Cummins ISBe- No Start

[mathura]

Need some help here with this one.
ISBe CM800 refuse to start but runs on starting fluid, insite shows no active or inactive faults, checked fuel pressure while cranking with insite
and all is well, pressure rising to 8000psi Checked with test lamp to injectors for power, found no power to injectors. Tested injectors wiring harness and proves ok.

What am I missing, presently I suspect the ECM but it is hard to condemn it because if I disconnect a sensor the ecm reconise that the sensor is disconnected and logs a fault code.

Your suggestions is appreciated

[jctech]

Need some help here with this one.
ISBe CM800 refuse to start but runs on starting fluid, insite shows no active or inactive faults, checked fuel pressure while cranking with insite
and all is well, pressure rising to 8000psi Checked with test lamp to injectors for power, found no power to injectors. Tested injectors wiring harness and proves ok.

What am I missing, presently I suspect the ECM but it is hard to condemn it because if I disconnect a sensor the ecm reconise that the sensor is disconnected and logs a fault code.

Your suggestions is appreciated

have you done a leakage test (measure return fuel from the back of the head.
RPM must be above 150 to start, injectors are not powered below 150 RPM.
can you check starting fuel pressure on a good engine, I think 8000 PSI is low

[mathura]

have you done a leakage test (measure return fuel from the back of the head.
RPM must be above 150 to start, injectors are not powered below 150 RPM.
can you check starting fuel pressure on a good engine, I think 8000 PSI is low


Thanks for the advice but when running on starting fluid the pressure goes as much as 16000psi and rpm about 800-900 rpm

[RUCKUS]

I had a similar problem, solve it by recalibrating the module ECM

I hope it is useful



Greetings!

[mathura]

I had a similar problem, solve it by recalibrating the module ECM

I hope it is useful



Greetings!

Good to know

[mathura]

Well, I took the ECM off and tried it on another engine and it started the engine, so I am now sure that it is not the probelm with the ECM.
However after reinstalling the ECM back on the original engine and I attempted to start it is now throwing fault code 731-
Engine Speed Sensor/Position Camshaft and Crankshaft Misalignment - Mechanical System Not Responding Properly or Out of Adjustment. Mechanical misalignment between the crankshaft and camshaft engine speed sensors.
I ran all test according the T&R manual which proves that cam and crank sensors are ok.
I was made to understand that the engine was overhauled by a mechanic and it never started but my question is if the mechanic did not timed the engine correctly why is it running on starting fluid.

Your response is much appreciated

[sskarroum]

Well, I took the ECM off and tried it on another engine and it started the engine, so I am now sure that it is not the probelm with the ECM.
However after reinstalling the ECM back on the original engine and I attempted to start it is now throwing fault code 731-
Engine Speed Sensor/Position Camshaft and Crankshaft Misalignment - Mechanical System Not Responding Properly or Out of Adjustment. Mechanical misalignment between the crankshaft and camshaft engine speed sensors.
I ran all test according the T&R manual which proves that cam and crank sensors are ok.
I was made to understand that the engine was overhauled by a mechanic and it never started but my question is if the mechanic did not timed the engine correctly why is it running on starting fluid.

Your response is much appreciated


dear sir, check distribution, I think you will find a broken gear on distribution gears, this is a mechanical failure, I myself experienced this situation with a QX15 engine... this is m?chanical trouble...

i hope i helped

[jctech]

Well, I took the ECM off and tried it on another engine and it started the engine, so I am now sure that it is not the probelm with the ECM.
However after reinstalling the ECM back on the original engine and I attempted to start it is now throwing fault code 731-
Engine Speed Sensor/Position Camshaft and Crankshaft Misalignment - Mechanical System Not Responding Properly or Out of Adjustment. Mechanical misalignment between the crankshaft and camshaft engine speed sensors.
I ran all test according the T&R manual which proves that cam and crank sensors are ok.
I was made to understand that the engine was overhauled by a mechanic and it never started but my question is if the mechanic did not timed the engine correctly why is it running on starting fluid.

Your response is much appreciated

You will get this fault code with a mis-timed camshaft, and also if engine is trying to start on 1 or 2 cylinders, this happens because the crank sensor is on the front end of the engine and the cam sensor is on the back end of the engine.

