Dealing with some issues with my '05 CRD. It has 135k miles on it, virtually all of which have been without the EGR, with an EHM mod, and doing oil changes when the EVIC tells me (3125 miles). It had the timing belt replaced, along with the water pump and an idler pulley at 90k.

But this P0299 code keeps cropping up when the engine is cold. Perhaps because I keep clearing it with the code reader, it doesn't ever seem to trip the CEL, but it is very consistent: if the engine is below about the 25% mark on the temp gauge, and if I'm driving it normally (like a granny compared to most of you, I'd bet), I can read this code from the engine. But once the temp gauge gets past that mark or to the normal setting (50%), it doesn't seem to ever throw that code. If it were the boost hoses, I would expect temperature to have nothing to do with it.

Any ideas why this might happen? I have a theory (that I really don't like) that I could put out there, but I don't want to taint the responses.


For background, here is the list of things I did previously, when it had thrown the 299 code consistently, and when I was able to persuade it to throw an overboost code (P0234), too. I'm not sure if temperature had anything to do with the 299 code back then, because I hadn't yet spotted that pattern:

So over the weekend I opened things up. Here is a list of what I have done so far:
-I replaced the fuel and air filters.
-I disconnected the turbo hose at the FCV and plugged it, then disconnected the hose at the turbo and blew into it: no hissing noises, and no apparent loss of pressure. I know...I'm a blowhard, but not a 15PSI blowhard, so this probably isn't a great test. But if this were the issue, I wouldn't ever expect to see an overboost code.
-I did a visual inspection of vacuum hoses, and checked for leaks by plugging one end and sucking on the other (no comments, please) and making sure they held vacuum.
-I cleaned the MAF sensor with MAF cleaner
-I cleaned the MAP sensor with MAF cleaner
-I disconnected the pressure sensor that is in the air filter box (is that a MAP sensor?), and checked resistance across the various terminals, including when I was sucking and blowing into an attached piece of vacuum tube...no change in resistance according to the pressure, but perhaps this unit doesn't work that way?
-I wiggled the inlet turbine on the turbocharger. There is a little play, but not much. I didn't seem to be able to make it bind up or anything. No idea how or whether I could check if the variable vanes are working properly or not. Very little oil in there, and no carbon buildup that I could see, at least.

I recently replaced the MAP sensor on the manifold, after that, too. I had also started getting mysteriously hard starts and lots of smoke after starting, which I think I have narrowed down to air in the fuel filter assembly (a Racor unit) caused by the fact that my Kennedy lift pump has stopped working.

Thanks for the help!

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George Reiswig
2005 Jeep Liberty CRD
Suncoast, SEGR, lift, InMotion tune, homebrew B100
At 138k, new head & gasket, timing belt, rockers and swearing vocabulary

Check the vane travel at idle in park. Watch the control rod below the vac valve on turbo and remove/replace the vacuum tube that goes from turbo to evm a few times. The rod should move up and down about 1/2 inch, any less and the vanes are sticking.

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Providers of wholly developed aftermarket solutions for the KJ CRD.
(248) 977 - 9531

Thank you for this...I had heard in another post that this was the case, but it wasn't clear if it was really genuinely 1/2", or if that was sort of an estimate.

Two questions:
1. I can't see the armature with all the plumbing and coolant tank and such in the way, let alone see it well enough to measure the travel. How the heck did you do that?
2. Why would temperature affect this at all? Wouldn't it underboost even when warmed up if there was a problem with vane travel?

I forgot to mention before that I had also bypassed the vacuum solenoid for the turbocharger...doesn't seem to be the problem.

Is it possible for air in the fuel to cause this code to be thrown?

_________________
George Reiswig
2005 Jeep Liberty CRD
Suncoast, SEGR, lift, InMotion tune, homebrew B100
At 138k, new head & gasket, timing belt, rockers and swearing vocabulary

My CRD behaves similar. Until the turbo casting warms up and expands(usually in a quarter mile) the veins can hang up and either over or under boost. I am really light on the throttle until I can tell by watching boost gauge that the turbo veins are moving freely...

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2006 Liberty CRD 275K, JBA 2.5 with Fox Shocks, GDE Turbo Kit, GDE TCM Tune, Suncoast TC, OEM fuel filter housing converted to fit Caterpillar Fuel Filter 1R-0749, OEM themostat housing modified to accept Hemi 203 F thermostat.