LOST JEEPS
http://www.lostjeeps.com/forum/phpBB3/

Low Boost Pressure, Turbo Replaced
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=81002		 Page 1 of 3
Author:  canonoch1 [ Thu Jan 01, 2015 5:53 pm ]
Post subject:  Low Boost Pressure, Turbo Replaced
So recently our Turbo went out and replaced it with a New Stigans turbo (http://www.stigan.com/) CEL came on P0299. I pressure tested the CAC hoses and Intercooler has no problem holding pressure. Have new air filter, Vane rod moves and vacuum solinoid works for the turbo. Any ideas?

Also how much boost pressure should the Turbo be putting out?
Author:  ArmyChief [ Thu Jan 01, 2015 5:56 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
What part number turbo?

I believe the factory boost is about 16-20 PSI
Author:  gmctd [ Thu Jan 01, 2015 6:00 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
canonoch1 wrote:
So recently our Turbo went out and replaced it with a New Stigans turbo (http://www.stigan.com/) CEL came on P0299. I pressure tested the CAC hoses and Intercooler has no problem holding pressure. Have new air filter, Vane rod moves and vacuum solinoid works for the turbo. Any ideas?
P0299 is usually associated with overboost
- could be the diaphragm actuator is not happy with KJ applied vacuum levels
- could be the linkage is not adjusted correctly

Also how much boost pressure should the Turbo be putting out?
Author:  ArmyChief [ Thu Jan 01, 2015 6:03 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
viewtopic.php?f=5&t=80934&hilit=boost
Author:  ArmyChief [ Thu Jan 01, 2015 6:09 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
viewtopic.php?f=5&t=80848&hilit=boost
Author:  flman [ Thu Jan 01, 2015 6:16 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
I got a reading of about 17 on my Ultragauge today.
Author:  ArmyChief [ Thu Jan 01, 2015 6:21 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
flman wrote:
I got a reading of about 17 on my Ultragauge today.


I went to public school..and they have COMMON CORE here in Florida.... does that fall between 16-20? :)

Before you take it the wrong way..its a joke :)

Thanks for posting your results....I was actually looking for an affirmative answer (that's the kinda guy I am). I looked in the FSM under ALL the boost codes (you would think they would have the theory of operation...explain the tolerances..window..NOPE)

Then, I bought the Engine & Fuel MasterTech student books...NOTHING about engine specs (boost, F/P..etc)

Then I was doing a search here on the forum for some published specs...nothing.

Compound that with the various flashes that are available (boost CAN be adjusted with mapping)...not sure what OE spec is, and then after say a HOT tune is.
Author:  canonoch1 [ Thu Jan 01, 2015 6:35 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
gmctd wrote:
canonoch1 wrote:
So recently our Turbo went out and replaced it with a New Stigans turbo (http://www.stigan.com/) CEL came on P0299. I pressure tested the CAC hoses and Intercooler has no problem holding pressure. Have new air filter, Vane rod moves and vacuum solinoid works for the turbo. Any ideas?
P0299 is usually associated with overboost
- could be the diaphragm actuator is not happy with KJ applied vacuum levels
- could be the linkage is not adjusted correctly

Also how much boost pressure should the Turbo be putting out?


i may have gotten the code # messed up but the scanner indicated low boost code
Author:  canonoch1 [ Thu Jan 01, 2015 6:39 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
ArmyChief wrote:
What part number turbo?

