Fuel Injector Calibration [Condition] Is Important!

MagicBus

Designer of Magic Bus
Dear Sprinter-Forum Members,

My 2005 Dodge Sprinter 3500 SHC (4.11 differential) accumulated about 158,000 miles. I noticed a gradual increase in engine noise, like a knocking sound, particularly at about 2000-2500 rpm. At first, I simply dismissed it as common diesel noise. My van started and ran perfectly. Fuel mileage was fine, typically 17 - 20 mpg. There was no real indication anything was wrong other than the sound. But as I researched diesel fuel injectors I learned of the importance of testing for proper calibration. I also learned of the disastrous consequences of improperly functioning fuel injectors.

Luckily, I live near Express Diesel USA, Inc., the only Bosch Diesel Center in San Diego (www.expressdiesel.us). I paid them a visit to check out their facility. It is state-of-the-art! They have a Bosch EPS815 Test Bench. The staff was friendly, knowledgeable, and gave me a brief tour of the facility. They showed me a sample printout from the test. They test injectors for $60 a piece, if you bring the injectors to them. Turnaround is generally a few days. So for $300 and peace of mind, I figured I'd get them tested. Highly recommended!

Luckily, I also live near Sprinter Pit Stop, a sensational repair shop dedicated solely to Sprinters. I asked them to remove my injectors, take them to Express Diesel USA, report the test results, and then go from there. It turned out that 4 of 5 injectors failed testing! I opted for fully-rebuilt, factory-certified, warranted fuel injectors. Sprinter Pit Stop installed them with new hold-down bolts and copper seals. They programmed the ECM with the IMA codes.

The end result was surprisingly good! I say surprisingly because I didn't really know how injector calibration would affect the sound or performance of the engine. The newly rebuilt injectors dramatically improved the engine noise - it sounds like it did when it was new! It also runs smoother and has more torque. I wholeheartedly recommend you get your injectors tested! You'll be glad you did.

I also found the Bosch printout to be rather confusing and hard to interpret. To make it easier to interpret, I generated graphs of the results. My graphs are easy to interpret (see *.PDF attachment).

Warmest regards,
Jon
 

Attachments

Midwestdrifter

Engineer In Residence
Re: Fuel Injector Calibration Is Important!

What was your rationale behind rebuilding the injectors vs reclassifying them?

Nevermind, I missed the second/third pages of the document (viewing on my phone).
 
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Aqua Puttana

Poly - Thread Finder
First. Thanks for the information and followup. :thumbup:

There are varying schools of thought on whether injectors need periodic testing or replacement.

Thanks to Dennis Lindenengineering, some discussion is here.

T1N injectors
https://sprinter-source.com/forum/showthread.php?t=80319

If money weren't an object, and the only getting older T1N Sprinter is in excellent shape one path is to test or replace the injectors every 150,000 miles. Personally If I were going to put the effort into removing the injectors at 150,000 miles my method would be to not spend the money on testing and just replace all 5 injectors with Bosch reconditioned injectors. That puts all of the injectors at the same baseline going forward. (At least in theory.)

Given the condition of my 2004 as to rusting, my injector maintenance program is to respond to any changes that are noticed in engine operation. Given 330,000+ miles and rust the 2004 doesn't deserve the effort and money needed for new injectors, or even testing the injectors. :2cents:

You DID have operating issues. It would make sense to have the injectors tested to try to restore proper operation.

I don't particularly like your choice of words for the title though. I believe that "Fuel Injector Condition Is Important" is more accurate.

"Calibration" can be mixed up with the injector coding that is performed to address the slight differences in operating parameters between injectors. Your injectors were replaced with properly operating injectors, they weren't "calibrated" as such.

The PDF images.

It appears that the various injectors failed for different reasons.

T1N InjectorTest01.jpg

T1N InjectorTest02.jpg

T1N InjectorTest03.jpg

T1N InjectorTest04.jpg

:2cents: vic

Added:
I see that the injection timing increases as the test graphs progress.

Are there names for the various tests?

Test #1 - 4.9 +/- 2.8 =

Test #2 - 1.4 +/- 1.1 =

Test #3 - 17.6 +/- 4.2 =

Test #4 - 58.8 +/- 5.5 =
 
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Nautamaran

2004 140” HRC 2500 (Crewed)
I notice the tests varied n (frequency), fuel pressure, and pulse duration.
This would exercise the nozzle valve across a variety of duty patterns, and would appear to sense any valve hesitation/flaws present in these scenarios?
I don’t relish tackling injector renewal any more than I do replacing tires, but like tires injectors have the potential to suddenly subtract equity from a vehicle... whether to renew or scrap the vehicle becomes the decision.

-dave
 

Aqua Puttana

Poly - Thread Finder
I notice the tests varied n (frequency), fuel pressure, and pulse duration.
This would exercise the nozzle valve across a variety of duty patterns, and would appear to sense any valve hesitation/flaws present in these scenarios?
...

-dave
As a practical matter.

When the Sprinter engine is at typical operating loads, what is the typical frequency, fuel pressure, and pulse duration?

For decades I have used the climb up Lewiston Hill on "Lewiston Road" heading toward Niagara Falls as a test for engine power/condition. 45 mph posted speed limit. Within the lower 1/4 of the climb I set my cruise control. If the truck climbs the hill without downshifting I am fairly confident that power is still as expected. So far both the 2004 and 2006 present similar responses when climbing Lewiston Hill.

Maybe some of the injector test parameters which fail are not in the normal realm of an engine operating at, for example, 60 mph pushing the truck down the highway.

In other words, some of the failed testing parameters may only be experienced during minimal operating periods of time and therefore would have minimal negative impact on normal operation and service life of the engine.

The above comment assumes an engine that is running as expected and shows no other signs of deteriorated engine operating condition.

I don't know the answers. That is why I ask the questions.

:cheers: vic
 

Aqua Puttana

Poly - Thread Finder
I noticed the information that I asked for in another thread.

Injector Test Results Review Help -- out of spec for VE?
https://sprinter-source.com/forum/showthread.php?t=81018

I added it in blue here.

...

Added:
I see that the injection timing increases as the test graphs progress.

Are there names for the various tests?

Test #1 - 4.9 +/- 2.8 = LL – Idle

Test #2 - 1.4 +/- 1.1 = VE – Pre-injection

Test #3 - 17.6 +/- 4.2 = EM – Emission point

Test #4 - 58.8 +/- 5.5 = VL – Full Load
:cheers: vic
 
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bcman

Member
MagicBus, how much did Sprinter Pitstop charge for the injector replacements? Are you happy with them as a Sprinter specialist? I'm in Orange County and have yet to find a mechanic that is 100% trustworthy and experienced with Sprinters.
 

MagicBus

Designer of Magic Bus
$2000. I am VERY happy with Sprinter Pit Stop. They are 100% expert. They are busy. Schedule your appointment. My process took a few days. The bottleneck is the Bosch Diesel work, not SPS. They have 5 rebuilt injectors ready to go.
 

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