# Lsu4.9 tps signal fail, leanout problem? super strange **URL:** \ **Category:** V3 SOFTWARE\ **Created:** [July 27, 2024, 6:49am UTC](https://community.ecumaster.com/t/lsu4-9-tps-signal-fail-leanout-problem-super-strange/1912 "2024-07-27T06:49:53Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Napkin](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/napkin/32/375_2.png) [@Napkin](https://community.ecumaster.com/u/Napkin)\ **Post date:** [July 27, 2024, 6:49am UTC](https://community.ecumaster.com/t/lsu4-9-tps-signal-fail-leanout-problem-super-strange/1912/1 "2024-07-27T06:49:53Z")
hey guys. yesterday i take my car for a spin. i calibrated the lsu4.9 circuit first, car rans fine for about 35minutes. after a 5min stop at the gas station i drove and car startet leaning out. i first thought it was the lsu4.9 problem again so i unplugged the lsu, and car drove fine again. as the mapping is already 99% i was fine with it. at home i checked the log, and it seems like at the moment the leanouts started, my throttle signal was 0% all the time. the moment i unplugged the lsu4.9 my throttle signal was back again and i could drive the rest of the night. timestamp 35:00 car starts jumping and leanout happening up to min 44:00 where i unplugged the lambda sensor. and everything was back to normal any idea what this could be? [20240727\_0836.emublog3](https://community.ecumaster.com/uploads/short-url/8Ai5rgc2GLjMFnGfkSxxayaXniR.emublog3) (6.7 MB) [beste.emub3](https://community.ecumaster.com/uploads/short-url/xoJ1xPFN2GqhsKWPfcSx1LEDQy1.emub3) (59.1 KB) ---
**Author:** ![derUltraTT](https://avatars.discourse-cdn.com/v4/letter/d/ba8739/32.png) [@derUltraTT](https://community.ecumaster.com/u/derUltraTT)\ **Post date:** [July 27, 2024, 9:28am UTC](https://community.ecumaster.com/t/lsu4-9-tps-signal-fail-leanout-problem-super-strange/1912/2 "2024-07-27T09:28:13Z")
In the log not just ur TPS also ur PPS is 0 permananetly starting at some point. At this time ur engine stuck in idle…u then drove the car with fixed ignition angle 6°. Later u are fast switching between idle and overrun…there ur engine leans out. This can all be explained by PPS/TPS issues (although i would expect to see something else than 0 in those channels at this point). After unplugging lambda ur TPS came back…but still looks partially corrupted. Anyhow…i think u have an electrical issue with TPS/PPS…check ur wiring and find it and all will be good again. ---
**Author:** ![Napkin](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/napkin/32/375_2.png) [@Napkin](https://community.ecumaster.com/u/Napkin)\ **Post date:** [July 27, 2024, 12:49pm UTC](https://community.ecumaster.com/t/lsu4-9-tps-signal-fail-leanout-problem-super-strange/1912/3 "2024-07-27T12:49:51Z")
its cable driven, so i dont need pps. the wiring is the same as the last 5 years and its all good. with lsu4.2 i dont have any issues. i changed the lambda to lsu4.9 yesterday morning. ---
**Author:** ![Jadzwin\_ECUMASTER](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/jadzwin_ecumaster/32/28_2.png) [@Jadzwin\_ECUMASTER](https://community.ecumaster.com/u/Jadzwin_ECUMASTER)\ **Post date:** [July 27, 2024, 6:19pm UTC](https://community.ecumaster.com/t/lsu4-9-tps-signal-fail-leanout-problem-super-strange/1912/4 "2024-07-27T18:19:41Z")
If your EMU revision is lower than O, you need to add 150K resistor for reliable LSU 4.9 support. ![image](https://europe1.discourse-cdn.com/flex013/uploads/ecumaster/original/2X/7/7c7336cc440a663bf4b78b7578e3279c3c378c59.png) ---
**Author:** ![Napkin](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/napkin/32/375_2.png) [@Napkin](https://community.ecumaster.com/u/Napkin)\ **Post date:** [July 27, 2024, 6:31pm UTC](https://community.ecumaster.com/t/lsu4-9-tps-signal-fail-leanout-problem-super-strange/1912/5 "2024-07-27T18:31:47Z")
But will this cause a tps problem as well? ---
**Author:** ![Jadzwin\_ECUMASTER](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/jadzwin_ecumaster/32/28_2.png) [@Jadzwin\_ECUMASTER](https://community.ecumaster.com/u/Jadzwin_ECUMASTER)\ **Post date:** [July 27, 2024, 8:39pm UTC](https://community.ecumaster.com/t/lsu4-9-tps-signal-fail-leanout-problem-super-strange/1912/6 "2024-07-27T20:39:12Z")
The TPS looks really strange. It looks like the voltage is at proper value for 0% and fluctuate a little, but looking at RPM it looks that the throttle is fully open. However I cannot find any connection between WBO and TPS. ---
**Author:** ![Napkin](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/napkin/32/375_2.png) [@Napkin](https://community.ecumaster.com/u/Napkin)\ **Post date:** [July 27, 2024, 8:51pm UTC](https://community.ecumaster.com/t/lsu4-9-tps-signal-fail-leanout-problem-super-strange/1912/7 "2024-07-27T20:51:30Z")
i have a second tps poti here to test. maybe it died on heat ---
**Author:** ![Jadzwin\_ECUMASTER](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/jadzwin_ecumaster/32/28_2.png) [@Jadzwin\_ECUMASTER](https://community.ecumaster.com/u/Jadzwin_ECUMASTER)\ **Post date:** [July 27, 2024, 8:53pm UTC](https://community.ecumaster.com/t/lsu4-9-tps-signal-fail-leanout-problem-super-strange/1912/8 "2024-07-27T20:53:34Z")
that would explains the problem