2003 Cummmins wont start

[jere9be]

Does anybody have the same problem. My 2003 dodge cummins wont start unless i use ether. It started gradually only when it was cold and it progressed to it wont start at all without ether no mater how hot or cold it is. I replaced the lift pump, injectors, multiple sensors and i am at a stand still.





Pleas can anybody help. #@$%!

 

[Prairie Dog]

Have you checked for codes?

 

[jere9be]

well as far as the person that did the injectors, it was my dad and myself that replaced them. My dad is an ase certified tech but most of his experience is with fords. He was a ford tech for 25 years. He has a mac obd scanner for his curent job as a mechanic for the local fire department and there has never been anny codes. But when we hook it up the oil presure never registures. The dash gauge works but not on the scanner. My brother in law has a friend that does performance work on diesels and he thinks it is the ecm. He advised to maybe get the ecm flashed or replece it. Maybe i got a bad injecor body when i replaced them. After i replaced them it tried to start for a bout a second and it went back to the same ole after about ten seconds. I have to much money into this truck to get rid of it and i am quite fond of it. I would rather fix the problem and keep my truck until the frame rots from around the cummins engine.

 

[jere9be]

Well I replaced the lift pump with a fass system so I have eliminated that. We tried the leak test a while back but maybe its worth another try. I actually had to replace the engine back in 09 because of bad diesel. It had gas in it and i paid with cash and dont remember where i filled up at in Albuquerque, NM. I bought a used short block from somewhere back east and I was told it had the ecm on it but it was a bare block with just the internals. I had to transfer my valve springs and rockers from my old engine. I had originally took it to the local dodge dealer for the problem and they told me it was the injectors and the lift pump but they wouldnt tell me which injector. I replaced them and still the same problem. I'm getting a little frustrated. But it still runs damm good once you get it started. Oh and I forget to post that it will start if I roll start it on a incline. Thats the one that puzzles me.

 

[Wingate]

If doing the normal fuel injector tests doesnt give you any results, check the valve clearances... . I have seen before where an electric starter motor would not spin an engine fast enough to build sufficient compression due to tight valves. Stick it in gear and roll start it, low and behold, it fired right up everytime!!. . Also, if possible, load test both batteries..... just to make sure the pull down voltage from engaging the starter motor isn't shutting down the ECM... Another reason it would roll start and not start off the electric motor...

 

[sag2]

You really need to check the rail pressure first. The dealer can check it in just a few minutes with the DRBIII. If it is low, or below about 3,000 cranking and normal when idling you have a leak in the injectors or POV. As was said, buy at least one, and two is better on the cap off tools. Isolate the offending cylinder(s). When you installed the injectors what procedure did you use to torque the tubes and injectors? Look up my post "injector install with photos" if you want to see the proper way.

 

[rbattelle]

But when we hook it up the oil presure never registures. The dash gauge works but not on the scanner.

That's because there is no oil pressure sending unit on the engine. What's there is just a switch that trips at ~6psi.



-Ryan

 

[cerberusiam]

But it still runs damm good once you get it started. Oh and I forget to post that it will start if I roll start it on a incline. Thats the one that puzzles me.

You need to run the injector tests again, check cylinder contribution and rail pressure on crank to verify its all good. Rechecking the cross over tubes and their TQ is also a good idea.

That's because there is no oil pressure sending unit on the engine. What's there is just a switch that trips at ~6psi.



-Ryan

No, there is a sensor on the engine. The switch that trips is in the ECU.



If some of the engine is actually not reeadable from the data port its possible it is an ECU issue. However, that needs to be verified with a delaer tool because its possible the protocols are proprietary and not all scanners will read all data port outputs.

 

[rbattelle]

No, there is a sensor on the engine. The switch that trips is in the ECU.

I apologize, this must be another change since 2003. In 2003 there was no sensor, only a pressure switch.



So does that mean the 2006 dash oil pressure gauge reads actual pressure?



-Ryan

 

[HBarlow]

I apologize, this must be another change since 2003. In 2003 there was no sensor, only a pressure switch.

So does that mean the 2006 dash oil pressure gauge reads actual pressure?

-Ryan

No, it doesn't. The oil pressure sensor determines only the presence of oil pressure and the ECM simulates oil pressure at a "feel good" level.

