CRD Power Surge w/ Smoke

e010584 · **Posted:** Mon Jan 11, 2010 12:27 am

I've got a hand me down '05 CRD Sport w/ ~115K miles (wife upgraded to a lower mile Limited) that has been having some issues. My first issue was a near total loss of power on a road trip while climbing a grade as though I lost the turbo. After googling this one, I found indications that the problem resets itself and the Jeep runs fine, which I confirmed that evening with a major sigh of relief. I didn't get a DTC on that event but later had a P0234 (overboost) so I'm suspecting that is what happened and I ended up in a limp home mode (next time I'll shut it down on the highway and restart).

Later, my wife was complaining that it was harder starting on some cooler mornings and would smoke a lot more than usual.

On a more recent road trip, the jeep had was having uncommanded oscillations in the power at a fixed throttle position. This was generally more pronounced at slower speeds (<55mph) than at higher speeds and seemed to again go away the next day. On the next long road trip, the oscillating power returned after a fuel stop about an hour into the trip. I had my OBD2 scan tool and was trying to figure out what was going on and saw a corresponding fluctuation in the MAF along with the power surging and visible puffs of smoke. This continued through the rest of the trip despite repeated attempts to shutdown and restart in hopes that it might go away. I seemed to repeatably loose communication with the computer for some reason but didn't get any DTC's till I got home to mess with it some more and got a P0299 (underboost).

This is where I started searching this forum (and others) in hopes of solving my problems. I couldn't find anything quite like this issue but found the CAC line burst issues, the EGR issues, vacuum control issues, etc. I went out to drive the jeep around the block to see if the problem went away overnight and it was noticeably present right from the start so I went ahead and pulled the MAF connector finding my problem magically disappeared as others had indicated.

So, I haven't done anything more and was needing to obviously dig deeper. I was going to start with the MAF sensor itself as I have had problems with contamination of these sensors on other vehicles leading to a host of problems. Recognizing unplugging the MAF disables the EGR, this was my next area to explore which is likely a problem based on the numerous posts on EGR issues. Of course disabling the EGR with a GDE upgrade may be more desirable than dumping money into the EGR system but I'll probably still want to figure out the root cause of my power surging.

Anybody have any further thoughts ideas on this one. Of course having two CRD's makes component swap troubleshooting a little less painful (beyond raising the ire of the wife).

Joe Romas · **Posted:** Mon Jan 11, 2010 8:50 am

MrMopar states you can remove the EGR valve, take off the electrical part then soak the valve to clean it :SOMBRERO:

When your doing that you can remove both CAC hoses and inspect them for cracks and splits :seuss:

Clean your MAP sensor while your at it :ROTFL:

Have you replaced the timing belt :?:

linewarbr · **Posted:** Mon Jan 11, 2010 2:18 pm

Definitely pull and clean the MAP sensor with chlorine-free brake cleaner or good ole' #2. viewtopic.php?f=98&t=22630

Pull off and inspect the CAC hoses for oil weeping and splits. I haven't heard of anyone else having issues with the MAF sensor at the airbox, if so, I imagine it would throw a code specific to it, as you should see running without it plugged in. Also some scan tools don't connect all that well with the CRD, keep that in mind when you try to scan/ clear codes.

If it turns out to be an EGR issue, either do an SEGR or get the GDE tune and call it good. Beyond that, it may be an issue with the vacuum solenoid that controls the variable vanes in the turbo. That would lead to hesitant acceleration and black smoke if the vanes are (hopefully) getting stuck in the open position.

Hesitation/ shuddering at the speed you mentioned could be air in the fuel head (press the primer until it is firm then open the bleeder valve to bleed out any air in the head) or a torqu converter issue.

e010584 · **Posted:** Mon Jan 11, 2010 3:36 pm

Thanks for the replies Joe and linewarbr. I undersand the issue with the CAC hoses and MAP sensor but my problem went away when I unplugged the MAF so i think it is fair to rule these out as major contributors to my anomaly even if it is prudent to inspect them as a normal course of action. I'll be surprised if there is a MAF sensor issue and suspect it is an EGR issue but, I thought the EGR's usually fail in a fixed position rather than having a failure to control the position as would be necessary to cause the surging I'm experiencing. Likewise with the air in fuel and turbo control, although I am an engineer for the folks that make the turbo so I should be able to get some help there if needed. My anomaly seems like a classic undamped control issue, I just haven't figured out what parameter changed to cause it.

