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  #1  
Old 01-15-2011, 08:11 PM
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stodg73 stodg73 is offline
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Default Troubleshooting Your Diesel Engine

Diagnostic Flow Sheet: Trouble Shooting Your Diesel

This article is written is order of easiest to hardest, so that everything is taken into consideration when trouble shooting problems.

Check Air Filter

Check to make sure that the air filter is clean.


Check if fuel in tank

Make sure that you have sufficient fuel in the tank, often this is the most overlooked step. If you have done or had done a fuel system upgrade, you may have the tank issue. When the upgrade was done to the tank, the person who did it may have set the tank on the ground and the cut the drawstraw off too short, when the tank is remounted the tank sags in the middle, which in turn the drawstraw comes out of the fuel at less than as tank, thereby causing the engine to stop or sputter.


Check FP

When checking the fuel pressure, you need to make sure that it is above 14psi at idle and above 10 psi at wide open throttle (WOT), this is done with the truck running. There is a Schreader Valve on the side of the injection pump to test the lift pump pressure. If the truck is not running, then do the following trouble shooting. To make sure that the lift pump is working, bump the starter, DO NOT start the truck, the lift pump should run for about 20-25 seconds. If you don’t hear the lift pump running, try again and listen at the drivers’ side of truck by front tire, also listen at the fuel tank opening for the pump running. If you need more time to listen, just bump the starter again.

Now, if you hear the lift pump on the side of the engine running, the pump is down below and behind the fuel filter. This may be the original pump or a replacement, this test is to make sure that it is working.

Now, if you hear the pump near the tank, you may have an in-tank upgrade, or you may have a frame rail mounted system. If you have the in-tank upgrade from Dodge, you need to seriously think about getting an aftermarket upgrade soon, in order to ensure the life of the Injection Pump. With the frame rail type, make sure if the system has filters, to change them regularly.

When checking to see if the fuel pump is running, make sure that fuel is running out of the schreader valve. Some fuel pumps will run without pumping fuel, this means that you need to replace the low pressure fuel pump.


Check Fuel Filter

Open the fuel filter canister, drain the fuel canister of fuel and water, pull the filter out and check for blockages, sediment, etc. If the fuel filter is questionable, change the filter element out. By doing this, you are ruling out fuel filter blockage.


Check for Fuel at Injectors

If you think that you have enough fuel pressure, you can use your fuel pressure gauge hose to see if there is fuel flow to the injection pump, at the Schreader valve. By doing this, you are showing that there is fuel up to a certain point. The next thing to do is crack three injectors, usually 1, 3, & 4, as these are the normally easiest to get a wrench on. Try to start the truck and see if you get fuel out of the injectors. Be careful as fuel is pumped out of the open injector line it could be under high pressure or spraying everywhere. If the engine tries to start, tighten up the injectors, and try again to start the engine.


Check for Codes

For this you need some type of scanner. If you have a 2001 or newer vehicle, you can do the ‘key trick’, that is turn the key on, off, on, off, on, leaving the key on for the last cycle. The codes will show in the odometer window, make sure that for both of these procedures, you have a piece of paper and a pen/pencil available to write the codes down. If you get a ‘P dOnE’ and an ‘E dOnE’ in the odometer window, there are no codes stored in the computers.

The scanner should be a mid-range price ($125-$175), that way you can use it on different vehicles. The scanner should come with a list of DTC codes for all vehicles.


Check Fuses

Check the fuses in the underhood power distribution center (PDC), you will need a test light and a multimeter to see if every fuse is working. The PDC is on the drivers’ side fenderwell. When using a test light on the fuses, there should be power to both sides/ends of the fuse. Some of the fuses may need the key in the “on” position in order to check to see if they are good. When using a multimeter to test fuses, set the meter to read ohm’s and test both legs of the fuse. Sometimes the fuses ‘look’ good but test bad, so make sure that you have several spares to choose from.

Checking the inside fuse panel is easier. Use the test light and multimeter, in the same matter above, to test the fuses here also. Make sure that you have spare fuses for this.


