First time poster.
I have 87 NA SCCA EP with Wolf 3DV3. Been on car 4 years. Car starts and runs fine until high revs ... sometimes. Does't depend on ambient/engine temp or run time. Worsening slowly over the years.

Above 7- 8K RPM, up to 9+K = hi signal error count and max RPM logged on dash display. There is a hard cut in ign and FI when error(s) occurs as per WOLF firmware. Rev limit RPM set to 15+K.
Mazda FC4S CAS with ground off teeth. Reluctor space varied from .003" up to .020". CAS connector(s) good. Tried new machined CAS with "perfect" teeth. Shaft(s) runout at hi/lo RPM minimal. Tried several reluctors, always good resistance. Even tried resetting mag field. Even reversed mag field.
Occurs with and without 22 nF cap, changed to new caps several times. Wolf wires / connectors good, and run isolated from other wires and chaffing points. All wires/connectors continuous and soldered at junctions.
CAS trigger shielded wire routed away from alt/plug/ign/FI wires. Stock alt and igniters/coils - no CD.
Several grounds, engine block and intake, engine bay chassis, starter, also ECU box grounded. Batt has big grounds to starter/chassis.

Also tried inverting CAS trigger output - won't run. Tried CAS trigger ECU signal sensitivity switch to hi input type - won't run. O-scope CAS output at low to mid RPM is clean. Engine cut-offs are also seen on dyno pulls.
Tried Wolf's "reluctor interface" add-on for improved reluctor sensor signal and filtering" - won't run on this.

Don't know whether this is a wiring / sensor / ECU problem. Will the Mazda FC4S reluctor work for these hi revs? Or could there be too much signal at hi RPM into ECU or is the Wolf ECU poor? Wolf says the newer V4 and V500's have a better input filter circuit. Suggestions! Help!

 

Hi a Guy, have you looked at the CAS signal at high revs on the Scope?? My bet is that it will be clean, more likely you may have internal filtering problems in the Wolf itself. The ONLY real way is to look at the signal going to the ECU. I have only taken my turbo motors too 8000 rpm. If the signal is dirty you could try a MSD pulse shaper.

Cheers
Michael Smith
P.S. the output from the shaper is 0-5 Volts you need to change the input on the Wolf to suit.

 

Hi Michael,

Thanks for the reply. I see your inputs to this forum quite often.

I plan to scope the car this week at hi RPM, have to plan the time right due to the neighbors.

As I said in my initial post, I have tried Wolf's "reluctor interface" add-on box, which is supposed to improve the signal. The Wolf web site says this box has a square wave output. But my car won't start or run in any configuration with this box.

You mention a MSD pulse shapper ... where can I find info on this?

Thanks,
Guy

 

Hey Guy, Both the pulse shapers work the same way (Wolf and MSD). They require both battery and earth additionally as well as the signal leads from the reluctors but you need to change the input on the Wolf (dip switches) to Hall I think. This is because the output swings between 0 and 5 volts. The output is a pure square wave. If the Wolf is not changed it will not start because it is looking for a little pulses.

Cheers
Michael Smith

 

Michael,

Damn you're good. I have previously switched the dip switch inside the WOLF ECU for the different type trigger's signal ...
... but ...
... you got me thinking ... I think the WOLF "reluctor interface" box produces a positive going square wave triggered off the CAS reluctor's negative going pulse at zero crossing. Thus the pulse timing would be wrong that way. The way to correct that is to switch ths CAS reluctor's wires into the WOLF "reluctor interface" box. I see referenses to this in data from GM HEI ignition modules and MegaSquirt info (http://www.megasquirt.info/).

I'll try scoping the CAS for noise/signal at hi RPM and then hook up the WOLF "reluctor interface" with CAS wires switched and see what happens.

Thanks,
Guy.