[threethirtyfive]

FBO (minus cp/dv), JB4 G5 ISO, 4 gallons of e85 on Map 5.

Always had some breakup at high boost and RPM until I replaced the plugs. All was well.

I then noticed that if the car sat on a hill or just in general it would occasionally crank slow, start rough and run choppy until restarted. Ran well but occasional issue I attributed to the fuel pump. Had not pulled codes yet (clearing was on for the cats).

Last night I hit the gas in third and get the same complete loss of power and limp I have had happen a few times. Really just feels likes fuel. Car stalls as I pull off, restart and it's weak but I get home, anytime it hits higher RPMs it breaks up like is out of fuel.

Today the car is not well. Won't rev past 5k, making no real boost and it's giving me a 30FC code. Redid all of the couplings, tomorrow I'll throw on my vacuum pump and check the lines. I'm stumped though, the car will not leave this disabled mode and will not make boost. After a little load or a rev to 5k it launches half engine power mode. Less than 2k on new OEM turbos. My list of guesses.

- Wastegate jammed, this happened at 6500k.

- Vacuum line damaged

- Wastegate solenoid failed, I think mine is ticking. Bad or good?

- CP/DV valves leaking and or failed. I think the OEM CP to upper IC hose coupling may be toast.

- A boost leak I am missing, I have a pump so I will test this as well.

- New plugs were fouled quickly?

The trouble I am having is that it feels like its fuel pump related the way the car drops off, only at high RPM. The only code I get is 30FC and my ability to drive the car is very limited. Anything over 40 MPH and the car just does not want go which makes it dangerous and hard to drive. I'll try for some driving tomorrow to get additional codes. The tough part is that it just won't leave this reduced power mode. Even after a fresh start the car won't really rev last 6000 and quickly starts to drop before stopping at 5k and throwing reduced power mode. That's parked, if I drive the threshold is much less.

Tomorrow I start by pulling the JB4 just to rule that out. I am really hoping that at least gives me a normal running car. I'll also just make sure the WG's and solenoid a are working.

If that fails it's on to checking vacuum and boost lines. I'll also pull a plug to look at it. They have 2000 miles but why not.

I'll also end up doing this last one regardless, a CP and DV, just to eliminate any possible risk of leaks.

Anymore of the 30FC? There is NOTHING out there that has any details. It's a turbo density error, seems related to the 30FF. Aside from this I got nothing. What's concerning is the inability to leave the limp mode. It's a trifecta, no boost, RPM is limited and load makes it all come much much quicker.

I'll post updates tomorrow. Open to anything. Could it be Vanos it LPFP?

[135Hoser]

A quick google says that one person who had a 30FC code had an issue with their wastegate(s).

I would start there and work my way back.

If you had OE turbos installed under warranty or by a shop, take it to them and ask them to check the wastegate operation, should be free of charge.

Make sure they aren't hung up on anything.

If you think you have an issue with the intake, do a smoke test. Any big leaks should become obvious pretty quickly.

I'm not sure if a ticking wastegate solenoid is good or bad. Terry@BMS has a video up for how to check your wastegate solenoid. http://www.n54tech.com/forums/showthread.php?t=16548 or the video directly: http://www.youtube.com/watch?feature...&v=80TYILifxy4

Good luck!

[threethirtyfive]

Yeah I have been all over Google and the details appear it's a Wastegate control code. The dealer replaced the turbos under CPO in Feb. Warranty ended but they should at least look at this. The few lines I checked held vacuum with my pump but I didn't make it to the WGs.

Calling my SA tomorrow. If he will cover it I will just drop the car off.

[threethirtyfive]

After more digging....

Jumping into vacuum lines tomorrow. Most seem to be holding but this seems like a good bet.

I still think the fuel is the problem, this is a new feeling. I just can barely get the car up the street let alone into boost so it's hard to see if I'm not getting the fuel.

[135Hoser]

Originally Posted by threethirtyfive

After more digging....

Jumping into vacuum lines tomorrow. Most seem to be holding but this seems like a good bet.

I still think the fuel is the problem, this is a new feeling. I just can barely get the car up the street let alone into boost so it's hard to see if I'm not getting the fuel.

Do you have INPA? I know for sure you can check low/high pressure fuel pumps in there.

I think there is also a value JB4 tracks. Have you tried putting the car back to map0 and seeing if its still misbehaving?

Fuel could be an issue, but the DME which is pretty darn smart is saying its wastegates. Theres a whole smattering of fuel related codes for the car to throw. Since its not throwing any of those.. =\

If you haven't already, see if the car still acts stupid driving in map0, also make sure canclear is turned off just incase theres other codes getting cleared.

