Erratic RPM reading and intercepting

plaghi
Posts: 3
Joined: Sun Apr 15, 2012 8:14 pm

Erratic RPM reading and intercepting

Postby plaghi » Sat May 05, 2012 10:54 pm

Hope somebody can help on this issue.
I have a platinum interceptor I want to use to change the ignition phase only.
I'm trying to sort out what to do before I go to the engine.
I spliced 12V to battery +
Ground and signal ground to battery -
I'm feeding a square signal through Digin1
I'm measuring what comes out from DIGOUT REL+
The scope is grounded to battery -
For safe measure I also fed +5V to the throttle input, so that the engine load is stable at 100%.
I go online and I set the intercepting rpm high, so that I'm sure ECU not intercepting. I get a clean signal +-5V as an output (it follows the input signal by 100 microseconds), but no rpm reading or erratic rpm reading in the SW dial. No matter what sensor, threshold voltage or trigger voltage map I use.
Sometimes I get a rpm reading in the SW that follows the variations of the input signal, but when I go to intecept it, then whatever values I set in the trigger angle, I get no change.
Sometimes I get a rpm reading in the SW and I can also intercept the signal and it moves forward according to the setting (retards) but when I try to move it backword (anticipate) it suddently changes to an erratic 0-10V signal.
Once, just once, using Subaru 6 teeth sensor as sensor setting, threshold voltage 3, voltage map all 2, triggers per cicle 2 I could get the signal move both directions but I figured that it moved 3 times the trigger angle I input. Since then I've NEVER been able to replicate this situation again (see pic).
I also tried to change the input signal to +-5V, or sine wave form with no differnt results.
In reality I have to use a Denso sensor marked with the numbers 029600-0710 and I was planning to mount it on a rig to check voltage at different rpm, but before I spend more time and money I wanted to be a little more confident on a positive outcome.
Well, I'M CONFUSED AND FRUSTRATED. :cry:
Anybody can help me out PLEASE!
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plaghi
Posts: 3
Joined: Sun Apr 15, 2012 8:14 pm

Re: Erratic RPM reading and intercepting

Postby plaghi » Thu May 10, 2012 4:49 pm

Anyone? :roll:

plaghi
Posts: 3
Joined: Sun Apr 15, 2012 8:14 pm

Re: Erratic RPM reading and intercepting

Postby plaghi » Thu Jun 14, 2012 6:00 am

I made a rig with the sensor and the shaft. I uploaded the Toyota Sport map and since then rpm are read beautyfully (just had to change from 4 to 2 teeth). Then, the input signal is ok and the output (rel +) signal follows the ignition map. Now the only problem is that the ouput signal sometimes (and apparently when the ignition map is set to + values more than when it is set to - values) I get more then one peak (usually 3 one afer the other); hence I get more then one spark when I connect the original CPU.
The strange thing is that it happens regardless the original CPU is connected or not.
On the other hand if I set the intercepting rpm so high that the interceptor is not intercepting, the output (rel+) signal is regular.
Anyone has a clue?

harry_peter
Posts: 2
Joined: Sat Aug 04, 2012 2:39 am

Re: Erratic RPM reading and intercepting

Postby harry_peter » Sun Aug 12, 2012 12:55 am

plaghi wrote:I made a rig with the sensor and the shaft. I uploaded the Toyota Sport map and since then rpm are read beautyfully (just had to change from 4 to 2 teeth). Then, the input signal is ok and the output (rel +) signal follows the ignition map. Now the only problem is that the ouput signal sometimes (and apparently when the ignition map is set to + values more than when it is set to - values) I get more then one peak (usually 3 one afer the other); hence I get more then one spark when I connect the original CPU.
The strange thing is that it happens regardless the original CPU is connected or not.
On the other hand if I set the intercepting rpm so high that the interceptor is not intercepting, the output (rel+) signal is regular.
Anyone has a clue?
This is what i did too when i had this problem.. I noticed while driving on the highway that my RPM needle drops with 50-100 rpm. Good thing i got great toyota part from car-stuff..


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