1998 Patriot Crank/No Start

[Bill Drout]

Thanks for everyone's input so far -- I know it's been a while.  As you probably heard (or experienced) we had a really cold snap here in Texas, and I've been preoccupied cleaning up from that for a while.

I did get the ECM back, and finally got it installed.  The coach cranks and appears to run just fine.

BUT...

1) The tachometer pegs high when the engine starts (points straight down).   The tachometer also appears to have some "jitter" around 0 during key-on, engine off (before starting).  The Intellidrive displays a tachometer reading that appears to be correct.  It responds to the a change in engine speed like I would expect as well. 
2) Cruise control is INOP.  It will not set in neutral, and it will not set when up to speed and going down the road. 
3) The shift pad is not as responsive as normal.  Sometime I have to press it 2 or 3 times in order for it to detect the input.  I have no idea if it's related to the tach/cruise issue, but it's definitely a change in behavior.
4) The J-II leveling system warning bell tone sometimes will change.  At other times it will be normal.  When sounding irregular, the tone returns to normal if I press the boost/bond switch to join the house batteries to the chassis batteries.
5) The Intellidrive restarted when I was using the J-II controls to level the coach, so I'm guessing that was from low voltage.

So, in conclusion, I'm pretty sure that I still have gremlins in the electrical system, but I do not know if that is causing the tachometer/cruise control issue or if it is an ECM issue.  The tach and cruise control worked fine the last time I drove the RV before the ECM failure, so I'm suspicious that it's ECM related.  Nonetheless it's possible that the electrical issue is causing the problem, so I'm troubleshooting that to start off with.  It's also possible that the gremlins caused the ECM failure to begin with.

I'm suspicious of a weak ground or a chassis 12V connection somewhere.  The initial check looks good in battery compartment, and that was my prime suspect area.  I have new chassis batteries (about 1 month old now), so I would not expect that to be the problem.  I also cleaned terminal connections when I replace the batteries.

Another prime suspect would be the continuous duty solenoid in the electrical bay, but I replaced that recently. 

Everyone has been very helpful so far.  Let me know if anyone has jewels of wisdom. 

Thanks again (and in advance) for your help!

[Carl Boger]

My first guess would be a ground issue also.  I would jumper a ground wire from the tach ground back to a good grounding point maybe in the electrical bay and see if that improved anything.  If so great, if not I would start testing the signal wire.  There are a lot of wires and connection points in our RV's.

[Mack Turner]

The following file is a cat document that goes through the reasons for a no start, I have attempted to attach this before with no luck, I just sent it through email today. Please let me know if you can get to this attachment or not?

[Eric Maclean]

Bill
Looking at the wiring diagram for the 1996 Patriot it shows the tach driven by the alternator tach drive the 98 may be the same
If so I'd be looking for a ground issue to theta h and maybe to whole front electrical bay area .
With that said if you've had the batteries disconnect lately I'd look very closely at the cable routing make sure you have all the grounds in the right places ( you wouldn't be the first to have a cable drop down behind the batteries and not hooked back up.

The cruise switches are tied straight into the ECM but there is a brake interrupt relay that interrupts the cruise when brakes lights or exhaust brake is activated ( the cruise and or fast idle won't work with the exhaust brake switch turned on) .
With that said it would be possible a bad ground could effect the cruise via back feed through the cruise interrupt relay.
Hope this helps
Eric

[Bill Drout]

I think I found my gremlin in the battery ground.  That has now been resolved, but I still do not have a responsive tach.  The cruise still does not set, and the engine brake switch does not work either.

I peeked behind the front dash, and it appears that the tachometer is circuit 356 (see attached).  This corresponds to the numbering for the "2002-2003 Patriot Wiring Diagrams" schematic "C12 Engine Harness, No Serv Center" page 2.  For that coach the 356 Circuit maps to "CECM (engine connector)" pin 38 (ECM Tach Out +).  I'm thinking it's reasonable to assume that it's the same on my coach as well.

Also according to that same schematic, all of the items that are not working have direct connections to pins on the ECM.  I'm getting this sinking feeling that the ECM was not fully repaired.  I have reached out to 1EngineControl and hope to hear from them tomorrow.

[Bill Lampkin]

Could it be that the ECM needs to be programed for those functions to work?

[Eric Maclean]

Looking at the wiring diagram for the CECM that you are correct all those functions come straight from the ECM to the tach etc .
With that in mind there are the connection pins at the ECM plugs and connector # 51 near the e! electrical bay failing that it may be a programming failure in the ECM.
Let us know how you make out with your rebuilder
Eric

[Bill Drout]

Hi Bill L,
  I'm _really_ hoping that's the case.  I'm still recovering from the reinstall, so the thought of pulling it again will require some mental preparation :-)  I would gladly drive the RV somewhere to have it reprogrammed over pulling the ECM, even if I have to pay for it separately. 

