new opti didnt fix misfire... whats next?
12-14-2010, 09:14 AM
#1
new opti didnt fix misfire... whats next? Essentially I ripped open a perfectly good AC Delco Optispark last night and replaced the cap and rotor. Lock-tite the rotor screws and siliconed the cap and center piece to the base. Started it up and exact same damn misfire
While under the car, I checked wires - looked brand spankin new. Made sure they were fully clicked (is it 3 or 4 clicks?) on. Plugs could possibly be the issue but I'll be replacing them with headers next month.
When I backed the car out, I let it idle in the dark w/ no lights on and couldnt see any arching or sparks jumping...
Here's the symptoms - it idles like butter... nice and smooth (except for once this morning but I'm not gonna worry about that).
when I hit the gas, part throttle 50/50 it takes off like a scalded ape or it'll studder and hesitate and sound like dog ****
casual driving - again 50/50, sometimes its nice and smooth... sometimes, its like half the plug wires are missing
Its throwing three codes - two are not engine related and one is EGR... I have the block-off plates but its just a matter of finding time to rip off all that crap.
Could a faulty EGR cause an intermittent misfire? ...or what seems like a misfire?
I've spaced the ICM/coil from the head... should I replace both entirely? I've got a new ICM waiting for me next door...
oh, '93 TA, auto, 107k mi
While under the car, I checked wires - looked brand spankin new. Made sure they were fully clicked (is it 3 or 4 clicks?) on. Plugs could possibly be the issue but I'll be replacing them with headers next month.
When I backed the car out, I let it idle in the dark w/ no lights on and couldnt see any arching or sparks jumping...
Here's the symptoms - it idles like butter... nice and smooth (except for once this morning but I'm not gonna worry about that).
when I hit the gas, part throttle 50/50 it takes off like a scalded ape or it'll studder and hesitate and sound like dog ****
casual driving - again 50/50, sometimes its nice and smooth... sometimes, its like half the plug wires are missing
Its throwing three codes - two are not engine related and one is EGR... I have the block-off plates but its just a matter of finding time to rip off all that crap.
Could a faulty EGR cause an intermittent misfire? ...or what seems like a misfire?
I've spaced the ICM/coil from the head... should I replace both entirely? I've got a new ICM waiting for me next door...
oh, '93 TA, auto, 107k mi
12-14-2010, 12:09 PM
#2
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Do a 24x efi connections conversion, thats my plan this winter.
Its still a good possibility its the opti's optical side that is causing the misfire. Or plugs even.
I had a intermittant issue that the car would just die while driving then throw a opti low res code. I had no misfires or anything, car would just turn off like i turned the ignition off and would fire up like 2 minutes later like nothing happened. Replaced it and ran fine.
Its still a good possibility its the opti's optical side that is causing the misfire. Or plugs even.
I had a intermittant issue that the car would just die while driving then throw a opti low res code. I had no misfires or anything, car would just turn off like i turned the ignition off and would fire up like 2 minutes later like nothing happened. Replaced it and ran fine.
12-14-2010, 07:59 PM
#3
I feel your pain I chased a miss for about a year on my car....what a PITA!
After replacing everything that could possibly be the prob I went 24x and all has been good...
however....
the optical sensor itself could be going bad...all you replaced was the cap and rotor....
After replacing everything that could possibly be the prob I went 24x and all has been good...
however....
the optical sensor itself could be going bad...all you replaced was the cap and rotor....
12-14-2010, 09:57 PM
#7
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Essentially I ripped open a perfectly good AC Delco Optispark last night and replaced the cap and rotor. Lock-tite the rotor screws and siliconed the cap and center piece to the base. Started it up and exact same damn misfire
While under the car, I checked wires - looked brand spankin new. Made sure they were fully clicked (is it 3 or 4 clicks?) on. Plugs could possibly be the issue but I'll be replacing them with headers next month.
When I backed the car out, I let it idle in the dark w/ no lights on and couldnt see any arching or sparks jumping...
Here's the symptoms - it idles like butter... nice and smooth (except for once this morning but I'm not gonna worry about that).
when I hit the gas, part throttle 50/50 it takes off like a scalded ape or it'll studder and hesitate and sound like dog ****
casual driving - again 50/50, sometimes its nice and smooth... sometimes, its like half the plug wires are missing
Its throwing three codes - two are not engine related and one is EGR... I have the block-off plates but its just a matter of finding time to rip off all that crap.