Check Grounds/Wiring

When checking grounds and wiring, the best defense is a good offense. What I mean by this is to try and find all grounds and make sure that all are bare metal between the connectors, especially the grounds to the engine. You may have to grind, wire wheel, file, sand, or drill new holes, in order to get a good ground. When done making sure that the grounds are making good connections, make sure to put a rust retardant / inhibitor, over the newly exposed metal.

When checking the wiring, check all connections to make sure all of them are pushed tightly together. Make sure that all exposed wiring is in good shape, no burned spots, no missing wiring that you can see, unplugged connectors, etc.

Once you have completed these tests / checks, you will have done what most Diesel Mechanics will do. If the engine still does not start, posting the DTC’s will help us figure out what is going on.
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O.O., 01.5, Dodge, 2500, High Output (H.O.) Cummins Turbo Diesel (245/505), Quad Cab Long Bed (QCLB), 4x4, Sport, Original Bosch VP 44 Injection Pump, 6 Speed/NV5600 Transmission, 3.55 Gears, 105k, currently stock engine, Fram Air Filter, 285/75R16s, Glow Shift Gauges: Fuel Pressure (FP), Boost, Exhaust Gas Temperature (EGT), Oil Temperature, SMARTY@1, Airtex lift pump 19 psi @ idle, 14 psi @ WOT, Propane Injection, 2 Stroke Oil, Intake Air Temperature (IAT) Fooler = Better MPG, Bed Lined, Chrome Nerf Bars, more to come!!

Toys:
'79 CJ5, 258ci, 3" lift, 33x12.50x15, Stock Engine and 3 Speed Tranny
'05 Suzuki, GSX1300R, Hayabusa, All Stock, #3('00 blown engine, '00 stolen, & '05)
The complete live & learn and pass it on by H. Jackson Brown, Jr.

Last edited by stodg73; 01-19-2011 at 11:01 AM.
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  #2  
Old 01-15-2011, 09:05 PM
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ISX ISX is offline
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Fuel pressure varies from vehicle to vehicle. Look up the specs for it first. What he mentioned is for the Bosch VP44 24V Cummins Diesel.

Another thing to note is that error codes on 12V engines are pretty well worthless. The codes you get will be codes for conditions that you already know about. Sometimes it can be helpful, but most times I wouldn't even use them and would just go straight to testing things. On a 24V it is a different story.
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Removed AFC--No Plate--13.5* timing--BHAF--5" Exhaust--Valair Clutch
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Last edited by stodg73; 09-20-2012 at 04:36 PM.
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  #3  
Old 11-29-2011, 09:36 AM
Gutterwffw66 Gutterwffw66 is offline
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Okay... I got that. My truck is a 1998 Dodge Ram 3500 24V Cummins. I am not having a problem with it not starting. The problem is that I'm use to the truck starting right up after the start engine light comes on. The problem I have been having is now... the truck starts up after three turns of the key or constantly rolling it over till it fires up. Which was the reason I thought that I had one or more injectors that had gone bad. So I replaced what I thought was the suspect injectors (Three new one in the truck now) and cleaned up three of the ones that I thought were not suspect. I bled the lines, turned over the truck till it started, I let it run for 20 minutes, shut it off for 5 minutes, and then started the truck back up took it for a test run. The truck has more power and seems to be running great. but after leaving it sit for a couple of hours... the truck went back to the same problem I have been having. The engine turns over but will not fire up right away. after the third turning of the key and the third rolling of the engine the truck fires up and runs. I can hear the fuel pump in the tank and the one up front working. All my electrical terminals are connected and clean. Not sure what else it could be. LOL!
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Old 11-29-2011, 09:48 AM
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stodg73 stodg73 is offline
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So after it sits, nose up or nose down, does it take time to start. If nose up, try parking nose down. This will tell if there is an air leak somewhere in the fuel system.

What is your fuel pressure at the VP-44? If less than 10 psi, then you need a lift pump.

