Would a leaky BOV cause the car to do this (see images below)? The BOV on the car is by APS so it's 1/2 recirc and 1/2 vent. I also have a Buschur intake pipe and filter that might be relevant to the problem since aftermarket intakes and pipes sometimes drive the MAF crazy.

ECU+ screen shot:

Check out MAS Input Freq, Injector Pulse Width, Injector Duty Cyle, Knock Voltage, Boost, and Air/Fuel Ratio. The car sputters right when the curves act weird but picks up and drives fine after the curves calm down.


Here's the ECU+ log
http://home.comcast.net/~y2kevse/ima.../060706_03.ecd



LM-1 screen shot:

Again, same thing. You can see the boost drop and the A/F drop greatly. Only Boost, RPM and A/F Ratio apply (the other 3 aren't hooked up).



Comments? Suggestions? Thanks.

 

Do you think the BOV is leaking? If so then you could test it and adjust it accordenly. Or is it possible that you are hitting fuel cut or something?

 

It looks like either a boost cut or knock event.. but its hard to tell from the data..

 

I'm not 100% sure because the external WG opens up and it's really loud... loud enough to drown out other noises. However, I "think" I hear the BOV sputtering but can't be certain.

I've had the car flashed by Al so I assume there is no boost cut anymore. I'm also running EcuFlash.

I appreciate your input.

 

I have 4 more screen shots that may help, which I will post in another post. It looks like the knock event might be caused by being too rich so sudden. Do you think so?

 

As you can see here, timing isn't really being pulled during the erratic area. The sputter always seem to happen when peak boost is first reached, then it calms down after the incident. Note the high spike in knock voltage. IPW and IDC have blips as well.



Here is one that isn't at WOT. Note that boost goes only to 20.5 psi (1.3 bar WG spring) but the sputter happens before that... starts at about 4600 like the rest of the logs.



Here's one with no timing getting pulled. This time, however, AFR spikes up a bit instead of going rich.



One last quick pull (all runs done in 3rd gear). The curves change drastically.



Here is the ECU+ log:
http://home.comcast.net/~y2kevse/ima.../060706_01.ecd

Again, thanks for any input/suggestions.

 

Stupid question, ut do you still have the stock airbox and snorkle attached? If you do, make sure the snorkle has its hold-downs in place.. The drop in MAF is consistent with an obtruction (the snorkle getting sucked up under the hood)

 

nevermind, saw your first post with the buschur pipe and filter..

It very well could be the BOV opening on you..

The MAF reading is all over the place, and your knock voltage is overal high and climbing in those areas.. Timing doesnt appear to be pulled suddenly but the injector duty seems to jump around as the MAF jumps around..

Can you try putting a stock airbox and pipe back on? I've seen some intakes do similar weird things, but not the Buschur one, at least not as dramatic as that shows..

there are a few things to look at..

1) Fuel cut due to very fast spool (Ecu can do this)
2) A bad intermittant air leak or bad connection to the MAF
3) check the honeycomb on the MAF for damage or if its loose
4) Increase the seat pressure on your DV, make sure it seals up tight (too tight) to be sure thats not the problem.. (it does happen to me occasionally)

See if your not getting a P0300 code in the ECU, this type of surging sensation could be due to it detecting that..

I do notice on rare occasions that the vehicle speed sensor drops out (zero value) on my car I wonder if that would happen if it would momentarily engage your stationary launch control if you have it set.. I never noticed the sensor dropping out in the past due to no good logging options at the time.

Thats some stuff to look at..

 

It might have been raised, but might not have been disabled.. So its entirely possible.. Al generally sets the boost cut setting as high as it will go, and the delay timer for a very long time so it should never get triggered...

Usually if the car sputters and drops boost, the DV opens anyway as the differential changes.. But as a test, increase the spring pressure and see if it goes away.. If it does, then you can make your adjustments for the best balance of boost and easy opening..

Check the lines you have your boost control and DV connected to.. WHo knows if you have a restriction, leak, kink, or other thing preventing something from working right.. also make sure none of the couplers or pipes came off or is leaking.

 

I wish I can put the stock airbox in again, but I can't anymore because I just finished installing Buschur's GT35R about 6 days ago.

Swapped the APS BOV with a GReddy RS BOV (full recirc) today.

1) I don't think it's fuel cut because I can duplicate the issue in 4th and 5th gears at low PSI (I'll post the screen shots in another post)
2) I did a boost leak check today and everything was fine. Filled the car up to 15 psi without any issues except a couple VERY minor hissing sounds coming from the turbo itself. The two leaks are from the back of the compressor side on 2 bolts. I tightened them but the VERY VERY VERY small leaks are still there.
3) Honey comb looked perfect.
4) I included the BOV in the boost leak test, which was perfect.

Yes, I do get a P0300 code, but that's because of the ECU+. I tried the beta software, but found some bugs and reverted back to the older version per Tom's suggestion.

I occasionally get an upward spike for the vehicle speed, but never seen a dramatic drop.

 

Al increased the Boost Limit (seen in EcuFlash), which worked perfectly when I was on the stock turbo using methanol boosting 25 psi. Never hit boost or fuel cut then. Looks like Boost Cut Delay Timer is still the same, but I'm using a Blitz EBC (doubled checked the EBC hose connections today and confirmed that they were correct).

Today, I swapped the APS BOV with a GReddy Type RS BOV (fully recirc) but still had the same sputter issue.


I have a feeling the TiAL WG is opening too early for some reason. I've had a TiAL WG before on my turboed Maxima and the Evo sounds exactly like it when it's sputtering. It's doesn't sound like a BOV whoooooosh. It's more like how when the WG tries to control boost when it's opening and closing rapidly... like whoooo whoooo whoooo whoooo. Sorry, it's hard to describe.

Is there an easy way to check for a faulty WG? I turned off the EBC but the car still sputters.

Thanks for your input, Jack.

 

Here are the screen shots.

This pull is in 4th gear. Note the knock voltage is VERY quiet but the timing, MAS freq, ipw, idc go all over the place. AFR dip into lower 10's near the end.



This pull is in 5th gear. All relevant curves are erratic. Boost is under 7.5 psi but the car still sputters through the whole pull. Again, KV is VERY quiet.



Another pull in 5th. Curves aren't as erratic.



Hard pull in 4th. Curves get weird when approaching 20 psi. AFR dips dramatically right after the cursor. Another quiet KS run.



Quick pull in 5th. You can imagine how much the car was sputtering during this one.

 

If you look at your ECU's map, I'll bet your jumping outside the load cells, over 260 (if its still 0-260) I get the exact same symptoms under some circumstances (high MAF reading)

 

Actually.. I get an occasional P0300 code now too.. (same Turbo kit)

Anyway, I'll have to ponder this a bit because its nothing completely obvious from your logs..

 

kevin your timing in that region is way too high in some of those datalogs. the 35R does not need that kind of timing to make power. it also doesn't need to ramp up agressively like the stock timing profile.