Cat C-7 wont start

[totermaine]

The truck has been sitting for 8-9 months in a bldg. Changed both filters and the fuse is ok. This is in a '03 Freightliner FL 70. I don't know what to check out next. It's just is not getting fuel. It wants to run when I bump it with either (I know, very  carefully, wire off of preheater) It ran normally when last parked. :-\

 

[Mavarick]

Not a whole lot of info to go by here, might need more details. The engine sitting for 8-9 mo should not have an affect on the fuel system. I guess you already verified you have fuel in the tank and the air filter is not restricted correct? Did you change both fuel filters before trying to start because it sat or, after it cranked a while and didn?t start?
I presume you know how to change both filters and have done this successfully before so I won?t go through the routine. If the system is not getting fuel then it might be sucking air. The easiest way to check for air is to remove the primary filter out back and it will probably be half full of fuel, not full as it should be. Assuming you find the can half full then try the following. Make sure you remembered to remove the old rubber filter seals etc and the filter was on tight. Did you install them dry, if so it takes quite a bit of cranking to get fuel up to the fuel rail. If you have a hand prime pump then use it to fill the filters etc. If you don?t have a hand prime pump and don?t want to crank anymore then remove both filters. Fill them with fuel through the smaller outside holes (not the large center one) as best you can so the fuel goes through the filter before going into the fuel system. Go through the start procedure again including using the preheater etc. It will still need to crank a bit to get fuel at the injectors so don?t give up too soon. When the system sucks air it will pull the fuel from all the lines as well as the filter cans. Charge the batteries u p so you?re not drawing high amps, crank for a bit then let the starter cool, don?t over do it or you?ll be doing a starter also. Let us know how you make out or if we are going in the right direction here.

 

[Tom]

You might also check the voltage being seen by the ECM; If it's too low, the ECM won't turn on and the engine won't run. The ECMs on the CATs on our boat receive their 12V from the starter, and you'd need to check the voltage while the engine is being cranked. I don't recall the exact cutoff voltage, but I think it's 9V. If you're seeing less than this, I'd check the battery and connections between there and the starter.

I hope you don't have the same problem I had a year ago. After months of non-use, one of the CATs on our boat would crank, but wouldn't attempt to fire. I suspected it wasn't getting fuel. A local marine mechanic spent 3 hours trying to figure it out, including doing some of the things Mavarick mentioned, and the ether trick; It would fire on ether, but would not continue to run. Two more mechanics, including one from a large CAT dealership, failed to figure it out. In desperation I called a friend who had previously been a CAT mechanic. The issue turned out to be a failed ECM.

 

[Robert K]

Use silicone spray instead of starting fluid . It works good and it is better for your bearings and your preheater.

 

[Chet18013]

Check the electric fuel pump. I had this problem with an International diesel about a year ago. It turned out there was a separate fuse for the electric primary fuel pump that was located in the wiring harness under the cab. This fuse had blown. Replaced it after about two hours of searching and head scratching. Engine started just fine. It could be that your truck has the same type of problem.

 

[Cant Wait]

If memory serves me most CAT motors have a primer pump to bleed air out of the sys after changing fuel filters. There's a bleed valve you open and then pump the primer pump till fuel comes out the bleeder vlv. close the vlv and then try starting.

 

[totermaine]

Hey thanks!
Yes I changed the filters because it would not start after sitting and the fuel tanks are well over half full. The batteries are a year old and fully charged. And I filled the filters with fuel prior to installation.  And as I said the only fuse that is marked fuel is fine (as are all of the fuses that are visually "checkable")
I dont know how to check the voltage at the ECM, and don't know where to look for it.
When it comes to cranking, I do believe that I might be "shy" as suggested, and give up to early worrying about the starter, does cranking an engine "accumulate"? (say 5, 20 second cranks) or is it more like just a longer crank (a 30 second crank) will produce results? I do have an IR temp meter, what is the starter temp to try to stay below? Thanks again for your help. All I know is that it used to be that if a diesel got fuel and air, it would run. All of the wires scare me.

