Michael Smith

I am having trouble with my TII. It has been rebuilt and has been ported, New Wolf Version 4 , DFI with Bosch HEC716 coils and ignitors, 550/1000 cc injectors Hi flow S4 with TO4 comp. What happens is when it gets to about 4psi it loses power then coughs and misses. The mixture on the narrow band indicates a rich mixture 0.91Volts. I have new plugs and the leads are ok. I suspect a a poor power supply voltage or crook earth. Anyone had this problem afte changing to DFI???

Regards
Michael Smith

Mx6-Rx7 Addict

Is this the initial tune for your new setup? Maybe you should invest in a wide band system, or find someone with one. I haven't had to tune mine yet (still waiting on EMS to arrive), so i wouldn't be able to elaborate on AF ratios and such, simply because i haven't researched into it yet. How many miles on the new setup?


Who is tuning the car?

-Justin

iceblue

Pull the plugs out. What are there burning carectoristics? Realy check your timing and that all of your ignition items are working properly and each time. Put a multi meter on teh CAS as well.

Your narrow band is absolutly useless through it out the window. It can not give you a reading on these cars at all.

Allso are you not having a hesitation du to cold solder joints on the CPU?

myexlex

at what psi do you set your secondaries to come on ? or is it a staged setup ? if so what percent??

Michael Smith

I always tune my own cars and manage to get them very close. The dyno session usually takes less than a hour when I get it there. I have been playing with rotaries for 25 years. I usually get it vary close with a narrow band O2 and have tuned Wolf's before. The staging is setup correctly and done smoothly. I have never had problems using the Mazda coil setup. However I suspect this is not a fuel pressure or mixture problem. My CPU doesn't have anthing to do with my EFI or ignition and I doesn't have HR's and preforms perfectly. Does anyone know of a FAQ for fitting DFI's or fault finding the DFI. I suspect the factory wiring can't handle the additional current causing weak spark.

Michael Smith

SureShot

The only way I know to diagnose a weak spark is with an O-scope.

It's old school, but maybe someone here has a new school trick..

kontakt

Yeah, it's rare but every now and then i'm glad i have (though 20 years old) a ridiculously expensive o-scope.

RETed

That's wrong already.
Please don't rely on a narrow-band O2 for tuning like that.


-Ted

iceblue

Then you should know that a rotary runs outside of the range of a narrow making it useless.

Michael Smith

Have you ever looked at the data sheet for a bosch narrow band? I you did then you would know that it reads lower than 10.5...now I know this is not in the linier part of the graph but it does measure from 10.5 to 23 to 1 not only that, the accuracy is more stable in the Non linier part of the curve. Now if I wanted to fine tune this engine myself I would use a wide band. What I always do is make it richer and run it in, then take it for a dyno session where they have $500,000 dollars worth of tuning equipment and let them finish it off. Wide bands here are worth $290 and I can buy a narrow band for $80 and during normal driving a narrow band is all I require. I now have $210 bucks in my pocket for my DFI!!
Michael Smith
P.S. I think I have found my problem the DFI coil pack requires 28 Amps and there is too much voltage drop in the wiring I am using.

RETed

Is that equivalent US$ or AUS$?
I can get narrow band O2 sensors (Bosch, if it matters) for US$30 all day long.
If you want, I'll SEND some to you if it's that overpriced over there.

I don't care what Bosch tells you...a zirconium element based EGO is only designed to be linear around 14.7:1 AFR's + or - 0.5:1 AFR's.
It's made for OEM applications that have nothing to do with fuel delivery tuning; it's made for closed-loop fuel control.

Your O2 sensors does not know the difference between 10:1 versus 9:1 versus 8:1 (you get the picture).
You can be dumping tons of fuel in there, and not have a clue it's doing so.
At the same time, the 02 sensor does not know the difference between 16:1 versus 20:1 AFR's - 16:1 is "ok" in certain situations, but 20:1 will not allow the engine to run at all.

At the very least get an EGT gauge...
I don't like wide-bands myself - only people who can't use an EGT use wide-bands cause it's easier to adjust for.
Please don't tell me an EGT gauge is too expensive for you?


-Ted