Could a faulty EGR cause an intermittent misfire? ...or what seems like a misfire?
I've spaced the ICM/coil from the head... should I replace both entirely? I've got a new ICM waiting for me next door...
oh, '93 TA, auto, 107k mi
While under the car, I checked wires - looked brand spankin new. Made sure they were fully clicked (is it 3 or 4 clicks?) on. Plugs could possibly be the issue but I'll be replacing them with headers next month.
When I backed the car out, I let it idle in the dark w/ no lights on and couldnt see any arching or sparks jumping...
Here's the symptoms - it idles like butter... nice and smooth (except for once this morning but I'm not gonna worry about that).
when I hit the gas, part throttle 50/50 it takes off like a scalded ape or it'll studder and hesitate and sound like dog ****
casual driving - again 50/50, sometimes its nice and smooth... sometimes, its like half the plug wires are missing
Its throwing three codes - two are not engine related and one is EGR... I have the block-off plates but its just a matter of finding time to rip off all that crap.
Could a faulty EGR cause an intermittent misfire? ...or what seems like a misfire?
I've spaced the ICM/coil from the head... should I replace both entirely? I've got a new ICM waiting for me next door...
oh, '93 TA, auto, 107k mi
Pull all the plugs out and see what they look like.Always go back to your basics..Get a handheld vaccum pump on it an see if it holds vaccum.
If it doesn't it is bad.
Here is a test you can do.
With engine idling, opening the EGR valve should cause the engine to run rough or die. On the forward side of the valve there are openings where you can get your finger or thumb in to press the diaphragm toward the back (opening the valve). If there is no change in engine rpm, the passages in the manifold may be clogged. This does not appear to happen very often.
If you cannot get in there to push on the diaphragm, you can use a hand vacuum pump (like a Mityvac) connected to the EGR valve to open it. The valve should also hold vacuum, which would prove that the diaphragm is not leaking.
You can check that the solenoid is getting adequate vacuum by unplugging the vacuum supply hose at the solenoid and putting a vacuum gauge on it. There should be at least 7" Hg of vacuum at 2000 rpm. If not, make sure the hose has no leaks and check the vacuum at the manifold fitting.
Too much EGR flow will dilute the a/f mixture and make the engine run rough or stall. Excess flow weakens combustion and may result in the following conditions:
Engine stops after cold start
Engine stops at idle after deceleration
Vehicle surges during cruise
Rough idle
Too little or no EGR flow can allow combustion temps to get too high during acceleration and load conditions. This could cause:
Spark knock (detonation)
Engine overheating
Emission test failure
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12-15-2010, 11:56 AM
#9
ok, cool
no o2 codes and I have the 1-wire versions so I'm not too worried about that
C/Performance - I'm going to try the ICM next - I spaced it off the head a few weeks ago and frankly, it looked like the original 17yr old factory unit.
also, FYI - the car has never completely died or stalled. Its just rough acceleration and stumbling at cruise. I have had a few instances where I would attempt to start it immediately after turning it off and it would spin but never start... I would just wait a minute or two and it has always started on the 2nd attempt. This has happened *maybe* 5-6 times over the past month
it idles fine 99% of the time in park - maybe one little minor miss every now and the
in drive, stopped at a light it will miss slightly maybe once every other day
no o2 codes and I have the 1-wire versions so I'm not too worried about that
C/Performance - I'm going to try the ICM next - I spaced it off the head a few weeks ago and frankly, it looked like the original 17yr old factory unit.
also, FYI - the car has never completely died or stalled. Its just rough acceleration and stumbling at cruise. I have had a few instances where I would attempt to start it immediately after turning it off and it would spin but never start... I would just wait a minute or two and it has always started on the 2nd attempt. This has happened *maybe* 5-6 times over the past month
it idles fine 99% of the time in park - maybe one little minor miss every now and the
in drive, stopped at a light it will miss slightly maybe once every other day
12-15-2010, 12:10 PM
#10
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ok, cool
no o2 codes and I have the 1-wire versions so I'm not too worried about that
C/Performance - I'm going to try the ICM next - I spaced it off the head a few weeks ago and frankly, it looked like the original 17yr old factory unit.
