I'm stranded in a CG about six hours from home. Engine will start, but idles and runs rough, unresponsive to throttle intermittently, not enough power to pull slight incline into camping space. Changed all fuel filters and emptied their contents into a fine strainer--not enough contamination IMO to have caused any problem. Changing filters did not help. Running fine when I pulled in about a week ago.
Previously installed a FASS Titanium pump, and ran it uneventfully for several hundred miles.
Later installed an EGT gage in preparation for adding an Ag Solutions 12100 "chip". Found EGT in stock configuration to be uncomfortably high under "tortuous" conditions of WOT and low boost. Increased boost by modifying wastegate. That raised boost from 23 to 30 PSI, which lowered EGT by over 100*F at WOT.
I installed the Ag Solutions 12100 "chip". Tried that combination out for a few hundred miles and everything seemed OK. Fuel pressure remained at about 15 PSI (monitored from instrument panel at driver) and EGT's remained equal to or less than stock EGT.
Confident all was well, I set out on a slighter longer trip with a total mileage of about 1000 miles. Pulled into a CG at about halfway about a week ago. Trying to leave this morning, I had the symptoms given in the first paragraph.
For reasons that require too long an explanation, I suspect that my OEM lift pump is causing a problem. When I added the FASS pump, I did not bypass the OEM lift pump. I just inserted the FASS pump assembly in the place of the Primary Fuel Filter originally installed on the coach, so now I have the two FASS filters and my original secondary filter. In changing all filters and draining their contents into a paper towel filter, only the first filter in the line of three showed any contaminants, and not enough to be a problem IMO.
I want to bypass the OEM lift pump and I'm about to start that process now. If any of you bypassed your lift pump during a FASS or Air Dog pump installation, please describe how you did it. Removing the Ag Solutions "chip" made no difference.
I am about to remove the hose from the OEM lift pump to the secondary filter AT the OEM lift pump and install it directly to the FASS pump. I know I have to continue to use the OEM lift pump MANIFOLD since the injector pump and injector drains go through that manifold back to the fuel tank.
Any help would be appreciated. TIA Going to work on changing the fuel line now. I'll check back later on this forum.
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VanWill: Sounds like you want to rule out a fuel delivery problem first. Makes sense, but I would not rule out other electrical issues you can check easily to rule-out.
For example: You might try wiggling your fuel pressure valve wires and Stator (on Injection Control Valve-ICV) wires to see if see if that has any "+" or "-" affect on your running engine?
I understand you have +15PSI of positive fuel flow to your injection pump, but you think there may not be enough fuel pressure to keep your engine running right. And you hope a check-valve in the Lift Pump Manifold maybe the culprit. (TBD)
Do you have any white smoke when your engine starts? ...If so, that's more of an injection pump concern based on incorrect fuel timing. (Possibly Stator and ICV related, but it also can be due to a broken drive on the low pressure gear pump.)
If your engine idles okay and your exhaust it okay, then maybe your Throttle Position Sensor (TPS) needs to be looked at as these things have been known to cause all sorts of ECM problems that control fuel timing.
Further, if your TPS is located behind your foot peddle, these are the type of TPS (variable resistors) that fail more than any other types of TPS. ...And often you may find a broken or cracked wire?
When I lost my TPS it will flash a fault code you might be able to check and then go away. Consequently, if you never saw a CEL come on then maybe the TPS angle is not applicable here?
Back to fuel obstruction issues: The Cummins lift pumps shows a lift pump check-valve (#10) in the diagram below.
However, I have talked with Cummins about this drawing, because I'm not sure it shows the check-valve in the right place. (TBD) ...That said, the drawing may imply there is check-valve located somewhere else in the fuel line?
For example: On semi-trucks the check-valve is in the 90-degree fuel elbow that goes to the injection pump. (See picture.) ...So look at any of those fuel and AN-fittings closely to see if they could have a check-valve inside?
In any event, if you are by-passing your CAPS Lift Pump Manifold (LPM), I think the "IN" side of the LPM is completely separate from the "OUT" fuel return side... then I don't think you need to worry about adding caps on each 10AN fillng, because fuel flow through the "IN" side of the LPM is completely separate from the fuel flow "OUT" of the LPM. (AS FAR AS I KNOW.)
*** Good luck trying to find your fuel obstruction/delivery problems while you attempt to by-pass a check-valve located somewhere in your fuel line.
