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Discussion Starter · #1 · (Edited)
Hey all!

I've been doing a whole bunch of maintenance to bring my R to an acceptable level to receive a stage 1 tune. Fuel filter, spark plugs, o2 sensor, air filter, etc. Running a snabb turbo inlet as well.

I did a datalog the other night to see if the car was running healthy before i get the stage 1 and sent the log to the tuner. Boost was in the correct range, but my MAF was reading much lower than it should causing the car to lean out and causing severe engine knock within the upper RPM range.

Now obviously, the culprit could be the MAF sensor but i would like to troubleshoot before i throw $140 out for a sensor. I scanned the car and did have an evap code, 4007, signal too low. I checked the evap lines, and while they are aging they still hold vacuum. Evap code is likely due to a failed purge valve which will be ordered. I checked the CBV lines, the CBV itself opens when you apply vacuum to it. I did replace the PCV last september, but did not replace the line that runs to the intake. PTC is held onto the intake by a hose clamp and the PCV line is attached to the PTC with a hoseclamp as well. TCV lines are new silicone ones. At idle the MAF reading is 14.5-16.1 kg/hr, which according to the tuner, is within specifications. He did say the MAF might become innacurate as voltage increases, so at idle it might seem fine.

I'm going to adjust the SNABB intake tomorrow to make sure all the sections are tight and not causing a leak. Any ideas?
 

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Did you do a smoke test to see if you have a leak somewhere?
 

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Can someone decribe how to perform a smoke test? I bought one off Ebay but do not know where to connect it to my caR
 

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Can someone decribe how to perform a smoke test? I bought one off Ebay but do not know where to connect it to my caR
Block the intake inlet, anywhere you can. Air tight of course. Inject smote into inlet, using any inlet port that is convenient and look for leaks. Only place smoke should come out is the exhaust pipe.

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Discussion Starter · #6 ·
Little update, hopefully i can get some more advice.

I still have an evap code... ecm-4007 evap system - signal too low. I also have ecm-4024 leak diagnostic unit, pump - signal too high.

I pulled the evap lines and the check valve on the intake manifold side was blown, and was letting air go both ways. Clearly this was causing boost pressure to enter the evap system and not only recirculate boost back into the turbo inlet, but also pressurize the evap system. I swapped the check valves as the check valve on the turbo inlet side only ever sees vacuum anyways, and this has NOT resolved my evap issues. I am hoping that the back pressure has not trashed my evap system. I went ahead and ordered a new purge valve anyways but am not sure if that will resolve my issue. I also ordered a new maf... but we will see how that turns out.
 
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