also, FYI - the car has never completely died or stalled. Its just rough acceleration and stumbling at cruise. I have had a few instances where I would attempt to start it immediately after turning it off and it would spin but never start... I would just wait a minute or two and it has always started on the 2nd attempt. This has happened *maybe* 5-6 times over the past month
it idles fine 99% of the time in park - maybe one little minor miss every now and the
in drive, stopped at a light it will miss slightly maybe once every other day
no o2 codes and I have the 1-wire versions so I'm not too worried about that
C/Performance - I'm going to try the ICM next - I spaced it off the head a few weeks ago and frankly, it looked like the original 17yr old factory unit.
also, FYI - the car has never completely died or stalled. Its just rough acceleration and stumbling at cruise. I have had a few instances where I would attempt to start it immediately after turning it off and it would spin but never start... I would just wait a minute or two and it has always started on the 2nd attempt. This has happened *maybe* 5-6 times over the past month
it idles fine 99% of the time in park - maybe one little minor miss every now and the
in drive, stopped at a light it will miss slightly maybe once every other day
12-15-2010, 01:34 PM
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12-15-2010, 02:09 PM
#14
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I had a very similar issue and it ended up being the opti. As others have said it could be the opti sensor (that's what it was in my case).
Granted I'm no mechanic but the reason I think it's your opti (actually opti sensor) is this..
"I have had a few instances where I would attempt to start it immediately after turning it off and it would spin but never start... I would just wait a minute or two and it has always started on the 2nd attempt. This has happened *maybe* 5-6 times over the past month"
That is exactly how my issue started and it eventually got to the point where it would crank and not start - it didn't throw a code for opti low res until it would take several (4-5) attempts to start.
How old is your water pump? Check the weep hole on it and I'll bet you find that it's slowly taking a dump on your opti and corroding the opti sensor.
Granted I'm no mechanic but the reason I think it's your opti (actually opti sensor) is this..
"I have had a few instances where I would attempt to start it immediately after turning it off and it would spin but never start... I would just wait a minute or two and it has always started on the 2nd attempt. This has happened *maybe* 5-6 times over the past month"
That is exactly how my issue started and it eventually got to the point where it would crank and not start - it didn't throw a code for opti low res until it would take several (4-5) attempts to start.
How old is your water pump? Check the weep hole on it and I'll bet you find that it's slowly taking a dump on your opti and corroding the opti sensor.
12-15-2010, 03:51 PM
#15
my shifter is a bit stiff and doesnt always wanna come out of park but I just figured its getting rusty and I was planning on swapping it out anyway
12-15-2010, 03:55 PM
#16
I had a very similar issue and it ended up being the opti. As others have said it could be the opti sensor (that's what it was in my case).
Granted I'm no mechanic but the reason I think it's your opti (actually opti sensor) is this..
"I have had a few instances where I would attempt to start it immediately after turning it off and it would spin but never start... I would just wait a minute or two and it has always started on the 2nd attempt. This has happened *maybe* 5-6 times over the past month"
That is exactly how my issue started and it eventually got to the point where it would crank and not start - it didn't throw a code for opti low res until it would take several (4-5) attempts to start.
How old is your water pump? Check the weep hole on it and I'll bet you find that it's slowly taking a dump on your opti and corroding the opti sensor.
Granted I'm no mechanic but the reason I think it's your opti (actually opti sensor) is this..
"I have had a few instances where I would attempt to start it immediately after turning it off and it would spin but never start... I would just wait a minute or two and it has always started on the 2nd attempt. This has happened *maybe* 5-6 times over the past month"
That is exactly how my issue started and it eventually got to the point where it would crank and not start - it didn't throw a code for opti low res until it would take several (4-5) attempts to start.
How old is your water pump? Check the weep hole on it and I'll bet you find that it's slowly taking a dump on your opti and corroding the opti sensor.
waterpump looked good. The seller said he replaced it a few months ago. The car runs extremely cool and there wasn't a drop on the weep hole - not even a stain
12-15-2010, 04:55 PM
#17
when I pried the AC Delco opti open (it was siliconed), the sensor (had the Mitsubishi logo on it) looked beautiful, not a single speck of dust on it or the wheel. In fact, I felt I was being counter-productive by opening it once I saw how clean it was inside. The AC Delco rotor had a tiny bit of corrosion on it but otherwise looked brand spankin' new. Exterior-wise, besides some layers of dirt, it looked fine as well
waterpump looked good. The seller said he replaced it a few months ago. The car runs extremely cool and there wasn't a drop on the weep hole - not even a stain
waterpump looked good. The seller said he replaced it a few months ago. The car runs extremely cool and there wasn't a drop on the weep hole - not even a stain
Of course do the simple cheap solutions first but I think it could possibly be the opti...
