Archived HIgh EGTs with no power--Injectors?

[GElliott]

Hooked up a light TT (4000#) in Casper and tried to pull 300 mi to Fort Collins. Could barely hold 70mph on long hills with around 30 psi boost and 1400* EGT. Backed off to 60mph in 5th gear (my truck has never liked to rev above 2300 or so) and limped home. Very rough, weak power delivery and 9mpg!

Moved the TT later with a 1/2-ton gasser with little problem. Obviously a performance issue with the Cummins.

Local, independent diesel shop heard "injector knock" on test drive and suggested pulling injectors for bench testing. Seemed reasonable--they are original with 180k mi and factory fuel filtering. I agreed to $1000 in labor, assuming it would uncover an injector problem and "prepay" the labor for new injectors.

Testing found injectors are within "low-factory" spec. Lowest was "412 psi" (not sure exactly what that # means). Shop recommends replacing injectors with Bosch remans at $512 each "just to be safe." Seems overpriced and unnecessary to me, especially when we still don't know the root cause of my power problem.

Lift pump and injector pump evidently are not suspect, according to shop. New fuel, air, and oil filters.

This truck has always had high opacity numbers during emissions testing with stock tune. Still starts very easily, even when 0*. Just a little white smoke at cold idle. Generally runs OK without a load, but what's the point in that?

All this has been with Smarty Jr program removed. Any ideas?????? Thanks in advance...

 

[cerberusiam]

Quickly, get your truck back, get your money back, run do not walk away from them and find a shop that knows what they are doing. These guys do NOT know how to troubleshoot, only replace parts. The tip off should have been recommending reman injectors for that price, YOU can walk into any Bosch certified shop and buy that injector across the counter for about $350 and that is high for what most of them are worth.

The 30 psi of boost and 1400 degrees is normal under a heavy load and foot on the floor. If that was rolling down a fairly level road you have other problems, some of which may NOT be the engine. You have all the symptoms of restricted fuel flow under load, low power, high EGT's and drivability. That could be LP, could be filter, could be CP-3, or even the ECU. You need a scanner capable of logging to see what the rail pressure, engine load, and other parameters like LP pressure at the CP-3 inlet and EGT's are when the conditions happen. Without that they are just guessing and likely wrong, if you don't have that or witnessed it you are letting them convince you on opinion not facts.

The first thing that jumps out is you claim your truck doesn't like to run over 2300 rpms, with a Smarty, even a JR, it should scoot right to redline with no issues. That symptom itself tells me you have other problems, lack of fuel being the first to check for and easiest, a bad ECU is #2 on that list if fuel pressure checks out. The 06's have flaky ECU's and if it is an original the chances it can be the real source of a LOT of problems. You need to have it scanned by a dealer with the correct software to find if there are any deep issues and validate the LP and\or filter is not the issue.

 

[AH64ID]

If the Smarty Jr was removed the boost/EGT's sound normal. The 2006 trucks run up to 1450° continuous and power in 6th is dismal when stock compared to Smarty jr tuning.. My truck never felt like it wanted to go above 2300 rpms when I had the stock turbo/cam so I am not sure that is an issue... but it might be.

I agree with the above post... go get your stuff back.

 

[GElliott]

Thanks guys. Kind of what I thought, especially on the injector pricing. Assumed this shop might know something about diesels, as they work on medium duty trucks and farm equip and claim to be Bosch certified. Any suggestions on shops in the Northern CO area?

 

[cerberusiam]

There is a significant difference between the MD and Ag series platforms, some knowledge transfers but the platform specific stuff does not.

At one point I would, and have, recommended http://www.maxtorqdiesel.com/ in Golden CO. Might be just a personality clash but have butted heads on basic CR stuff and rumors are a motor or 2 did not fare so well under his care. He is\was a part timer diesel mechanic, the rest of the time a USAF reserve pilot. Might explain the attitude and ego when challenged. All you can do is research and form your own opinion.

ATS Diesel Performance is in Arvada. Again, the bad publicity they have garnered causes me to recommend with reservation. At one time I would have taken any problem to them and felt good about it. Not so much anymore. Still have to form your own opinions, they are competent and may be a good choice.

Both suggested places I feel you need a second opinion with, or, be on the ball with the problems you have and a good idea what the solution is. Never think a second opinion is a bad thing, lots of experienced people here that HAVE been thru a lot of the issues.

 

[NIsaacs]

You might try this shop in Colorado Springs, my son has had his '06 in there several times, including EFI Live installed. They have a bad 2.6 pulling truck if that helps, lol

http://www.pattersoncustomdiesel.com/default.asp

Nick

 

[Joseph Donnelly]

The catalytic converter could be partially plugged, especially since you mentioned high opacity when smog testing. The other things mentioned above also should be checked, such as lift pump and fuel filter replacement.

 

[bigceltic]

You might try this shop in Colorado Springs, my son has had his '06 in there several times, including EFI Live installed. They have a bad 2.6 pulling truck if that helps, lol

http://www.pattersoncustomdiesel.com/default.asp

Nick

x2 I have used Patterson and have been happy.

 

[wyosteve]

Don't know if he's still in business, but Bob's (can't remember the rest of the name) in Greeley on north side just off Hwy. 85 knows what he's doing.

