Watch Cheap Opti Fail on the Test Bench
12-11-2014, 12:17 PM
#1
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Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
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Watch Cheap Opti Fail on the Test Bench
I'm sure most of you have seen GaryDoug's Scan9495 program, and are aware of the service he has done to the LT1 community by developing this. He has also been working on building a simulator to study the operation of the LT1 PCM, and he has dissected most of the printed circuit boards in our cars. His skills as an electrical engineer really shine.
A member on another forum was having intermittent stalling of his 93 LT1, as the engine warmed up. We suspected it might be the Opti, but wanted to confirm it. Turns out this individual lived near Gary, and was able to provide the Opti in question to Gary for analysis. It was put on a test bench, hooked up to a power supply and an oscilloscope, and subjected to heat from a hair drier.
As expected, the heat caused the cam position signals from the Opti to shut down. The problem was traced to an intermittent ground wire connection to one of the two printed circuit boards in the cam position sensor.
Worth a look.... believe me. The opti was from Advanced Auto, as far as the owner recalls.
93 Firebird Optispark failure analysis - Firebird Nation
http://api.viglink.com/api/click?for...%2FU2kIVyid4bw
A member on another forum was having intermittent stalling of his 93 LT1, as the engine warmed up. We suspected it might be the Opti, but wanted to confirm it. Turns out this individual lived near Gary, and was able to provide the Opti in question to Gary for analysis. It was put on a test bench, hooked up to a power supply and an oscilloscope, and subjected to heat from a hair drier.
As expected, the heat caused the cam position signals from the Opti to shut down. The problem was traced to an intermittent ground wire connection to one of the two printed circuit boards in the cam position sensor.
Worth a look.... believe me. The opti was from Advanced Auto, as far as the owner recalls.
93 Firebird Optispark failure analysis - Firebird Nation
http://api.viglink.com/api/click?for...%2FU2kIVyid4bw
Last edited by Injuneer; 12-11-2014 at 12:20 PM.
12-12-2014, 03:15 AM
#2
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Join Date: Mar 1999
Location: Kernersville, NC
Posts: 2,058
Re: Watch Cheap Opti Fail on the Test Bench
Wow, it just flat died. No intermittent signals, just dead all at once. Makes it a little easier on the troubleshooting though. Interesting how cracked solder joints react. The soldering of those four terminals looks kinda crappy from manufacturing, but it may just be where the coating was removed.
LH+-, is that Low Res, High Res, 12V, Gnd? Are those post terminals that go to a harness that plugs into on the other side of the board? Makes me wonder if the terminal saw some mechanical stress from a connector of some sort to cause it to break the joint like that(maybe a slightly out of shape pin that the harness smacked when plugging it in....). If not, that is some terrible quality control.
LH+-, is that Low Res, High Res, 12V, Gnd? Are those post terminals that go to a harness that plugs into on the other side of the board? Makes me wonder if the terminal saw some mechanical stress from a connector of some sort to cause it to break the joint like that(maybe a slightly out of shape pin that the harness smacked when plugging it in....). If not, that is some terrible quality control.
Last edited by ACE1252; 12-12-2014 at 03:18 AM.
12-12-2014, 07:04 AM
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Re: Watch Cheap Opti Fail on the Test Bench
The optical emitter module did not have the Mitsubishi logo on it, so I suspect it's a Chinese rip-off.
As labeled - low/high/+B/ground. The conductors are embedded in the plastic, and the plastic is going to expand as it heats up. I would think that could stress the solder joint. It's interesting that the failure only happened with the cap in place, and not with the cap removed. But the loose joint did fail while tapping the unit with the cap off.
As labeled - low/high/+B/ground. The conductors are embedded in the plastic, and the plastic is going to expand as it heats up. I would think that could stress the solder joint. It's interesting that the failure only happened with the cap in place, and not with the cap removed. But the loose joint did fail while tapping the unit with the cap off.
Last edited by Injuneer; 12-12-2014 at 07:07 AM.
12-15-2014, 08:05 AM
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Join Date: Mar 2006
Location: Ga
Posts: 151
Re: Watch Cheap Opti Fail on the Test Bench
Excellent information. That opti flat lined big time. I am glad I went with a Delphi when I replaced mine. Expensive but worth it.
Last edited by Matts97camaro; 12-15-2014 at 08:13 AM.
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