RICESP Water Injected RX7

[RICE RACING]

Originally Posted by Richard L

You are right, the FJO didn't seem to switch to peak and hold at around ~4 A. I am not sure of the peak can only be triggered above two mS, even the current is allowed to creep pass the 4A threshold.

However, it shouldn't any affect on your idle and light cruise unless the injectors are over heating. If this is the case, it might create local vapuor lock. When you open your throttle, the higher fuel flow may take away the heat from the injector winding.

The funny thing about all this is that it gets better when the engine gets hotter and the intake manifold and fuel rail heats up (all AFR's and timing staying constant). It is perplexing to me as I dont understand why it is doing what it is. This morning I set the injector lag time to 0.750 milliseconds and it is much better (re trimmed the fuel mapping so that was constant) than the 0.550 millisecond value.

Do you think I should eliminate the FJO and go to good old resistors and see who things function? I just cant figure out why the engine wants to stop if I have spark and fuel and the injector opening timings are fully visible on the scope :? I always seem to come up with these odd ball problems.

Here is what FJO had to say about the capture I gave them.

Peter,

The reason the injector current rises in a slope is because it is an inductor. Current through an inductor does not turn on/off instantly, that is the electrical properties of an inductor. This will also vary depending on the inductance and resistance of the injector as well as the supply voltage. The box is connected to the ground side of the injector and controls the current at that end so the voltage is irrelevant. However, you will see some voltage at the ground because there is always some ground resistance. With 4A and 1.4v you have a ground resistance of 0.35 ohms. This includes the ground resistance where the driver is grounded. The current measurement depends on how you are measuring it. The only accurate method is by using a fast response inductive pickup on the ground-side of a single injector. What is the injector pulse width during these random lean spikes?

Technical Support
________________________________
FJO Racing Products
Winnipeg, Manitoba, Canada
mailto:techsupport@fjoracing.com
http://www.fjoracing.com
ph: 204-254-5623 ext 3
fax:204-257-3190
________________________________________

[Richard L]

First of all, mimimise the ground resistance and inductance by using a thicker or shorter gauge wire. Remeasure the wave again by putting the pico probes between the FJO's wire ends.

I still don't understand why the peak and hold is not triggered. Can you ask FJO at what conditions does the "peak and hold" trigger.

What is the coil resistance of your fuel injectors and are they paralleled up electrically?

[RICE RACING]

I have had a gut full of the FJO crap, started installing the resistors tonight and will not do anything else except eliminate the FJO and remeasure the injector pattern. < I am sure this thing is faulty! it is not performing as stated full stop and all they can come up with is an excuse with my measurement equipment :roll: *like obviously why is it pulling over 5amps! if its a 4A peak unit then holds at 1amp?*

Touch wood I will get it done tomorrow and hope this resolves my issues. I will post up the injector trace running the ECU manufacturers suggested resistor size (supplied by dealer I got ECU from).

[Richard L]

Can you measure the coil resistance of your injector for me, I can help selecting a suitable inline resistor for you.

When you remeasure, can you blip the throttle so that the trace goes beyond 2mS. If it still does't trigger, then we can say it is faulty unit. Be sure the probes are clipped to the wire end of FJO unit, there is no deny what you are seeing and recording.

[RICE RACING]

Originally Posted by Richard L

Can you measure the coil resistance of your injector for me, I can help selecting a suitable inline resistor for you.

When you remeasure, can you blip the throttle so that the trace goes beyond 2mS. If it still does't trigger, then we can say it is faulty unit. Be sure the probes are clipped to the wire end of FJO unit, there is no deny what you are seeing and recording.

3 Ohm Primaries and 4.5 Ohm secondaries, LINK have already calculated and supplied me 4.7 Ohm 25 watt resistors (they are anodized gold alloy mini heat sink type). On the further trace's ......When I rev'd the car and also when the car near stalled and the pulse width went well past 2m/s (closer to 3m/s range the patterns did not change from what I pictured) .

Wish me luck tomorrow, my patience is running out after doing such a marathon job building this car :sad: On a positive note the WI is working well and I have used about 2 liters so far and by accident ran 20 psi boost ops: due to a wrong setting on the boost controller :roll: but the 10.4:1 AFR and WI means she took it in her stride. I guess I should be thankful that my ECU drivers still work and my engine is in one piece since it looks like the FJO is faulty, will know if the problems magically disappear.when I test I take the injector plug off and use a pico 2pin bosch plug female/male and do the current clamp to it and voltage supply to the other, so its what is coming from the FJO output

[Richard L]

If you run one injector per FJO P&H channel, the coil resistance of your fuel injector is on the border line of 4A.

3 ohm draws:
4A at 12V, 4.6A at 13.8V

4.5ohm draws:
2.67A at 12V, 3.06A at 13.8V

This could be the reason why the P&H is not triggering consistantly fo the 3 ohm injector, if the voltage is fluctuation between 12V to 13.8V. Depending on how you measured the current will give you false readings.

The only way to read current accurately is by breaking one of the wires to the fuel injector and put the two probes to each of the cut wire. Ensure the PICO is not grounded or connected elsewhere.

[RICE RACING]

Here is "finished" engien bay pics I am glad this is over :smile:

[Richard L]

Process of elmination, one step at a time is the best way forward.

You car is walking exhibition, it is so nice with all thise fabrication - I just wish people will appreciate just how much work is involved to arrive at this stage.

As power tuning, allow the engine to do a few more easy miles, lety everything settle down. Water injection and CDi is a good combination. Please don't go too fast for big power.

I will resize the picture for you if you don't mind, it is slightly bigger than most monitor can display.

[RICE RACING]

It's been a long time since I updated.

Decided to change the fuel injectors & eliminate all of the resistors and other devices, also re-engineered some fundamental settings and specifications of the fuel delivery, should have it tested any day now and will let you know how I go.

[RICE RACING]

Well I have had good results on the new fuel injectors (no resistors or P&H boxes anymore), car idles well and drives perfectly, I wanted to test the Stock Mazda ignition coils, lead set up and HKS amplifier (DLI) box and found it is far lower in capacity to the custom coil on plug full CDI system I originally made. It can only take less than half the water amount and the AFR needs to be set around 11.10:1 for it to reliably fire the mixture.

I am refitting the full CDI coil on plug system and will run the water injection system back up to its higher capacity after finding the limitation of the upgraded stock system.

With testing so far on 10psi inlet boost pressure on low water flow I have air inlet temperatures that are consistently 5 to 10 degrees above ambient temperature water temperature in all conditions is between 77 and 79 deg C (regardless of ambient temperature *tested to 36 deg C*).