7M-GTE stock 440cc injector latency (dead/lag time)?

[assassin10000]

Anyone know what the 7M-GTE stock 440cc injector latency (dead/lag time) is? Perhaps peak & hold amps as well?

I've been searching but haven't found anything. Need it to setup a standalone.

Thanks,
Andrew

[auto351]

Andrew,

This is not so easy to answer as the times & Peak currents would change due the changes of supply voltage, this data would most likely be in the form of a graph and not a simple table.

I know the toyota ECU advances the injector pulse with lower battery voltages.

what standalone are you setting up ?

[assassin10000]

ViPEC V44

I'm aware of that, it'd be a (relatively) simple 2d table of the varying opening times with each voltage that could be listed fairly easily ( 8v 1.7, 9v 1.5, 10v 1.2, etc). The amps I only need something simple like 2.0 peak .5 hold.

Andrew

[nick.parker]

4A peak / 1A hold should be fine for a low impedance denso injector, so long as time spent at peak current is less than say 2-3 milliseconds.
--------------------------
A crude way to figure out opening and closing times.
--------------------------
Stick (even with sellotape!) a knock sensor (or anything piezo electric) to your injectors and drive them from the ECU (no fuel involved!!) and crank the engine, or get the ECU to pulse the injectors somehow.
View both the injector drive voltage and the piezo (knock) output on an oscilloscope, you will then be able to see the 'vibration' when the injector opens and the pintle hits the end stop, then following the drive voltage disappearing, you will see some time later, a vibration as the pintle closes.

General observations ::

Opening time is affected be battery voltage. You might expect to see 1200usec opening time at 14v.

Closing time is affected slightly by fuel pressure, nothing to do with battery voltage (because the injector driver is current mode) and say 800-ish usec closing might be expected.

These times are just examples.

Hope this is helpful info.

Cheers, Nick

[auto351]

You wont find the peak/hold currents listed because these injector operate in satuation mode in toyota ECUs.

You have to mesure the times & currents and posted the data,
I was thinking 3D table would be needed to factor fuel presure?.

Would also be interseted to know the normal injector current for toyota ECU?

Manuel

[assassin10000]

Unfortunately I don't have an oscilloscope, or access to one. If I did I'd be a lot further along than I am now .

As the motor these are going in is N/A I don't need to worry about rising fuel pressure (usually under boost) as a factor and can get away with a simple 2d table.

Andrew

[auto351]

Im interested & have access to an oscilloscope, if anyone has a 440cc 7M injector which I could use for testing, I can pickup if local, (sdyney south)

Manuel

[oldeskewltoy]

Im interested & have access to an oscilloscope, if anyone has a 440cc 7M injector which I could use for testing, I can pickup if local, (sdyney south)

Manuel

THIS is why I love this forum

People will go out of their way to help... even if you are 9000 miles away.......

[TERRA Operative]

If you could do a MAP 4AGZE injector too, you would be my hero.

[Supra967]

You can probably take one of mine for testing manny. what's the chances of damage?

[assassin10000]

Chances should be little to none.

Andrew

[nick.parker]

I was thinking 3D table would be needed to factor fuel presure?.

Nope, well at least not usually. This isn't required because the fuel pressure regulator's job is to keep the feel pressure vs manifold pressure differential at a constant value eg 2.5bar in 4AGZE for example. So flow rate can be considered constant.

[auto351]

Matt,

The ECU you are installing can it run the injectors in this peak/hold mode?

With the testing, I would not drive the injector over the standard ECU currents so they would not get damaged.

As for the testing this is what I have in mind.
Pick 3 voltage points for testing (12V, 10V, 8V) apply a short pulse to the injector (using the factory resistor pack) the current and time can be measured by the voltage drop across the factory resistor, there will be a change in current flow when the injector pintle stops moving
From these readings we will be able to calculate times for higher voltages and currents.

The only errors I can see will arise from no pressure in the injector giving a faster result & fuel will start flowing before the injector is fully open giving a slower result.

PM you Matt

[nick.parker]

there will be a change in current flow when the injector pintle stops moving

The inductance is changing WHILE the pintle is moving, its constant (and different) when it has stopped moving. With a particular injector I found that through the change of inductance (and hence current) reading it was hard to figure out when the pintle had stopped moving. So I chose to use physical feedback (ie vibration sensor) YMMV.

[assassin10000]

I'd recommended 4 (or more if you feel like it) voltages, considering alternators typically run 12.6 - 14.2v.

14v 12v 10v 8v

Andrew