G'day

Ozvtr wrote: ↑Sun Feb 12, 2023 10:52 am Well in that case I wouldn't expect much of a difference. But I'm still interested in if the fuel is atomized better.

That sounds like a job for someone with an injector test rig

Ha Ha!
On Saturday I helped my son do a bee "cut out". That's removal of bees from the walls of a house. All went well until it came time to put them into their new box. We vacuum the bees off the comb and into a box. Then transfer them into a "10 frame" brood box out side.
Well the bees were NOT happy. My son did the transfer and he was wearing a bee suit. I was about 20 feet away and not wearing a suit. The bees had been very calm during the removal but were NOT happy with being in the vacuum box!!
Well I got stung on the right eye brow, the left eye lid and the right nostril! Today (Sunday) both of my eyes were swollen shut! Well I had 2 slits to look through. I looked like I'd gone toe-to-toe with Mohamed Ali...and lost!
Suffice to say that I didn't get to the fuel injector tester today. LOL!

Well this post is turning out to be the adventures...of a twit! LOL!
I'm not sure that these injectors are in fact "dual fuel". I'm tending to think that they are just pink versions of the 1.6 TU5JP4 engine's injectors!!
At this point I can not find any "official" versions of a dual fueled TU3 engine. If I am proved wrong...well...I'm still wrong!
Well here is the write up I did before the penny dropped, for what it's worth. In retrospect, the reader might get a chuckle.


I have managed to get the injector tester up and running again and have tested the pink "dual fuel" injectors. (oz from the future says..LOL!)
As a control I also ran the stock injectors from the "black" C3.
I ran 2 of the dual fuel and 2 stock injectors just to see if there were any anomalies. The 2 pink injectors produced the same results as each other. The 2 stock injector also produced the same volume of fluid as each other.
HOWEVER. The 2 pairs did not produce the same volume as each other!!
While the stock injectors produced 20 milliliters of fluid the pink injectors produced 35mls!!
That's 1.75 times more fluid!! The the injector fluid pattern was more dispersed and would probably atomize into the air stream better.
Sorry I didn't get a good photo. But you can see that the pattern is not a single stream. The stock injectors produce a single stream of fluid. What does this mean? Well the engine ECU is going to have to reduce the injection pulse width...a lot! In fact the ECU can only increase or decrease the pulse width by a certain amount. I think the ECU may not be able to control the flow coming from the injectors!! I think the engine ECU would only be capable of reducing the volume by about 20%. Even reducing the volume by 20% still results in about 1.5 times more fuel! The ECU would need to reduce the flow by a little under 50%.
Bugger!
I am reticent to try these in the engine as a very rich mixture would damage the catalytic converter!!

Well I don't know if the above is worth anything to anyone, but as I said it may be worth a chuckle to some one.

Hmm. The reader might wonder why I am going through all this pain when the engine is effectively running fine?

Well 2 reasons really. 1) the "other" C3 I had, I'm sure, ran better than this. I.E. more "poke". Mine is "boggy".
2) according to the specs, my old 1.5 litre carbureted Ford is supposed to have virtually the same horsepower as my 1.4 fuel injected Citroen. But I can tell you that my old 1984 ford has more poke!! Not a massive amount, but when you need just a little more power the Ford has it but the C3 doesn't!
Now the C3 gets a little over 6 litres per 100Km but the Ford gets 10L/100Km. Yes, that's not good on the Fords part.
So My question is: am I sacrificing horsepower for fuel economy? Or should I get better power for the same economy? How can I squeeze a bit more power out of the 'ol girl.
OK, OK, I'm not expecting sub 8 second 1/4 mile times, but as I said, I'm sure the "other" C3 had a bit more power.

Exhibit 'A'. Without the engine under load I.E. just revving the engine, at around 1500-2000RPM I get a short term (live) fuel trim of -20%.
This means the Oxy sensor is saying that the fuel/air mixture is too rich, so the engine ECU reduces the amount of fuel by 20% of the "ideal" amount.

Generally there are 2 fuel trims. Long term and short term. What's displayed above in the "rapid fuel correction (1)" is the short term fuel trim. This is the instantaneous deviation, in fuel, from the perfect calculated amount that the engine should be consuming at that point in time.
What does this mean? Well...I don't know.
Could it mean that the the engine is not under load (just revving) and so I needs 20% less fuel than if it was actually propelling the car along?
Is there 1 or more injectors providing too much fuel per injection cycle?
By the way at idle the fuel trim looks OK. I'll explain why the short term fuel trims are hard to read, especially at idle in a moment.

The "slow fuel correction (1)" should show an averaged accumulation of the fuel deviation over time. But as you can see the engine ECU is not providing that information. Drat!
Unfortunately the short term fuel trim can jump all over the place as the engine demands more or less fuel. And so it can be hard to gauge what is going on. That's the whole point of the long term fuel trim, a better over-all picture.

If you go back to the "Chinese Vs genuine" injector test, the Chinese injectors were only about 1ml per minute more than the genuine. So that's only about 8% difference (at worst).

Hmm where to go from here?