1UZ + 440cc Injectors

[dansblackcat]

Hi All,

Does anyone know if 440cc injectors are too big to use on a stock 1UZ engine?
I originally fitted them because I was going to turbo charge the engine but decided not to for now.
The car runs fine but uses a lot of fuel and smells of petrol.
I've tried changing the duty cycle / injector trim of the ECU but the car runs horribly when I do so.

[George]

No you need stock ones. Injector performance is nonlinear at low duration times so having just trimmed overall duration to say 80% you still have inconsistent fuel maps.

[dansblackcat]

Oh ok thanks George.
Does what your saying still apply to aftermarket ECU's? I forgot to mention I'm not running a stock ECU.
I've had it tuned several times with the 440's in it. I would have thought that the tuner would have told me if they were too big.

[RA35GT]

PM Sciflyer. He ran 440cc injectors in his car for a while, N/A. With adaptronic ecu. Ran fine.

May need to be tuned properly by the sounds? Or maybe some other issue?

(PS: I'm not doubting the fact you may have worse small duty cycle fueling issues if the computer doesn't have the requried resolution for the big injectors, but they seemed to work fine on Sciflyers car)

[George]

With aftermarket ECU the only issues that can arise - excessively big injectors and low qualified tuner.
When switching to bigger injectors (assuming they are adequate for your engine though and no other changes made) you have to completely remap fuel.

[trdee]

why has nobody asked this yet... what ecu are you using?

[dansblackcat]

Ahh sorry, yeah I really should have mentioned that.

I have a Wolf3D V4. I stopped driving the car ages a go and pretty much gave up on it.
I had it on the dyno about 4 times at three different places. Each time I got it back it ran really well but only for around 2-3 weeks.
The last time I had it tuned it ran the best it ever had for about a month and then started running like crap. I gave up on it for ages but when I got stuck into it again I discovered that one of the ignition coils was tracking through the housing.
I still have what I think are the original maps from the tuners but all of them cause the car to run rich. I never remember it using this much fuel and it certainly didn't smell as much as it does now.

I cannot for the life of me think what else could be causing my issues.

[stradlater]

Sounds like some fuel quality of fuel pressure degredation or something?

I know when I tune mine it's great, and then I'll come back to it a few weeks later and it's crap (Or one of the wires lets it's smoke out - like happened today).

Often it's temperature, voltage, or any number of other things that can effect it.

A thought - has the tuner(s) looked at the injector dead time table? Could have something to do with that? Who knows.

Sounds like it's richening up, which is a good thing (as opposed to leaning out!!!)

[trdee]

spark plugs fouling up?
fuel pressure reg dodgy?
sensor wiring dodgy?
corrections tables in the ecu not confogured properly?

too many variables. you need to methodically go through your setup and eliminate possible causes. The fact that the tune is ok for a while and then "becomes crap" to me seems like a wiring/sensor issue. Tunes dont disappear into the ether over time (unless your ecu is corrupting the data saved on it somehow) so I would be looking at the signals that are being fed to the ecu.....

[stradlater]

Just the same way I need to go and methodically figure out which wire was letting it's smoke out....

[trdee]

yeah magic smoke escaping is generally not ideal

[dansblackcat]

spark plugs fouling up?
fuel pressure reg dodgy?
sensor wiring dodgy?
corrections tables in the ecu not confogured properly?

too many variables. you need to methodically go through your setup and eliminate possible causes. The fact that the tune is ok for a while and then "becomes crap" to me seems like a wiring/sensor issue. Tunes dont disappear into the ether over time (unless your ecu is corrupting the data saved on it somehow) so I would be looking at the signals that are being fed to the ecu.....

Yes spark plugs are fouling up. Covered in black soot, but I would expect to see this as I know its running rich.
Fuel pressure reg is new and fuel pressure is spot on according to the pressure gauge.
From what I can tell the sensor wiring is fine. Crank and cam sensors give no errors and engine temp seems to be where it should be and matches the gauge on the dash.
Correction tables are something I will take a look at over the weekend.

I ran a data logging program yesterday on the drive to and from work. I noticed the TPS signal has a few flat spots where it drops to zero volts. It's right in the sweet spot where the pedal would be when cruising. I checked the
TPS signal with a multimeter and it seemed fine but it is hard to keep it steady while moving it.
I'm sure a faulty TPS certainly isn't helping me?

[trdee]

depends on your tuning parameters. i have mine set to MAP only so a faulty TPS wont make the tune crap itself, just affects idle and WOT enrichment. if you have it tuned in TPS vs MAP or something then it might have an effect though... dunno

[dansblackcat]

Mine is set to use the internal MAP for load and the TPS is set for transient.

I really wish I had just stuck with the stock ECU. If it wasn't so hard to find and ECU and a complete harness I'd convert it back.

I might just buy another complete engine package...eventually.

[dumbass]

get a decent ecu and an even better tuner
90% of tuners are fkt or rough

another thing is if your battery has been off or flat for over
a year some cheap ecus loose their memory

I always tell people buy good ecu and get good tune
might cost more at start but in afew years u have made your
money back due to fk ups