Code 16 Low res. failure
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,107
Likes: 0
From: RI
Code 16 Low res. failure
Picked up the code after scanning and followed Helms instructions testing terminal A at the ECM side of the harness. All signs pointed to a faulty distributor.
But upon further investigation on this forum and a camaro forum, with code 16, the car shouldn't have started. My 93 did but ran like crap. Before spending a boatload ofmoney and time on a new opti, how, if any, can I determine if my opti IS bad?
But upon further investigation on this forum and a camaro forum, with code 16, the car shouldn't have started. My 93 did but ran like crap. Before spending a boatload ofmoney and time on a new opti, how, if any, can I determine if my opti IS bad?
Instructor
Joined: Nov 1999
Posts: 143
Likes: 3
From: Erie PA
Its the opti-spark.My '93 was running great most of the time,then it would die on the road.Start immediately and die again.Sometime I could drive it for weeks without any problem,then it would die again.Today it happened again.Managed to get it home,checked the codes.Both 16 and 36,which means opti.
Ray
Ray
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Originally Posted by sonomacrew01
Picked up the code after scanning and followed Helms instructions testing terminal A at the ECM side of the harness. All signs pointed to a faulty distributor. But upon further investigation on this forum and a camaro forum, with code 16, the car shouldn't have started. My 93 did but ran like crap. Before spending a boatload ofmoney and time on a new opti, how, if any, can I determine if my opti IS bad?
But upon further investigation on this forum and a camaro forum, with code 16, the car shouldn't have started. My 93 did but ran like crap. Before spending a boatload ofmoney and time on a new opti, how, if any, can I determine if my opti IS bad?
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,107
Likes: 0
From: RI
brand spankin new. Bought a supposed "factory sealed, new in box" deal from ebay....It has 120 miles on it but was giving metrouble from the day I cranked the rebuilt motor... Bought the opti back in november. Doubt I can get my $$$$$$ back...
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Since no one mentioned it check your wiring.Yes code 16 is caused by the opti but it could be a wire in the plug or elsewhere.Code 36 is the real RIP code but 16 is pretty close to it.Check all connections,use Di-Electric grease when re connceting it.Use the FSM to do the checking.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
Code 16 will st if the ECM detects the high resolution pulse without detecting the low resolution timing pulse. With this code the engine will crank but not run. I agree with Redeasysport, you might not have connected the circuits correctly and this is why you have had problems since day one. After doing all this and still no good, you might have a defective opti.
"Last thing I did was the first thing that messed up"
"Last thing I did was the first thing that messed up"
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Le Mans Master
Joined: May 2005
Posts: 7,359
Likes: 2,281
From: Central Maryland
The ECM is seeing a fault with the pulse train coming from the low-res sensor in the Opti. That means that either the Opti has a faulty low-res sensor, or there's an intermittent contact in the wiring harness between the Opti's low-res sensor and the ECM. Check all of the connections.
If the Opti is dying (rotten luck there), I'd strongly suggest you NOT install another OEM Opti. The first-gen OEM Opti is a POS. With the DynaSpark and the new MSD unit available, I see no sense in ever installing an OEM first-gen Opti as a replacement.
Best of luck with it. Let us know what you find.
Be well,
SJW
If the Opti is dying (rotten luck there), I'd strongly suggest you NOT install another OEM Opti. The first-gen OEM Opti is a POS. With the DynaSpark and the new MSD unit available, I see no sense in ever installing an OEM first-gen Opti as a replacement.
Best of luck with it. Let us know what you find.
Be well,
SJW
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,107
Likes: 0
From: RI
I've followed all steps according to helms making sure it has between 4-6 volts between the ECM and the distributorand it does. I've checked all plug connections and they are good. I've converted the gen1 opti to the gen 2 vented opti properly. I just have a few questions...
1)if there is a bad plug or wire, would it set code 16?
I think I'll pull all the plugs and make a simple battery circuit to see if they are ok. That way there, I know the plug wires are good and I know the harness from the ecm to the opti is good but what about the coil or anything related?
2)Would a bad coil set code 16?
Spending a few hours reading up on troubleshooting this problem could save me some $$$...
