docwyte

Shop dropped it off last night! Gave it a bath this morning and put my plates on it.

Did a quick drive in it last night and it runs very well. Vacuum is disappearing though. Before this whole oddessey started I saw 15 inches of Hg on the gauge, then 12 when the car was running pig rich, then the shop saw 8 and now the gauge reads 5.

Connections to the gauge are good. Shop checked all connections in the engine bay and they're also good. Additionally, boost is dropping on the gauge. It hits the target amount, then falls off, which it shouldn't be doing. Power doesn't feel like it's dropping though.

Any thoughts? Shop thinks maybe the Vitesse boost solenoid seals are bad? I was thinking maybe the wastegate is loose as the car was blowing off the intercooler boost coupler at around 18psi.

Car had no vacuum issues until we hooked up the boost solenoid and MAP sensor. Car still drives fine and A/F are fine. Idles well, no issues. Help!

Pics!

2bridges

Hey Doc

so first thing I would do is validate your notion and disconnect the feed to the boost solenoid and MAP sensor. If that is the source you should see vac change at idle.

Then connect one of the two and idle again.... by process of elimination you should be able to drive down to the source whether a hose, Tee, map sensor, solenoid.

Good luck

2B

dillon410021

car looks great.

fast951

Boost solenoid is connected to the IC pipe. It's in front of the TB, how could it affect vacuum with TB closed?
Check the line to the MAP sensor..

Pressure test the system, you'll find the leak!

docwyte

Need to find someone with a pressure tester locally. Good idea bridges, I'll check that out and thanks for eliminating the boost solenoid John!

reno808

very nice

gregeast

Doc, I have a pressure tester rigged up that you're welcome to borrow. Come on up, we'll hook it up to the compressor, soak her down with soapy water and play find the bubble...

reno808

or starter fluid

gregeast

I've never had much luck w/starter fluid. I recently diagnosed a leak that turns out to be coming from the ISV body. With the pressure tester hooked up I could hear that it was coming from under the manifold but couldn't tell from where until I squirted the soapy water in there. Big 'ole bubble on the ISV made it pretty obvious.

Sure am excited about taking the intake off again...

gregeast

Oh and just a heads up Doc, I and several others got stopped on the way out to HPR for the recent BMW CCA DE for not having a front plate (or a fake one in my case). Just got a warning but you might want to throw the front plate on there for the drive out and save yourself the hassle.

LS1Porch

I don't know if anyone has ever told you this before or not, but you have good taste in cars!

ehall

Greg, can't you keep your creepy fetishes privat?! Dammit man!

gregeast

Isn't that what everyone does on Friday afternoons? You guys need to move to Colorado...

ehall

EEEEE YIKES!

docwyte

OK, little more info. Vacuum doesn't change on decel, ordinary I'd expect to see at least another 5-8 inches of vacuum under decel, but it stays the same.

On the high boost map (17-18psi) I'm blowing off the IC boost hose. Wastegate appears to be hooked up properly, no loose bolts and I don't hear an open wastegate dump as if it were loose.

Disconnected the MAP sensor, no change in vacuum. All engine compartment vacuum lines look good.

Seeing 17-18 psi steady on high boost, but only seeing wastegate pressure on low boost ~10psi. I'll hook up the laptop to the SMT6 and look at the low boost map, maybe the info didn't transfer over.

What are you guys seeing oil temperature wise? The car has a KISS supplementary oil cooler, I'm seeing 210-220 when in city traffic, which quickly drops to 180-190 on the freeway. When really getting on it, oil temp rises pretty quickly.

This is beginning to drive me crazy and make me think I should've just put an LS1 in here from the get go or spent the big bucks for a 996 GT3.

If anyone can help here troubleshooting I'd appreciate it!