I believe the factory boost is about 16-20 PSI


Stigan Turbocharger 847-1018

installed new oil feed line, exhaust to turbo gasket, mounting nuts, banjo bolt and washers, cleaned and flushed return line, oil and filter changed, new air filter. FCV not stuck closed.
Author:  canonoch1 [ Thu Jan 01, 2015 6:46 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
gmctd wrote:
canonoch1 wrote:
So recently our Turbo went out and replaced it with a New Stigans turbo (http://www.stigan.com/) CEL came on P0299. I pressure tested the CAC hoses and Intercooler has no problem holding pressure. Have new air filter, Vane rod moves and vacuum solinoid works for the turbo. Any ideas?
P0299 is usually associated with overboost
- could be the diaphragm actuator is not happy with KJ applied vacuum levels
- could be the linkage is not adjusted correctly

Also how much boost pressure should the Turbo be putting out?


how would some one adjust the linkage?
Author:  gmctd [ Thu Jan 01, 2015 8:10 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
Some of the KJ turbos had adjustable link between vanes and actuator - don't recall seeing any specifics, and dunno anything about that replacement turbo, but if the linkage is adjustable, but not to correct dimension, Boost can be over or under KJ spec - first thing is to determine adjustable link or not

Also, if you replaced the turbo because of incorrect\over Boost P0299, could be BPS BOOST Pressure Solenoid, the one with the small clear filter dangling below it, is not responsive to ECM command

That other solenoid connects the vacuum pump to the vacuum reservoir, defective VRS usually results in under-Boost
- that's the one GDE suggests bypassing to improve BOOST
- but, as ELVIS once said: don' never, don' never, don' never, don' never bypass the BPS, or you could fry the heads'n'pistons
Author:  ArmyChief [ Thu Jan 01, 2015 8:17 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
gmctd wrote:
as ELVIS once said: don' never, don' never, don' never, don' never bypass the BPS, or you could fry the heads'n'pistons


Thank you, thank you very much!
Author:  thermorex [ Thu Jan 01, 2015 8:45 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
Chief, the mechanical gauge showed me a brief 25-ish psi then dropped to 20-ish within next couple seconds, that was pedal to the metal going on ramp into the highway. I think the boost pressure solenoid kicked in and opened the vanes to drop the boost to "acceptable levels"
Author:  ArmyChief [ Fri Jan 02, 2015 11:23 am ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
thermo,

I would imagine that boost pressure will be different between OE stock PCM and "tuned"

Would be curious to hear others numbers. 25PSI is about the highest I've read.

Thanks
Author:  canonoch1 [ Fri Jan 02, 2015 1:28 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
Last night I unplugged the MAF sensor - this should dis-able the EGR and drove it into town = no change threw code P0299

did the bypass on the vacuum solinoid = no change threw code P0299

pressure tested CAC hoses and Intercooler = blew my plug out about 18 PSI, reset plug and pumped it up to 15 PSI and left it for about 30 mins still had pressure.

I pulled and cleaned MAP sensor ( it wasn't bad replaced it a year ago - I'm the one who did map sensor cheap viewtopic.php?f=5&t=74785 )

I replaced the turbo because the original one failed. i replaced it with a CHEAP :furious: turbo and it failed in 95 days (good thing I bought one with a 1 yr warranty not a 90 day. I decided to try the STIGANS turbo as it was the price of a rebuilt Garrett and it has a manufactors warranty of 24 months
Author:  ArmyChief [ Fri Jan 02, 2015 2:04 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
Have you tapped into intake to measure boost?
Do you have a capable scan tool to monitor boost?

many good scan tools will actually allow you to set up a "movie" function that will take a snap shot of data when a code matures
Author:  gmctd [ Fri Jan 02, 2015 4:13 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
canonoch1 wrote:
Last night I unplugged the MAF sensor - this should dis-able the EGR and drove it into town = no change threw code P0299EGR malfunction would cause under-BOOST - ur new EGR should not

did the bypass on the vacuum solinoid = no change threw code P0299low vacuum would cause under-BOOST

pressure tested CAC hoses and Intercooler = blew my plug out about 18 PSI, reset plug and pumped it up to 15 PSI and left it for about 30 mins still had pressure.BOOST-path leak would cause under-BOOST

I pulled and cleaned MAP sensor ( it wasn't bad replaced it a year ago - I'm the one who did map sensor cheap viewtopic.php?f=5&t=74785 ) defective MAP sensor could cause under-BOOST or over-BOOST - ur new MAP should cause neither

