LOW RES failure, help
Thread Starter
Racer
Joined: Dec 2007
Posts: 345
Likes: 0
From: Flint Michigan, #2 in unemployment, #3 in Violent crimes
LOW RES failure, help
my car has been suffering from an intermittent miss. sometimes part throttle, sometimes at idle, sometimes never.
well, I changed the opti today, and low and behold, it wont start at all now.
no spark at all. I get a code 16
low res circuit failure
I changed the coil, ESC and checked all the fuses and followed the FSM to a "T"
checked out and it said the opti circuit can cause this by no pickup field in the opti.
greek to me but I just wanted to confirm I was not nuts and my "NEW" opti has given up the ghost, so to speak.
well, I changed the opti today, and low and behold, it wont start at all now.
no spark at all. I get a code 16
low res circuit failure
I changed the coil, ESC and checked all the fuses and followed the FSM to a "T"
checked out and it said the opti circuit can cause this by no pickup field in the opti.
greek to me but I just wanted to confirm I was not nuts and my "NEW" opti has given up the ghost, so to speak.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
You may have a bad connection or plug. Since it is a 95(right?) it would be almost impossible to install it wrong. The other obvious thing is it is bad sooo looks like check the plugs and pull the cap and take a look at the insides.There are actually 2 signals generated by the opti with one disc that rotates. the outer part of it has 720(2 for every degree) little slots that are for timing the inner side has 8 divisions that are used for firing. A code 36 has to do with the timing and the car may run with it but bad. A code 16 means it will not fire. If it is the opti the optical sensor is not seeing those 8 divisions for some reason.Maybe disc is loose or sensor has crap on it.
Last edited by Redeasysport; Aug 3, 2008 at 09:27 PM.
Thread Starter
Racer
Joined: Dec 2007
Posts: 345
Likes: 0
From: Flint Michigan, #2 in unemployment, #3 in Violent crimes
yes 95 and NO other codes except the 16, no blown fuses or bad plugs.
it was gone over by 4 different mechanics to make sure it was installed correctly and all plugs were good.
I checked it myself and seen nothing that looked bad. I even pulled the plugs and made sure they were all the way out and not recessed. cranks, no spark at plug or coil.
this is not uncommon on these. I have seen them go through 3 opti units before getting a good one.
same problem, crank but no spark, 4th opti fired right up.
plugs meaning weather packs, not spark plugs, they were not removed.
it was gone over by 4 different mechanics to make sure it was installed correctly and all plugs were good.
I checked it myself and seen nothing that looked bad. I even pulled the plugs and made sure they were all the way out and not recessed. cranks, no spark at plug or coil.
this is not uncommon on these. I have seen them go through 3 opti units before getting a good one.
same problem, crank but no spark, 4th opti fired right up.
plugs meaning weather packs, not spark plugs, they were not removed.
Last edited by Overboost; Aug 3, 2008 at 09:29 PM.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Did you check the plug on the side of the intake. I always use electrical contact cleaner and dielectric grease when disconnecting electrical plugs.If you have access to an "O" scope you could look for the signal on the wires.Good Luck
Melting Slicks
Joined: Apr 1999
Posts: 2,521
Likes: 4
From: Windham, NH
Go to MSD's web site. There is an area to send your comments to them. They DO monitor this. They are pretty good at getting back to you with their recommendations. You could have gotten a bad Opti.
Jim
Jim
Thread Starter
Racer
Joined: Dec 2007
Posts: 345
Likes: 0
From: Flint Michigan, #2 in unemployment, #3 in Violent crimes
there was power before I pulled it, it drove fine, just had a miss, now it is dead. CCM goes into diag mode just fine and all other traces that the FSM pointed to are fine.
no spark at coil, there are very few plugs to pull to change this, acually kind of simple all but the lower pulley. everything else went like clockwork, except the no start.
also, put old opti back in, started right up so I know it is the opti now, I guess I just got a dead one.
no spark at coil, there are very few plugs to pull to change this, acually kind of simple all but the lower pulley. everything else went like clockwork, except the no start.
also, put old opti back in, started right up so I know it is the opti now, I guess I just got a dead one.
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Racer
Joined: Sep 2007
Posts: 393
Likes: 0
From: Bartonville Illinois
I can't figure out these Opti's. It's just an optical encoder and they are very reliable. Moisture is their biggest enemy and I have cleaned very dirty ones and they worked fine afterwards.
It must be the manufacturing process. I guess you got a bad one. I have replaced two this year.
It must be the manufacturing process. I guess you got a bad one. I have replaced two this year.
Le Mans Master
Joined: Feb 1999
Posts: 9,916
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
I can't figure out these Opti's. It's just an optical encoder and they are very reliable. Moisture is their biggest enemy and I have cleaned very dirty ones and they worked fine afterwards.
It must be the manufacturing process. I guess you got a bad one. I have replaced two this year.
It must be the manufacturing process. I guess you got a bad one. I have replaced two this year.
It doesnt seem to take much for the Optis to be bad.
Pro
Joined: Jun 2008
Posts: 610
Likes: 1
I haven't had mine apart yet, but I used to build and calibrate optical encoders for a living. I would use denatured alcohol, the best quality you can obtain, for cleaning the optics. It will work fine on the disk also.
I would avoid using acetone or other stronger solvents as they will degrade plastic parts.
