Got a 2005 CRD with an irritating problem. It starts and runs fine but on restarting it has little boost.

I can turn it off, remove the MAP sensor and clean it (even though it looks fine), fire it back up and it's fine (5 miles or 500 miles doesn't matter) until I tun it off. When I restart it, it'll have little boost until I repeat the whole thing. Doesn't feel like limp mode and it'll run 65+ on the flats, but bogs on a grade and smokes a tad.

I can still hear the turbo but just barely.

Had codes pulled today and with a weeks stage 1 done, I just ignore the egr related ones. However, it's throwing these also...

P0107, seems like a MAP
P0113, Not sure this has much to do wiht it?
P1250, solenoid stuck or something?
P0299, yep, feeling that one.
P0101, I used to unplug the MAF so don't think this is it.

So am I just resetting something by unplugging and cleaning the MAP over and over to clean it? Seems if a sensor was bad it would just be bad and not go bad when you turn her off and fire her back up. For the $20GM part, I may just order another.

Thank for any enlightenment.

Edit: I took the hose from the vacuum reservoir output that feeds the Vacuum Solenoid (with the blue ports) and ran it strait to the Boost Pressure Solenoid (with the filter), bypassing the solenoid. It ran fine.

Should I get a new Solenoid or just leave it bypassed?

I would replace it, it serves a purpose!

_________________
Supporting Vendor and Moderator of LOST
05 Jeep Liberty CRD Limited
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount
98 Dodge Cummins 24 Valve

Well, I ordered the solenoid and put it on. Went on a test drive today as it's not a daily driver. Drove it on a 15 minute drive and it was fine, turned it off for about a half hour, cranked it back up and it was fine back home Just for giggles I went out and cranked it up a bit ago to take another test drive and the same problem returned. Feels like only 60% of power and you can barely hear the turbo. Foot in the throttle to force a down shift puts a small cloud out the back.

I think I'll order the GM part # MAP sensor and see if that's it.

Good idea, you ruling them out, hopefully you will find the culprit!

_________________
Supporting Vendor and Moderator of LOST
05 Jeep Liberty CRD Limited
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount
98 Dodge Cummins 24 Valve

I'm having the same problem, P0299 CEL code,
I have vacuum before the vacuum control stuff, no vacuum at the top of the turbo.

Bypassing the vacuum control device would probably cause the turbo to put out continuous high boost, so I don't think that's a safe solution.

Have you got any further to resolving this issue?

I'm going to call Green Diesel tomorrow AM to see if they have any suggestions on the cause of this P0299 & vacuum problem.

_________________
Dennis
Considering sound advice, invent your own solutions
CRD

Problem resolved.
Did a search here on Turbo & Vacuum.
Read some threads about the vacuum modulator and solenoid and did some analysis try to find vacuum further downstream of each fitting and device. Tested the electrical connections & made sure the wiring was intact. So at the last point where the vacuum leaves the modulator there was vacuum but not at the top of the device that sits atop of the turbo. So I pulled off the entire line from the modulator to the top of the turbo device and discovered a hole in the metal part of the line. The metal line had been rubbing against the heat shield around the top of the device on top of the turbo causing a total loss of vacuum at the turbo.

_________________
Dennis
Considering sound advice, invent your own solutions
CRD

I'm still waiting on the new MAP to get here from Arizona so no resolution yet. I did look over all the hoses I could find and didn't see a problem. I bypassed the new solenoid again Sunday and went on a 45 minute drive and I honestly couldn't tell the turbo was acting any different that usual. I assume the solenoid just acts as a safety shutoff from the ECM and doesn't regulate anything.

I searched the CRD manual for diagrams or descriptions of how the vacuum system works with the turbo but couldn't find anything. If anyone knows what page in that 2400pg manual it's in, please let me know.

One thing I did notice when I was running down my problem, when I unplugged the elec. to the solenoid,
I got a P045 code. So if the vacuum solenoid is bad, you may get this code.

_________________
Dennis
Considering sound advice, invent your own solutions
CRD

There are two vacuum solenoids. A big one and a small one.
The small solenoid is just a on/off device that closes when off to maintain vacuum in the reservoir.
The big one has a small filter stuck at the bottom of it and is what modulates vacuum to the turbo actuator, therefore controlling boost.

With the engine running at idle, you can disconnect the vacuum line at the turbo. You should feel strong vacuum from the line.
Also, look between the engine and turbo to find the rod that connects the actuator to the turbine housing.
Disconnect the vacuum line and watch the rod drop.
Reconnect it and watch the rod pull up.

Diagnosing boost problems is kinda hard without a boost gauge.
If you dont want to install a boost gauge, get a ELM327 OBD bluetooth adapter and run the torquepro app on your android device.
It can give you boost readings as well as data from other sensors.

_________________
U.S. Army Retired

The ECM regulates it a lot. The ECM sends a PWM signal to the vacuum solenoid which adjusts how much vacuum is sent to the VNT actuator. It is constantly adjusting based on RPM and load to provide the correct vane angle to achieve the boost that the ECM wants.

If you hooked the actuator directly to the vacuum supply line then it should have been creating excess boost and I would imagine it would throw an overboost code. I doubt you would notice any difference in how it feels while driving because its still going to spray as much fuel and produce as much power regardless of boost until it went to limp mode.

_________________
2006 CRD - GTB2056 turbo by Dieselguy86, Eco Trans Tune, Lift Pump, Week's, HDS Tstat, Racor Filter, ARP's, OME 790's+Top Plate, JBA 2.5", JBA UCA, Moab's+265/75R16, ARB Bull Bar, 4.10's, TrueTracs

Thanks for the explanation. All I did was unplug the input to the solenoid (first one with the blue ports) and bypass to the next stage with the paper filter thing behind the airbox. What I bypassed should just be the on/off safety, unless I'm wrong. It doesn't seem to regulate anything.

It seems that every time I read a thread, everyone is calling the same thing something different and it lends to the confusion. The piece I replaced is OEM Part Number: 4606226AC. It's also the part I've bypassed. Can anyone confirm that this is in fact the on/off solenoid and not the regulator of vacuum to the actuator?

Thanks for all the knowledge.

The MAP sensor came in Friday so I dropped it in and headed out to Tennessee. It did fine all weekend so I think that was the problem.

Thanks to everyone for the help.