[mathura]

You will get this fault code with a mis-timed camshaft, and also if engine is trying to start on 1 or 2 cylinders, this happens because the crank sensor is on the front end of the engine and the cam sensor is on the back end of the engine.

Thanks jc

I will have to remove engine to check timing but is there any shortcut to doing this job without removing engine. Any way of checking static timing with engine in chassis.

Another thing if valve clearance is wrong (have not checked as yet) can this trigger the fault code.

[han2542]

Thanks jc

I will have to remove engine to check timing but is there any shortcut to doing this job without removing engine. Any way of checking static timing with engine in chassis.

Another thing if valve clearance is wrong (have not checked as yet) can this trigger the fault code.
my friend there is no way around the timing cover removal if it is a mechanical problem but just in case i had a similar problem on 2 units and one had the wiring for the groun on the ecm broken and it didnt let the unit complete the circuit for starting it was very hard to see because it broke on the plug that feeds the ecm you may want to check that
the second was the sensor that goes on the fuel injection pump i dont remember the name of it but mine didnt give me any code but it was not opening fully to let the engine start
hope this helps
please dot forget to push thaks

[jctech]

Thanks jc

I will have to remove engine to check timing but is there any shortcut to doing this job without removing engine. Any way of checking static timing with engine in chassis.

Another thing if valve clearance is wrong (have not checked as yet) can this trigger the fault code.

You can do a rough static timing check, but it would not be accurate enough for what you need.
You need a screwdriver that can fit down the number 1 injector hole and protrude about 30-40 mm into the bore, bar the engine over RH until the piston just touches the screwdriver. Make a mark on the damper at the 12 oclock position, and make a mark on the front of the engine in line with the mark on the damper. Now turn the engine over LH until the piston just touches the screwdriver, make a mark on the damper in line with the mark on the block. Now measure between the two marks on the damper, make a mark on the damper half way betwen the two marks, erase the other two, and line the third mark up with the one on the block. This is TDC number 1 and 6.
The valves on number 1 or 6 should be rocking, rotate the engine 1 turn to get the valves rocking on number 1 if required.
BUT - you will get this with the cam timing 1 tooth out.

Make sure you do not have a 4 cylinder calibration in a 6 cylinder engine.

[mathura]

You can do a rough static timing check, but it would not be accurate enough for what you need.
You need a screwdriver that can fit down the number 1 injector hole and protrude about 30-40 mm into the bore, bar the engine over RH until the piston just touches the screwdriver. Make a mark on the damper at the 12 oclock position, and make a mark on the front of the engine in line with the mark on the damper. Now turn the engine over LH until the piston just touches the screwdriver, make a mark on the damper in line with the mark on the block. Now measure between the two marks on the damper, make a mark on the damper half way betwen the two marks, erase the other two, and line the third mark up with the one on the block. This is TDC number 1 and 6.
The valves on number 1 or 6 should be rocking, rotate the engine 1 turn to get the valves rocking on number 1 if required.
BUT - you will get this with the cam timing 1 tooth out.

Make sure you do not have a 4 cylinder calibration in a 6 cylinder engine.

Thanks jc
Been busy on other jobs but planned on doing this one this week, the truck is not at my location so I have to travel to do the job.

Thanks again bro you have been very helpful

[mathura]

UPDATE

Today I attended this job and what I found is that when running on starting fluid the 731 code is active but if I crank then the code goes inactive. If I clear the code and crank the engine I do not see the code.

I did overhead adjustments and tried but no start, I removed the return hose from high pressure accumulator and no fuel from accumulator. I removed hose from rear of head and fuel dripping when cranking
While cranking with both fuel return hose off the engine suddely started with a lot of white smoke from exhaust but no fuel from accumulator return and a little increase from cylinder head return.
try accelerating and no response from engine only increase by 100rpm.

What is this probelm high pressure pump

Please share your thoughts

[jctech]

UPDATE

Today I attended this job and what I found is that when running on starting fluid the 731 code is active but if I crank then the code goes inactive. If I clear the code and crank the engine I do not see the code.