OTHER ISSUES IF BY-PASSING THE CHECK VALVE & LPM DOES NOT WORK
* TPS problem
* * Fuel pressure sensor or Stator wires (to ICV) have internal connection problems.... try wiggling each of these to see if your engine responds + or -.
* High pressure side of your injection pump failed. (But if you don't have white smoke when you start your engine this should not be the problem.)
* Are those 3 lift pump bolts lose, tight or broke? ...that could be letting air into your fuel lines?
* And that fuel line between your #3 filter and your Injection Gear Pump... it's in good shape, right? ...I.e.,. no "flappers" inside an old fuel line causing problems?
I have removed the fuel line FROM the OEM lift pump TO the secondary (final) OEM filter on my coach. The removed fuel line was just the right length to connect the FASS pump's OUTPUT directly to the INPUT of the OEM final filter. The OUTPUT of the OEM final filter goes directly to the CAPS injection pump.
My OEM lift pump is electrically disconnected and a "dummy load" relay installed to prevent the Cummins ECM from showing a fault code.
As soon as I can get some hydraulic fittings tomorrow morning to close off the (now unused) fuel delivery lines to and from the OEM lift pump, I will have a system in which the OEM lift PUMP and MANIFOLD is totally out of the circuit on the fuel SUPPLY side. The fuel will come straight from the tank, through the FASS pump and its two integral filters and into the FINAL (original secondary) filter. The CAPS pump INTERNAL drain (from the CAPS pump) and fuel injector drains (coming off the back of the cylinder head) will remain intact and connect to the lift pump MANIFOLD, as original. Both of those lines use banjo fittings on the OEM lift pump MANIFOLD and return fuel to the tank. The FASS pump has a dedicated 1/2" fuel return line of its own, which I installed when I installed the FASS pump.
I have an instrument panel gage to read fuel pressure directly at the OUTLET of the OEM final filter as it goes to the CAPS pump. Ever since installing the FASS pump, that gage has read 15-16 PSI at idle or low throttle and 14 PSI at WOT.
After you rule out fuel delivery concerns, be that air in the line or obstruction by a stuck check-valve, and you are sure your FASS pump is working right...
...then you have to assume you may have an electrical problem or mechanical problem. So to address the mechanical issues of a CAPS system pump I would try to determine if your Low Pressure Gear Pump failed.
When this happens, there is a key on the shaft brakes. This is called a "Distributor Drive Hub" and it keeps your Fuel Distributor properly timed. (See attached .pdf)
So if you have have +15 PSI getting to the Low Pressure Gear Pump, but not enough fuel pressure coming out of the high pressure side of the CAPS pump, then maybe your Low Pressure Gear Pump "distributor drive hub" sheered off? ...Note there are tow of these. (See #6 in picture one below; and see #4 in picture two below.)
Note: That 10-micron metal screen in the Low Pressure Gear Pump is there to prevent metal fragments from entering the high pressure side of the CAPS pump.
If you see white smoke then one of the reasons for this is poor injector timing... but when you trace the problem that back to the source... you find fuel distributor timing comes from the Low Pressure Gear Pump "Hub"... which is ultimately timed to TDC. I.e., it's all connected together.
LOW PRESSURE GEAR PUMP REMOVAL
To remove low pressure gear pump you first remove the fuel distributor and ICV on top. (See those long bolts in the second picture below #5.) Then you can separate the distributor from the gear pump.
Note: I do not think you need to remove the CAPS injection pump to do this repair... but that distributor has 6 fuel lines coming out of it that are a pain. ...And no, I have never done this before, but when I lost my CAPS pump I was working with (arguing would be more accurate) with the Cummins Shop Foreman about how to repair my pump vs. replacing it the whole CAPS injection system. And to be honest with you.. I replaced the entire CAPS injection system because I did not trust the abilities of the Cummins shop I was working with in Colburg, Oregon. ...And I'm still pissed off about that experience. So to all of you looking for a shop to repair a CAPS injection pump, I would not go to Cummins if it can be helped!
Note: I love Cummins QuickServe and telephone support, but somewhere along the line Cummins pulled their franchise licenses out of the field (2-3years ago) and that really damaged the quality of customer service in the field. ...Now maybe they have recovered, but I still feel strongly about NOT using Cummins for RV repairs and generator repairs if I can avoid it.
What you need is an older mechanic who knows how to repair CAPS injection systems, which would be considered normal through 2010, but that was 10 years ago and most of these guys are retired or they are running their own shop.