 

[cerberusiam]

I apologize, this must be another change since 2003. In 2003 there was no sensor, only a pressure switch.



So does that mean the 2006 dash oil pressure gauge reads actual pressure?



-Ryan

From the 03-06 FSM:



On vehicles with a diesel engine, the ECM continually monitors the engine oil pressure sensor

to determine the engine oil pressure. The PCM or ECM then sends the proper engine oil pressure messages to the

instrument cluster.





The ECU outputs parameters to the instrument cluster to set the gauge and turn on any trouble lights. The algorithm in the ECU smooths this signal so the gauage does not see the constant fluctuations that are always present on a manual gauge. When the ECU sees pressure below a preset value for too long it will drop the gauge and turn on trouble lights. The low pressure "switch" is virtual, in the ECU as a table driven value.



The sensor MUST read a pressure data stream of some sort or the ECU cannot output it to the scanners as a data stream. The sensor is a pressure sensor, like the MAP, that constantly outputs an electrical signal interpreted and converted by the ECU to pressure.

 

[rbattelle]

The sensor MUST read a pressure data stream of some sort or the ECU cannot output it to the scanners as a data stream. The sensor is a pressure sensor, like the MAP, that constantly outputs an electrical signal interpreted and converted by the ECU to pressure.

Fair enough, but my engine is not built this way. I know because I tested the "sensor" on the bench. My sensor is binary. I wrote a thread about it some time ago, here.



My ECM has no idea what the actual oil pressure is - only that it is above or below ~6 psi.



So there must have been a change between 2003 and 2006 that implemented a real sensor as you describe. This is the first I've heard of it, but I have no reason to doubt you, since I haven't laid hands on anything newer than my '03.



-Ryan

 

[TCDiesel]

Fair enough, but my engine is not built this way. I know because I tested the "sensor" on the bench. My sensor is binary. I wrote a thread about it some time ago, here.



My ECM has no idea what the actual oil pressure is - only that it is above or below ~6 psi.



So there must have been a change between 2003 and 2006 that implemented a real sensor as you describe. This is the first I've heard of it, but I have no reason to doubt you, since I haven't laid hands on anything newer than my '03.



-Ryan

I tested My sensor also it acts like a switch... In fact all 03 autos with the additional Chrysler PCM act in this manner.

 

[TCDiesel]

Thats why When I engage My fan Override the Oil pressure Drops and the coolant temp raises. If Necessary a video can made...

 

[sag2]

Sorry, but Ryan is correct. Same "switch" PN 5083366AA is used 2003-2010.

 

[rbattelle]

Sorry, but Ryan is correct. Same "switch" PN 5083366AA is used 2003-2010.

cerberusiam, I'm not sure how reconcile that with your experience.



So the point is, I guess, that jere9be should not be worried that he has no oil pressure reading from his scan tool.



-Ryan

 

[cerberusiam]

cerberusiam, I'm not sure how reconcile that with your experience.



So the point is, I guess, that jere9be should not be worried that he has no oil pressure reading from his scan tool.



-Ryan

I don't know how to reconcile the FSM to whats installed either. All I know is all 4 FSM's unequivocally state the same thing. Would not be the first smoke screen from the FSM thats for sure.



As for no data stream, thats another story entirely. Every time these things start loosing data streams and functionality its ends an ECU problem. If its supposed to stream oil pressure readings and it doesn't, what else is not functional? What other sensor reading is off enough the ECU can't\won't perform to spec?



The defuel at 2600-2800 problems, the Smarty defueling at certain points, inability to run tests with the dealer tools, unusual engine operation, all point to the ECU at times. Even the final engineering diagnosis from Dodge is ECU.



I would not rule out the ECU on any of the years with issues that crop up at times. The 03's and 06's are probably the worst for problems.

 

[rbattelle]

I don't know how to reconcile the FSM to whats installed either. All I know is all 4 FSM's unequivocally state the same thing. Would not be the first smoke screen from the FSM thats for sure.

Have you or have you not physically verified that the sensor on your truck is measuring actual oil pressure, and is not equipped with the 6psi switch the rest of us seem to have?

