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I've been trying to find solid information on whether a 1227165 is capable of running peak and hold injectors, 6 or them, and what needs to be done to make this happen.
I'm toying with the idea of testing some code for the '165 and would like to be able to use my current low-Z injectors, if not now, then in the future with the next engine.
Is this possible and what changes need to be made?
a 7165 only has 1 injector driver... i'm not sure if you'll find a suitable FET capable of handling 6 in PNH mode. even then, the injection controller may kick the injectors out into hold mode too soon. a resistor change MAY fix that.
but.... it is possible to run in PNH mode with the 7165. the injector portion is setup the same as a 7727/7730/7749. the injector sensing pin is D9.
info here for drawing similarities and to keep my info straight:
a 7749 in PNH uses C10 and C11 for injector outputs. there is a jumper from D5 to D6 and from C13 to C15 for peak and hold operation. D5 is injector 1 sense pin, D6 is injector 1 ground. C13 is injector 2 ground, C15 is injector 2 sense.
to make the same connections on a 7165:
D15 is injector output. you'll need to jumper from D9 to D3 to allow the sense function.
or at least, this is what it all looks like in the Ludis diagrams.
the resistor change may not do it, now that i look at it more.... however, if you setup a voltage divider on that circuit, you could skew the voltage the controller sees, changing the peak/hold voltage/current threshold.
I had to change the sense resistors in the '7749, at least according to information I found on the net, and it has worked so far.
Looks like I might have to switch back to my smaller injectors if I want to test this code, at least until I figure out how to run 6 low-Z injectors off a single injector driver.
I'd love to know how you go. I had a close look at the 808 on the bench in front of me comparing to the pics in your other thread the other day, but it looks like the edge of the board where you fit some of the extra components doesnt exist in the 808. Thats not to say its impossible though. It would open up a lot of options for the jap crew with the delcos. There are high impedance options around, we found some flow matched reconditioned items from an american company for the VG30ET we delco'd and put some circlips around some ford XR6-T injectors for the L28ET and that made them fit, but a lot of people do want low. I take it you have the low impedance already and want to use those?
The '165 can and does drive PnH in an OEM application. But like all GM factory applications, it's limited to one TBI PnH injector per driver. And like other OEM applications, you can step up to two port PnH injectors per driver with no additional modifications. But if you want to run more injectors the sense resistor can be changed just like the 7730 / 7749. However, keep in mind that the total resistance of the circuit will be even lower than a two TBI injector per driver system and you might want to make changes to accommodate a fair amount of heat from the ecm.