The Wizard

iTrader: (43)

I've come across my second hurdle with the Max. First problem was the coilpacks that reared their ugly heads once I became boosted 2 years ago. Now, I have a new dilemma, I mysteriously lost 2 psi of boost.

Here's the timeline of events:

1. Installed UR Ultra SC lightweight crank pulley and custom CAI
2. Lost 2psi of boost (9.5 to 7.5psi)**
3. Realized crank pulley was not stock size. Blamed lost 2 psi on slightly smaller crank pulley. Made arrangements with UR to make a true OEM stock size crank pulley
4. Installed MEVI
5. Installed Cattman Headers (fully ceramic coated*) with O2 simulator
6. Installed Innovative LC-1 WB O2 kit
7. Receive stock size UR lightweight crank pulley
8. Installed and expected to get 2psi back
9. Denied!!
10. Reinstalls OEM crank pulley for the heck of it. Still at 7.5 psi.
11. Spent days and days troubleshooting every single component on the car (boost leak, spark plugs, etc etc)
12. Gives up and posts on the org!

13. Suspects simulated downstream O2's are the culprit. See link:
http://forums.maxima.org/showthread.php?t=516441

14. Suspects mysterious knock sensor code could be the culprit. See link before you jump to conclusions. Note: I've had this weird knock sensor code forever, even when I was able to boost to 10psi.
http://forums.maxima.org/showthread.php?t=515963

*Headers were sent to HPC prior to install to be ceramic coated (inside and out) to help exhaust scaveging, lower engine bay temps

**I was convinced the UR pulley (incorrect size) was the culprit, as I helped Ptatohed install his UR crank pulley only days prior to mine, and he lost 2psi as well (12 to 10psi). We figured, that when we got the correct size crank pulley, we would get our 2psi back. Now it appears to be something else.


Cliffs: Did a bunch of mods, lost 2 psi, doesn't know who the culprit is,


Current mods: 3.25 pulley, Vortech FMU with 8:1 disc, Vortech Aux Fuel pump, MEVI, Cattman headers, fastcat, and catback, OEM one step colder platinum plugs at .038 (to be changed to copper and gapped at .035) I'm still using the stock injectors, stock MAF, and stock ECU. All 3 were about to be changed, but I'm holding off until I figure out my problem.

Things that are noteworthy, potential clues:
Used to hit 9.5psi, now can only hit 7.5psi
Fuel pressure has dropped from a maximum of 100psi to 65-70 psi
WB XD-16 gauge says I'm running pig rich, often 9.9 at WOT!!

Things I've looked at/for:
Spark plugs
Boost leaks
Leaky BOV
All vacuum lines/connections
Slipping belt
MEVI butterfly screws are intact

I'm pulling my hair out and my head. Please help.

SonicDust187

iTrader: (11)

Maybe the belt is slipping. Also the boost gauge could have gone bad.

The Wizard

iTrader: (43)

I edited my first post as I forgot to mention that I have checked and double checked my belt tension.

As far as the boost guage, I thought of that too. But, the fuel pressure is low at the same time. Also, on the butt dyno, my car feels slower. For the heck of it though, I'm going to install Ptatoheds's boost guage and see if I get different readings....

slimer

iTrader: (13)

I think its because you're ugly.


No seriously, what type of clamps do you have?

Did you install the AWAC like Josh?

Check your MEVI gaskets (TB, etc.).

Matt93SE

iTrader: (44)

Exactly where have you looked for boost leaks?
on/near/around/below the manifold?

manifold itself?

how are you looking for leaks?

slimer

iTrader: (13)

Have you done the soap water trick?

The Wizard

iTrader: (43)

I've looked for boost leaks everywhere using my eye and feeling for the presence of air using my hand. Checked all vacuum lines, checked the BOV (even put back on the Bosch stock BOV), checked all silicone couplers for rips, checked tightness of bolts for TB, egr, IACV, checked manifold gasket and torque of 4 bolts holding it down.

Part of me thinks it's a boost leak, but my boost gauge reads a normal -20 vacuum at idle.....so I kinda dismiss the boost leak theory, but still checking none the less.

slimer

iTrader: (13)

I had a pinhole in a hose underneath the TB at one time. Idled at -18inhg.

It wasn't until I boosted that there was a problem.

The Wizard

iTrader: (43)

Not yet Steve.

As far as clamps, I have the nice heavy duty T-clamps. I rechecked them for what it's worth.

When I installed the MEVI, I used brand new OEM gaskets for the manifold, TB, IACV, and EGR.

As far as the AWAC, it's not installed at the moment. While my car was down waiting for HPC to coat the headers, I installed the heat exchanger, mounted the water pump, and started on the plumbing. Could be done in a couple of hours, but I'm not looking forward to the many hours of taking off the SC and putting on the 2.87 pulley to compensate for additional lost boost.

Alex_V

How many miles are on the blower? I know nothing about the SC's, but are there oil lines? Maybe it needs rebuilt?

~Alex

Kevlo911

iTrader: (36)

LEDs made up for the hp loss


Maybe a bad fuel bump since your fuel pressure is messed up?

trialt

I honestly think this is belt slippage... Ive checked many things as you probably saw in my earlier posts. I even had it tensioned and triple checked. I sprayed some belt dressing and that fixed it. maybe you could try that? I found that solution on the vw forums.

Mad-MAX_SE

iTrader: (2)

you know, i really don't have any basis to input any information to this discussion, but sometimes the most likely solution to a problem is the most obvious. What kind of miles do you have on your blower? is there any chance that the impeller could have gotten damaged when you installed your CAI?

Anyway, i just figured i would toss that out there.