 

[Tom]

[quote author=totermaine]I dont know how to check the voltage at the ECM, and don't know where to look for it. [/quote]

If you don't have one, buy an inexpensive digital multimeter, and set it to measure 'DC voltage'. Since the ECM gets 12V from the starter, measure the voltage on the large stud on the starter (the one with the large wire attached to it). Measure the voltage with the positive lead (from the multimeter) on the large stud, and the negative lead on a good ground. Just remember to measure the voltage while someone cranks the engine. Given that your batteries are good and charged, if you see a low voltage on the stud while cranking, look for a bad connection on one end of that large cable, where it's attached to the stud, and the other end, where it connects to the battery.

 

[Mavarick]

In regards to fuel priming the cranking would be successive. You can do 20-30 sec and let it cool a bit, then do it again, etc until you feel it is doing no good and then check the filter can again. How long you need to crank depends on how much prime you lost originally. It?s not only the fuel in the cans but the fuel lines etc. and if any drained back to tank. Not sure about temp as I?ve never shot one with an IR camera.
If you filled the filters by hand then I will assume no prime pump. You should have app 20+ psi of fuel pressure when cranking if all is ok. You said it would not fire at all when you originally tried to start it and then you changed the fuel filters. So was the primary filter can full of fuel when you first removed it? What about pulling the primary now after cranking, is it full of fuel? If they are low on fuel then you are still sucking air. If they are full of fuel and still won?t start then you probably have another problem and more cranking will not help.
Did you check connections and cranking voltage as Tom suggested? You are sure the ECM fuse is good by checking with a VOM? Just looking at fuse will not verify anything. They can look Ok and still not work, check voltage through it. Electrical problems after sitting seem to be more common than fuel problems IMO because of corrosion and critters.
I can?t say specifically where your ECM is located on your truck but they are usually around the top rear of the engine firewall or on the starter side. Google used ECM?s to get a picture if you don?t know what one looks like. This is probably not something you are going to do but you need battery voltage on two pins and then with the key on you light up pin 70 if your fuses are all ok. I can send a pin location if you want. If you don?t feel comfortable doing this that?s fine. A mobile mechanic costs a few $ but It?s better than damaging something or just guessing. I also figure you need to get the truck back on the road making $.
If all your basics are covered, low pressure oil ok, fuel ok, battery volts ok, fuses and ECM power ok, then you are going to need someone to check trouble codes etc anyways. You can do this through your cruise and the light on the dash or use the software. This will let you know the condition of other sensors that the ECM needs to see in order for it to start. Once the ECM is happy then the engine will see the fuel & air you are talking about and start. There is no external fuel solenoid or shut off like on a Cummins engine. You need to be methodical here, before you get into the ECM tests recheck your basics above (fuel and electrical) and then go from there.

 

[Tom]

[quote author=Mavarick]Google used ECM?s ....[/quote]

Wish I'd thought of that when I replaced the ECM on one of my 3196's. I paid $2,400 for a new one, although CAT had 'refurbished' ones for $1,800. The suggested Google search turns up used ones that are much cheaper. Mine look just like this one, except CAT paints all their marine engines white. Don't know if the 3176 and 3196 use the same ECM (quite a difference in HP - 660 vs 350).

 

[Chet18013]

Wish I'd thought of that when I replaced the ECM on one of my 3196's. I paid $2,400 for a new one, although CAT had 'refurbished' ones for $1,800. The suggested Google search turns up used ones that are much cheaper. Mine look just like this one, except CAT paints all their marine engines white. Don't know if the 3176 and 3196 use the same ECM (quite a difference in HP - 660 vs 350).

Marine versions are much different than the over the road. My 3176 is rated at 365 HP and can be uprated to almost 1000 hp in the marine version, according to the CAT literature I have. It has to do with the cooling. In a boat, you've got a ready source of cooling, whereas in a vehicle, you are limited by radiator size. Many who open up the injectors and higher fuel flow, pay the price by not having enough cooling.

 

[Chet18013]

Another thing you might try before you go for a new ECM is get a can of spray contact cleaner from RadioShack. Unplug all the connectors on the engine and ECM wiring harness and clean the contacts. You might have had a little corrosion get started that's just enough to cause the low voltage condition previously mentioned.

 

[Mavarick]

Toter, this is what your ECM should look like: http://www.ebay.com/itm/Caterpillar-C7-KAL-ECM-/160766255286#vi-content  Keep in mind this is for conversation and what to look for only. I do not think for a minute you have a bad ECM, a bad IAP or problems with the HPOP are far more common than a bad ECM. Unfortunately as Tom found out they do fail, just not that often. That is why there are many used ones out there.
As Chet says the habit of pumping up the HP in trucks were the cause of many 3126 failures from lack of cooling. Not enough HP for a truck but a 330 in a 30k lb MH is perfect!