 

[GElliott]

Quick update. As suggested by several, had LP checked by Fry's Auto in Ft Collins (Should have gone there first!). It was functioning enough to start and run, but starving the CP3 under load. Still not quite 100%, but much better with TT this past weekend.

 

[GElliott]

Final thought: LP seems to have been the problem. I wasn't going to pass judgment on the original shop, but Cerberusiam was spot-on. They can't diagnose a problem, just suggest replacement with their over-priced parts . I specifically asked about the LP before they tore down my injectors--"It's fine." When I told them the LP was the problem that they grossly missed and asked if they'd like to help with the cost for the "real" solution after taking me for a grand, "Nope. LP may have failed on the 25 mi trip home." BS! Avoid Rocky Mountain Diesel Services in Greeley, CO!

Thanks again to all!

 

[AH64ID]

Interesting, I would have more expected low EGT's and low power with a failing lift pump as it's really hard to have high EGT's with a lack of fuel, and even harder to make boost.... As I mentioned earlier your boost/EGT's were where they are supposed to be with stock programming.

What pressure was the LP dropping to under load?

 

[cerberusiam]

Interesting, I would have more expected low EGT's and low power with a failing lift pump as it's really hard to have high EGT's with a lack of fuel, and even harder to make boost

That is a dead lift pump, the dying ones hide it better. The ECU will stretch duration as RP drops to try maintain to maintain power until it runs out of adjustment. At that point the truck feels like it hits a wall and the EGT's spike because duration is stretched both ways on timing and the low RP further retards the event. You still get boost but EGT's start spiking as the event is getting way late. When the rail drains and it cannot support the demands the truck just bucks and stutters, that one is easy to find. The former is a lot harder to find as it will show good pressure and flow at idle then just fade out as demand increases.

 

[AH64ID]

To a point yes, but volume is volume. If volume drops it doesn't matter how far you stretch the duration the fuel just isn't being delivered, and with the max post TDC timing values the duration can only be increased so far before the fuel is shutoff before the desired rate is hit, and then you don't get the fuel.

Stock tuning also has some pretty good low pressure codes it can set too.

It just doesn't look like a LP to me, and not to mention the OP stated it wasn't compleatly fixed at first.

 

[cerberusiam]

Volume has 2 components, it is time over pressure. The same volume can be created by varying either, within a range the duration gets stretched to meet the needs. The ECU doesn't really know how fuel is being injected, it is projecting how much is need based input variables APPS, RP, etc, and setting duration accordingly. Some trucks won't even set a CEL when they start bucking, probably set codes but not a CEL. Codes and CEL's are both set based on readings being out of a range for a consistent time period, the rail draining then building up will not set codes while causing drivability issues if it happens fast enough. If one is easy on the throttle and not trying to push things when accelerating it will bounce EGT's up while feeling flat. RP was probably oscillating when that happened but not completely flat lining.

The way I am reading it the OP seems to say the problem is fixed now even though he had some questions at first.

 

[AH64ID]

Yes the ECM will adjust duration based on rail pressure to get the desired mm3; however, if the LP cannot supply the required volume it doesn't matter how far the ECM stretches the duration there is a lack of fuel. It doesn't take all that long, with stock timing, to extend duration and hit the ATDC limit for the injector to be open.

30psi/1400° isn't a spike it's normal. 20psi/1500° would be a spike.

70 with 285's and a G56 is ~2200 rpms.

Looking at the OEM tune data for ~2200 rpms the pressure only has to drop 3-5K and fuel is reduced based on end of injection limits.

I hope it's fixed for the OP, but it just doesn't seem correct with the data he posted.

 

[cerberusiam]

Looking at the OEM tune data for ~2200 rpms the pressure only has to drop 3-5K and fuel is reduced based on end of injection limits.

That is what the tables say, what the actual code that implements the values does and the time frame has always been a question. It doesn't seem to have a hard cutoff based on the table values all the time.

 

[AH64ID]

I'm not sure why it wouldn't work as programmed. There are also two different tables limiting EOI.


There is also the ambient air pressure adjustment table that will pull timing based on elevation. Above approx 5000' the ECM starts to retard the timing which would then limit fuel more based on the EOI tables.

Remember the OP was talking about high EGT's, even named the thread after them, yet they were not high for OEM tuning and boost levels, especially towing above 5000'.

 

[cerberusiam]

That is the issue, we don't know how it is actually programmed, all we can see are the table values use to drive the operation. Based on what I have been told and the way it functions, the ECU has the ability to interpolate and project values beyond the ends of the tables. A table may show a hard drop off with an abrupt transition but that is not how it is applied in the programming. The ECU smoothes those transitions quite a bit, with out that the actual engine operation would be very abrupt and not acceptable.

I agree the posted EGT's and boost were not out of line, but, maybe they were higher than he was used to seeing in the same circumstances. I am interpolating that also so those assumptions may not be totally accurate.

 

[AH64ID]

Yes from what I have seen in tuning the tables are interpolated/blended between values. Above the max value it appears to use the max value.


I was wondering if the OP was comparing the EGTs to the smarty EGTs? There will be a difference there.