jackal8788 Posted November 11, 2015 Share Posted November 11, 2015 I know I'm in the wrong section but in hopes of gleaning more ideas for my issue, I'm reaching my wide, bulky, 5th gen ass out for help. My car is down on power by ~60% but there are no unusual symptoms that I can find to cause this. Here are the salient details: - Running e85, confirmed blend is ~83% ethanol - DAM at 1.0 - AFRs normal in both open loop ( ~11.0 at WOT) and closed loop (14-15) - No stuttering, jerking, or noticeable abnormality when driving or accelerating - No rough idle or hard starting - Normal boost (~21 PSI peak tapering to ~20 PSI redline) - Leak-tested entire intake tract for boost leaks - none found - Inspected throttle to ensure plate is opening fully. Appears to be working fine. This is substantiated by a 100% throttle reading in datalogs - TGV voltage signals in datalogs show that the valve are opening properly. I will be deleting them this weekend just to rule them out as a potential cause. - No collapsing of intake pipe - No slipping of clutch or drivetrain - No noted dragging of brakes, transmission, or other driveline components - No anvils, sandbags, corpses, or other forms of weight have been added - No observed exhaust leaks, no cat in the DP to plug up - Cold engine compression test shows ~100 PSI in all cylinders. I'm told this is to be expected from a cold engine. Again, someone who didn't know what the car should feel like would not know there was a problem. My full build thread has all of this and some other stuff if you care to peruse it (http://legacygt.com/forums/showthread.php/jackals-20g-e85-upgrade-228517.html). Any suggestions or help would be greatly appreciated! VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
Max Capacity Posted November 11, 2015 Share Posted November 11, 2015 Do you know what the fuel pressure is ? 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
jackal8788 Posted November 12, 2015 Author Share Posted November 12, 2015 Do you know what the fuel pressure is ? I do not. I'm not sure if that is a loggable parameter in the Accessport but I can check. If FP was low, would that show up in my AFRs? VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
Max Capacity Posted November 12, 2015 Share Posted November 12, 2015 I'm not sure. PM corvertrussian, he seems to be pretty good with that kind of stuff. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
jackal8788 Posted November 18, 2015 Author Share Posted November 18, 2015 Update: fuel pump is working properly as reflected by AFRs and the TGV delete helped a little bit but wasn't the root cause. I will be doing a hot compression test hopefully in the next few days just to fully rule that out but otherwise I'm pretty much stumped as to what could be wrong. Any suggestions or thoughts would be greatly appreciated! VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
AMileHighLGT Posted November 18, 2015 Share Posted November 18, 2015 Have you reset the pcm and the condition continues? Im not saying to go out and try it now, just asking if you have done it. Link to comment Share on other sites More sharing options...
mondtster Posted November 19, 2015 Share Posted November 19, 2015 I do not. I'm not sure if that is a loggable parameter in the Accessport but I can check. If FP was low, would that show up in my AFRs? As far as I know, there is no fuel pressure transducer. Regardless of what fuel pressure is, I'd expect to see an AFR problem if the thing was leaning out. The real question is, what makes you think you've lost 60% of your power? How have you measured this? Does your manifold pressure and mass flow rate still match what you think it should? Link to comment Share on other sites More sharing options...
jackal8788 Posted November 19, 2015 Author Share Posted November 19, 2015 Thanks for the responses. More info below: Have you reset the pcm and the condition continues? Im not saying to go out and try it now, just asking if you have done it. Yes, I've re-flashed a few different maps and also tried switching to my 93 octane map just to rule out both the tune and the fuel as causes. The issue was not resolved. As far as I know, there is no fuel pressure transducer. Regardless of what fuel pressure is, I'd expect to see an AFR problem if the thing was leaning out. The real question is, what makes you think you've lost 60% of your power? How have you measured this? Does your manifold pressure and mass flow rate still match what you think it should? I've taken datalogs and used Virutal Dyno to get a baseline. I found it to be pretty accurate when I compared it to my actual dyno plot the e85 tuning. Additionally, if I simply start a timer and monitor how long it takes to accelerate in 3rd gear at WOT from 30 MPH - 70 MPH (assuming similar atmospheric conditions) on the same stretch of road, it now takes me around 11 seconds when it used to take ~4.5 seconds. Manifold pressure still appears to be correct, registering a bit over 21 PSI peak and maintaining ~20 PSI at redline. MAF rates are down a bit from what they were in datalogs after my tune by 10-12% but I should note that my boost is running about 2 PSI lower across the band than it was after the initial tune. I had some overboost issues when I put on Borla so I ported my wastegate and had my tuner make some adjustments. This current map just has slightly lower boost. VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
travrach Posted November 20, 2015 Share Posted November 20, 2015 Update: I will be doing a hot compression test hopefully in the next few days just to fully rule that out but otherwise I'm pretty much stumped as to what could be wrong. ^I highly recommend this, 100 psi cold seems low to me unless the car had been sitting for a extremely long time allowing all oil to stop sealing the rings. Make sure the test is done w/ all plugs out and WOT. Dry test then wet. Spec on this car is 142-171 psi. Also how was the smoke test performed? -Any pressure applied? Link to comment Share on other sites More sharing options...
jackal8788 Posted November 24, 2015 Author Share Posted November 24, 2015 In place of the hot compression, we did a leakdown test. No leakage greater than 2% with 100 PSI applied in any of the cylinders. I was starting to suspect a burned valve but that should have presented in the leakdown test. Yes, pressure was also applied during the smoke test at the start of the charge pipe (at the compressor outlet). Any other thoughts? VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
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