Opti Signal Floating?
09-21-2005, 03:27 PM
#1
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Join Date: Feb 2000
Posts: 510
Opti Signal Floating?
I may be experiencing a problem where my timing is fluctuating.
Recently upgraded to Deltec and eliminated all but the optical portion of the OPtiSpark. Can the optical section fluctuate at higher RPMs discordant from actual RPM / cam position?
Recently upgraded to Deltec and eliminated all but the optical portion of the OPtiSpark. Can the optical section fluctuate at higher RPMs discordant from actual RPM / cam position?
09-21-2005, 03:59 PM
#2
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Join Date: Dec 1969
Location: Tallahassee, FL USA
Posts: 165
Re: Opti Signal Floating?
The Delteq does not control igntion or fuel injection timing -- these two functions are still controlled by the ECM/PCM as they were before.
All the Delteq does is determine which coil is "fired" by the EST (Electronic Spark Timing) signal from the ECM.
So, ignition advance, knock retard, etc are still an ECM function.
With the OEM system, the cap and rotor in the Opti-Spark deterimine which cylinder gets fired; and, on the Delteq system, the Delteq box and the coil pak determine which cylinder gets fired.
Just think of the Delteq as replacing the Opti-Spark cap and rotor only -- not the ECM functionality.
Tom Piper
All the Delteq does is determine which coil is "fired" by the EST (Electronic Spark Timing) signal from the ECM.
So, ignition advance, knock retard, etc are still an ECM function.
With the OEM system, the cap and rotor in the Opti-Spark deterimine which cylinder gets fired; and, on the Delteq system, the Delteq box and the coil pak determine which cylinder gets fired.
Just think of the Delteq as replacing the Opti-Spark cap and rotor only -- not the ECM functionality.
Tom Piper
09-21-2005, 05:42 PM
#3
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Join Date: Feb 2000
Posts: 510
Re: Opti Signal Floating?
Thanks for the general overview of Deltec, I am already familiar with.
Allow me to restate my question, "Is the Optical portion of the Opti-Spark capable of deviating significantly at high RPMs?" This may be due to any related issue, but specifically, my timing is moving around at upper RPMs and with Deltec and the programming static...I am befuddled!!
Allow me to restate my question, "Is the Optical portion of the Opti-Spark capable of deviating significantly at high RPMs?" This may be due to any related issue, but specifically, my timing is moving around at upper RPMs and with Deltec and the programming static...I am befuddled!!
09-22-2005, 05:41 AM
#4
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Join Date: Dec 1969
Location: Tallahassee, FL USA
Posts: 165
Re: Opti Signal Floating?
Ooops, went down the wrong road.
The Opti-Spark has two signals:
1) low-res pulse that is used for both injection and ignition timing.
2) high-res pulse that is used to make the ignition timing more accurate.
The vehicle will run, at reduced performance, without the high-res pulse because the ignition timing is not as accurate.
But, if the low-res pulse is consistently not there, the engine won't run at all.
If the high-res pulse was intermittent, that may cause ignition timing changes.
But, I would expect a trouble-code to set for that missing pulse.
The ECM creates the EST (Electronic Spark Timing) signal initially from the Opti-Spark pulses, but it also takes into account engine rpm, engine load, knock counts, engine temperature, etc.
I could see where the ECM may change the timing because of erroneous input from any of these sensors.
The Optical wheel is mechanically coupled to the camshaft -- seems like it would be difficult for it to move around unless the dowel pin in the camshaft wasn't in the opti-Spark correctly.
Tom Piper
The Opti-Spark has two signals:
1) low-res pulse that is used for both injection and ignition timing.
2) high-res pulse that is used to make the ignition timing more accurate.
The vehicle will run, at reduced performance, without the high-res pulse because the ignition timing is not as accurate.
But, if the low-res pulse is consistently not there, the engine won't run at all.
If the high-res pulse was intermittent, that may cause ignition timing changes.
But, I would expect a trouble-code to set for that missing pulse.
The ECM creates the EST (Electronic Spark Timing) signal initially from the Opti-Spark pulses, but it also takes into account engine rpm, engine load, knock counts, engine temperature, etc.
I could see where the ECM may change the timing because of erroneous input from any of these sensors.
The Optical wheel is mechanically coupled to the camshaft -- seems like it would be difficult for it to move around unless the dowel pin in the camshaft wasn't in the opti-Spark correctly.
Tom Piper
Last edited by Tom Piper; 09-22-2005 at 09:13 AM.
09-23-2005, 03:08 PM
#6
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Join Date: Dec 2003
Location: Northern Virginia
Posts: 39
Re: Opti Signal Floating?
Ultra Dog said:
"Is the Optical portion of the Opti-Spark capable of deviating significantly at high RPMs?" This may be due to any related issue, but specifically, my timing is moving around at upper RPMs and with Deltec and the programming static"
First off - there are two ways to determine that the timing is off (OK three ways if you have an oscilliscope!). they are:
1. Use a timing light and observe the timing marker (which you'd have to make yourself on an LT1). you have to trust the timing light too...dial back lights aren't trustworthy for highly-accurate measurements by the way, especially with waste spark.
2. Using an ECM scanner and seeing the timing values shifting around, even though the timing maps show that the timing should be constant.
3. Use an oscilliscope on the actual coil signals, and sync with the optical sensors. We use this method to determine that the system is working properly when developing kits for new vehicles.
Bottom line here is that methods 1 and 2 are showing completely different things.
That is:
If your timing is jumping around on a scanner datalog, it means that something is effecting timing, or the scanner is not functioning properly. Knock retard will effect timing for example, as will MAT and other stuff.
If your timing is jumping around with a timing light, but it is showing a steady reading with a datalog or ECM monitor, it is possible that the ECM is in low-res mode, and that the high res pulse is out of whack.
As an added variable, worn opti bearings can cause problems at one rpm that disappear at another. Fun to diagnose!
Let me know which method you are using and I can try and help...but it won't be until monday - going to visit mother in-law this weekend...no progress on '92 Z28 for me.
Pete Visser
Delteq
703-476-3566
"Is the Optical portion of the Opti-Spark capable of deviating significantly at high RPMs?" This may be due to any related issue, but specifically, my timing is moving around at upper RPMs and with Deltec and the programming static"
First off - there are two ways to determine that the timing is off (OK three ways if you have an oscilliscope!). they are:
1. Use a timing light and observe the timing marker (which you'd have to make yourself on an LT1). you have to trust the timing light too...dial back lights aren't trustworthy for highly-accurate measurements by the way, especially with waste spark.
2. Using an ECM scanner and seeing the timing values shifting around, even though the timing maps show that the timing should be constant.
3. Use an oscilliscope on the actual coil signals, and sync with the optical sensors. We use this method to determine that the system is working properly when developing kits for new vehicles.
Bottom line here is that methods 1 and 2 are showing completely different things.
That is:
If your timing is jumping around on a scanner datalog, it means that something is effecting timing, or the scanner is not functioning properly. Knock retard will effect timing for example, as will MAT and other stuff.
If your timing is jumping around with a timing light, but it is showing a steady reading with a datalog or ECM monitor, it is possible that the ECM is in low-res mode, and that the high res pulse is out of whack.
As an added variable, worn opti bearings can cause problems at one rpm that disappear at another. Fun to diagnose!
Let me know which method you are using and I can try and help...but it won't be until monday - going to visit mother in-law this weekend...no progress on '92 Z28 for me.
Pete Visser
Delteq
703-476-3566
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