Next you need a young mechanic who can work in small spaces. My point is that if you know what to do, you an coach a young mechanic to repair your pump, but I would still entrust it to a shop so they tank "ownership" of the repair and have the tools to measure fuel pressures before you get started replacing parts "unknown".
==> The problem you have now is that you do NOT know what the high side fuel pressure; and until you do you can't say what your next step will be.
=> The fact that you have $15 oil filled fuel pressure gauge on top of your #3 filter (or can measure fuel pressure in electrically) means you can confirm positive fuel pressure to your CAPS injection pump. And this is half of the battle won when it comes to diagnosing a fuel delivery concern. So for others reading this post, you guys should install one of these liquid fuel gauges so you can help your mechanic get started... and help you know where to look next.
Measuring the high pressure side is not as easy and I have never done it. So I'm sorry I cannot tell you how it's done.
I know you are doing what you can in the field to avoid a tow. So I will offer you this tip... hoping it works for you:
Many diesel shops who specialize in road service have a policy to NOT charge you if they can't fix your problem on the road. So you might want to find one of these REPUTABLE shops in your area with a "roaming mechanic" on duty and with your mechanical experience, and their diesel tools, you might be able to affect a CAPS repair in the field without removing the pump. ...Assuming you have a "mechanical" problem. Just be sure you get their guarantee before they dispatch a mechanic to help you and now you have another set of eyes on your problem and he should come with fuel pressure measurement tools and his experience separating fuel delivery issues from electronic issues... and he can look at your ECM fault codes for free if he can't fix your problem.
I hope this information helps you negotiate with a local shop to get your back on the road for less than the cost of a tow! Good luck.
White smoke stumble.
Pull the fuel drain line banjo fitting on the back of the cylinder head and run the engine.
There should be only enough fuel to be measured in drops per minute.
If there is more, there is a problem with the connection between the injector and the high-pressure connector.
Reference: Appendix page A-23.
Check if drain rail is "breathing".
Air flow detected at the drain rail is a symptom of poor injector seal with the cylinder head.
Inspect copper injector shims (Could possibly have 2, or none if any injector has been removed or replaced previously.)
Reference: Appendix A-23.
Remove the rate shape snubber and inspect valve for metal debris. If debris is found, replace the entire fuel pump.
Reference: Appendix page A-4.
NOTE: If the rate shape snubber is removed, it must be replaced. Reference: Appendix page A-3.
I also can email you a Cummins ISC/ILS Troubleshooting Guide that is a 250 page Cummins document. However, I can only email it to you, because this document is too big to attach it to this post. ...I you would like this document, you need to to send me a private message... with your email.
Have cleaned and renewed every connector I can find--Fuel Pressure sensor, ECM connections, Fuel Quantity sensor and others I cannot identify but are related to the engine's electronics.
Re-routed fuel SUPPLY plumbing to exclude the OEM lift pump and manifold. Fuel supply goes straight out of FASS pump (and its two filters) into the OEM secondary filter. Gages (both filter-head-mounted mechanical gage and instrument panel remote gage) show 16 PSI at outlet of secondary filter. There is only a short hose from the secondary filter to the CAPS pump. The RETURN lines in the OEM lift pump MANIFOLD are still connected.
Engine will start and respond to throttle, at least for now. Engine still runs very rough and sporadically bellows black smoke. Sounds the way a diesel tractor engine (small 3-cyl Perkins) I rebuilt sounded when it needed air bled from the system. In this case, I cannot imagine how air could have gotten in the system. It was running normally when I parked it. One week later, I have these symptoms almost immediately after start-up.
I think there is an air-bleed built into the BODY of the CAPS pump. With constant pressure at the CAPS inlet one would assume that the CAPS pump internally would be free of air if sitting with the FASS pump running, keeping the CAPS pump body at 16 PSI, and the CAPS pump dumping excess fuel into the return line in the OEM lift pump MANIFOLD. That would not expel air in the injection lines, of course. No personal experience with that, so I'm just guessing.
I cannot imagine how the two events could be related, but my generator has developed a problem of low output voltage. The Progressive Industries surge protector disconnected it while it was running as I was attempting to pull out of the CG a couple of days ago. Since being plugged into a pedestal again, inverter-charger is charging batteries as normal.
Still trying to solve the problem, but I'm running out of LIKELY ideas. There are HUNDREDS of long-shot, unlikely causes, but I think I've covered all the ones that are truly likely to be the problem, at least the ones I'm able to solve without INSITE software.
