Hard starting when at operating temp
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Interesting that they would openly admit something as blatant as its "faulty" but yet still require an inspection to verify.....
In saying that, just beware because its common for members to send their VP back to the vendor only to have the vendor to claim that the returned VP is void of warranty because of water ingestion which supposedly ruined the internals.
I'm not sure how you'd prevent such deception but maybe taking lots of pictures would help.
But in regards to the hard start, the only other reason a VP will cause a hard "hot" start besides what I've already mentioned is if the PSG (computer) was not replaced with a brand new unit upon rebuilding. Some vendors practice this cheaper method too whereby they only fix what needs to be fixed and if the PSG is working then they reinstall it and send it on its way. The problem with doing that is the PSG (especially the older ones) are very prone to excessive heat from heat soaking off the engine and/or low fuel pressures and that causes the lead free solder to crystallize. The crystallization will form intermittent electronic connections and lead to hard hot starts, white smoke upon starting, and dead pedal. You may or may not have experienced any of those other issues if truly the PSG was old and showing its age. One way to find if this is the cause is to pour a gallon or two of cool water directly on top of the PSG when experiencing the hard hot start and see if starts better. Obviously the water cools the PSG and helps settle the solder connections.
Lastly lastly.....if you do end up sending the VP back to them, just be absolutely certain that the new VP they send you also has a brand new PSG. Do NOT settle for a used older PSG.
In saying that, just beware because its common for members to send their VP back to the vendor only to have the vendor to claim that the returned VP is void of warranty because of water ingestion which supposedly ruined the internals.
I'm not sure how you'd prevent such deception but maybe taking lots of pictures would help.
But in regards to the hard start, the only other reason a VP will cause a hard "hot" start besides what I've already mentioned is if the PSG (computer) was not replaced with a brand new unit upon rebuilding. Some vendors practice this cheaper method too whereby they only fix what needs to be fixed and if the PSG is working then they reinstall it and send it on its way. The problem with doing that is the PSG (especially the older ones) are very prone to excessive heat from heat soaking off the engine and/or low fuel pressures and that causes the lead free solder to crystallize. The crystallization will form intermittent electronic connections and lead to hard hot starts, white smoke upon starting, and dead pedal. You may or may not have experienced any of those other issues if truly the PSG was old and showing its age. One way to find if this is the cause is to pour a gallon or two of cool water directly on top of the PSG when experiencing the hard hot start and see if starts better. Obviously the water cools the PSG and helps settle the solder connections.
Lastly lastly.....if you do end up sending the VP back to them, just be absolutely certain that the new VP they send you also has a brand new PSG. Do NOT settle for a used older PSG.
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Joined: Jan 2003
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From: The "real" Northern CA
Hmmm..... The distributor is mechanical so I'm not sure what would be wrong with it to cause a hard hot start issue. The items in there in relation to the distributor which would though are the timing ring and fuel solenoid. But as we discussed before, those items are affected by overly high fuel pressures during cranking.
You can confirm if the PSG is new by the code numbers. There's a long list of numbers on the side by the bar code and on some on the top of the cover.
You can confirm if the PSG is new by the code numbers. There's a long list of numbers on the side by the bar code and on some on the top of the cover.
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From: The "real" Northern CA
I think that would constitute a whole nother conversation because thats not normal..... As long as the VP is fed a constant, good clean, supply of fuel at no less that around 14-15 psi under all running conditions, never run out of fuel, and use a fuel lubrication, the VP should be reliable.
The re-manufactured VP's are supposed to be built on a Bosch 815 bench which is required to achieve the correct calibration. That doesnt mean all builders are of the same "quality". This is why I feel its important to buy from only reputable vendors. Yes, everyone has had an experience with most if not all vendors but only a few of those listed vendors have a Bosch 815.