I would avoid using acetone or other stronger solvents as they will degrade plastic parts.
Thread Starter
Racer
Joined: Dec 2007
Posts: 345
Likes: 0
From: Flint Michigan, #2 in unemployment, #3 in Violent crimes
I just installed a rebuilt stocker from advance, seems to run fine but I hear bad things about these "other" rebuilt opti's
the guy at the parts store has a 97 firebird and he said the only problem he had from the opti they sell is the rotor kept breaking from him revving so high. otherwise, no problems.
the guy at the parts store has a 97 firebird and he said the only problem he had from the opti they sell is the rotor kept breaking from him revving so high. otherwise, no problems.
Racer
Joined: Sep 2007
Posts: 393
Likes: 0
From: Bartonville Illinois
I haven't had mine apart yet, but I used to build and calibrate optical encoders for a living. I would use denatured alcohol, the best quality you can obtain, for cleaning the optics. It will work fine on the disk also.
I would avoid using acetone or other stronger solvents as they will degrade plastic parts.
I would avoid using acetone or other stronger solvents as they will degrade plastic parts.
I also noticed that the bearing was sloppy on the one I took out. If you built encoders you then know that side pressure from poor alignment will also cause failure, just as in resolvers. Mechanical alignment is critical. It should be difficult to install an Opti wrong but I guess it could be done. They are probably prone to mechanical failure than electrical.
When I looked at the signals (square wave) from the Opti, they were noisy. The ECM must count these pulses, 360 holes but it counts 720 transitions. I had a Hi Res failure, but it can be caused by incorrect count or missing signal.
We used the higher grade rubbing alcohol (98-99%)when we didn't have the denatured stuff on glass scales and optics.
Pro
Joined: Jun 2008
Posts: 610
Likes: 1
I would have expected the output from the opti to be sine and the squaring-up to be done at the receiving end. Sure, play in the shaft, face wobble in the disk, or other damage or misalignment is going to impact the signal quality.
I will be getting into mine in the near future. The car has 114k on it and afaik it is the original. Kinda curious about what it is going to look like.
I will be getting into mine in the near future. The car has 114k on it and afaik it is the original. Kinda curious about what it is going to look like.
Racer
Joined: Sep 2007
Posts: 393
Likes: 0
From: Bartonville Illinois
I would have expected the output from the opti to be sine and the squaring-up to be done at the receiving end. Sure, play in the shaft, face wobble in the disk, or other damage or misalignment is going to impact the signal quality.
I will be getting into mine in the near future. The car has 114k on it and afaik it is the original. Kinda curious about what it is going to look like.
I will be getting into mine in the near future. The car has 114k on it and afaik it is the original. Kinda curious about what it is going to look like.
5 volt square wave, for digital counting on high res.
Low res is same value but different on times for cylinder identification.
Thread Starter
Racer
Joined: Dec 2007
Posts: 345
Likes: 0
From: Flint Michigan, #2 in unemployment, #3 in Violent crimes
never unhooked anything except what I needed to take it out.
like I said, I installed a rebuilt advance auto brand opti and it runs perfect so far, no misses or hickups. I was chasing down a miss when hot which is why I changed it in the first place, now it is gone, all of it, I can turn on the air again and it dont so much as surge.
Intermediate
Joined: Sep 2006
Posts: 41
Likes: 0
From: Jacksonville Fl
Did you figure it out? Do you have an AC signal at the ignition module ? Do your ignition module connector test for 12 volts, 12 volts, ground, and last hole your AC volts. Then check your harness connector with everything pluged in for the 12 volts, 5 volts, 5 volts and ground by back probing. I feel you have a wire/electrical problem. you may not have the power coming from your computer to the opti but it almost seems you have a connector problem on the opti plug on top of the opti.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Did you figure it out? Do you have an AC signal at the ignition module ? Do your ignition module connector test for 12 volts, 12 volts, ground, and last hole your AC volts. Then check your harness connector with everything pluged in for the 12 volts, 5 volts, 5 volts and ground by back probing. I feel you have a wire/electrical problem. you may not have the power coming from your computer to the opti but it almost seems you have a connector problem on the opti plug on top of the opti.
"like I said, I installed a rebuilt advance auto brand opti and it runs perfect so far, no misses or hickups. I was chasing down a miss when hot which is why I changed it in the first place, now it is gone, all of it, I can turn on the air again and it dont so much as surge"
The culprit was a bad MSD opti out of the box.
Thread Starter
Racer
Joined: Dec 2007
Posts: 345
Likes: 0
From: Flint Michigan, #2 in unemployment, #3 in Violent crimes
Obviously he did
"like I said, I installed a rebuilt advance auto brand opti and it runs perfect so far, no misses or hickups. I was chasing down a miss when hot which is why I changed it in the first place, now it is gone, all of it, I can turn on the air again and it dont so much as surge"
The culprit was a bad MSD opti out of the box.
"like I said, I installed a rebuilt advance auto brand opti and it runs perfect so far, no misses or hickups. I was chasing down a miss when hot which is why I changed it in the first place, now it is gone, all of it, I can turn on the air again and it dont so much as surge"
The culprit was a bad MSD opti out of the box.
yup, stiffed me before I even got one plug to fire.
all my previous problems are now solved, so the opti and plug wires MUST have been the cause of my misfiring all along.
the MSD looked nice, but gave up the ghost on the first crank of the starter.