1)if there is a bad plug or wire, would it set code 16?
I think I'll pull all the plugs and make a simple battery circuit to see if they are ok. That way there, I know the plug wires are good and I know the harness from the ecm to the opti is good but what about the coil or anything related?
2)Would a bad coil set code 16?
Spending a few hours reading up on troubleshooting this problem could save me some $$$...
Race Director
Joined: Jan 2002
Posts: 12,263
Likes: 86
From: O'Fallon Missouri
Since you upgraded your opti, that means you had to change the opti wire harness. Have you made sure each wire is making a connection. Working at GM, sometimes we see a new wire harness with a pushed out pin. This can be a real PITA to diagnose.
-Mike
-Mike
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Originally Posted by STL94LT1
Since you upgraded your opti, that means you had to change the opti wire harness. Have you made sure each wire is making a connection. Working at GM, sometimes we see a new wire harness with a pushed out pin. This can be a real PITA to diagnose.
-Mike
-Mike
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Originally Posted by sonomacrew01
1)if there is a bad plug or wire, would it set code 16?
Yes
I think I'll pull all the plugs and make a simple battery circuit to see if they are ok. That way there, I know the plug wires are good and I know the harness from the ecm to the opti is good but what about the coil or anything related?
Sometimes a wire can intermittanly short or open so try wiggling everything while checking for continuity.Get a VOM and check the Ohms from one end to the other of the suspect circuit.As stated above check the plugs especially close use contact cleaner on them and follow my above suggestions.
2)Would a bad coil set code 16?
No
Spending a few hours reading up on troubleshooting this problem could save me some $$$...
YES
Le Mans Master
Joined: May 2005
Posts: 7,359
Likes: 2,281
From: Central Maryland
Originally Posted by sonomacrew01
1)if there is a bad plug or wire, would it set code 16?
I think I'll pull all the plugs and make a simple battery circuit to see if they are ok. That way there, I know the plug wires are good and I know the harness from the ecm to the opti is good but what about the coil or anything related?
2)Would a bad coil set code 16?
2. No.
The only things I can think of that could cause a Code 16 are a fault with the low-res sensor in the Opti, a wiring harness fault on the low-res signal line between the Opti and ECM, or a fault in the ECM on the input that reads the low-res signal.
If you are satisfied that the harness connections are faultless, it really does look like there's a 95% chance it's the Opti. Sorry...
Be well,
SJW
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,107
Likes: 0
From: RI
I'm 100% sure the harness is good. I checked the black/red wire (low res. signal) from the ECm to the opti and it was measuring 4.8 voltsright at the plug into the opti. And the prongs at the opti looked healthy...
Le Mans Master
Joined: May 2005
Posts: 7,359
Likes: 2,281
From: Central Maryland
Originally Posted by sonomacrew01
I'm 100% sure the harness is good. I checked the black/red wire (low res. signal) from the ECm to the opti and it was measuring 4.8 voltsright at the plug into the opti. And the prongs at the opti looked healthy...
Be well,
SJW
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Originally Posted by Redeasysport
Since no one mentioned it check your wiring.Yes code 16 is caused by the opti but it could be a wire in the plug or elsewhere.Code 36 is the real RIP code but 16 is pretty close to it.Check all connections,use Di-Electric grease when re connceting it.Use the FSM to do the checking.
And both can be caused by a bad connector.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
Originally Posted by SJW
The only things I can think of that could cause a Code 16 are a fault with the low-res sensor in the Opti, a wiring harness fault on the low-res signal line between the Opti and ECM, or a fault in the ECM on the input that reads the low-res signal.
If you are satisfied that the harness connections are faultless, it really does look like there's a 95% chance it's the Opti. Sorry...
Be well,
SJW
If you are satisfied that the harness connections are faultless, it really does look like there's a 95% chance it's the Opti. Sorry...
Be well,
SJW
with SJW these would be the only things that could go wrong to set the code. As stated if you are satisfied with the connections and the wiring test good. Only one other problem besides a faulty ECM (which is not likely, because you would probably have more than code 16 show up) is the opti. Not good news...no.