Extreme rich condition

[-=Jeff=-]

Sounds liek the injectors are not wired correctly, however it is concerning that you don't have a wiring diagram or pinout for the custom harness

[Perry Mitchell]

I'm not sure why you say you don't think they're wired correctly. Could you explain why you are concerned?

[-=Jeff=-]

Well, you don?t have the secondary injector modules so it sounds like the injectors are tied in pairs. Doing that will change the resistance of them. That also changes the load to the ECM . I was going to suggest disconnecting one injector at each cylinder and starting the car to see how it is.

Do you have a harness Pinout to show the connections from the ECM? Sounds like it is with the harness itself, but I am just guessing.

[Perry Mitchell]

But with the vacuum actuated secondaries removed and the prom re-calibrated for that condition, aren't both injectors working all the time, although equally, so no need for a secondary module? Where was the module located in a stock ZR? I know I'm being a bother but please don't give up on me.

[grahambehan]

Hi Perry. Ok so Mark already said that over 5% the secondary will turn on. So if you have the primary and secondary injectors wired to the same ground they will both fire up until that point, hence rich fuelling since when the ecm commands secondary function there is a multiplier of 0.51 to the pulse width. Im sure that if that if the wiring layout is explained to Mark he can send you a calibration that fixes the issue.

Graham

[Perry Mitchell]

Looks like I have some work to do!

[grahambehan]

Perry, not really its a simple fix once Mark is aware.

Graham

[Marc Haibeck]

I will modify your calibration so that it delivers 50% less fuel at idle.

We will see if the fuel injectors can deliver such a short pulse. Like Jeff pointed out the ECM will be driving twice the normal load with two injectors in parallel. It's already doing that so we are off to a good start.

[XfireZ51]

Originally Posted by Marc Haibeck

I will modify your calibration so that it delivers 50% less fuel at idle.

We will see if the fuel injectors can deliver such a short pulse. Like Jeff pointed out the ECM will be driving twice the normal load with two injectors in parallel.

Good question Marc. Will the ECM be capable of sustainably driving 16 injectors without blowing a fuse? Apparently doing that at idle now.

[-=Jeff=-]

Originally Posted by Perry Mitchell

But with the vacuum actuated secondaries removed and the prom re-calibrated for that condition, aren't both injectors working all the time, although equally, so no need for a secondary module? Where was the module located in a stock ZR? I know I'm being a bother but please don't give up on me.

Secondary modules balance the injector load placed on the ECM. Example.. typical injector is ~16-18Ohms.. The ECM is set up to drive that 16-18 Ohms, with some room for error..

Now, I have 2 injectors @ 16 ohm in parallel to the ECM, I am now at a total load of 8 ohms, which will require the ECM to drive harder, more heat and potentially premature failure..

The secondary module compensates for this, the ECM still sees the 16 ohm load but I can run 2 injectors. When the ECM is told to run Full power (above idle) the Secondary module receives a signal (like a switch) to power the added injectors.

Now if you ran a higher impedance injector (like ~40Ohms) then you are fine to pair them as the ECM sees the ~16-18 load..

As for location , the modules were located near the battery either on the firewall or just in front of the battery on the wheel well