Short of regaining normal EGR operation (or inspite of), I'd probably go with the GDE tune, but where does one get a SEGR as a cheaper option or is this a DIY job?

linewarbr · **Posted:** Mon Jan 11, 2010 3:54 pm

This is a link to the SEGR install: viewtopic.php?f=98&t=27359
It is a DIY job to install the box; some members here make a pre-assembled SEGR that you can buy.

If you are interested, PM LocoCRD or UFO to see if they have any available. I ordered a pre-assembled box from Loco before getting the GDE tune and it was about $275. Not sure what they're going for now. This will allow you to have NO EGR flow into the intake whatsoever. It involves splicing into the wiring harness that goes to the ECU, which makes some (like me!) very, very nervous.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

The hestitation is definitely an EGR flow issue. The EGR valve is still functioning, however it has lost flow capability due to soot build-up over time. The build-up occurs on the valve stem, which prevents the valve from fully opening and it builds up in the EGR outlet tube going to the intake manifold, just a flow retriction. In either case, the closed-loop control system will demand a higher duty cycle to the valve to open it further and at the same time is will command the intake throttle (FCV) to further close to increase the delta pressure to make it easier to flow EGR. The FCV closing too far will lead to a P0299 code and hestitation issues along with very non-linear acceleration and some smoke. Other forum members have suggested methods to fix the issue. Cleaning the valve will help temporarily and takes 2-4 hours of labor. Make sure to clean the tube going into the intake manifold if you decide to tear into it.

Good Luck!

GDE

e010584 · **Posted:** Wed Jan 13, 2010 10:21 am

Thanks again linewarbr and GDE. Unfortunately the pics on the SEGR are gone but I gather it is a DIY installation but you still need to buy the hardware to do the installation. Obviously the GDE approach looks to be the best.

As a clarification to GDE's comments, I wouldn't call it a hesitation in that it is truly an uncommanded accel/decel anomaly that I am experiencing. I agree it is more than likely an EGR flow issue and just tryin to understand what is driving it. As you mentioned, increased resistance or limitations to valve movement and restricted flows may very well be the drivers setting up the undamped response. I'm sure I'll have to dig in deeper to satisfy my own curiosity.

Thx,

John

e010584 · **Posted:** Mon Feb 01, 2010 8:45 pm

OK, I finally got to ripping and tearing over the weekend and it turns out the only thing obvious was the CAC hose on the driver side (very common). I'm gathering that the leakage was sufficient enough to cause the EGR to have tizzies, which was temporarily remedied by defeating the EGR through unplugging the MAF. The hose split appeared that it was caused through rubbing but could easily of been exacerbated by the previous over boost anomaly. While I was at it, I did also remove and clean the MAP, FCV ad EGR (valve, body & cooler). While things were certainly dirty, none of it seemed significant enough to cause blockage or affect the EGR valve's operation.

So what is the latest consensus on the best source for the CAC hoses? OEM vs. aftermarket? Cheapest source? ETC.

I ended up affecting a temporary repair on the hose by patching it with an inner tube patch and rapping the repair with duct tape then foil tape. Seems to be holding up pretty good so far.

Now I've got a glow plug (and cold start) issue that I'll need to post on a different thread.

linewarbr · **Posted:** Mon Feb 01, 2010 9:26 pm

Many here have installed Samco silicon-lined hoses with great success. However, they tend to expand a little more under boost pressure, and can rub against other components in the engine bay. Also OEM hoses were redesigned late in the life-cycle of North American-sold CRD's and tend to hold up better than earlier ones. www.moparpartsamerica.com has them for a reasonable price, about $50 cheaper than Samco's.

I like the cool blue Samco's though. . .

CRD Power Surge w/ Smoke

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