Hi, new here - 98 HR in Limp Mode

[Sintashia]

lease help! We have a 98 holiday rambler with a cummins diesel. We are in limp mode. We have gone to 3 different mechanics. All said the ECU is the likely culprit. So, we replaced it, all fuel filters, changed oil and filter, blew out air filter.... still... limp mode. WTH?!?! I'm ready to cry like a 5 year old.

[MSHappyCampers]

Hi ! Welcome to IRV2! We're sure glad you joined us!

Hopefully someone will be along that can help!

Good luck, happy trails, and God bless!

[Skip426]

Welcome to iRV2.

Sorry you first post is about problems .
Were any of these mechanics at a certified Cummins dealer ?

Two different Cummins engines available, that used an ECU in 98 motorhome chassis so knowing exactly what you have would be more than helpful .

ISB engine 5.9 liter displacement
ISC engine 8.3 liter displacement
These engines didn't use the same fuel injection high pressure pump , so to provide good answers members will need this information.

Did the shop list any fault codes that lead them to replace the ECU ?
Have you any idea what codes currently exist , that have the engine in limp mode?

[Lt Dan]

You said you changed the fuel filters but coach builders sometimes install another filter in the fuel line along the chassis rail. You might do a search along the rails for an extra filter.

[TStravel]

Not nearly enough info to diagnose the problem. But if you have a 5.9 ISB I would be Googling the Bosch VP44 injection pump

[JBDISCOVERY]

We had an interesting issue with a 1999 Discovery with a 5.9 Cummins on
a Freightliner chassis.
It seems during late 1998 and early 1999 there was a problem with the Cummings engine going to a "de rate status. Low power, limp home mode.
It took awhile to scope out the problem which, in our case, was connected to
the exhaust brake on the Cummins engine. Not a problem with the engine,
but with the wiring that controls the engine brake.
A old hand at Fleetwood remembered a "fix" that came out to address the
problem.
The root of the problem was/is when the engine brake kicks out, there is an
electrical spike that travels back up the wiring harness to the ECM.
The ECM thinks it has a problem and goes into de rate with low power, creep
mode. (We had this at least a half dozen times, some that were interesting).
The solution was a "Fix" that Freightliner created to insert a diaode into the
wire that activates the engine brake solinode.
The diaode blocks the spike returning to the ECM.
We bought the last kit five years ago from the Freightline salvage storage yard.
The circuit is simple to insert a diaode into the hot side of the wire to the engine brake.
Maybe this can help you. We have not had the problem for the past five years.
Regards,
JimB

I just reread your first posting and believe my reason most likely is not
your problem.
At 75,000 miles we had a problem in Virginia with the Bosch VP44 high pressure fuel injection pump. The coach limped into the Cummins
service center where the techs determined the VP44 had failed.
Same low power symptoms.
The Bosch VP44 does not have a great rep. Look it up.
Only rebuilt units are available now. There are several shops that offer rebuilt units.
Good luck.
JimB

[CountryB]

Originally Posted by Sintashia

lease help! We have a 98 holiday rambler with a cummins diesel. We are in limp mode.

How do you know your Coach is in "Limp Mode"?

Limp mode is an ECM state where the ECM detects a problem and reduces engine power. The "Check Engine" light would be on, and there will be a fault code.

Or, is the Coach just running poorly - but with no dash lights or fault codes displayed?


Side note -- when a mechanic tells you the ECM is bad and then replaces it, and that doesn't solve the problem. Why are you paying for it?
(I expect the mechanic will say it was bad, but there are other things wrong too. I think that is bs.)

[R.Wold]

A lot of so-called mechanics are just glorified, high-priced parts swappers. The solution to this is to go only to certified shops, get estimates in writing, be clear on expectations, and do your research before, during and after repairs. You shouldn’t have to do all that when paying $150/hour to have someone else handle your problem, but if you don’t you are at their mercy.

Also Invest in a code reader and go in armed with information, and then check their work. I just bought an adapter for my OBD2 code readers to plug into the nine pin on my coach. Not sure if it will be sufficient but i’ll find out. A if not I’ll buy a good code reader for this thing (just had my own de-rate/limp problems last week). Yours may be five-pin, but whatever it is, find out and get a code reader so you can look up codes and ask specific questions here and elsewhere before turning your coach over to a shop.

OP, fortunately you posted here and we both have already learned more about your issue than your mechanic probably knows. Hope it gets sorted, and please report back on results.

Lastly, where are you? You can always get recommendations for good shops on the forums, and even if you are already into this shop for more than you should be, sometimes it’s best to consider it a sunk fund and move on. Hopefully not in your case, but....

[RKins]

I'm not sure he has a port to read anything from an ECM. Could be wrong - I know mine doesn't have a port to read a ECM. That year was the transition from non-smart to smart. Some were smart others were not depending on the time of the year they were released.
On my coach the only plug I have is an ALDL for the tranny. The only thing that could read the data was a very old Snap on reader and of course Allison. $$$

[deandec]

Originally Posted by Sintashia

lease help! We have a 98 holiday rambler with a cummins diesel. We are in limp mode. We have gone to 3 different mechanics. All said the ECU is the likely culprit. So, we replaced it, all fuel filters, changed oil and filter, blew out air filter.... still... limp mode. WTH?!?! I'm ready to cry like a 5 year old.

Which 1998 Cummins engine?

C8.3L
ISC 8.3L
ISB 5.9L

What are the symptoms of your "limp mode"?

Help us, help you by providing some info.

[Skip426]

Starting this thread was the OP's only visit to the site.

Without more input from the member , I'm thinking more posts are unnecessary.

[Paul1709]

Hallo ich habe einen 98' HR Navigator, dieses in Notlauf schalten kenn ich, bei mir war es ein Stromleitungsproblem, der Kabelbaum liegt in Fahrtrichtung links im Rahmen, in dem Bereich Motor /Getriebe, kommen die Kabel vom Generator und den Batterien zusammen, bei mir war dort eine Scheuerstelle und bei jeder größeren Erschütterung hatte es Masse Kontakt, der Strom für die Steuerteile vom Getriebe wurden unterbrochen und das System ging in Notlauf, das zu überprüfen kann man selber machen, einer tastet den Kabelbaum ab und ein andere beobachtet die kontrollleuchten,

[Skip426]

Originally Posted by Paul1709

Hallo ich habe einen 98' HR Navigator, dieses in Notlauf schalten kenn ich, bei mir war es ein Stromleitungsproblem, der Kabelbaum liegt in Fahrtrichtung links im Rahmen, in dem Bereich Motor /Getriebe, kommen die Kabel vom Generator und den Batterien zusammen, bei mir war dort eine Scheuerstelle und bei jeder größeren Erschütterung hatte es Masse Kontakt, der Strom für die Steuerteile vom Getriebe wurden unterbrochen und das System ging in Notlauf, das zu überprüfen kann man selber machen, einer tastet den Kabelbaum ab und ein andere beobachtet die kontrollleuchten,

Paul1709 ; my French is bad , my German , even worse , are you replying to Sintashia's problem or asking about your own .
We can probably help if this is a problem with your coach , but are going to need a translation, to English .

[engine103]

Rough translation: Hello I have a 98' HR Navigator, Switching this in emergency run I know, with me it was a power line problem, the harness is in the direction of travel left in the frame, in the area motor/gearbox, the cables come together from the generator and the batteries, with me there was a abrasion and with every major shock there had mass contact, the power for the control parts of the gearbox were interrupted and the system went into emergency run, which you can make yourself to check, one scans the wiring