12-15-2010, 05:28 PM
#18
TECH Veteran
My friend it looks like you might have a bad ignition module as it gets hot behind the ignition coil.Its not your optispark.Assuming you have good wires and plugs.
Pull all the plugs out and see what they look like.Always go back to your basics..Get a handheld vaccum pump on it an see if it holds vaccum.
If it doesn't it is bad.
Here is a test you can do.
With engine idling, opening the EGR valve should cause the engine to run rough or die. On the forward side of the valve there are openings where you can get your finger or thumb in to press the diaphragm toward the back (opening the valve). If there is no change in engine rpm, the passages in the manifold may be clogged. This does not appear to happen very often.
If you cannot get in there to push on the diaphragm, you can use a hand vacuum pump (like a Mityvac) connected to the EGR valve to open it. The valve should also hold vacuum, which would prove that the diaphragm is not leaking.
You can check that the solenoid is getting adequate vacuum by unplugging the vacuum supply hose at the solenoid and putting a vacuum gauge on it. There should be at least 7" Hg of vacuum at 2000 rpm. If not, make sure the hose has no leaks and check the vacuum at the manifold fitting.
Too much EGR flow will dilute the a/f mixture and make the engine run rough or stall. Excess flow weakens combustion and may result in the following conditions:
Engine stops after cold start
Engine stops at idle after deceleration
Vehicle surges during cruise
Rough idle
Too little or no EGR flow can allow combustion temps to get too high during acceleration and load conditions. This could cause:
Spark knock (detonation)
Engine overheating
Emission test failure
Pull all the plugs out and see what they look like.Always go back to your basics..Get a handheld vaccum pump on it an see if it holds vaccum.
If it doesn't it is bad.
Here is a test you can do.
With engine idling, opening the EGR valve should cause the engine to run rough or die. On the forward side of the valve there are openings where you can get your finger or thumb in to press the diaphragm toward the back (opening the valve). If there is no change in engine rpm, the passages in the manifold may be clogged. This does not appear to happen very often.
If you cannot get in there to push on the diaphragm, you can use a hand vacuum pump (like a Mityvac) connected to the EGR valve to open it. The valve should also hold vacuum, which would prove that the diaphragm is not leaking.
You can check that the solenoid is getting adequate vacuum by unplugging the vacuum supply hose at the solenoid and putting a vacuum gauge on it. There should be at least 7" Hg of vacuum at 2000 rpm. If not, make sure the hose has no leaks and check the vacuum at the manifold fitting.
Too much EGR flow will dilute the a/f mixture and make the engine run rough or stall. Excess flow weakens combustion and may result in the following conditions:
Engine stops after cold start
Engine stops at idle after deceleration
Vehicle surges during cruise
Rough idle
Too little or no EGR flow can allow combustion temps to get too high during acceleration and load conditions. This could cause:
Spark knock (detonation)
Engine overheating
Emission test failure
12-23-2010, 02:23 PM
#19
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when I pried the AC Delco opti open (it was siliconed), the sensor (had the Mitsubishi logo on it) looked beautiful, not a single speck of dust on it or the wheel. In fact, I felt I was being counter-productive by opening it once I saw how clean it was inside. The AC Delco rotor had a tiny bit of corrosion on it but otherwise looked brand spankin' new. Exterior-wise, besides some layers of dirt, it looked fine as well
waterpump looked good. The seller said he replaced it a few months ago. The car runs extremely cool and there wasn't a drop on the weep hole - not even a stain
waterpump looked good. The seller said he replaced it a few months ago. The car runs extremely cool and there wasn't a drop on the weep hole - not even a stain
12-23-2010, 03:54 PM
#20
"Looking beautiful" is not an indication of an optispark's running condition. That being said, if the misfire is exactly the same, its not likely the optispark. If the RPM range or amount of misfiring changed, you could have changed a bad opti with a bad opti.
I havent had time to mess with it with holidays, etc but I may have time sunday. Ive narrowed it down to either a bad plug wire, arching wire, or the egr... I have plates, its just a matter of getting in there and ripping all that crap out