As for no data stream, thats another story entirely. Every time these things start loosing data streams and functionality its ends an ECU problem. If its supposed to stream oil pressure readings and it doesn't, what else is not functional?

If these trucks don't have an oil pressure sending unit, then the lack of an oil pressure reading is not, in and of itself, an indication of a bad ECU. That's my whole point - do not write off the ECU based on the fact that a nonexistent sensor is not producing any data.



-Ryan

 

[cerberusiam]

Have you or have you not physically verified that the sensor on your truck is measuring actual oil pressure, and is not equipped with the 6psi switch the rest of us seem to have?

Sag2 says its the same from 2003-2010, I don't have anything to say it isn't. The FSM calls it a switch\sensor and states it monitors oil pressure. I can't find anything the says it does NOT monitor pressure.



Question; Considering the cost of the item, is it realistic to think it is a switch only?

If these trucks don't have an oil pressure sending unit, then the lack of an oil pressure reading is not, in and of itself, an indication of a bad ECU. That's my whole point - do not write off the ECU based on the fact that a nonexistent sensor is not producing any data.

Your missing the point, completely ignoring HOW the data stream for oil pressure is generated, if it is missing it IS a potential problem.



The scan tools indicate that data should be there. IIRC there are several of the monitors on the market that allow tapping into some of the streams the ECU outputs.



Is the data stream fake or real, doesn't matter. If the ECU should be putting it on the data port bus and it is not, why?



Better yet, is the scanner he used actually 100% compatible and capable of reading all the data streams. If not, what ELSE is it missing?



The OP didn't say his oil pressure gauge was non-functional so SOMETHING is going to the cluster controller in the form of a data stream. Is that the same data stream that is supposed to go to the data port?



The OP replaced the injectors, these trucks normally respond pretty well to new injectors for hard starts, still have a hard start problem that is solved by ether or roll starting.



Could it still be mechanical? Yes, cross over tubes, CP-3, etc, etc,etc.



Could it be electrical? Yes, batteries, battery connections, ECU, ECU harness, ECU connectors, etc, etc.



Again, given the problems that surface when the ECU does not respond to commands from scan tools, does not output expected data streams, you can't rule it out or in.



Whether or not the oil pressure semsor\switch does\doesn't measure pressure is truly immaterial.

 

[rbattelle]

Question; Considering the cost of the item, is it realistic to think it is a switch only?

Last I checked it was ~$15, compared with the 2nd gen sensor, which was ~$210. In my opinion, yes it is realistic to think that it's a switch only. Not to mention the fact that I tested one.

Your missing the point, completely ignoring HOW the data stream for oil pressure is generated, if it is missing it IS a potential problem.

Is the data stream fake or real, doesn't matter. If the ECU should be putting it on the data port bus and it is not, why?

2003 FSM, page 8J-32:

Engine Oil Pressure Message - The instrument cluster circuitry restricts the oil pressure gauge needle operation in order to provide readings that are consistent with customer expectations. Each time the cluster receives a message from the PCM or ECM indicating the engine oil pressure is above about 41 kPa (6 psi) the cluster holds the gauge needle at a point near the middle increment within the normal range on the gauge scale. [emphasis added]

The ECM transmits a "yes or no the pressure is above 6psi" signal and the instrument cluster computer moves the needle.

However, I recognize the FSM could be incorrect here, and that the ECM is actually providing the continuous signal to the cluster, not just a binary signal. But if that's the case, then the scantool would require the correct demultiplexer algorithm and the ability to log into the PCI bus in order to read that signal. This is plausible, of course, but jere9be states he, "... has a mac obd scanner. " An OBD-II scanner will not be permitted onto the network to read the PCI bus. I know because I've tried to do it.

Whether or not the oil pressure semsor\switch does\doesn't measure pressure is truly immaterial.

Maybe, maybe not. If it doesn't measure actual pressure, then any value on the PCI bus is not a reliable indicator of oil system health. And if you can't log into the PCI bus, then it's also unreadable. Taken together, that means you cannot write off either the engine oil system or the ECM on the basis of a lack of oil pressure reading from an OBD-II type scan tool.

I don't know, maybe I've gone way off topic here. But I think these little details are important, especially when we're talking about a no-start and trying not to panic the owner into thinking he has no oil pressure.

-Ryan