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Supplied deadtimes look wrong (FiveO)

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Hi All, I've recently bought some Denso/FiveO 550cc injectors for a 2zz-ge application. I was supplied a data sheet, but the deadtimes look wrong. Injectors have been tested and are definitely the 14.5ohm high impedence ones expected.

I've queried with FiveO and I got a response saying that they "look right" but a number of tuners I've spoken with disagree, and my car won't run when configuring the ECU (EMU Black) with the new settings.

It runs "ok" on my old settings from the incumbent DW440s, but I'd really like to set these right if possible. Is there something I'm missing with this data? A modifier or multiplier for example that I should be factoring in?

You realize those values are milliseconds, right? So if your ECU uses microseconds you would need to multiply by 1000 (so 646, 545, 445 uS). Tell us what ECU you are using, and what does your configuration for injector deadtimes look like?

What do you think "looks wrong"? Are you expecting larger values? Have you used a similar Denso injector with different values? The data sheet doesn't state what the differential fuel pressure is, but I would guess 3 bar? What fuel pressure are you running?

Hi David, thanks for the reply.

I use an EMU Black which uses milliseconds. The ECU has a bunch of preloaded injectors and not a single one have ms values this low. A fairly average value for 14v is around 0.6-0.8 it seems. The car simply won't run when providing the FiveO values, but it runs 'ok' if I just use the settings from pretty much any other preloaded injector in the software.

Car has a 3.2ish bar base pressure. The Injectors are sold as plug and play for my engine with stock pressure, which is I guess why it's not explicitly listed on the data sheet.

The fact it says offset rather than dead time would suggest it is additive to the value for theinjector its based on or factory injector? Have you tried adding those values to standard latency?

That is a very good suggestion, thanks for that.

Now all I need to do is find out what the reference is! The 2ZZ-GE came with a number of injector options, and I'm not sure how different the deadtimes are likely to be, but I can do some digging.

I've got a set of Fuel Injector Clinic injectors. Before I purchased I noticed that they have multiple datasheets with different deadtime values for the same injectors.

I asked them about this, and they said it's because the deadtimes are specific to the injector/ecu combination. They say some ecu's handle injectors differently. And they were able to provide me with a specific datasheet for my injectors with my ecu.

So if the values they provide look wrong, then maybe those values are tuned for a different ecu.

Just to hopefully close this out, the vendor got the following from their manufacturer which looks a lot more realistic. Will hopefully test these out next week.

Offset is just an interchangeable name for dead time. Hook up a scope and look for the indicators of a completely open injector and a completely closed injector and measure the time at different voltages with a power supply.

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