The re-manufactured VP's are supposed to be built on a Bosch 815 bench which is required to achieve the correct calibration. That doesnt mean all builders are of the same "quality". This is why I feel its important to buy from only reputable vendors. Yes, everyone has had an experience with most if not all vendors but only a few of those listed vendors have a Bosch 815.
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I think that would constitute a whole nother conversation because thats not normal..... As long as the VP is fed a constant, good clean, supply of fuel at no less that around 14-15 psi under all running conditions, never run out of fuel, and use a fuel lubrication, the VP should be reliable.
The re-manufactured VP's are supposed to be built on a Bosch 815 bench which is required to achieve the correct calibration. That doesnt mean all builders are of the same "quality". This is why I feel its important to buy from only reputable vendors. Yes, everyone has had an experience with most if not all vendors but only a few of those listed vendors have a Bosch 815.
The re-manufactured VP's are supposed to be built on a Bosch 815 bench which is required to achieve the correct calibration. That doesnt mean all builders are of the same "quality". This is why I feel its important to buy from only reputable vendors. Yes, everyone has had an experience with most if not all vendors but only a few of those listed vendors have a Bosch 815.
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Joined: Jan 2003
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From: The "real" Northern CA
No discredit to any of those mechanics nor their ability or knowledge of the diesel world. The only problem is the VP engines have proven to be quite the challenge for even the best diesel mechanics. You almost have to work on them all the time to fully understand what makes them tick.....and keep ticking.
So for someone to tell you that it would cost in excess of $5000 to get your truck running is crazy. There's only so many things to look for.
What I listed so far is where to start, but the problem with internet diagnosing is that all too many people leave out critical information whereby only giving half the story. Generally the half they want to share too.
Nonetheless, not to go too far off on that tangent, the only other thing I can think of which will wreak havoc on the VP is the charging system. Meaning, if the batteries are weak or have dead cells, corrosion is bad and attacking connections and cables, and/or the alternator has diode issues which is causing an excessive AC voltage sin wave, then the other neighboring sensitive electronics will take the brunt. The APPS, the torque converter solenoid, and the VP PSG to name the more prone to any electronic anomalies in the charging system.
There are AC voltage filters you can install but those only mask the real problem.
So for someone to tell you that it would cost in excess of $5000 to get your truck running is crazy. There's only so many things to look for.
What I listed so far is where to start, but the problem with internet diagnosing is that all too many people leave out critical information whereby only giving half the story. Generally the half they want to share too.
Nonetheless, not to go too far off on that tangent, the only other thing I can think of which will wreak havoc on the VP is the charging system. Meaning, if the batteries are weak or have dead cells, corrosion is bad and attacking connections and cables, and/or the alternator has diode issues which is causing an excessive AC voltage sin wave, then the other neighboring sensitive electronics will take the brunt. The APPS, the torque converter solenoid, and the VP PSG to name the more prone to any electronic anomalies in the charging system.
There are AC voltage filters you can install but those only mask the real problem.
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Registered User
Joined: Oct 2011
Posts: 55
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No discredit to any of those mechanics nor their ability or knowledge of the diesel world. The only problem is the VP engines have proven to be quite the challenge for even the best diesel mechanics. You almost have to work on them all the time to fully understand what makes them tick.....and keep ticking.
So for someone to tell you that it would cost in excess of $5000 to get your truck running is crazy. There's only so many things to look for.
What I listed so far is where to start, but the problem with internet diagnosing is that all too many people leave out critical information whereby only giving half the story. Generally the half they want to share too.
Nonetheless, not to go too far off on that tangent, the only other thing I can think of which will wreak havoc on the VP is the charging system. Meaning, if the batteries are weak or have dead cells, corrosion is bad and attacking connections and cables, and/or the alternator has diode issues which is causing an excessive AC voltage sin wave, then the other neighboring sensitive electronics will take the brunt. The APPS, the torque converter solenoid, and the VP PSG to name the more prone to any electronic anomalies in the charging system.
There are AC voltage filters you can install but those only mask the real problem.
