injector wiring

I'm putting a 99' engine into my renix cherokee and I'm still retaining the old bendix system to fire it all. So far I have everything figured out, tps adapter, fuel rail, etc., except one thing...On the obdII the injectors are constantly hot and are grounded when they need to pulse. On the 89' bendix system the injectors are constantly grounded and are hot when they need to pulse. How should I go about wiring in the new 99' injectors into my old wiring harness? They're just a circuit it shouldn't matter one way or the other should it? Thanks.

5-90?

Anyone???

:eyes:

Please...

It shouldn't make any difference to the injector if one side is hot or at ground. What would be important is the resistance of each injector. The resistance determines the amount of current the ECM must handle, regardless of whether it's switching a ground, or 12v.
So, insure the new injectors have the same resistance as the old, and that your new wiring harness reflects the Renix connections.

Thanks for the info.

I soldered the 99' injector connectors onto the old wiring harness, but I guess I do need to measure the resistance.

Dumb question, but why not just use the '89 injectors? are the new injectors and manifold bungs a different size?

According to my info, the Renix injectors are supposed to read about 16 ohms (Chilton FI manual), the 95 injectors ~14.5 (FSM) , and the 99 FSM calls for ~12 ohms. I'm guessing that any change occurred in 96 when the PCU design and the wiring harness connectors changed. That doesn't add up to a lot of amperage difference, so I'm guessing that it won't be critical, but if you're concerned, the safest way to run HO injectors on a Renix rig would be 91-95 vintage.g That would also mean you could use the Renix style connectors. Although the design of the clips on the connectors changed two or three times, they're all interchangeable between 87 and 95.