[Vroom]

This thread discusses searching for boost leaks and vacuum line leaks on cars where the boost target is normal, JB4 PWM (duty cycle) is high, but boost is heavily below target.

We suggest first looking for obvious leaks like a blown off chargepipe, loose diverter valve, missing oring or meth bung plug from chargepipe (if newly installed), and then if you can't find anything do the vacuum line test shown in this video before digging deeper in to possible boost leaks.

After doing the test in the video if vacuum remains at 0 or low regardless of the DWP JB4 setting then you likely have a vacuum line leak, faulty JB4 board, wiring harness issue, or faulty boost solenoid. If vacuum is 18" or higher with DWP = 100 then you likely have a blown off chargepipe or intercooler pipe.

Should you determine you have a faulty or worn solenoid, we've got brand new OEM quality (e.g. not the Chinese fakes going around) in stock and ready to roll for $99 each: http://www.burgertuning.com/N54_JB4_upgrades.html






Spent a lot of time the past week trying to diagnose a 30FF. (Boost Log is NOT matching Target)
Thanks to: Terry for supplying lots of technical data via a few dozen emails, and Rob @ RB.
Since 30FF can be from a leak in the pressurized section of the intake track and/or the turbo just isn’t putting out enough, I broke this up into 2 areas:










1. Turbo compressor (COOL side) to intake manifold/head interface.

a. Test entire intake system.

b. Test Diverter Valves

2. Turbo compressor operation(HOT side) –

a. Vacuum system & line integrity

b. Wastegate actuator & line integrity

c. Solenoid functionality

The sequence of the tests is not so important. You can start with the tests you already have the tools or time for and stop if you are lucky enough to detect & fix the problem. Just remember that there can be more than 1 source for the 30FF. You’re not done till the 30FF’s stop popping up.

OK, I had already made several fittings to tap into, plug and pressurize sections of the OEM intake system.
After removing sections of the intake system and checking them independently, it was obvious they could leak when they were put back together.
So after playing with all the new gadgets I wanted to test the system w/o removing any parts that are exposed to boost pressure.


Step 1a Tools & Equipment
• Compressor w/ regulator, GOOD pressure gauge, hose
• Very quiet garage to listen for leaks – beware of neighbors watering the lawn
• Squirt bottle w/ Dish soap & water
• (2) - 1-1/2” PVC pipe cap ($0.77 each @ Menards)
• (1) - ¼” NPT male hose fitting ($0.25 @ Harbor Freight)

Prep work:
Remove any bumps (injection molding gates) on the OD of each cap w/ a file (if necessary, depending on mfg.). Make it smoothed.
Drill & tap 1 cap to install air fitting. (7/16” drill, ¼” NPT tap)



Next,
Get front wheels off the ground – ramps, jack stands or lift
Car off and cool
Remove the 14 screws & engine splash pan
Remove the DCI’s (or air filter box) to access the 2-1/4” accordion intake tubes.
Install plain PVC cap in the F tube and the other cap w/ air fitting into the R tube and tighten hose clamps.
**If running OEM crankcase venting system you must Plug the rear air intake tube at the PCV return tube heater element**-edit on 8/25/11
Set the air pressure regulator to ZERO and connect air hose to cap fitting.



You are now “in Theory” ready to pressurize the whole intake & exhaust system from the air inlet to exhaust tips. Not sure why but didn’t need to use exhaust tip plugs I made cause air was not exiting the exhaust. Only thing that comes to mind is no overlap between intake & exhaust valves. Ideas welcome…

SLOWLY increase regulator air pressure to 10 psi (it’s high enough to find a pretty small leak).
Filling up the whole system takes some time and can sound like a leak when filling. Give it time & let pressure stabilize.
The air intake tubes are not designed to hold pressure but they do hold some. Mine held to 12 psi B4 rear turbo inlet started hissing. This is NOT a boost leak but the weakest joint in this test method.
Don’t go leak hunting if a turbo inlet is leaking @ 10 psi. You may need a buddy to hold intake tube onto turbo @ 10 psi if leaking there or get creative and wedge it in place.

Reference Picture from Hotrod's post, I did NOT remove my engine!


Listen & look, squirt soapy water anywhere/everywhere you suspect & look for bubbles to confirm leak. Get under the car & check both turbo connections, piping, connectors, FMIC, elbow, DV or BOV & recirculation tubes, vacuum/boost lines to DV’s, Charge pipe, Throttle body, intake manifold to engine head. Fix any leaks & retest. If air tight @ 10psi you are done with this step.

Here’s what I found!





Step 1b.Test DV’s

See Terry’s Post http://www.n54tech.com/forums/showth...light=diverter

A few other options




I also rigged up a way to pressurize the DV’s , CP & elbow as an assembly. Used syringe w/ Tee to both DV’s.




Step 2a. Vacuum system & line integrity - Tools & Equipment
• Vacuum gauge
• Pick or small pry tool to remove vacuum hose




Vacuum to Wastegate solenoids
Follow hose from the top a canister to a solenoid. Remove hose at the solenoid and connect vacuum gage. Start car, gauge should read about 26” Hg at idle. Don’t know acceptable limits but if it’s much lower than 26” trace ALL hoses all the way back to vacuum pump (behind oil filter). Replace leaking or pinched hose.
Reconnect the hose and repeat the vacuum test on remaining solenoid.