[threethirtyfive]

I do, good call, I will also look to see if the new firmware of the JB4 has the ability to check requested vs. actual fuel pressure.

Morning update. On the way to grab some tacos this AM I try to start the car in the garage. This time no stumbling, no rough start or idle, car levels right off. One press of the gas pedal brings me back to reality. The car just won't rev, it's giving me reduced engine power from the start, feel like the crank is in peanut butter over 3k RPM.

This is odd, in the past the only problem I have had that was consistent like this was cold starts to rough idle until I restart or the motor catches up. This is why I always assumed it was fuel pump related.

I need to pull the rain tray to check the vacuum lines so I will also just pull the JB4. If neither of those steps work then its on to the WG solenoid, WG's themselves.

The one thing that is REALLY throwing me off is the reduced RPM and sinking RPM even from a cold start. All of the examples of half engine power I have seen clear after a start and then begin with an error and code. The car starts with the limit and a second or two at 5k causes half power mode it makes me feel like something with timing/vanos could be a culprit as well.

If I could just get some more codes! I seem to have gotten the most random code out there with 30FC. Everyone gets 30FF, boost leak. I have seen very few 30FC examples and sadly most of them seem to be randomly posting help questions in threads with no response.

Originally Posted by 135Hoser

Do you have INPA? I know for sure you can check low/high pressure fuel pumps in there.

I think there is also a value JB4 tracks. Have you tried putting the car back to map0 and seeing if its still misbehaving?

Fuel could be an issue, but the DME which is pretty darn smart is saying its wastegates. Theres a whole smattering of fuel related codes for the car to throw. Since its not throwing any of those.. =\

If you haven't already, see if the car still acts stupid driving in map0, also make sure canclear is turned off just incase theres other codes getting cleared.

[threethirtyfive]

Well... Not sure what to make of this.

I tried two things.

- Pull the Stett CAI, I left just the bridge between the two turbo inlets.

- Resealed the vacuum line to the exhaust valve, this time in the engine bay.

Get in the car, start, perfect. Drove around the block, warmed up her, hit full boost. No codes, no stutter. Wow. Stett is back in and car is still running well. This was odd, I have to say. I'd like to chalk it up to just a chance but the fact that it persisted through three days is WEIRD.

I am going to start pulling some logs and leave the code clearing off. Well at least she is back in action.

[johmei]

Bump, i get a 30FC after JB4 + NLS kit install. Already had Cobb installed with stage 0 with DP code suppression.

Googled on my phone a bit but only found threads with a question. Now I find this thread and the conclusion is seal exhaust valve line?! Mine is sealed but I have opened valve using Jb4. I also reinstalled forge DVs and DCI at the same time the JB went in. Installs seems ok but will refit DVs just to make sure.

Also have a aquamist HfS-4 installed and not integrated with Jb4. It uses the stand alone fail safe opening WGs and triggering 30FF.

Any ideas where to start this search?! Already went through the classic 30ff problem last year. Changed all vacuum lines, solenoids, charge pipe and refitted IC and charge piping from turbo to TB. Probably had smaller charge leak(s) that triggered 30ff at high RPM (5800+) in 4-5 gear.

The 30FC seems like something different as it triggers a lot easier. Not always a limp but had half engine light come on multiple times in jB4 map 4, 1, 2 and 5. Could it be Jb4 install issue?

[johmei]

Update: With JB4 on stage 0 and cobb stage 0 I still get the same problem after reinstalling DVs. Seems like I have to uninstall JB4 and see if the install is the source of my problems. Car boosts really well until it stumbles and stops boosting. If I keep holding the accelerator down the ECU throws half engine light after a couple of seconds.

[johmei]

Resolved 30FC by serviceing my Forge diverter valves. One was clogged in the small "maneuver pipe".

This was found after hours of testing to all components on the vacuum side as the 30FC code suggest it is on this side. I even tried deleting components that are redundant in the vacuum system. Finally made som runs while tapping in 2 vacuum/boost gauges on both boost and vacuum sides.

My logs from low RPM looked as follows in Cobb (recuested+actual boost) and JB4. As soon as I hit good boost I loost it quickly until I had close to 0PSI, the I could start to build boost again. The logs are 3-4 WOT pulls from low RPM and aggressive mappings. The same happened on lower mappings. 12-14 PSI was enough to open the DV and leak all boost. Weitrd thing is that it triggered 30FC time and time again and not 30FF.

If you have Forge DVs I urge you to service them and remove all paint from the springs in the process as this mix with the grease and create a sticky mess that should not be in there.

[enrita]

Many have issues with the new style forge dvs