Peace Posted August 17, 2023 Report Share Posted August 17, 2023 Hello I'm struggling to fight TPS delta. On a full throttle run TPS delta shows oscilation in +/-10% which causes CLL to be locked, and Transient ignition trims to be present. Yeah i know i can setup CLL and Trims to not act in such precentage TPS delta but i want to try and find the reason why this happen. Any idea? My build for information is RB30(26head) with EFR9274, 280(10) cams, with stock RB26 ITB Attaching my log file. If needed can put a tune also TPS DELTA why.llgx Quote Link to comment Share on other sites More sharing options...
Adamw Posted August 17, 2023 Report Share Posted August 17, 2023 It is a little worse than typical, but my initial feeling is its probably not bad enough to cause a real tuning issue. Your TPS delta at WOT doesnt go about about 5 very often so that is still low enough to not be considered a transient for most functions. Accel deadband would need to be around there. Your "TPS" may look stable since it only has a 0.1% resolution and the calibration span tops out at 100.0, but if you look at the raw voltage you will see a different story. In the short WOT blast shown below your TPS voltage varies from 3.55 to 3.47V (80mV) when you would expect the throttle should be hard against the mechanical stop. Nissan, like many others around that era had pretty horrible grounding design with some sensors grounding through chassis ground etc, so it could potentially be a grounding issue, but if we compare the AN volt 1 and AN temp 1 at the bottom of the pic, they only vary by about 10mV over the same period, so that gives some hope it is not a wide spread ground issue. The first thing I would look at is the mechanical coupling of the TPS sensor, from memory the RB26 sensors arent spring loaded, so if there is any backlash in the "D" drive then the sensor can bounce backwards and forwards with vibration. I have a vague recollection of one doing this on a car I tuned years ago and I pulled it off, put a blob of silicone in the D cavity, then refitted it and let it dry. Quote Link to comment Share on other sites More sharing options...
Peace Posted August 18, 2023 Author Report Share Posted August 18, 2023 Thank you Adam for explanation. Mainly i wanted to know is this a big issue or i can just tune around it. So if thats what is comon i just setup everything to ignore TPS delta up to 8-10%. I will also try to take a look on the sensor as you said. Quote Link to comment Share on other sites More sharing options...
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