Attachment 7811


Step 2b. Wastegate actuator & line integrity - Tools & Equipment
• 100cc or larger syringe
• 5/35” Tee
• Towel Clamp or long nose vice grip

Test can be done w/o a Tee by connecting syringe directly to braided hose going to wastegate actuator. (Easier said than done)
Since a Tee is needed for Step 2C you can save time & aggravation if you:
Cut the 5” long hose that’s between the 2 OEM tees (see below)
Use clamp to Pinch the short hose that runs down from the Rear Tee to the Rear Solenoid
Connect syringe to the Hose you just cut


Apply vacuum by pulling syringe plunger and check for smooth movement of actuator rod and a metal to metal sound when the wastegate closes.
Once wastegate is closed it must remain closed and the force needed to hold the plunger steady must remain constant. If it gets easier to hold the plunger in place it means the hose and or actuator is leaking.
Repeat for front actuator connecting syringe to remaining 1” of OEM tube & pinching front line between Tee to Solenoid. The front actuator that is NOT visible from above engine. If you don’t have access to a borescope to watch the rod movement, listen closely to the sound and compare to the front. If you can’t see the actuation rod you will have to make the call (by listening) if it’s operating like the rear actuator.
Connect Tee and go to next step or plug the open end of the Tee if you are done.

Step 2c. Solenoid Functionality - Tools & Equipment
• Vacuum gauge
• 6’ of 5/32” vacuum hose
• 5/32” Tee ( if you didn’t take my advice in 2b)

EDIT See Terry's Video: http://www.n54tech.com/forums/showthread.php?t=16548

Install 5/32” Tee into vacuum hose you cut in 2b.
Connect 6’ hose to Tee & gauge


Route gauge thru drivers window & into car
Getter warmed up, cruse at about 60 mph in 3rd,
Go WOT, w/ a Tune the gauge should spike then hold at about 20” while under boost.

If the 30FF is not gone then there’s only 2 more options:
1. Wastegate rod adjustment per Mr. 5 http://www.n54tech.com/forums/showth...ight=wastegate
2. New Turbos – Contact Rob @ RB

Best of Luck!

[Bimmerocious]

Very nice!

[Terry @ BMS]

Nice DIY! I'll move it to the DIY section and sticky it tonight.

[Vroom]

Originally Posted by Bimmerocious

Very nice!

Thanks, I Hope it gets some mileage.

Spent more time on the DIY than the leak.

[Vroom]

Thanks dzenno, you have certainly done your fair share of technical stuff.

[rwalker]

How did that IC o-ring get so buggered?

[Vroom]

My Insurance company paid BMW auto body shop to replaced my HPF FMIC and some other parts after I drove over road debris. While the body shop was at seperate location from the mechanics/techs, I figured they would have known better.

[E36graduate]

Nice write up.......curious, how did you gain access to the turbos as seen in the 3rd picture? It looks like the engine is out of the car????? I have not yet had to do any work on my turbo area and have not quite figured out how to get in there so I'm hoping you can tell me how you took that picture?

[Vroom]

Whoa. I didn't remove the engine, I'll clear that up. I copied the Picture from Hotrod's post.

[xbox_fan]

Great DIY!!!!

[Vroom]

Thanks xbox, I have used a number of DIY's and it was time to spend some time doing one.

[Hocky]

Originally Posted by Vroom

You are now “in Theory” ready to pressurize the whole intake & exhaust system from the air inlet to exhaust tips. Not sure why but didn’t need to use exhaust tip plugs I made cause air was not exiting the exhaust. Only thing that comes to mind is no overlap between intake & exhaust valves. Ideas welcome…

Air didn't come out because you're not pushing any air into the exhaust system. The throttle body is closed.

[NJrep335I]

Very Nice write up!

[NetEagle]

Awesome piece. You da man!!!

[Vroom]

Originally Posted by Hocky

Air didn't come out because you're not pushing any air into the exhaust system. The throttle body is closed.

Throttle body is closed, but I don't believe it makes an air tight seal. Thought about this and remembered in one of my many trials I had front DV recirculation tube disconnected & pressurizeed thru the 1" fitting the tube was connected to. If there was a 10 psi differential across the TB the DV would have opened as they did when I bench tested the CP & DV assy. To put an end to this I need to check intake manifold pressure @ DV hose nipple when I pressurize. Too darn HOT thru the rest of the week.

[Vroom]

Originally Posted by NJrep335I

Very Nice write up!

Thanks man,

BTW, I lived in the Meadowlands most of my life.

[Vroom]

Originally Posted by NetEagle

Awesome piece. You da man!!!

Thanks, may you never have to read it again!

[Vroom]

Originally Posted by Hocky

Air didn't come out because you're not pushing any air into the exhaust system. The throttle body is closed.

Not the throttle body. Retested and pulled the small hose off intake manifold & air was passing right by the TB & thru the hose.

[Nick0780]

Getting boost leak code not to far after changing my inter-cooler. Gonna boost test this weekend hoping the leak is at the inter-cooler couplers like yours. Wish me luck. Thanks for the DIY

[Vroom]

Most likely you nicked an o-ring. I dumped the OEM "Quad" o-rings and went to a standard round cross-section BROWN VITON O-RING -230 (2-1/2" ID X 2-3/4" OD). You can find them on eBay. PM me if you need help.

[Nick0780]

Just got em off ebay thanks. I will swap the O-rings before I waste time pressure testing.

[Vroom]

Change the o-rings and log boost & target. If boost is tracking close to target, you're done!

[Terry @ BMS]

Made this a sticky in the support section.

[Nick0780]

I'm pressure checking right now because of 30ff and my oil cap hisses at 12 psi. Car holds pressure fine when when i press down on oil cap. Can anyone chime in on whats going on?

[dreamk]

i did this and after i stared the car, all this smoke came out the tailpipes. im guessing it was burning all of the oil in the fmic....