Main question as follows: Can there be a boost leak if sometimes car gives full boost and sometimes not? I am thinking this is an electrical gremlin somewhere!

The problem is I'm in disagreement with my engine builder...and now searching the fault with a friend of mine.

Background:

Basic setup with K24/18G turbos, Bosch injectors from EPL, exhaust, ic's, dv's etc. and a safe dyno tune at MAHA dyno for approx 1.2bar, ~600hp.

Car has seen lots of race track use, started misfiring cylinder bank 2 last year, could always fix it with new coils/plugs but it was silly to change them all the time, it would sometimes start misfire again after 2 days, sometimes after 2 months.

Thus I decided to do engine overhaul during winter. I selected a shop with references and active customer service www.albert-motorsport.de - they made the engine overhaul. Everything looked good inside the engine, so PERHAPS (not sure) the reason for cylinder bank 2 misfires was just a Variocam solenoid.

I told these Albert guys I want bit power in their dyno as they installed stronger rods. However for my surprise they changed the stock FPR to a 5bar FPR and tinkered wastegates to show me 600hp+ figures on the dyno WITHOUT touching the ECU software at all. Very strange!? Dangerous?

Now, my buddy picks up the car and these errors start to show up after driving some miles: P1250 and P1109

By deleting the codes the car works perfect for 10-20 miles with full boost and then these codes hit with loss of power.

Albert Motorsport says car worked perfect when they had it (which I kind of believe, seeing their dyno chart etc), but now they are too busy and won't help. They tell the reason is car being RWD with deleted PSM, car needing a GT2 ECU etc. silly ideas after I paying them over 19 000 EUROS for the rebuild!

So, I'm now alone with my friend to find the fault. I have all the pictures of the engine rebuild so that should be a proper work.

I am buying a boost leak tester, but does sound strange if the car can give full boost for those 20 miles with an existing boost leak? I'm thinking it's an electrical gremlin somewhere. N75, MAF, coils, plugs are new or recent.

Any ideas? How should I study the wastegates for example? I'm worried I bring the car to a $$$$ dyno tune and there again it works perfect but on my way home it starts giving these errors with loss of power.

Could still be Air/Fuel related so perhaps somehow test the fuel injector connections? Even though they were checked during rebuild IF I can trust that Albert shop.

Any comments, related or not, please share them with me!

 

Boost leak for sure buddy

Pressure test to Markskis instructions.

Get ready to pressure test reguarly if you want constant max performance

Good luck

Cheers Tim

 

Epl tune? Tony doesnt use a 5 bar fpr w/72 lb inj. Also using injector adaptors are asking for trouble .i had 3 bad epl inj. 1bar w/g?

You need to set the w/g to 14 psi and install a 3.8 fpr hardwire the inj. Connectors then boost test log and retune

 

Car was originally tuned by well known VGS Motorsport in a MAHA dyno with stock FPR and bigger injectors.

I don't understand why the heck this other shop Albert Motorsport who did the engine rebuild changed the FPR to a 5 bar version, I didn't ask for it.

 

Doesnt matter needs to be changed

 

Kaizu,

here are explanations of those codes from The Diagnostic Manual:

P1109 Input variables, charge measurement above limit

Diagnostic conditions
*Engine running
Possible fault cause
*Heavily soiled throttle
*Throttle adjusting unit faulty
*Mass air flow sensor faulty
Note! In case of a defect in the MAF sensor, this fault must also be stored in the fault memory.
Diagnostics/Troubleshooting
1. Check throttle adjusting unit for dirt (visual inspection)
2. Check voltage signal of MAF sensor
-Ignition on 0.9 - 1.1V
-Engine running idle 1.2 - 1.5V
*If not OK, replace MAF
P1250 Boost Pressure Control Deviation - Above Limit

Diagnostic conditions
*Boost pressure control active (operating condition close to full load)
*No faults in mixture adaptation, pressure sensor, ambient pressure sensor, frquency valve
Possible fault cause
*Bypass flaps incorrectly adjusted
*Turbocharger faulty

Diagnostics/Troubleshooting
1. Check adjustment of bypass flaps
2. Check whether turbocharger compressor shaft can rotate freely.

I'd suggest clearing all codes and logging with Durametric :
-throttle position (and voltage, if it was available...)
-MAF voltage and flow
-boost pressure
-RPM
-ignition angle
-engine load
-fuel trims
-injection duration

EDIT (after getting info that boost is peaking to 1.6 bar...):
IMO the logic behind these two codes together is that throttle is commanded fully open, but yet the boost pressure and/or engine load doesn't correlate with what it is expected to be. And MAF flow compared to lambda sensor readings is within some range. Ie I'm not betting on boost leak, I'm betting on stuck (partially) closed WG(s). OR WG rods lenghtened too much! You mention that Albert has tinkered wastegates. You should ask them what they exactly did.


So, just to confirm that everything is OK, I'd
-remove the Y-pipe and see if TB moves freely / ignition on but engine not running, pressing the throttle
-remove compressor inlet pipes and handcheck compressors rotation (and blades condition)
-check WG actuator rods movement by hand and if adjustable, "shorten" rods few mm's and test.
(Go to VGS for retune.)

 

They're overriding the ECU's ability to control boost rather than changing the ECU's internal target boost numbers. This would explain at least one of the codes! Replace the FPR with a standard one, set the W/G for proper base expected boost, make sure you have enough injector, have it properly tuned...