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ERIC@BABIN.COM

CHECK ENGINE LIGHT / CODE READER IMPORTANCE

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2014 Itasca (Winnebago) Ellipse (Tour)  /  Cummins 450hp

Driving down the Florida Turnpike yesterday my check engine light came on.  I found a safe place to pull over, and pulled out my Nexas Diagnostic Scanner.  I had purchased this almost a year ago, and never had to use it.... it certainly came in handy!   

(here is the scanner on Amazon:  https://www.amazon.com/gp/product/B01N4GH6UZ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 )

I plugged it in, and ran a diagnostic and got SPN 157.  A problem with fuel rail pressure.... I remember getting a similar code back before I had the reader and had to go through the painful process of figuring out how to find the code using the installed system on the dash.... and I remembered that code comes up when you have a loose gas cap.  Prior to having the code reader I tightened the gas cap and had to wait what seemed like an hour for the code to clear.... using the Nexas I was able to tighten the gas cap, clear the code immediately,  then run diagnostics again.... boom.... no check engine light.... issue fixed.   (To clear the code I had to turn engine off, put ignition back in the accessory position without cranking engine on.... go back to the reader and "clear current codes" and then I got "success").  

Just sharing a little info that having a reader can save you some time.  Once you get the code then google is your friend.  

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Eric, fuel rail pressure code has nothing to do with a loose fuel cap. Gasoline engines monitor fuel tank pressure for evaporative emissions, diesels do not.

Most times fuel rail pressure faults are from clogged fuel filters or a sticking fuel return check valve. Other areas could be a faulty fuel injection pump, fuel leak (internal or external) or fuel injectors.

Could it have been a glitch, absolutely, should it come back on have it looked at ASAP.  

I agree, that is a handy tool to have!

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2 hours ago, jleamont said:

Eric, fuel rail pressure code has nothing to do with a loose fuel cap. Gasoline engines monitor fuel tank pressure for evaporative emissions, diesels do not.

Most times fuel rail pressure faults are from clogged fuel filters or a sticking fuel return check valve. Other areas could be a faulty fuel injection pump, fuel leak (internal or external) or fuel injectors.

Could it have been a glitch, absolutely, should it come back on have it looked at ASAP.  

I agree, that is a handy tool to have!

Good info, but certainly not what I wanted to hear! 

I'll keep an eye on it.

 

However, I did find this:

The Motor Control Module (MCM) monitors the rail pressure and when rail pressure deviation is greater than 200 bar for eight seconds, the MCM sets the code. This fault can occur due to the conditions listed below:

  • External fuel leakage between the high pressure pump and fuel injectors
  • Pressure limiting valve leakage (internal)
  • Fuel filter integrity (loose caps, plugged filters)
  • Fuel supply issues (fuel level, fuel aeration, leaking fuel lines, fuel restrictions)
  • Intermittent loss of engine speed signal
  • High pressure pump internal failure
  • Fuel injector (amplifier or needle) leakage
  • Fuel Contamination
  • Rail pressure sensor
  • Motor Control Module (MCM)

 

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Cheap, easy start is to replace the fuel filter(s).  That is the most likely cause and the least expensive to address.  And, if it/they are restricting fuel flow, will shorten fuel injection component life.

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Good advice. I had this exact problem with a clogged fuel filter triggering limp mode and a check engine light. I'm glad I had a code reader and access to a filter so we could get back on the road with just a minor delay. 

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Well...… it happened again.... and, it won't clear.

We lost power fairly drastically.... pulled over.... tried the same things as before.... but code would still not clear.... we decided to drive a little.... it SEEMED to be working fine, good power, but.... as I said.... check engine stayed on. 

We were able to make it home to Pipe Creek Texas (north west San Antonio).

Now.... my question - 

any recommendations for mechanics / shops in the NW San Antonio Area?  The nearest Cummins and Freightliner are both on the east side of San Antonio (about 50 miles away).