I did overhead adjustments and tried but no start, I removed the return hose from high pressure accumulator and no fuel from accumulator. I removed hose from rear of head and fuel dripping when cranking
While cranking with both fuel return hose off the engine suddely started with a lot of white smoke from exhaust but no fuel from accumulator return and a little increase from cylinder head return.
try accelerating and no response from engine only increase by 100rpm.

What is this probelm high pressure pump

Please share your thoughts

once it is running, you can monitor commanded rail pressure and measured rail pressure, this will tell you if you have a high pressure pump problem

[mathura]

Worked on it today, engine started with rpm only at 490-520, lots of white smoke no acceleration.
Commanded fuel pressure 1460
Measured fuel pressure 1467

Active code while runningsame as before 731, after engine shuts down the code goes inactive.
Decided to instruct mechanics to remove engine to verify timing.

Am I on the right path

[jctech]

Worked on it today, engine started with rpm only at 490-520, lots of white smoke no acceleration.
Commanded fuel pressure 1460
Measured fuel pressure 1467

Active code while runningsame as before 731, after engine shuts down the code goes inactive.
Decided to instruct mechanics to remove engine to verify timing.

Am I on the right path

It could be other things, Was the cylinder head skimmed, you cannot do that in ISB/ISBe engines, wrong pistons, wrong injector sealing washer (not likely), but you need to reslove the active fault and only way to check timing is visual, timing is easy to get wrong on rear geartrain ISBe.

[mathura]

It could be other things, Was the cylinder head skimmed, you cannot do that in ISB/ISBe engines, wrong pistons, wrong injector sealing washer (not likely), but you need to reslove the active fault and only way to check timing is visual, timing is easy to get wrong on rear geartrain ISBe.


Well Jc I checked the timing today and it was spot on so that leaves me to find out what else was done with engine.

You see these guys here are hesitant to tell the truth, they feel insecure when an outside technician is called in to do the job, I have encounterd this situation many times and even the Manager does not have the facts.

Hope I dont have to tear the engine apart to solve this one.

Thanks

[Poptest]

Well Jc I checked the timing today and it was spot on so that leaves me to find out what else was done with engine.

You see these guys here are hesitant to tell the truth, they feel insecure when an outside technician is called in to do the job, I have encounterd this situation many times and even the Manager does not have the facts.

Hope I dont have to tear the engine apart to solve this one.

Thanks

I know the feeling Mathura. Not giving you the complete story sucks, but sabotage is the baddest. I hope it's not the 2nd one. Sincerely befriending the guys will be the best.

I once had a sabotage experience on a Mits truck with the same symptoms you're having. Someone switched the injector wires on the harness connector. Injectors were firing on the wrong cylinders......took me some time to figure it out.

Another thing, if cranking rpm is unusually high, compression pressure could be low.

Good luck......

[mathura]

Today the Manager called and told me that the injectors, pistons, rings, bearings were replaced, I will take a look at again tommorrow and let you know how it goes, however I plan on pulling the head.

All Comments are welcome friends and thanks again for your contribution

[mathura]

UPDATE
Well I decided to take the engine apart and found the following
1. Cylinder liner worn
2. All top rings were used rings with clearance way out of normal
3, Head bolts not torqed to specs, because compression were escaping upon close inspection
4. Con rod bolts felt as though the were not thightened accoring to specs
5. Leaking valves

This was a cover up situation because the manager told me the engine was removed and overhauled but I found that the engine mount bolts were never touched.
All bearings con & main were not changed, however the pistons were new.

I am now thinking of leaving this job alone because when I report on my findings the manager became upset.

[Poptest]

UPDATE
Well I decided to take the engine apart and found the following
1. Cylinder liner worn
2. All top rings were used rings with clearance way out of normal
3, Head bolts not torqed to specs, because compression were escaping upon close inspection
4. Con rod bolts felt as though the were not thightened accoring to specs
5. Leaking valves

This was a cover up situation because the manager told me the engine was removed and overhauled but I found that the engine mount bolts were never touched.
All bearings con & main were not changed, however the pistons were new.

I am now thinking of leaving this job alone because when I report on my findings the manager became upset.

Hi mathura,

Thanks for this update. We learn from every situation. I'm quite sure other DKs were curious about this thread.

I hope you get paid for your time.