So for someone to tell you that it would cost in excess of $5000 to get your truck running is crazy. There's only so many things to look for.
What I listed so far is where to start, but the problem with internet diagnosing is that all too many people leave out critical information whereby only giving half the story. Generally the half they want to share too.
Nonetheless, not to go too far off on that tangent, the only other thing I can think of which will wreak havoc on the VP is the charging system. Meaning, if the batteries are weak or have dead cells, corrosion is bad and attacking connections and cables, and/or the alternator has diode issues which is causing an excessive AC voltage sin wave, then the other neighboring sensitive electronics will take the brunt. The APPS, the torque converter solenoid, and the VP PSG to name the more prone to any electronic anomalies in the charging system.
There are AC voltage filters you can install but those only mask the real problem.
If I decide to keep it, the Phoenix option seems the most practical for me.
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Would the cam pos sensor or crank pos sensor not produce a code if faulty? Thanks for giving me your time and efforts.
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From: League City, TX
A faulty crank/cam shaft position sensor can also fool the PCM into thinking the truck is not running. When that happens the PCM disables the A/C, cruise control, and alternator. Plus the tach will be erratic or just read 0 RPM.
On the gas engine Rams and Dakotas, a bad cam/crank sensor will also shut down the engine.
Our diesel engines are different since the ECM and VP44 run the engine and not the PCM. Plus the base timing is fixed since the VP44 is gear driven by the camshaft, and the VP44 can function in the absence of a valid cam/crank signal. The engine will just keep running.
I'd like to try and figure out why your engine has eaten 5 VP44's. That is not normal. If I were you, I would consider replacing your Intake Air Temp (IAT) and Manifold Absolute Pressure (MAP). Those two sensors have a huge role in both fuel timing and fuel control.
On the gas engine Rams and Dakotas, a bad cam/crank sensor will also shut down the engine.
Our diesel engines are different since the ECM and VP44 run the engine and not the PCM. Plus the base timing is fixed since the VP44 is gear driven by the camshaft, and the VP44 can function in the absence of a valid cam/crank signal. The engine will just keep running.
I'd like to try and figure out why your engine has eaten 5 VP44's. That is not normal. If I were you, I would consider replacing your Intake Air Temp (IAT) and Manifold Absolute Pressure (MAP). Those two sensors have a huge role in both fuel timing and fuel control.
Registered User
Joined: Jan 2003
Posts: 4,179
Likes: 142
From: The "real" Northern CA
A faulty crank/cam shaft position sensor can also fool the PCM into thinking the truck is not running. When that happens the PCM disables the A/C, cruise control, and alternator. Plus the tach will be erratic or just read 0 RPM.
On the gas engine Rams and Dakotas, a bad cam/crank sensor will also shut down the engine.
Our diesel engines are different since the ECM and VP44 run the engine and not the PCM. Plus the base timing is fixed since the VP44 is gear driven by the camshaft, and the VP44 can function in the absence of a valid cam/crank signal. The engine will just keep running.
I'd like to try and figure out why your engine has eaten 5 VP44's. That is not normal. If I were you, I would consider replacing your Intake Air Temp (IAT) and Manifold Absolute Pressure (MAP). Those two sensors have a huge role in both fuel timing and fuel control.
On the gas engine Rams and Dakotas, a bad cam/crank sensor will also shut down the engine.
Our diesel engines are different since the ECM and VP44 run the engine and not the PCM. Plus the base timing is fixed since the VP44 is gear driven by the camshaft, and the VP44 can function in the absence of a valid cam/crank signal. The engine will just keep running.
I'd like to try and figure out why your engine has eaten 5 VP44's. That is not normal. If I were you, I would consider replacing your Intake Air Temp (IAT) and Manifold Absolute Pressure (MAP). Those two sensors have a huge role in both fuel timing and fuel control.
