five7driver wrote:
Car sounds great at idle. Very smooth. When the rpm goes through about 1500 the rattling starts and I'm putting out a smoke screen. Under load on the road it's even worse: hammering noise and rolling coal.
Here is what has been done so far:
New MAP sensor installed (old one was only a year old and didn't look bad)--no change
New vacuum modulator installed--no change
Bypassed vacuum solenoid--no change
Checked vacuum in all lines--ok
Vacuum reservoir checks ok
Turbo actuator moves freely up and down at least 1/2 inch
EGR pipe from exhaust manifold blocked with a plate at the egr
FCV butterfly valve removed
Pressure tested from turbo to intake--ok
Codes set: P0401 (EGR deleted)
P0299 underboost
Here is some scantool data:
MAF idle: 13.6-15.6 g/s
@2K rpm: 37.5-38.0
Fuel Pressure @idle 4843 psi
@2k rpm: 9570 psi
MAP @idle: 13.9 psi
@2K rpm 14.9 psi
@3K rpm 17.2 psi
Boost: Desired Actual
@idle 16.1 psi 14.3
@2K rpm 27.6called 23.2measured (level ground)
@2K uphill 33.4called 23.2measured (up a small hill)
@2.5K 33.4called 21.8measured (up a very steep hill, pedal floored)Measured at a tee between the vac modulator and the turbo actuator. (I had the gauge taped to the windscreen
)
Vacuum from pump is good and steady at 28 in Hg.
Right now I'm trying to get a block off plate going at the union of the exhaust manifold and the egr pipe, since my other block off plate at the other end of this pipe (where it goes into the egr) was leaking some. Having a devil of a time getting the v-band clamp back on... I am noticing some smoke swirling around in the engine compartment when I stomp the accelerator, so maybe that's the whole issue (?). Trying to completely rule out exhaust leak.
So, I'm down to:
1. Exhaust leak
2. Clogged Cat
3. Busted rocker arms
4. Bad injectors
5. Bad turbo (BTW I checked the spindle for play, none present)
6. ???
It seems to me that no boost is being produced at all, so that would point to exhaust leak not allowing the turbo to spin up, or stuck vanes.
Any help at all would be greatly appreciated....the next tool I throw might hurt someone!
I see your turbo is "all in" at under 2000rpm, regardless of accelerator pedal position or engine speed.
It actually loses boost when revved past 2000 to 2500rpm under load.
These numbers bring two things immediately to mind, that
can produce them, which are restricted air intake and restricted exhaust.
I'm assuming you checked your air filter, but want to be certain that you actually pulled the filter from the airbox and held it between your eyes and either the sun or a very bright light. If you can't see the light pretty clearly, then it needs changing. People frequently open the air box, and when they see the filter there all pretty and clean, they don't bother to take it out and check the dirty bottom-side. "Clean on top" simply means it's still trying to prevent dirt, dust, feathers, etc from getting past it. Not that it is actually still good. The higher the engine revs, the harder it tries to pull air through the dirty filter, increasing pre-turbo vacuum, causing the turbo to over-spin, increase heat, and decrease boost.
The plugged exhaust part is easier to understand, especially if you still have the catalyst converter in place. The lack of flow neutralizes the turbo's ability to build boost, and enough exhaust back pressure eventually becomes it's own kind of EGR, as it shoves compressed exhaust back through the closing exhaust valves and, if bad enough, all the way back through the opening intake valves.
Even though your Cat, if still in place, is well beyond it's useful emissions service life, it may serve as a way to check if your turbine blades have been wiped. Any turbo bits that have broken loose will be caught by the honeycomb in the converter. If you cut the exhaust forward of the converter, you can check the front for metal or rattly bits clogging up the works, then re-attach it with SS band clamp if for some reason you are attached to the thing.
I think that if you have a pre-turbo exhaust leak bad enough to make those numbers, you would have already identified and fixed it.
The others you're down to, well, if you haven't found it above, they wouldn't hurt to check, also, to do a timing pin insert check, to make sure nothing has gone awry there.