Prins vsi on a jeep wj grand cherokee 4.0l

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demonicwillow
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Re: Prins vsi on a jeep wj grand cherokee 4.0l

#21 Post by demonicwillow » Sat Oct 20, 2018 1:31 pm

Sorted

Gilbertd
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Re: Prins vsi on a jeep wj grand cherokee 4.0l

#22 Post by Gilbertd » Sat Oct 20, 2018 5:54 pm

How?
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demonicwillow
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Re: Prins vsi on a jeep wj grand cherokee 4.0l

#23 Post by demonicwillow » Sat Oct 20, 2018 8:37 pm

One of my thoughts on the problem was the power supply to the petrol injectors from pinout no26 on the vsi ecu, it didnt appear on any diagram so I returned the wiring back to the original, this also left pinout no27 with nothing to do, no 27 was connected to the petrol ecu then linked through the vsi ecu and out on to the petrol injectors via no 26 another question was pinout no54, its a red and black wire, simply says simulator on it, diagram says its a ground so I joined it to the emulator ground and indeed grounded it, no26 was then connected to inj command at the emulator which left no27 which was now hanging in space with nothing to do.

In the vsi manual there are two similar diagrams one with two fuses, one with three fuses, I was following the diagram with three fuses because mine has three but this one didnt show what to do with pinout no27 so refering to the other diagram I clagged it on to pinout no13 (ignition +) turned the key and nearly fell over when it switched faultlessly to lpg.

Now I can see in my obd2 scan tool the long term, short term trims and the o2 sensor readings on lpg because its in closed loop, there is no check engine light and under load and idle the short term trims flip plus and minus around 2% max and it pulls like a train, all in all im quite chuffed :) and relieved because I was getting really frustrated with it, almost ripped the thing out and replace it with my omvl dream system I have for the other jheep.

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Re: Prins vsi on a jeep wj grand cherokee 4.0l

#24 Post by LPGC » Mon Oct 22, 2018 11:59 pm

The injector module disconnects the petrol injectors when it gets 12v on it's command input, this would be the same as putting 12v to the blue wire on (say) a Pitagora emulator. When the emulator is active it disconnects the petrol injectors and provides the emulation. The Prins emulators are like a Pitagora but the extra wires that run to the VSI ECU connect to petrol injectors so that the VSI ECU can see would-be petrol injectors pulse duration.

Pin 26 shouldn't provide 12v to petrol injectors.
It may be wired to disconnect 12v feed to petrol injectors via a double pole relay (relay off petrol injectors get 12v as normal)... If this is the case it might suggest a previous bodge.
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demonicwillow
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Re: Prins vsi on a jeep wj grand cherokee 4.0l

#25 Post by demonicwillow » Tue Oct 23, 2018 8:32 am

There was no double relay, wires went direct but looking at the prins diagram it shows me that what goes in at no27 comes out at no26 via an internal relay or mosfet, some kind of switch anyway, but as for a bodge maybe more of a fudge to get it to work because it must have worked correctly at some point before itcame into my possession, I havent seen a wiring diagram for the old emulator so I dont know how it was supposed to be wired up, either way its wired as per the diagram now and will be interesting to see how the mpg's work out, the switchover is seamless, better than before

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