Injector resistance reading out of spec

[disco stu]

So the manual states that resistance between terminals on injector are meant to be 13-16 ohm. Mine read 11-11.1 for the 3 on one side, and 11.8-11.9 for the 3 on the other side

What sort of issue does the resistance being low cause?

I'm also slightly confused why resistance lowers over time on these, most things resistance increases over time.

Connectors are pretty much all rooted on the pajero harness-broke off probably half the retaining tabs trying to take them off, one looks like its melted, and the wire for at least 1 has a nick in it and corrosion has set in. Got the magna harness that I can use, but unfortunately its got 2 extra wires in the plug. Have tried removing the connectors in the plug so I can use the whole length, but can't get them out so will just solder them on I think.

So much dirt in this thing. Some of the injectors had dirt up above the top seal, between seal and o-ring

[erad]

Having resistances lower than spec would cause the power transistor to push out more current than it otherwise would. I wouldn't worry too much about your readings - they are all nearly equal and that is more important. The lower readings are probably more to do with your ohm meter than the injectors themselves. Lower resistance on the injector solenoids may cause them to open quicker, but the difference would be minimal.

[disco stu]

Thanks erad. I thought it was funny that each cylinder bank had similar readings. I'm fairly sure one side has copped a lot of heat-one of the connectors looked a bit melted.

[erad]

If the plastic around the injectors has melted, maybe the lower resistance has caused extra current (equals extra heat, equals melting plastic)?

[disco stu]

Hmm, although it appeared to be on the outside of the wiring harness side connector so i think I'm safe.
I've got to solder on the magna wiring connectors seeing these were so brittle. If you think its a concern I could always throw in a ~3ohm resistor on each to make sure the current doesn't get too high.

Although......one of the injectors appeared to leak through intermittently while I was cleaning them. Can't get it to repeat now though, but I'm looking once again at using the magna injectors seeing they are here and not going to be used...but that means stuffing around with injector timing. I'm sitting on this one for the moment

[disco stu]

Realised my issue with resistance-it's getting cold at our place now, and it's down around 12-14deg. That is going to lower resistance. Put them in front of the heater for a while, and now the multimeter wants to play silly buggers. Gave me 14-15 on thousands setting at least, which is a bit better.

Wiring is all stiff and cracking, so I'm changing the magna harness to run the same way and will change pins to pajero connector. So much stuffed on this car!

[disco stu]

Multi meter worked-14.3 to 14.6 ohm at around 20deg. I'm happy with that

[erad]

...

Although......one of the injectors appeared to leak through intermittently while I was cleaning them. Can't get it to repeat now though, but I'm looking once again at using the magna injectors seeing they are here and not going to be used...but that means stuffing around with injector timing. I'm sitting on this one for the moment

I cannot see why changing injectors for something nearly equal would affect things that much. They are, after all simply a solenoid controlled valve. Timing of the injector pulse will no affect things very much at all. If the injectors were squirting fuel into the cylinders, it would be different, but they are merely feeding fuel into the intake manifold, and that should not have any significant effect. It is the valve timing and spark timing which are important.

As for putting resistors in series with the injectors, I think you are introducing more potential points of failure for little if any gain. I cannot see why the Magna injectors won't work properly. They may inject slightly more or less fuel than the original ones, but I would hope that the feedback from the oxygen sensor would compensate for the change.

[disco stu]

I went back through and read the thread I started about that-magna injectors are a lot bigger. I'll just stick with these for the moment, sends to be alright now. I'll try the magna injectors and remap if I get dramas later on I think