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Joined: Nov 2003
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From: League City, TX
KATOOM, I think this will explain it:
The manual does not have much more than that. That said, pin 5 is the VP44 FUEL SHUTOFF signal wire, which comes from the ECM. The ECM will apply 12 Volts to that wire for three seconds only when the key is switched off, and I think I know the process for this. The PCM controls the Automatic Shutdown (ASD) relay in the power distribution center. The ASD relay is both an input and output to the PCM. The ASD relay is on when the key is in the on position, and off when the key is off. So, as long as the key is on, the PCM will stay on, and the ECM/VP44 as well. The shutdown sequence I think goes like this: key switched to off, PCM sends signal to ECM via bus, ECM then sends 3 second shutdown signal to VP44 on pin 5. The 12 Volt power at pin 7 is also turned off at the same time.
Pin 8 is the engine speed reference signal to the VP44 from ECM which in turn comes from the CKP/CPS sensor. But as noted above, the VP44 can operate without that signal. The service manual does not cover any of the details on the VP44 internals. However, I did find this over at dodgeram.org on a page that details the VP44:
VP44 Electronic Injection Pump
The pin 7 trick works, but can only idle since there is no information or commands coming from the ECM datalink on pins 1, 2, and 3.
ECM - OPERATION
The main functions of the Engine Control Module (ECM) and Fuel Injection Pump Control Module (FPCM) are to electrically control the fuel system. The Powertrain Control Module (PCM) does not control the fuel system.
The main functions of the Engine Control Module (ECM) and Fuel Injection Pump Control Module (FPCM) are to electrically control the fuel system. The Powertrain Control Module (PCM) does not control the fuel system.
PCM - OPERATION - DIESEL
Two different control modules are used: The Powertrain Control Module (PCM), and the Engine Control Module (ECM). The ECM controls the fuel system. The PCM does not control the fuel system. The PCM’s main function is to control: the vehicle charging system, speed control system, transmission, air conditioning system and certain bussed messages.
Two different control modules are used: The Powertrain Control Module (PCM), and the Engine Control Module (ECM). The ECM controls the fuel system. The PCM does not control the fuel system. The PCM’s main function is to control: the vehicle charging system, speed control system, transmission, air conditioning system and certain bussed messages.
VP44 - OPERATION
The injection pump is driven by the engine camshaft. A gear on the end of the pump shaft meshes with the camshaft gear. The pump is timed to the engine. The VP44 is controlled by an integral (and non-serviceable) Fuel Pump Control Module (FPCM) (Fig. 15). The FPCM can operate the engine as an engine controller if a Crankshaft Position Sensor (CKP) signal is not present.
The injection pump is driven by the engine camshaft. A gear on the end of the pump shaft meshes with the camshaft gear. The pump is timed to the engine. The VP44 is controlled by an integral (and non-serviceable) Fuel Pump Control Module (FPCM) (Fig. 15). The FPCM can operate the engine as an engine controller if a Crankshaft Position Sensor (CKP) signal is not present.
Pin 8 is the engine speed reference signal to the VP44 from ECM which in turn comes from the CKP/CPS sensor. But as noted above, the VP44 can operate without that signal. The service manual does not cover any of the details on the VP44 internals. However, I did find this over at dodgeram.org on a page that details the VP44:
VP44 Electronic Injection Pump
The pump also contains a speed sensor (IAT) that gives the fuel pump control module (FPCM) data on the position and speed of the pump shaft. A reference pulse that marks top dead center (TDC) of cylinder No. 1 is sent from the ECM once every pump revolution. By comparing this reference pulse from the ECM to the position signal from the speed sensor (IAT), the fuel pump control module (FPCM) can reference the pump's position in relation to the engine's position. This allows the fuel pump control module (FPCM) to adjust the pump timing to compensate for minor position differences between the fuel pump shaft and the engine camshaft. If the difference between the pump position and engine position becomes too great, then a fault will be logged in the fuel pump control module (FPCM)
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