. What makes this difficult is you need a helper and a somewhat dark area (careful). "IF" you are getting a good and consistent spark at the plug I can't imagine it is the OPTI. IMO it is the computer or the ignition module. Do you program your own computer? If you do I would try reading the computer just to see if you can communicate with it. Danno74Z Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 9, 2006 Author Share Posted October 9, 2006 Bart, I might be asking the same question again - sorry. Did you check the spark with a pulled spark plug? Pull a plug, attach the plug wire and ground the plug on the block. You should hear a snap and see a bright flash every time that cylinder fires. What makes this difficult is you need a helper and a somewhat dark area (careful). "IF" you are getting a good and consistent spark at the plug I can't imagine it is the OPTI. IMO it is the computer or the ignition module. Do you program your own computer? If you do I would try reading the computer just to see if you can communicate with it. Danno74Z I'm getting spark at the plugs and I had the computer programmed for me. I can communicate with the PCM using DataMaster (unless I'm cranking the engine), and it was running fine before it died on the freeway. Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 9, 2006 Author Share Posted October 9, 2006 I think I'm just going to go ahead and buy a new opti. I read on another forum that the optical sensor can come apart and still create spark, but it would be random. It is getting spark, but it doesn't seem to be timed right...so this could explain the problem. Mine has quite a few miles on it anyway...so what the heck. Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted October 9, 2006 Share Posted October 9, 2006 Well, we have covered all the obvious items and you say all is good so now we have to really dig our heels in. You said that the Opti you have on your engine is used Ebay unit. Do you know how old it is? It could be 10 years old by now, so if you have doubts about it you should change it out with a new one. I hate to shotgun a problem but the Opti is without doubt a weak link in the LT1 electrical system and who knows how much time you have left on the used one you have. I think what people forget (myself included) is that the Opti is still a distributor with contacts and a spinning disk put in a harsher environment then the Gen1 engine. Also your engine and it's electrical system for the most part has components which are over 10 years old so you will have to go through each subsystem and try to narrow down the problem. I know I'm telling you the obvious and I don't mean to preach. By chance did you wash your engine (o_o) never, never wash an LT1! Bart, I was responding to you before I saw you latest note - Good Plan Danno74z Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 9, 2006 Author Share Posted October 9, 2006 I just looked at the eBay listing for the Opti I installed and it had about 52,000 miles on it, so even if the Opti isn't the problem it sure wouldn't hurt to get a new one anyway. I've got one on order and I'll post up the results. Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted October 9, 2006 Share Posted October 9, 2006 When I put my engine in this is what I'm buying. It costs more but I think it will be worth the extra cost and some timing can be adjusted +- 5 or so degrees. Danno74Z Quote Link to comment Share on other sites More sharing options...
that240guy Posted October 11, 2006 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. Quote Link to comment Share on other sites More sharing options...
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