Boost Surge/Cut? PCV Clog? Videos Linked
Not yet. I've been waiting to post until I was sure about something. I only have weekends to work on the car, so I haven't made too much progress and don't have a definitive answer yet. I'm still leaning towards the vacuum leak theory; today while working on it I tested the vac lines between the wastegate and pressure converter again and found a tiny leak coming from either the pressure converter itself (it is brand new... but you can't assume new parts work) or the lines right where they connect to the nipple. I switched it out again, vacuum tested with no visible leaks, and the car seemed improved, though not completely fixed. I'm wondering if pressure isn't escaping at those connections somehow under full boost. I'll be at the Dragon this coming weekend, and so won't have a chance to work on the car again until weekend after that. I'll let you all know whenever I figure something out.
Hey, sorry nothing yet. The car was very inconsistent at the Dragon, and I had some dv issues so in fixing that I added more variables to the situation and did not get any closer to a solution. Since then I haven't had much time to diagnose as I've been focusing on body work/cosmetics preparing for a show next weekend. I did switch out the dv, again, to include the gfb dv+ and the car seemed to only struggle with boost past 16-17psi at that point. Today after finishing with the body kit I pressure tested the car and found another boost leak only letting loose past that boost threshold (around 15-16), but did not test drive as it was cold and raining outside (wheelspin is not good for trying to diagnose high boost specific issues). I assure you I will post up here when I have figured it out. Thanks
Over the weekend the wastegate became stuck shut. This happened before with this turbo, (Gpop remanufactured) and the turbo was rebuilt and sent back to me. I made the mistake of thinking it was good to go. I'll replace the turbo again likely some time early next year. At the moment I don't have the budget or, mainly, the patience to buy another turbo again. There's a chance my particular issue had something to do with the wastegate/actuator sticking. I'll let you know once I've got another turbo on the car.
Just an update. Got the car back together with a new OEM turbo. First test drive started out great, then the car began to behave strangely, like the dv was delayed in actuating. Checked the codes, and sure enough there was a code for short circuit to the dv, checked and the connector had slid off slightly. A long time ago I broke the plastic clip on the connector, so there's no telling how long that's caused an issue. With so much heat and vibration up there it'd be quite easy for it to slide down when not clipped in, at least enough to make the connection weak. At that point I taped it in place, test drove again and the car performed well. Last weekend I replaced the connector itself so that the connection is secured, but I have not had a chance to test drive since. I'll be back with more info once I've driven the car this coming weekend. Fingers crossed this is the end of this whole ordeal.
Test drove today and the car did not surge. Performed very well but not perfect. I believe I've still got a boost leak somewhere, so I'll try to track that down. Let me know what the dealership says when you go. Thanks
That's a shame. Let me know if you switch out the dv and if that helps anything. Also if you have a local shop you trust maybe get it smoke tested/pressure tested. I drove mine pretty hard over a weekend up in the mountains, I think I still have a leak letting go past 15psi. The car feels strong but as I mentioned before not 100% right. As I've explained, the car's a weekend warrior now, and I work on it when I can, so I'll update here if/when I have anything else. Hopefully one day we'll figure this out. Do you have any videos of yours? Is it exactly the same as mine was in the original videos? Thanks
Seem to have fixed it, at least for the most part. Swapped out the hpfp even though fuel rail pressure seemed to be in spec. Old hpfp was coated in oily residue on the bottom side; there were trails where crankcase pressure & oil had escaped past the o-ring. Not enough to form a big leak, just built up like oily dust. Never saw this from the top of the engine. Just thought to look along the sides of the head for leaks with a mirror. Car is pulling much smoother now, no more obvious surging...
Last edited by Kalibdor; Oct 8, 2018 at 05:24 PM.
So, I still had some hesitation here and there. The car was running strong but still not perfect, and would give hints of surging here and there, most noticeable at the beginning of each gear during the boost spike, and under very heavy load. Replaced the fuel injectors and the car is back at 100%. Fuel injector seals were allowing blowby under heavy load essentially reducing compression. Injectors were 208k miles old and the seals were not replaced when they were swapped over from one motor to another.