 

[Tom]

[quote author=Chet18013]I have. It has to do with the cooling. In a boat, you've got a ready source of cooling, whereas in a vehicle, you are limited by radiator size.[/quote]

Good point Chet.

... get a can of spray contact cleaner from RadioShack. Unplug all the connectors on the engine and ECM wiring harness and clean the contacts. You might have had a little corrosion...

That was on a list of first suggestions I received over the phone from a CAT service manager. In my case, those contacts were all very clean, which I attributed to the excellent seals on the connectors, and the "dry" environment in the engine room.

 

[totermaine]

Thanks guys. I gotta crawl under it. PITA with storage boxes, Not enough room for me AND the creeper, and right now it's in a dirt floor bldg. Just been busy with "Sandy".

 

[totermaine]

:Well. I got a buddy over here with a diag. scanner. Truck showed no 'codes' but the fuel pres. test showed no pressure at the IAP sensor (injector actuation pressure). Now I need a 'CAT' guy out here with his laptop. Boy I miss the good old days of mechanical diesels!
Does anyone know if this sensor is under the valve cover?

 

[Tom]

I don't know where the sensor is, but a heads up if you have a CAT guy come out. They should know this, but CAT has a special harness available that can short out any or all sensors, thereby eliminating one or more sensor failures as the cause.

The last CAT dealer tech who worked on our boat seemed to have no clue about diagnosing this stuff, which was why I had to go to another source who works on this stuff for a living.

 

[John From Detroit]

With one possible excdeption I can't help you but this thread looked like a good place for this to fit..... Two things I noticed in the campground where I'm parked today.

ONE: A music group that was here 2 weeks ago.. one of their busses is in long-term parking.. Deader than a doornail, (Won't start) Likely a Detroit Diesel based on the body style.

Two, The RV next to me clearly has a CAT engine.. How do I know this,  Two answers

1: Cat cap on dash,, 2: Fuel door says (in very large letters) CAT FOOD.

Did you remember to feed the cat?  (Run out of diesel?)

 

[Mavarick]

Well glad to see you are making some progress but you didn?t answer the questions above. Have you done a voltage check when cranking? Have you pulled a fuel filter to verify it was still full after cranking? Has your tech verified 20+ fuel psi at the filter outlet? If not you could have a bad fuel psi regulator or transfer pump. What about voltage at the ECM so you know it is powering up which, if not, it should throw a code.
You say you have no codes and no pressure at the IAP doing a fuel psi test. The IAP sensor monitors oil, not fuel psi so I assume that is what your tech is talking about. When cranking this should be around 800 psi here at the oil rail. I also asked you above to check your low pressure oil and assume you did. This would require pulling the stick to check oil level and see the oil psi working either on the dash gauge or a hand held gauge. The low oil psi feeds the high pressure oil pump. Assuming the low pressure oil circuit is Ok then you need to check the high pressure circuit coming out of the fuel injection pumps oil port. This will have a line going to the head and will be above 3000 psi minimum when cranking so I assume you will have your tech do this.
If your psi is low you could have a bad IAP control valve. He will need to block off the valve and recheck pressure or just replace it if you have a good one. You could also have a bad IAP sensor (more likely) which monitors psi in the HP rail and sends an electronic signal to the ECM (this sensor is what you checked above). You could have good psi from the HPOP but if the sensor is bad the ECM will not know it. On some models you could just unplug the electrical connector at the IAP sensor and see if the engine wants to start, if so replace the sensor. The IAP valve and sensors are subject to fail, either of which will not let you start. Your tech will know how to test these and if you have a Cat tech he can just bypass them as Tom says.

Does anyone know if this sensor is under the valve cover?

The IAP sensor and control valve are both on the left side (looking from the back of the engine forward) of the engine.
There are still a lot of issues here above that could cause a no start condition. Your tech needs to verify all of them if he hasn?t already. Good luck with it and let us know what he finds.

 

[totermaine]

Well the "Cat man" says, or his laptop says that I need a new IAP valve. I noticed that the hose involved with this HEUI ? system is leaking, with cranking only so while at the parts counter........ They have an up date and have switched to a hard steel line. He'll be back Fri. and hopefully with a purring Kitty! I'll let you know.