Have you just bumped the starter and let the lift pump run for the set time, and then tried to start the truck? Did it start or just turn over?

Have you checked for trouble codes, if so, please post them. You may need to borrow a code reader from AutoZone, Orielly's, etc. if you don't have one. Write them down and then clear them if possible. Drive around a bit, then go back and see if any codes came back.

From what you have described, is that you have an air leak somewhere in the fuel system and making it a hard start.

You might also read This Gauge Information about getting gauges for your truck. This way you will have a better feel as to what is going on at any given time.
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O.O., 01.5, Dodge, 2500, High Output (H.O.) Cummins Turbo Diesel (245/505), Quad Cab Long Bed (QCLB), 4x4, Sport, Original Bosch VP 44 Injection Pump, 6 Speed/NV5600 Transmission, 3.55 Gears, 105k, currently stock engine, Fram Air Filter, 285/75R16s, Glow Shift Gauges: Fuel Pressure (FP), Boost, Exhaust Gas Temperature (EGT), Oil Temperature, SMARTY@1, Airtex lift pump 19 psi @ idle, 14 psi @ WOT, Propane Injection, 2 Stroke Oil, Intake Air Temperature (IAT) Fooler = Better MPG, Bed Lined, Chrome Nerf Bars, more to come!!

Toys:
'79 CJ5, 258ci, 3" lift, 33x12.50x15, Stock Engine and 3 Speed Tranny
'05 Suzuki, GSX1300R, Hayabusa, All Stock, #3('00 blown engine, '00 stolen, & '05)
The complete live & learn and pass it on by H. Jackson Brown, Jr.

Last edited by stodg73; 11-29-2011 at 10:24 AM. Reason: more info
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  #5  
Old 11-29-2011, 11:42 AM
Gutterwffw66 Gutterwffw66 is offline
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Thank you once again very. I will double check theses area you have described up above. And the answer too two of your questions. 1.) you asked about nose up or down. Answer: It doesn't matter it it's level, nose up, or down. while starting it... I have to turn it over two or three times and then it fires up.

It may be what you said about an air leak somewhere. Or a lift pump.

Thanks very much!
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  #6  
Old 11-29-2011, 11:50 AM
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If either parking nose up, nose down, or flat, did you replace the o-ring on the fuel filter? If so, you may have pinched it to where there is a tiny air leak, thus allowing air into the system.
__________________
O.O., 01.5, Dodge, 2500, High Output (H.O.) Cummins Turbo Diesel (245/505), Quad Cab Long Bed (QCLB), 4x4, Sport, Original Bosch VP 44 Injection Pump, 6 Speed/NV5600 Transmission, 3.55 Gears, 105k, currently stock engine, Fram Air Filter, 285/75R16s, Glow Shift Gauges: Fuel Pressure (FP), Boost, Exhaust Gas Temperature (EGT), Oil Temperature, SMARTY@1, Airtex lift pump 19 psi @ idle, 14 psi @ WOT, Propane Injection, 2 Stroke Oil, Intake Air Temperature (IAT) Fooler = Better MPG, Bed Lined, Chrome Nerf Bars, more to come!!

Toys:
'79 CJ5, 258ci, 3" lift, 33x12.50x15, Stock Engine and 3 Speed Tranny
'05 Suzuki, GSX1300R, Hayabusa, All Stock, #3('00 blown engine, '00 stolen, & '05)
The complete live & learn and pass it on by H. Jackson Brown, Jr.
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  #7  
Old 11-29-2011, 01:09 PM
Gutterwffw66 Gutterwffw66 is offline
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That is a good question. Yes I did replace the fuel filter. Maybe I did pinch the O-rings. I replaced both of them. they came with the filter. I'll check or just buy another filter. Maybe the whole thing was faulty.
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Old 12-04-2011, 09:45 PM
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Then there is trucks like the Ford Powerstrokes which are a whole different animal too. High pressure oil to drive the injectors. Glowplugs to be aware of.
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