If there is something closer I'd prefer that..... OR.... should I just suck it up and drive the 50 miles.  And... if I do, would there be a preference between Cummins or Freightliner?  (they are very near each other)

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2 hours ago, ERIC@BABIN.COM said:

Well...… it happened again.... and, it won't clear.

We lost power fairly drastically.... pulled over.... tried the same things as before.... but code would still not clear.... we decided to drive a little.... it SEEMED to be working fine, good power, but.... as I said.... check engine stayed on. 

We were able to make it home to Pipe Creek Texas (north west San Antonio).

Now.... my question - 

any recommendations for mechanics / shops in the NW San Antonio Area?  The nearest Cummins and Freightliner are both on the east side of San Antonio (about 50 miles away).

If there is something closer I'd prefer that..... OR.... should I just suck it up and drive the 50 miles.  And... if I do, would there be a preference between Cummins or Freightliner?  (they are very near each other)

Did you follow Brett advice and replace the fuel filters?  

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Eric. Follow Brett's advice, if you have not done so...if you have, do it again.  TCC does not have a engine tech anymore & Dave spends most of his time at his Lake LBJ home, so your stuck with Mike.  I will use the body shop, but that's all.  Just a heads up!

Sorry about the windmill palm pups, the got wet feet & died..we have more now, let me know.

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19 hours ago, WILDEBILL308 said:

I would talk to Texas custom Coach there in Pipe Creek (888) 761-4225 See  if they can do it or who they recommend.

Bill

Yes... Mike gave me the number of someone to call in San Antonio. 

17 hours ago, huffypuff said:

Did you follow Brett advice and replace the fuel filters?  

Not yet.... but may be next step... but see update below.

9 hours ago, manholt said:

Eric. Follow Brett's advice, if you have not done so...if you have, do it again.  TCC does not have a engine tech anymore & Dave spends most of his time at his Lake LBJ home, so your stuck with Mike.  I will use the body shop, but that's all.  Just a heads up!

Sorry about the windmill palm pups, the got wet feet & died..we have more now, let me know.

Yep... talked to Mike and he gave me a number to call.

UPDATE: Started coach today just to see if I could force the code to reset..... guess what..... check engine is off.... code reader shows no active codes!

ok... with that said.... we are on the roads a lot so..... I'm going to take it in to have a professional look at it.....   

Here is something I just remembered yesterday... and this MIGHT be the culprit?  You tell me if it is possible.... (I guess anything is possible).

You know those fuel additives.....the ones with the foil on the top..... well, I was using one with the foil that is about the size of a dime.... and, it fell into the fuel tank while I was putting the additive in about 4,000 miles ago / a couple of months.... hmmm.... could be causing the intermittent issue.... stops up something... then when coach sits, it floats back down? 

Just for more numbers.... yesterday I was getting, according to my Nexas Code Reader, 99-100 MPa fuel rail pressure.... today, with no check engine light showing, I'm getting 79-80 MPa.  So, maybe the issue it was HIGH?  I guess this is why I need to take it in to have it looked at. 

 

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Well the original code was low fuel rail pressure, then it sounds line it went to the high side with the fault yesterday. This is a tough one to pinpoint by guessing. It could be a bunch of components causing this fault. It needs to go to a Cummins authorized shop before it causes other components to weaken or fail and really runs up your tab.

Both MPA readings above are in range, but at what RPM it set the fault is the real question? Said another way, it could have had 15000 PSI at idle which is too high but at 2000 RPM's it was in spec.

 

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3 hours ago, ERIC@BABIN.COM said:

You know those fuel additives.....the ones with the foil on the top..... well, I was using one with the foil that is about the size of a dime.... and, it fell into the fuel tank while I was putting the additive in about 4,000 miles ago / a couple of months.... hmmm.... could be causing the intermittent issue.... stops up something... then when coach sits, it floats back down? 

Seriously doubt it could be a problem. Most pickups have a big screen covering the pick up opening. 

Bill 

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