Copyninja Posted December 4, 2022 Report Share Posted December 4, 2022 Gentlemen, Was doing some dragy gps testing and randomly i had a power cut, looking at the logs - fuel, boost, spark all cut at 6597rpm. TP still at 100% until 6700 rpm. I've gone over the logs and cant see any gp rpm limit, map limit, rpm limit get activated. Anyone able to offer insight into why this happened? Sounded like something popped off....but checked all boost lines, turbo, engine etc...and all looks fine. Drove car home and again all in fine. Random G4+ ecu glitch?? which maybe activated a gp rpm limit or something but didn't log the activation? Quote Link to comment Share on other sites More sharing options...
remski2 Posted December 5, 2022 Report Share Posted December 5, 2022 Hi. Two things that poped up... Your Driven Wheel Speed is all over the place... Take a look at your fuel pressure... multiple drops by as much as 18psi... Quote Link to comment Share on other sites More sharing options...
Copyninja Posted December 5, 2022 Author Report Share Posted December 5, 2022 Thanks, I noticed that. Was there any limits that got activated? I cant see any evidence. Likely some kinda electrical gremlin. My Afr reading did not seem to lean out but at the point of the boost cut I cant seem to understand why Boost, Spark and Fuel stopped at the same point. Almost like a rotary cut. I'll look underneath the car next to see if any wg lines have popped off. Quote Link to comment Share on other sites More sharing options...
Adamw Posted December 5, 2022 Report Share Posted December 5, 2022 On 12/5/2022 at 9:29 AM, Copyninja said: looking at the logs - fuel, boost, spark all cut at 6597rpm What time point is this? I dont see any such thing, there are no cuts at all in the whole log and I see boost, inj PW and dwell at all times the TP is at 100%? The main thing that jumps out at me is it looks like you have a fuel surge or cavitation issue, fuel pressure drops and becomes very erratic under high acceleration - but that issue is not present at the 6600RPM problem area that you refer to above in this log. Quote Link to comment Share on other sites More sharing options...
Pete_89t2 Posted December 5, 2022 Report Share Posted December 5, 2022 I'm not seeing any evidence of a fuel or spark cut happening anywhere in that log where TP(main) is above 90% and/or RPMs at approx. 6000RPMs and above. But I am seeing the same erratic differential fuel pressure and wheel speed data that the others pointed out. Quote Link to comment Share on other sites More sharing options...
Copyninja Posted December 6, 2022 Author Report Share Posted December 6, 2022 23 hours ago, Adamw said: What time point is this? I dont see any such thing, there are no cuts at all in the whole log and I see boost, inj PW and dwell at all times the TP is at 100%? The main thing that jumps out at me is it looks like you have a fuel surge or cavitation issue, fuel pressure drops and becomes very erratic under high acceleration - but that issue is not present at the 6600RPM problem area that you refer to above in this log. I noticed the points you have referred to. I was referring to this area under 100% load but looks like I've suddenly lost boost. Perhaps a boost hose popped off! In your opinion do you feel the G4X platform is a lot better than the g4+? or is there a newer link ecu which is coming out which is going to replace the x platform soon? # 22 hours ago, Pete_89t2 said: I'm not seeing any evidence of a fuel or spark cut happening anywhere in that log where TP(main) is above 90% and/or RPMs at approx. 6000RPMs and above. But I am seeing the same erratic differential fuel pressure and wheel speed data that the others pointed out. Agreed, i could not see any limits get activated and wanted to be sure that was the case. Just strange there was a boost cut very suddenly. Quote Link to comment Share on other sites More sharing options...
Pete_89t2 Posted December 6, 2022 Report Share Posted December 6, 2022 5 hours ago, Copyninja said: I noticed the points you have referred to. I was referring to this area under 100% load but looks like I've suddenly lost boost. Perhaps a boost hose popped off! In your opinion do you feel the G4X platform is a lot better than the g4+? or is there a newer link ecu which is coming out which is going to replace the x platform soon? # Agreed, i could see any limits get activated and wanted to be sure that was the case. Just strange there was a boost cut very suddenly. Looking at the circled part of the log, I would agree that a plumbing leak is a plausible cause for the boost suddenly dropping rapidly from about 18ish psi MGP down to about baro pressure while the throttle was still floored. May have popped a hose/coupler or had a BOV failure. Start inspecting all the joints/connections & plumbing between the turbo compressor output and throttle body. Should be an easy fix for that; I'd be more concerned with the weird fuel pressure fluctuations elsewhere in the log though. Copyninja 1 Quote Link to comment Share on other sites More sharing options...
Adamw Posted December 6, 2022 Report Share Posted December 6, 2022 Yeah a sudden total loss of pressure like that could only be a large leak. Turbines at 100000RPM have a lot of inertia so there is not much the ecu can do to influence it that much that quickly. Copyninja 1 Quote Link to comment Share on other sites More sharing options...
Copyninja Posted December 6, 2022 Author Report Share Posted December 6, 2022 Thank you both. That's very helpful. I'll start looking into boost leaks and start replacing silicone hoses etc with an fittings and braided hard lines now. Quote Link to comment Share on other sites More sharing options...
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