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Greetings! Long time lurker, first time poster here. I appreciate the great advice I have gleaned from the forum since buying my first S back in 08.
Anyway, I have an issue with my daily driver ( 50 miles / day all highway) '12 coupe that I have not yet been able to resolve. Below is a chronological timeline that details what was done and when.
Long story short is that I my modified 2012 JCW Coupe is no longer building boost beyond about 7 psi.
1. JCW was running fine at 50k miles; warranty ran out so here come the upgrades.
2. Installed the remanufactured JM Turbo quick spool 42mm turbo from MiniMania here: http://new.minimania.com/part/G2NME2801R/ with no issues. Broke in very slowly over the course of about 4k miles. Did NOT have a boost gauge, but the seat of the pants feel showed quite a bit of improvement.
3. Later installed a Wagner performance high flow intercooler.
4. Sent the ECU off to JM Turbo for the re-flash. Re-installed the ECU; ran great for about 1k miles. Tons of power; just kept building as long as the RPMs kept going up it seemed.
5. Figuring everything was broken in, I finally got the engine up to about 5500 rpm and it felt like the boost fell away. After this event, the 'seat of the pants' feel seemed like it was lacking a ton of boost.
6. Finally installed a boost gauge (should have done in the beginning), and it showed that I was only building between 6.5 and 8 psi and then it falls away to 1 or 2 psi very quickly.
7. Checked all intercooler connections that I had touched and none were loose. Checked other clamped connections on the small hoses by the intercooler. Inspected vacuum lines - all appear ok.
8. Found a little bit of an oil film on the rubber hose near the turbo inlet. Talked to JM Turbo and sent turbo back to have it checked. Reported all ok from JM Turbo
9. Reinstalled turbo and still have the same low boost scenario. No ECU codes have thrown and there is no substantial oil burning at this point either. No other drive-ability issues either.
Help - can I unplug the diverter harness or wire vac gate to see if those help to try to pin down if it is an electrical or mechanical issue? Any other suggestions?
Sounds like you popped something and it is leaking. Excellent suggestion to check the DV. After that you're going to have to pressure test the plumbing post turbo.
Busy weekend! I did the following over the weekend:
Pressure checked everything from the turbo outlet to the intake - no leaks observed up to 15 lbs.
Cleaned sensors with MAF cleaner.
Checked fuses - hey why not?
Vacuum shows about 18" at idle with the AC off. Left the car running, popped the hood and watched the vacuum waste gate close as the wife turned the car off. I'm guessing that is good?
Has anyone used Euro Car in St. Louis MO? I'm about ready to take it somewhere to get some adult supervision.
Are you using stock plumbing hoses to the new intercooler? Is it possible that although everything is installed correctly that the sealing of these connections is not 100%? Do you have software support to make sure that the boost and temp parameters are correct? Is there a difference between the cars running condition and related boost when the car is cold VS warming up VS hot? Given the quality of the items you have chosen, the solution may be something simple. Don't give up!
Greeting! Thanks again for all of the suggestions and help. After double checking connections, cleaning sensors, etc. I finally got the Torque App hooked up and some data pulled. I really like this App!!
Attached is an Excel file with the data from a 3rd gear, 1300 to 5500 rpm run with my foot all the way to the floor the whole time. I have done this several times and the data is pretty consistent. I tried pasting the info into the thread but struck out. Below are two screenshots; one building boost and a second at the max boost that I can achieve.
After reading more on this forum and looking at my own data, I'm beginning to suspect that the high pressure fuel pump may be an issue? It looks like the A/F ratio is almost always UNDER what the commanded ratio is? That or the throttle demand from the pedal is messed up?
Any help is appreciated! HPFP replacement looks expensive, so I'd like to be fairly sure before replacing it. I'd take it to the dealership if I was confident that they wouldn't wipe my tune out.
The dealer should be able to scan the high pressure fuel pump output! Quick and simple. Even if the charge the $125 diag fee its worth it given your situation.
HPFP numbers look reasonable to me. Turbo has been checked and found to be OK, but what about the waste gate vacuum lines, tank, and pump. If the WG is opening early, that could also cause low boost. I don't know how to check the vacuum pump, but I've read that it's a common failure, and if it locks up, destroys the engine.
Check/replace the vent for the fuel tank? It's plumbed into the intake manifold and is under it.
My original turbo, waste gate ultimately wore out, but I changed exhaust manifold at the same time- there were a few nuts that were like hand tight, you could see where it was leaking past on the gasket after it was all apart
And also curious what the "reflash" consisted off, doesnt look like manic , it boosts hpfp up above 2000psi usually and engine temp dropped to 185* for stage 2, stock is 226*
Well I THINK that I may finally have it resolved!!! Skip to item 22 below for (hopefully) the fix. Otherwise, here is the Rest of the Story...
13. Took to the dealership. Brought along the Torque data that I gathered (above in thread). They indicated that the turbo wastegate was opening under load. They thought that it was a collapsing vac hose that caused it to lose boost. They bypassed all of the existing vac hoses and ran it straight from the vac pump to the turbo. This ran okay for a while but experienced some misfire while driving it hard on the way home. Tried several platinum and iridium (and even copper) plugs to try to remedy. Still cut out above 15 psi. Reduced gap down to .026 and still had cut out issues. Platinum plugs at .026 are left in. Ordered Ignition Projects coil packs.
14. No codes were found by the dealership either on arrival or departure. High Pressure Fuel Pump was deemed okay. Did confirm that this is covered as part of the extended warranty on this component though.
15. Low boost issue problem resurfaced.
16. Disconnected the vac pump-to-wastegate setup. Re-used the original vac hoses that go to the bottom of the engine and back. Hooked up a vacuum gauge immediately next to the wastegate. While driving the now-inside-the-car temp vacuum shows that it starts off okay (~20")and then decays to less that 5" and it appears that the wastegate was opening again at this point.
17. Hooked up a vac pump directly to the wastegate and it operates when vacuum gets to ~10". Movement is >5/8". This is more than what is on JM Turbo website, but I'm taking that it is okay since JM Turbo had checked out the turbo when I sent it back in.
18. Replaced all vacuum hoses thinking they may be collapsing. Installed the Ignition Projects coil packs. No change (yet - see below) but the red looks cool.
19. Same vac readings as line 16 above. No improvement. Boost only goes up to about 9 psi or so.
20. Went back to the same vac pump-to-wastegate vacuum line setup as done by the dealer in line. Vacuum immediately next to the wastegate is 28". Boost does not go above 9 or so.
21. Put all vac lines back to normal.
22. Got to thinking that it would run fine after the tuner visit and the dealership visit, so I hooked up the Torque app. Sure enough, it showed a 'pending' code for misfire (no code thrown on the dash). I suspect that this was leftover from before the Ignition Project coil pack change. I went ahead and cleared the code. While in there, I also went in through the odometer reset, unlocked the test function on test 19, and then did a 'reset' on test 21. This is supposed to wipe out the 'learned driving' data?
23. Took it out for a spin. HOLY COW - running great!!!!! I'm fairly confident now that the ECU was cutting power because the factory coil packs had been too weak and I was getting spark blow by above ~16psi of boost. It seems that the coil packs were just the next 'weakest link' while doing the mods.
Hopefully this gets it. I HIGHLY recommend purchasing the Torque App and Bluetooth module.
08-08-2017, 12:52 PM
