Error INJ Combined Open

[xgrapher]

Is there any documentation that elaborates the Injector error section? I haven't found any online.

I need something that tells me what are the different types of injector errors that Motec picks up and what are the potential causes. For example I want to know if Motec can pick up if an injector is not able to flow adequately due to debris in the injector? I don't think that is possible because the only way Motec could determine malfunctioning is by monitoring the voltage. And since debris would not cause the coil to work any harder it should not be able to detect any abnormalities. However, If an injector is sticky due to old fuel gluing up inside that would cause the coils to work harder thereby demanding more current which could be picked up by Motec. These are all my assumptions but it would have been so nice to find out more from Motec about this in some kind of technical documentation. Each and every topic should be detailed in some document. Please point me to it if it exists already.

I'm really struggling with this injector combined open error happening randomly on different injectors totally random on my 2JZ supra. They are high 1000cc ID1000 and the injector current is set to 0. A pro tuner suggested that I try -0.1 and that made it even worse.

Tune file attached

[AdamW]

The injector errors are described on page 41 of the user manual and in ecu manager help file under "errors". They are based purely on the electrical characteristics or response and will not give you any indication of a problem with the fuel flow.
If you are getting an injector open error that means the ecu is seeing an open circuit. Most likely a bad connection, if you see the errors on different injectors then that would indicate the problem is on the 12v supply side.

[xgrapher]

Thanks. First thing that we did was pull a wire straight from the battery 12V and supplied it to all the injectors. Then we changed the fuel pumps although they were new and didn't have any pressure drops. We also got the injectors cleaned even though they were brand new thinking that the shop guys must have installed them with grease causing gunk to build up. Next I'm being told to change the injectors but I really don't want to do that.

I think remove the ground pins from the A connector (pin A10 and A11) and install new pins and wire them under the intake just to make sure. Since this was a loom that I didn't make. This is because I'm assuming that Motec relays ground to the injectors from these wires.

Did you check my tune file? Does everything look ok there? Does battery comp play any role in this aspect?

[Stephen Dean]

Hi,

The only way to tell on the engine easily if an injector is not flowing the same as the other injectors in the engine is by having Lambda sensors in the individual exhaust manifolds and comparing the values under load (at idle with low mass flows the readings will vary more than under load). You can also try varying the individual cylinder trims and seeing if the engine goes richer or leaner, depending on how you move the trim.

As AdamW said, a lot of injector errors like this are related to either power supply or ground issues, check to make sure that the power supply is consistent and that your grounds are good, with continuity back to the battery.

[xgrapher]

Since we're not having any physical problems with the injectors that we can notice. Also by reading the spark plugs all cylinders are receiving equal fuel I suppose. Can we simply ignore this and move on? I mean do you know of people living with this error on the side.

[AdamW]

Can we simply ignore this and move on? I mean do you know of people living with this error on the side.

I wouldn't be comfortable running a turbo engine like yours very hard with an open injector error present. You should not see this error when everything is working properly so something in your set up is not right.

Also by reading the spark plugs all cylinders are receiving equal fuel I suppose.

The error may only be present for short periods so I don't think I would rely too much on spark plug colour.

[Sean]

Try unplugging the injectors and cleaning the contacts, both in the injector and plug. The Bosch plugs that fit those injectors allow the contact to fret under vibration and the resulting bad connection can lead to injector open errors. If you are using adapters from tan OEM harness to the injector check them too. We have had to hard wire our injectors to flyleads to get around this problem.

[xgrapher]

We are actually using the adapters. Wish we could try this earlier. We have already swapped the injectors out for some 850 denso ones. Some fuel line mods need to be done and then we'll see what's the outcome.

[xgrapher]

And by the way, nothing beats hardwiring