CTSV_510

iTrader: (1)

A little background: 2005 CTS-V (LS6), installed a mp112 three weeks ago. I had to send it back to Magnuson immediately because the rotor bearings were shot and they had to rebuild it. The got it back to me in 4 days so it wasn't too bad. After I got it on again, it fired up and everything seemed great except 20 minutes into the test drive the magnavolt died and the car shut off. They overnighted me a new magnavolt, then I added 3 extra ground wires to it (assuming that was the first problem), and then everything was finally working well.

Everything was perfect for a week or so then I started having a new problem. At WOT or near WOT and only above 3500 rpms, all of a sudden it will feel like the boost turns off and the power drops out. It will continue to rev up to redline, then I shift and everything is fine. I can describe the sound as a deep fluttering sound that happens above 3500 rpms at WOT, or very near WOT.

It feels like maybe the bypass valve is opening when it shouldn't be? I don't know. I don't think it's the belt - it's a Gatorback and everything seems nice and tight. Not sure what tests to go through.

I checked the lines (including vacuum hose to the magnavolt) and all are connected with no pinching, kinks, or loose connection. I re-read the DTCs (I am used to seeing the light on from the O2 sensors due to the headers).

P0113 - Intake Air Temperature (IAT) Sensor Circuit High Voltage
According to what I have read, this MIL will be thrown if the following conditions are met for 4.5 seconds or more:
- Vehicle speed less than 7 mph
- MAF less than 15 grams per second
- Engine coolant temp greater than 32 F
- Intake air temp below -35 F ????

P0332 - Knock Sensor 2 Circuit Low Input (Bank 2)

I'm thinking that the one knock sensor wire may have gotten pinched or something the second time I put the maggie on. I don't know about the IAT sensor - that one's got me stumped.

Needless to say, there will be no more flogging it until I can get everything fixed. Anyone think these issue could in any way contribute to my issue? It really feels/sounds like the bypass valve isn't working properly. I don't have hptuners or anything and I have no extra boost, A/F, etc. gauges to get data.

Any input is welcome, except the "You should have gotten a procharger."

OHSIXCTSV

u shoulda got a turbo...jk! you know i had to do it...
the "herpes is spreading" thing is a bitch. ya~meeeen!??
u want me to ask my guy about the henway?

98catfish

iTrader: (13)

Sounds like the bypass valve to me as well or some sort of vacuum problem w/ the line going to the bypass valve. Check for cracked or collapsed vacuum line going to the bypass.

Can you post pics of your setup so we can see if everything looks correct.
BTW see link in sig for other problems w/ maggie.

Doug

CTSV_510

iTrader: (1)

I triple checked the bypass vacuum line and it seems fine. There's not much to it, it's just a simple hose.

I'll get some pictures tomorrow when I pull the maggie off to fix the knock sensor wire that I believe is pinched. Could bad signals from the knock sensor cause it to retard the spark and cause me to lose power?

Does anyone know which knock sensor is #2? Front or rear?

BadMonkey

iTrader: (1)

Check both while your at it but #2 is the back one ( i think) i pinched that one almost all the time. Even though one may be pinched that code should not do anything do get what you got going on (not that code for the KS anyway). If one of those codes was the issue it would be something with the IAT sensor.

Also check your Fuel Pressure your fuel pump may not be liking the added voltage from your Magnavolt, mine went out right after it was installed and it was a High Flow Racetronix. I had to replace the racetronix. At about that range of 3500rpm's or so you will be pumping some serious fuel into the engine, your at full boost. Before you go to replacing the FP, I would definitly look for maybe a broken wire or bad splice to your Magnavolt, I am sure the CTS-V's FP is not any funner then the Corvette or F Bodies I messed with.

My previous car (98catfish's above current car) went through a magnavolt and fuel pump when it was first installed. When my FP went out it would drive normal unless I flog it or go into WOT. When it went out it seemed to work fine out of boost but when the Magnavolt pushed more voltage (like anyother boost a pump would) it would give up or break down and not want to play nice. Hope you figure it out.

Just some things to check hopefully its just something simple.

Oh and welcome to F/I

XLR8NSS

iTrader: (4)

Do you have a 5 wire MAF with the IAT integrated? If so did you cut and splice the correct wires to the IAT? Just something to check.

Hope you get it figured out.

CTSV_510

iTrader: (1)

I do have the 5 wire MAF - I double checked even though it's hard to screw that one up. Yellow, black and red wire & 2 brown. The 2 brown are the IAT.

I pulled the maggie today and found the rear knock sensor submerged in water. It's kind of a long story but I think I know how that happened.

Anyway, I replaced it with a new knock sensor and put everything back together. Test drove around and tried to get through a few ignition cycles to look for MILs, but none showed yet. I read the codes and all that showed were rear 02 sensor related and to be expected since I don't have any.

Through several WOT runs, the "fluttering" issue only happened one time and only for 1 second.

I will run a fuel pressure test tomorrow to see if that shows anything. Could a clogged fuel filter be a suspect? I have 42k miles and I guess it wouldn't hurt to change it out anyway.

CTSV_510

iTrader: (1)

Fuel pressure test resulting in 59 psi at idle, hold steady with throttle. WOT it drops for a split second to about 57 before shooting up to 62, then falls to normal.

Knock sensor & IAT codes are gone and haven't returned. WOT runs have been perfect so far. Hopefully the issue is fixed, we'll see how it continues to run in the next week. Thanks for the help guys.