Do our older engines even have an idle shutdown timer? I thought only newer commercial trucks had this to limit idling. Sounds like you have fuel to CAPS covered. At least it runs so they can get readings off the ECM. Wish you luck!
Bill
__________________
2003 Country Coach Intrigue 36'
Cummins ISL 400
(Note: Despite what some say, fault code 111 does not conclusively mean a bad ECM. I.e., you only should replace the ECM when all else fails.)
If you do not have any of these fault codes then maybe you do NOT have a CAPS failure?
Further, I would think if the mechanical side of the pump was bad, if your Low Pressure Gear Pump distributor coupler broke, or is out of time, then IO would think you might have metal in that 10-micron Gear Pump Screen... which is very hard to get to unless your remove your ICV... or you would see other Fault Codes like: #328, or #329; and/or #268 and #456 for the Accumulator would trip.... because not enough fuel will be supplied to achieve a high pressure side of the CAPS pump. …But in my case, none of these are active.
So I wanted to know, from the experts at Cummins, Colburg, Oregon.. what do you think is the problem with my engine? ...And how will you isolate and fix my CAPS injection pump problem?
...And you know what? ...They never diagnosed a CAPS failure before!!! (To say the least I was so upset! ...Only to later find out this is more common than you would think.)
So if I had I "do over" and found a qualified CAPS mechanic, I would think these were the steps he would follow to save me some money:
1) Verify distributor is “in time”. If not…
2) Replace the stator STATOR Kit $95 (Part #4089399) & Suppression Diode $110 (Part #3944110).. more importantly, the ICV. ($??? Can't remember, but not that expensive. Relatively).
3) Still nothing… Replace the entire CAPS pump. (Very expensive.)
4) As a last option replace the ECM. ($1100 after Cummins QuickService Discount.)
Note: Older mechanics have told me... that 90% of the time when you lose your CAPS pump you blow your ECM.
I hope you find a solution to your problem without having to lose too many toes in the process! ...My guess is you have a better change with an older mechanic in a private shop vs. Cummins.
THERE IS NO JUSTICE IN THIS WORLD!
ONLY IRONY...
...AND THE OCCASIONAL HOPE SOMEONE CARES!
* IMO, the prefect combination of help you need to fix or replace a CAPS or HPFR injection pump is: 1) A 55+ year old mechanic with CAPS over haul experience; and 2) A 35 year old younger mechanic to do the work!!!
Do our older engines even have an idle shutdown timer? I thought only newer commercial trucks had this to limit idling. Sounds like you have fuel to CAPS covered. At least it runs so they can get readings off the ECM. Wish you luck!
Bill
Bill, did you bypass your OEM lift pump? If so, how did you do it? What lines are left connected to your OEM lift pump? My FASS pump works properly and supplies 16 PSI to the CAPS pump, but its inlet is still connected to the OEM lift pump MANIFOLD. Its OUTLET (FASS pump) goes straight to the secondary filter. From there, fuel goes straight to the CAPS pump.
I don't know the answer to the "idle timer" question. Like you, I did not think the older engines had one, either.
Bill, did you bypass your OEM lift pump? If so, how did you do it? What lines are left connected to your OEM lift pump? My FASS pump works properly and supplies 16 PSI to the CAPS pump, but its inlet is still connected to the OEM lift pump MANIFOLD. Its OUTLET (FASS pump) goes straight to the secondary filter. From there, fuel goes straight to the CAPS pump.
I don't know the answer to the "idle timer" question. Like you, I did not think the older engines had one, either.
Going to be towed to a heavy truck shop shortly.
Thanks for your reply.
My stock Country Coach filters are located in the rear passenger bay. I used the existing fuel line from the tank that was routed to the primary filter in this bay. From there, a fuel line from the output of the primary was routed to the lift pump input. From there, a fuel line from the output of the lift pump was routed back to the rear bay to the input of the secondary filter.
So it was very easy to disconnect the lift pump fuel lines from the filters and cap them in the rear bay. This was done so I could easily reconnect the lines and use the old lift pump as a backup. I then installed the Fass pump in the rear bay with two short fuel lines to the existing filters. All other fuel lines at the lift pump manifold were left intact.
I didn’t use the same model Fass fuel pump as you. I didn’t feel I needed the extra filtration and air removal and my Fass pump has worked out well for many years.
Bill
__________________
2003 Country Coach Intrigue 36'
Cummins ISL 400
Linear Mode