  Pulling the ECM off the side of that engine and reinstalling it was a bear of a job.  Most of the work is done from underneath, and I'm working on it outside in an area that's just dirt and sand.  You have to pull the air filter, the air filter mounting brackets, and the crankcase breather hose even to see the ECM.  Even then the view of the ECM is limited, and your vision is almost always blocked because you have to put your hand though the same small field of view you're looking through to work on the ECM.  Then to remove the 4 bolts that hold it on you have to be somewhat of a contortionist to get around the chassis C-beam that goes in front of it.  I can't even see the bottom right bolt at all, so I have to wrap my arm over and around the C-beam and then get the wrench on the bolt (don't round it off) and loosen or tighten as appropriate totally by feel.  The stand-offs are comprised of several different components, and many pieces have to be removed/reassembled by feel.  Don't have any part of them fall down into a crevice and get stuck, because you can't see down there.  Several parts are not metallic, so using a magnet to retrieve them will not work.  Finding them will only be via the same Braille method used to remove/reinstall the bolts.  I had to do that several times, and a few of those times I thought I would not be able to find/retrieve the part.

  I'm not whining (okay maybe a little) -- just sharing.  I'm sure we could all tell a similar war stories.  This will be one of mine.  I guess that's just part of owning an older RV.

[Steve Huber Co-Admin]

Bill,
To the best of my knowledge ECU programing should be via the diagnostic connector, either under the dash or in the rear run box area. There should be no need to pull the ECU. Dave Atherton should be able to confirm.
Steve

[Dave Atherton]

Bill, after checking wiring would suggest going to back of your tachometer on top at 12 o’clock there
Is a Yellow wire and wire number 450 connected to pin 17 on ECM side J-1.  Next at 6 o’clock there
Is a brown wire number 451 connected to pin 11 on ECM side J-1.

Note if there is only one wire on tachometer which the plus wire is Yellow and wire number is 450,
can be connected to either pin 17 or pin 11. Note one wire than should be left disconnected. The
Ground wire for tachometer should be attached to starting motor housing ground. After getting the
Tachometer working than can help with the cruise. Dave Atherton Retired Cat Mechanic

[Bill Drout]

Hi Steve,
  Thanks for the heads-up.  I do see a "Diagnostic Data Link" connector in the service center, so I'm thinking that's the place to go.  If it's just a programming issue then I agree that someone can probably do it with the ECM still in the coach.  I'm just hoping that it's not an overlooked component (hardware) failure inside of the ECM.

Hi Dave,
  Thanks for looking up that information for me.  I took a peek behind the dash at the tachometer, and I do see the signal wire going to the tach.  That wire is labeled "356 Tachometer" on my coach, but I think we're talking about the same connection going back to the ECM.  I'll respond to this thread once the rebuilder gets back to me -- hopefully today.

Thanks again!

[Dave Atherton]

Bill, I do not know where you are located but if you take motorhome to a cat dealer your problem
can be corrected with Caterpillar service tool call ET. The same time so an your other functions can
be corrected. I take it you bought a ECM that programmed off the engine. The cruise control has a
Soft or hard setting on down shifting that can be set with Cat ET service tool. Last my suggestion
would be after your ECM is operating correct for your motorhome than have a copy made up of all
information on your ECM to carry with your motorhome. If this cannot be preformed having copy
made for a backup , I can print out your information at Quartzsite in January at the beaver rally
In the desert. Last when I connect my ET for a Diagnostic ECM readout/ printout this is information
many beaver members all ready have for there motorhomes. Dave Atherton Retired Cat Mechanic

[Bill Drout]

Hi Dave,
  Yes it may be time for a trip into Mustang Cat in Bryan, TX.  The response I got from the rebuilder was that they set the ECM parameters to something that they thought was similar, but apparently it was not identical. 

  One of the things they are asking me for now is the PPM (Pulse Per Mile).  Apparently that's a parameter they need to configure the ECM for proper function.  Would CAT know this if I took it to them, or would they be asking me for it too?  I'm guessing that's specific to a Beaver motor coach.  The rebuilder said it should be in my owner's manual, but I'm pretty sure my Beaver owner's manual would not have that.  If I had to guess it would have something to do with tire size, but I don't know that for sure.

  Does anyone have the PPM value for a 1998 Patriot?  If not, would this be something that Beaver Coach Sales might know?

[Dave Atherton]

Bill, the caterpillar service shop is well aware of setting a ECM using Cat ET on your motorhome.
Been down this trail many times and one thing cat service, may remove your valve cover so they
can get the numbers off electronic injector personally code. Guess I’m not to woozy ordering a pre
program ECM just for the reason you are having. One question I do have, did your ECM just shut
down your engine than a no start or how did a determination bring you to the ECM. Reasons for
this question it is very rare for failure in this area. Dave Atherton Retired Cat Mechanic

[Bill Drout]

Hi Dave,
  Everything related to the ECM (speedo, tach, cruise, exhaust brake, etc) worked just fine prior to shutting down the engine the last time I had run it.  I came back a month later to exercise the coach only to find that she would crank but not start.  The tach was not responding during the crank, and I had no check engine light test come on when switching the to key ON.  I also could not get the ECM to give me any flash codes - not even the "all is well" 55 flash code.  I had no engine data (like intake manifold temperature) on the Intellidrive with the key switched on.  As far as I could tell I was not getting any signals from the ECM, and the coach would not start.  After a lot of troubleshooting and as a last resort, I got down to removing the ECM J1 connector.  I confirmed pins 52, 53 had good constant power,  pins 65, 67 had good ground, and pin 70 had good switched power. 
  At that point in time I made the call that it was the ECM.  I pulled it and sent it off for repair.  The tech report diagnosis was "faulty battery" and that they could not retrieve the original settings off the ECM.  So they said they programed it with the profile for an RV.  They sent it back, I installed it, and here we are.  The coach runs but the tach, cruise, and exhaust brake are inoperative.