Mods in SIG.

A few weeks ago or so I was driving my car pretty tough through some turns and all of a sudden I lost boost pressure. The only thing that was changed recently before this was the install of a ZZP highflow cat DP. I couldn't build any boost for the drive home unless I restarted my car. Once it was restarted, I could again boost up but not as high as before, and by no means use my tune. If I full throttled and built above 10psi or so it would loose boost again and go back into the limp mode and not build up again until a restart.

Since the problem started, I've tried reinstalling all the charge piping with new clamps and making sure the alignment is right. Attempted to adjust the wastegate, but those nuts are in such an awkward angle I wasn't really able to do much with them. I've visually inspected the intercooler and yes its a little scratched up, I didn't see any real significant damage.

I took my car to the dealership yesterday and I was informed that there is a recall on the fuel pump. They ordered it and will install it next week. They however wouldn't check out my turbo, or over the phone it didn't sound like they really did since I have after market intercooler and charge piping. They noted that the intercooler had some rock chips and scratches, stating the issue could be it. I will definitely reinspect the intercooler and take it off this time and look over it completely. I didn't do the most thorough check previously.


My ideas on what could be wrong,
Losing fuel rail pressure, which would explain why a restart would again allow me to build up some boost again. (Hopefully the new pump or part the dealer ordered for the recall could fix some issues if this is the problem)

Boost leak from piping, which I'll be checking for again but this time with a compressor and some soap water. What size PVC cap do you need to use to plug the start of the piping?

Boost leak from broken/cracked intercooler, I really hope it isn't this since I'm on an aftermarket intercooler already. It is possible because I have bottomed out a number of times.

MAF and O2 sensors could need a good cleaning. I did recently (after the start of the losing boost issue started) install a new hot side charge piping tube.

Other side effects making it not drive well, maybe spark plugs need to be checked? I replaced them a few months ago but I didn't adjust the gapping at all. I used the default gapping the AC delco plugs came with. Is this an issue?



So here are all the codes my car has had in the last few months or so. I've replaced the EVAP solonoid and haven't had any issues with the EVAP codes. The lean/rich and misfires are what worry me. The first set of codes are from about two months ago and I cleared them to see what returned. The second set is from a month after the first set to see what codes would reoccur.
SET1
P2178 dev:05E8 history ses stored system too rich off idle bank 1
P2187 dev:05E8 history ses stored system too lean at idle bank 1
P0300 dev:05e8 history engine misfire detected
P0304 dev:05e8 history cylinder 4 misfire detected
P2187 dev:05e8 history stored system too lean at idle bank 1
P0496 dev:05e8 history current evaporative emission (evap) system flow during non purge3.


SET2
Codes 10/29/12 (After install cold side charge piping)
Two Times P2178 dev:05E8 history ses stored system too rich off idle bank 1
P0101 Dev:05E8 History Mass Air Flow (MAF) Sensor Performance
P0299 Dev:05E8 History SES Current Stored Turbocharger/Supercharger A underboost Condition
P2187 Dev: 05E8 History System Too Lean at Idle Bank 1




Any advice or tips on what to check/work on would be appreciated. Are my idea's on what could be causing it to drive like **** right?

 

I would go with the intercooler on this one (I know you don't have the stock one). Perhaps a weld broke?! Or, a BIG ASS boost leak. Boost leak test to find leak. I would start there.

 

I cleaned the MAF near the intake, seeme to help a little bit. Im going to clean the one on the cold side next and see if it helps any.

Have you ever heard of testing for boost leaks with ether or starter fluid? A buddy told me to spray areas that are thought to be leaking with the engine on. The engine will rev up if it sucks in any of the fluid and it'll show if you have a leak or not. Seems way easier than making a PVC plug and testing with shop air.

 

I know this thread is a few months old, but I'd do the boost leak test first with soapy water. You can spray some carb cleaner on the mating surfaces, but the engine has to be COLD (Smokey the Bear would be upset).
Propane is the preferred method. Just crack it open, and then listen for a change in rpm (rise).