Cummins 1998/Frightliner engine problems - HELP!

Hi guys, now this one involves a late (computer controlled) cummins so it is a bit out of my league and being for a mate as well needs a bit more thought.

The vehicle is a 1998 Frightliner FL112 bonneted prime mover which was converted to a tipper about 5 years ago. It has a Cummins M11 400 which is coupled to a 18 speed Spicer trans.

Prognosis:
Engine, when in neutral and foot not on clutch pedal, will happily free rev to max revs.
Engine when in gear and trying to drive will not go over idle.
The problem is in the computer controls somewhere...

Cummins, where the truck is at present, and has been for the last week, say that the computer failure report says the foot actuator is at fault, but they have changed that already however it still says that.
They have reportedly changed the main computer to no success either. So far, they are telling my mate that he is already up to $4000 in diagnostic costs and have not repaired the problem.

Now, I am a bit old school and therefore made the suggestion that he may be able to get rid of the computer controlled system and go "back" to a manual pump system.

Do any of you knowledgeable guys in HCVC land know if this can be done, and how?
I would imagine that he would be changing the entire pump to a manual pump, and putting in an accelerator linkage system as his current system is drive by wire.

Cummins have also scared the sh&t out of him by telling him that "if it needs a main computer, they are $6600 on their own".

Appreciate any and ALL thoughts and comments...
cheers,
Bretto
PS: I couldn't help myself in that I told him he should of bought a White, he agreed then hung up

TRB Man
GuddayM8

I feel for your M8'z problem
with computers me thinks we R go n backwards

I've never heard of flikn the pewter n go n back to hardware
earlier Cummins U had a choice
Hi HP n output Computer controlled
or
Less HP n manual control with no pewter

I aint no xpurt
but may B a few of the ol skool tricks may help (May not)
LOL
make sure all earth wires R 100% with out corrosion goin up under the plastic cover

the magnet doodadds mounted here there n everywhere do collect metal fileings etc specially from the flywheel when the startr is ground into engage
clean them jiggers if U can

other than th@
sacrfice a red fox on a full moon light facing north
chanting
"Wish it twaz a screeemer"

LOL

best o luk
n let us all kno wotcha find

Cya
[ch9787]

mate if its got 2 speed sensors on the back of the gearbox try swapping the wires from one to the other. it may work but you will have no speedo but it should go.
like the swish said, check all earths are good. fuse connectors going to computer from battery. could be a wiring fault, sometimes a smart auto elecy is the way to go. it shouldnt be a computer if they have already tried one. the trouble now is cummins go through that many blokes they probably havent seen a M11.
you wont be able to convert it back to mechanical.

Brett, I'd be looking at something like the motion sensor (on the back of the engine, in the flywheel housing from memory? Can someone confirm?) It is telling the truck that it's not moving, and won't let the engine rev. Or something dumb like that. BUT being at Cummins you can't exactly lob in an start telling them to do this or that. They are supposed to be the experts!
Another good idea- find a site called "just answers" on the web. They can pretty much fix anything, I reckon. They have mechanics online, you decide how much to pay, (usually $20-$80) and in my experience, there isn't much they can't work out. There was lots of M11's in the states, I'd say they would have seen this problem before. I had a Volvo truck a while ago, with an electronic engine, with an intermittent engine stopping problem. My local Volvo dealer told me 'computer- $6000". Just answers told me "earth fault to the computer"- secondhand computer plug from the wreckers. $110 for the auto elec to wire up. And this was a truck that was actually traded in, because the previous owner (a biggish company) , in another town, hadn't been able to get the problem fixed, with all their resources. So i reckon Justanswer is pretty good... better than throwing stupid money at it when they can't fix it, anyway!
Good luck keep us posted.
Cheers
Richard

Another suggestion - from experience the speed sensor on the back of the gearbox could be the culprit . Over time the pot metal they are made from grows and expands to the point that they become very problematic and stuff every thing up to the point of not working . Your problem does sound familiar - M11 and 525 Redhead both developed a problem with sensor on gearbox , cheers Clarke .

the sensor screwed in to the bellhousing counts engine revolutions. it usually wont start if its that one. like i said before, on the back of the gearbox if there is 2 sensors try swapping the wires from one to the other. the sensors are the same. if it works you wont have a speedo. replace that sensor. they should be around $150 from memory. when you replace it, screw it in by hand until it bottoms out on the pick up then back it off half a turn. that will give you the correct clearance. good luck hope it works for your mate.

Hi guys, my mate that owns the truck has had yet another horrific day at the mercy of Cummins. Today they replaced all of the wiring from the foot pedal to the main computer, and guess what - it still is the same, no good.
The plot thickens somewhat..
The problem that it went there for was not the problem that I described at the start, that problem (no revs above idle when in gear) only happened after they started changing stuff.
The original problem that it went there for was an intermittent loss of 2 cylinders.

Now that I am aware that the injectors are electronically controlled, I know that it cannot be changed to a manual as there is no other injector that will fit.

Cummins apparently hooked it up to their computer and the fault was supposed to be in the foot actuator; they changed that and presto the thing will not go over idle when in gear. They checked the earths, replaced a shorted main earth strap, changed the main compooter, put in yet another foot actuator, now have replaced all of the wiring from foor actuator to main compooter, and it is still the same. The bill so far is over $10k and it still ain't fixed.

I told Brian, who in turn told Cummins, of the speed sensors on top of the gear box. Perhaps, just perhaps, they might listen to what Brian told them...

Not looking good for him, and no answers for sure as yet.

Will keep yaz posted as and when news comes in
cheers all
Bretto

iz the ashtray full ??


LOL

best of luk with this modern compewter crap
Cya
[ch9787]

Just a suggestion here, has anybody steam cleaned/ washed around the engine bay, wiring, lately have known wires to rub thru on the coverflex then water gets in causes all sorts of gremlins.As suggested before i ve had problems with earth wires as well.

Sounds ugly , the fact that the progress is making things worse raises an eyebrow too.

Might sound really silly "I'm known for saying and doing silly things " but did someone look at the net to see if these engines have a program that shuts cylinders off by either mistake or intentionally, like if the engine is overheating - or thinking it's overheating. I remember the ford petrol engines had a similar system that cylinders would shut down when head temps got over a certain amount. It only takes a crook sensor or bad wire and all things go to hell.

I know a limited amount about the petrol EFI engines, but got out of mechanics when the big bangers went common rail. I've heard a lot of nightmare stories though.

Keep us posted hey!!



A