16V 4AGE + ITB on E420d > Injector upgrade

[GeeEss]

Hi . . .


I'm currently running 3SGE Gen 4 "Pink" Denso Injectors on my 4AGE. Specs are 315 cc / 13.8 Ohm / 6 hole . . .


Car idles well enough (but fuelly) & quite smooth on highway at 3500 rpm+ but low speed running is not that refined.


ECU logs show maximum injector duty is only 52% at maximum Power / Torque < IIRC @ ~ 6000 rpm in 3rd. >


I think I'd like to try smaller capacity & more modern (12 hole) injectors to get closer to 80% Duty at max power + see whether slow speed running is improved.


Question:


Will OEM/ Denso 1MZ-FE, 3MZ-FE High Impedance 250cc injectors fit / work on a 4AGE with E420d ECU ?


Both are Top Feed, High Impedance so OK for ECU; look pretty much the same physically. . . . .


Only thing I'm not sure about is the issue of air assisted + shrouded V non air assisted / non shrouded design.


AFAIK the 1MZ, 3MZ injectors are non air assisted / non shrouded > I'm not sure what the 3SGE units are. . . .


Can anyone enlighten me?

[LittleRedSpirit]

Make sure the dwell time vs voltage table is filled in. Otherwise you can have odd injector timing and will run like a bag of dicks down low.

My idle stabilised and dropped when I got the settings right.

[GeeEss]

The car idles fine; I have an ISCV with effort corrections for the various electrical loads ; i.e. headlights, blower fan, radiator fan etc. The issue is that even though the AFR's are OK it just smells bloody rich.

There are only 2 reason's this could be happening, over-fuelling or incorrect injector timing; and I've played around with the Fuel Map to know its not the former.

That leaves dead time; 10-to-1 the injectors are firing too soon at idle meaning the fuel is being squirted right through an open exhaust valve so yes; I am quite aware of the need for correct dead-time settings but that's easier said than done when they're not available. Just try finding ANY dwell tables for Denso's. . . .

Sure you can find them from aftermarket manufacturers like ID or EC Eng. but even if I did need (or want) to spend $500+ on a set of injectors the smallest ID makes is 725cc which is total overkill for a 4AGZE let alone an N/A 4AGE. ( Called ID myself & they confirmed this.)

I'm running an Adaptronic E420d and I can tell you the Dead Time Wizard on WARI V14 just plain doesn't work . . Increasing Dead Time has no effect on AFR's (even though they leaned out from 13.8 to 18+ when I toggled to "double" mode). Even then you have to apply at least 10% Fuel Trim o/wise the engine just stalls as soon as the s/ware toggles to "double" mode.

* The Dealer who supplied the harness+ECU+Injectors stated on the Invoice they were OEM Gen4 3SGE units with flow of 315cc/min but ECU drive Logs show Injector Duty Cycle = only 52% at 6000 rpm in 3rd; so its very likely he mistakenly supplied (near identical) OEM AE92 4AGZE units with flow of 365cc/min. . . . .

No damn wonder I've got a rich idle; even if the Dead Time settings were correct my car would run rough at low rpm. The fact they're out just compounds the situation. Its amazing it runs as well as it does.

In any case I've bitten the bullet & ordered some more appropriately sized 255/cc 12-hole 1MZFE units. I have found some information on how to calculate dead times empirically so I will try those methods to see if I can arrive at the correct figures & see how that affects my "fuelly" idle issue.

Depending on the above results I may also retard the injection timing at idle via the WARI software "Tuning Modes" tab to see if that makes any difference.

Aside from that it will be interesting to see what effect more modern 12-hole injectors have on low rpm running.

[LittleRedSpirit]

My 2az has 12 hole injectors with the super fine mist and it idles pretty low and smooth now i worked out how to adjust itbs. In the table I posted above all the denso injectors regardless of cc have similar values for their dead times, you could make a close approximation to test the theory.

[GeeEss]

Thanks;

The 1/3MZ-FE injectors should arrive tomorrow so looking forward to seeing if they make a difference. . .

[LittleRedSpirit]

You try the new injectors or the guess of the values?