First some background on the car:

AEM ecu
E-85
AMS FMIC
Nisei IC piping
1000cc injectors
walbro fuel pump
FP White turbo
turbo back 3" exhaust
Hallman MBC with in-car adjuster
radiator fan wired always-on

Last weekend, I brought the car out to an off-road test facility. When we've raced the car before, we've never seen the temp gauge ever go past the 9'clock position.

I was running the car for ~5 minutes straight, running it pretty hard, and had a bit of a hard impact landing from one jump. I tore off the front lip on the driver's side, but everything else looked ok. I'm wearing a helmet so I can't hear much, but at some point afte the jumb I began hearing a noise that's "jet engine like" a loud whooshing noise, when the car is at high revs and high boost. I figured it was a boost leak, but the engine is still making a solid 20psi. Unfortunately, I don't remember if the car was running any more boost earlier in the day.

Then, a minute or two later, I noticed the temp gauge was nearing the 10 o'clock position. Figuring something was off, I pulled into the pits, and the car died. I fliped thru the AEM serial gauge and water temp showed 105-108. Air temps during normal hillclimbs range between 45-55, and today I was seeing 50-55 after sustained driving with the IC sprayers on. I did a quick inspection on all the IC piping & coupers, and nothing looked weird or broken. So I tried re-starting the car, and it would idle, but just barely. It wanted to idle at ~600 rpm or so. In addition, with the hood open, we could hear a clicking noise coming from the back of the engine on the driver's side. Using the screwdriver handle listening method, we ruled out an extra loud injector, and it also didn't seem like valve tick.

We turned the car around and pointed it into the wind with the hood open to let things cool down. After 20 minutes, we fired it up and the noise was gone and it was back to normal idling at 1000rpm. A quick spin around the course showed that the loud jet like noise was still present, and the temp gauge was just a bit higher than 9 o'clock, so we decided to pack it in for the weekend.

Today, in hopes of further diagnosis, we fired up the car again, after installing the new AMS V-band cat-back exhaust. With the exhaust now much quiter, we started driving the car around in the alley behind the shop. The car was making 20psi boost, and turning the MBC all the way off netted 15psi. So, something is up with the boost for sure. The car seemed to accellerate with less oomph than normal, and there was no fall-off in power up top, but that could be because of the lower boost levels too. I had my buddy do a run thru 2 gears with me standing in the alley. As he accellerated towards us, you could hear a ticking sound coming from the front of the car. This sound was not audible when driving the car...you could only hear it from the front of the car when it was under high load, no weird noises were noticable when it was idling with the hood up.

My first thought was that the turbo was fubar'd, but after letting things cool down, we pulled off the intake and felt the shaft in the turbo. There was a little free play and I was worried, but when I got home I tested my stock turbo, and the play in that was very similar to the FP turbo.

Any thoughts, tips or things to check would be greatly appreciated!

Dave

 

you have a hfc or cat?

 

The engine noise could be causing the timing to be pulled. Pulled timing will adversly affect the breathing of the engine. So, I'd suggest concentrating on finding the cause of the engine noise.

Also, and this is so simple it is often overlooked, swap the thermostat.

 

During the driving last weekend, the car had a 3" straight pipe all the way back to the rear axle, which ended in a downturn....no cat.

The car now has a full AMS exhaust with a high flow cat and muffler.

Good suggestions ...now that I think about it, the feeling like timing is being pulled could be the issue. Any guesses on how to isolate a noise that only occurs when the car is moving that you can't hear from the inside of the car.

Dave

 

I would do a boost leak test of the system. You need to figure out why it's making the jet engine sound. The jump could have cracked the manifold or part of the turbo housings. It's also worth taking off the valve cover and looking inside for clues.

Also check the IC it might have cracked and is leaking. Again - boost leak test.

Good luck, these type of issues are always a game of Sherlock Holmes-ing around

 

Just finished pulling off the front bumper...out to the garage again for more investigating.

Dave

 

Ok, so I just closely inspected the intercooler clamps and couplers. Nothing out of the ordinary. 2nd was to inspect the actual piping. On the drivers side (where we had the hard impact), the IC pipe is now contacting the bracket for the ACD pump. The pipe is dented in a tiny bit and the paint has been chipped off. In addition, the bracket that holds the IC piping to the radiator support part of the frame is slightly cracked. Careful inspection of the inside of the pipe shows no cracking or holes in the pipe.

So, my question to the ECU gurus is: could an IC pipe banging against the ACD pump cause enough noise that the knock sensor is picking it up?

Thanks!

Dave

 

Easy enough to find out - get the pipe off of the pump and go for a spin.

 

Yes it can. Downpipes touching the oil pan or cross members have been known to cause false knock as well.

Don't skimp out on the boost leak test. If you don't have the equipment it takes a couple bucks and a trip to Home Depot to round up the supplies.

 

id compression test it. and make sure all the timing marks are lining up ......a compression test should tell you if this is correct anyway

 

So, I didn't have a chance to build a proper pressure tester, but I did use the bottom of an ice-tea can that almost fit perfectly. I was able to pressurize the system to ~5psi before the can blew off, and was able to identify a leak. There was a slight leak from the Tial BOV, which has a V-band style attachment. Since it wasn't sealing properly, I went in and uset a bit of high temp RTV sealant to take care of that leak. Quick pressure test again, and couldn't hear anything else.

I also did a bit of weight reduction on the front of the car, chasing down any wiring that wasn't being used in the sake of weight reduction. Basically removed the bulk of the HID levelers, wiring for AC fans.

Anyway, just got back from a drive around the block. The car definately has more pep now, but its still not making more than 20psi. I did see it spike to 21psi on the AEM serial gauge, but I've never used this gauge for looking at boost before, so I'm unsure if this was more boost than it ran before. I've got a mechanical boost gauge that I normally look at, but its not lighted. FWIW, that 'jet like' noise was only heard the one time. In addition, as I was planted in 3rd on the highway, I could finally hear that fluttering/ticking noise when inside the car (AMS exhaust quiets things down a bit). Sounds like the WG is fluttering despite me being WOT.

I'll do a compression test on the motor tomorrow.

Dave

 

Just finished with the compression test. Car was dead nutz on, 110 across all 4 cyl and plugs looked the same as well. Keep in mind that I'm at 5400 feet, so I'm not sure how that effects the PSI reading.

Dave

 

Perhaps the wastegate inside the turbo is broken. Try disconnecting the waste gate actuator and see if the waste gate opens and closes like it should by twisting it by hand.

 

I have one of the FP White turbos with the twin flapper doors and the HP wastegate actuator. Anybody know if these have somewhat common failures? What would the failure point be?

Thanks,

Dave

 

Ok, so I finally got around to doing the pressure test. I hooked up my air tank and let-er-rip. At 20 psi, I've seeing several small leaks.

1st leak: and probably the loudest, not sure if that means the largest by volume or not. I can't feel this leak, but if I press lightly on the piece on the throttle body right next to the return spring, I can make that leak go away.

2nd leak: My Tial BOV has a slight leak between the cover and the unit. This leak was only visible after I sprayed the whole area with soapy water. I could hear a leak, but couldn't feel it, its that minimal.

3rd leak: I bought the upper IC pipe used, and someone had put a bolt into it and sealed it up with some gunk, but it shows small bubbles as well, but this is the smallest of the three leaks.

I used a leak down tester to regulate the air going into the system. At 5psi, the leakdown tester is indicating a 15-20% leak, but when I go up to 20psi, the leak percentage drops to 0-2%. Anybody have any thoughts of where to go from here?

Thanks!

Dave