I replaced the turbo because the original one failed. i replaced it with a CHEAP :furious: turbo and it failed in 95 days (good thing I bought one with a 1 yr warranty not a 90 day. I decided to try the STIGANS turbo as it was the price of a rebuilt Garrett and it has a manufactors warranty of 24 monthsdefective turbo usually causes under-BOOST, but defective vanes or\and vacuum-actuated controller could cause over-BOOST - a new GARRET turbo should cause neither

Did I miss something, or still no comment on result of FCV inspection - ?????????????


An inexpensive BOOST gage would give you some better hint as to resolution
Author:  taroo [ Fri Jan 02, 2015 4:56 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
ArmyChief wrote:
thermo,

I would imagine that boost pressure will be different between OE stock PCM and "tuned"

Would be curious to hear others numbers. 25PSI is about the highest I've read.

Thanks


Hmmm....these readings are without FCV, EGR, etc.

That peak MAP converts to about 35 PSI.

Thoughts?

Image
Author:  gmctd [ Fri Jan 02, 2015 5:06 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
?
That chart is to ABSOLUTE manifold pressure, beginning at 30"HG abs = 15psi BARO or 0psi gage, what you would see on ur (hopefully installed) BOOST gage at idle
- 30"HG abs would be 00psig(age) BOOST (idle conditions)
- 60"HG abs would be 15psig BOOST
- 90"HG abs would be 30psig BOOST

Scalar, 30"HG = 15psi

Those orange peaks are not much above 70"HG abs, well below 30psig BOOST

ECM uses "HG ABSOLUTE to accurately compensate for changes in altitude thru-out the KJ's grazing ranges, world-wide

'Nuther words, yer KJ on the floor of Death Valley is gonna show a whole buncha different BOOST than at the Lookout on top of Pike's Peak unless ECM can compensate for the difference in altitude - mean BARO around the world is 14.696psia(bsolute), or actual

Hint: Next time ur watching Bambi the weather-girl, cover your eyes so her obvious attributes don't confuse your brain while she's talking hi-pressures and lo-pressures and falling or rising inches, and note her associated numerical references to the barometer - it all should then become clearer to you

And, thanks for that very informative chart - we needed that, eh................
Author:  taroo [ Fri Jan 02, 2015 5:44 pm ]
Post subject:  Re: Low Boost Pressure, Turbo Replaced
gmctd wrote:
?
That chart is to ABSOLUTE manifold pressure, beginning at 30"HG = 15psi BARO or 0psi gage, what you would see on ur (hopefully installed) BOOST gage at idle
- 60"HG would be 15psi BOOST
- 90"HG would be 30psi BOOST

30"HG = 15psi

That peak is not much above 70"HG abs, well below 30psi BOOST

ECM uses "HG ABSOLUTE to accurately compensate for changes in altitude thru-out the KJ's grazing ranges, world-wide


Next time ur watching Bambi the weather-girl, cover your eyes so her obvious attributes don't confuse your brain while she's talking hi-pressures and lo-pressures and falling or rising inches, and note her associated numerical references to the barometer - it all should then become clearer to you


Okay...learning here. And by the way...have ordered a GlowShift 3-in-1 gauge for Boost on the gauge needle, EGT on one digital first readout, and temp (will go for oil temp) on the second digital readout.

Ahhhh.....29.92 inHg = 14.696 psi = 1 atmosphere....therefore 0 on a gauge. So, 60""HG=30PSI, which is 2 atmosphere therefore 15 PSI on gauge or 15PSI of Boost.....etc.

Okay...now...with that understood, what are normal or good boost numbers/ranges for our CRD?

I am just concerned about overboost with the removal of the FCV and essentially running open between the output of the turbo and the intake.

Thanks for the education and help.
Page 1 of 3 All times are UTC - 5 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/