jimmylemon Posted July 24, 2021 Report Share Posted July 24, 2021 Hi guys, Running a rb26/30 on a link g4+ ecu with the ross cam/crank trigger kit on it, cherry sensors. Car is running well, but losing timing up top for some reason. Limiter set to 8200, made it to 6600 on the dyno the other day before a loud backfire. Had to abandon the tune. Tuner said something is going on where its losing timing up top, suspect sensors or wiring. Now I have ran new wiring to both the crank and cam twice now trying to fix this issue, to no avail. I'm using shielded stepper motor wiring. I have been fighting this thing with noise up top for lord knows how long now. As well as re-wiring it, have also dropped both sensors out and re-checked air gap etc also. Anyway, I would like to confirm a couple of things. Based on this thread here: Would I be correct in saying, that if I am supplying 5v to both sensors, that I should be using a 1kohm, with pullup set to off? I have ordered 2x new sensors, the gs1005021, I believe they are a replacement for what came with my ross kit. So as well as chucking in 2x new sensors to eliminate that issue, I want to make sure I have the fkn things wired up properly. From the above thread, they way I read that, I potentially should have been running a 1kohm right from the beginning? Cheers. Quote Link to comment Share on other sites More sharing options...
aerace_fab Posted July 24, 2021 Report Share Posted July 24, 2021 use the internal pull up. And are you grounding the shielding to the ecu at one end only? I use these sensor regularly. Quote Link to comment Share on other sites More sharing options...
jimmylemon Posted July 25, 2021 Author Report Share Posted July 25, 2021 No I don't have it grounded currently, as in the shielding, thanks for letting me know that. So I just ground the shielding at the ECU side? The thing that gets me, is I have seen these things work properly with un shielded trailer wire, so would it really be that causing my issue? Don't get me wrong, I'm going to fix it anyway, but I'm just not sure if it's the root cause. Would there be any benefit at all in putting in my own 1kohm resistor. Understand the internal pull up will work, but would the external 1k be better? That's what I'm trying to ascertain ATM. Based on Adam's comments in that thread, and info from ZF, it should really be running a 1k. Cheers. Quote Link to comment Share on other sites More sharing options...
aerace_fab Posted July 25, 2021 Report Share Posted July 25, 2021 Can’t remember the pull up value off the top, like I said it’s there to serve this purpose. And yes your issue could be as simple as EMI so ground one side of the shielding to a drain/ground… sensor ground will suffice. I build harnesses regularly this is a common practice in my workshop. Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 25, 2021 Report Share Posted July 25, 2021 Whats the tooth count on the trigger wheel? The ZF sensors do work better with the correct pull-up. Although I have only ever seen one that wasnt happy and it was on a 60-2 wheel. In that case it would skip teeth at high RPM with the ecu pull-up (internal is 4.7K) and fitting the correct pull-up solved it. I have used them on 12 and 24T wheels with the internal pull-up with no drama. It looks like Ross offer either the GT101 or a GS1005. GT101 definitely wont be happy if you have a missing tooth crank pattern. And yes, both should be shielded with the shield grounded at one end only. Quote Link to comment Share on other sites More sharing options...
jimmylemon Posted July 25, 2021 Author Report Share Posted July 25, 2021 Thanks Adam. It's running the ross 36-2 profile for crank. It hasn't stopped it from being tuned for the most part, but every single time I have got it back, someone has mentioned it losing timing at the very top end. The other day it was that bad they just pulled the pin on the tune entirely. Yeh its running the gs1005 currently, which I'm led to believe are OK for missing tooth pattern. So in your opinion Adam, don't bother trying the external 1k? Cheers. Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 25, 2021 Report Share Posted July 25, 2021 I would try adding the 1k. Quote Link to comment Share on other sites More sharing options...
jimmylemon Posted July 25, 2021 Author Report Share Posted July 25, 2021 Thanks Adam. It's not much effort to try right, so as well as grounding the shielding, I'm going to give it a crack. Is there a preference for where the resistor should be located? ie ECU side or near the sensor output? I assume because the internal 4.7 is in the ECU, that ecu side is OK. Just easier to protect it inside the ECU case. Cheers. Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 25, 2021 Report Share Posted July 25, 2021 Normally best near the ECU where it is easier to strain relieve and less vunerable. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.