VP44 replaced, Injectors replaced, now P0112

[Tim Waldo]

Ok, I know things can cascade, now I'm wondering what all sensors I SHOULD replace.  Started with a replaced VP, was running rough and lots of white smoke.... so replaced with remanufactured Injectors and new tubes... still white smoke but was improving. Scanned for pending codes and nothing showed up. Took for a test drive the smoke cleared up A LOT but still loss of power going into 3rd gear and again going into 4th gear... and then it just shut down on me with a code of P0112... fired right back up and got it home with the same power loss on gear changes.  

Can an IAT shut the engine down?

Should I replace any other sensors?

I replaced the IAT, MAP and Crank position sensors all in 2008. Just because, no codes were being generated, Crank position sensor was replaced in or about 2013 because it was throwing codes.

 

Thanks,

Tim

 

[Mopar1973Man]

Simply no the IAT will not cause the engine to die. It's not a required sensor it can be unplugged and drive normal. To test plug in a live data tool or pull up a iQuad app and check your IAT and ECT sensor temp should match at key on engine not running. P0112 basically states the voltage of that sensor is out of normal range.

 

Shift issues are typically AC noise from the alternator and bad ground on the ECM and VP44 hence the W-T ground wire mod. Also most likely why the VP44 failed (possibly).

 

White smoke is either air in the fuel which retards timing being air is compressible and makes the injectors fire late. The other is if the key been crushed because of mis-installed pump shaft. I've also seen the shaft key fall out during install of the VP44. Then timing could be off. Rare but I've seen rebuilt VP44 with bad PSG that started and white smoked and weak power. 

[Tim Waldo]

So after new injectors it may very well come back to the timing is off on the VP44 (shift issues are in a manual transmission, power loss anyway). the W-T mod has been mostly completed, ground wires specifically.  My code reader can't see both the IAT and ECT (what is a suggestion on a code reader that will give me everything I need specific to this truck).  What would have made the truck just die with no other codes?

 

Also, other than low fuel, what could be letting air into the system?

 

Thanks,

Tim

 

Edited February 15, 2023 by Tim Waldo

[Mopar1973Man]

1 hour ago, Tim Waldo said:

Also, other than low fuel, what could be letting air into the system?

Suction leak between the tank and the lift pump. Any joint or connection would have to be checked from the pump back to the tank. 

 

1 hour ago, Tim Waldo said:

My code reader can't see both the IAT and ECT (what is a suggestion on a code reader that will give me everything I need specific to this truck).

OBDLink MX, OBDLink LX, Innova Code Reader, Quadzilla Adrenaline Tuner, etc. All the above I know work and display live data...

 

1 hour ago, Tim Waldo said:

What would have made the truck just die with no other codes?

Bad VP44... Is the only thing that I know that can cause the engine to die without codes. 

[Tim Waldo]

Just talked to TD, where I got my pump and injectors... they said based on the original code that started the issue P1689, that the ECM was very likely at fault... they are sending me a breakout box to see how the truck runs with the ECM out of the picture... they also suggested cleaning the MAP and IAT sensors.  I do not believe that I have air in the fuel lines.

 

Honestly I don't see how the pump running independent of the ECM would make a difference, but willing to try it.... I guess the ECM could be telling the pump to do things that are out of band....

 

[VMac822]

Just to make sure, you used the woodruff key that came with the new VP44?

[Tim Waldo]

after hooking up the breakout box, the engine ran the same with or without it, they had me pull the VP44 out and send it back for a run on the bench, I am upgrading to a pump with all new electronics... rather than the refurbed pump only.

[Mopar1973Man]

If you purchase a Bosch Certified pump it should have a NEW PSG module. If so it is sold blank which means it will be ran on a Bosch 815 test stand for 3 hour to calibrate and test. After passing all test then the PSG is flashed. It is policy for all Bosch certified builders to core out the old PSG and replace.

 

One's that reuse the old PSG are not a certified rebuiler and are not test standing the rebuilt pumps.

[Tim Waldo]

I"m sort of stuck at this point, from listening to it they believe it is the sensor that gives the PSG timing information... but won't know until they put it on the bench... and even though I'm going to pay the difference to get new electronics, I'm going to specifically ask what exactly failed on the original pump I purchased.

 

[Mopar1973Man]

The ECM provides timing information based on RPM and engine load which is based on throttle position.

[Tim Waldo]

There is a sensor mounted on the VP44, I don't know if it feeds the ECM or the PSG... but running on the ECM or on the breakout box the VP44 runs the same... like it is out of time.

They are bench testing the VP44 they sent me and I am upgrading to a VP44 with new electronics.

[Mopar1973Man]

23 minutes ago, Tim Waldo said:

There is a sensor mounted on the VP44

 

Yup, there is but the only thing that sensor does is report the cam speed which is the same as the VP44 (half of the crank speed). Then there is a fuel temp sensor that reports the fuel temp in the VP44. The P0112 code is the IAT sensor IIRC is low volt code meaning the sensor line is shorted to ground. Remember the IAT sets timing on the VP44 basically in a nutshell if IAT falls below +80*F then ECM calls for an extra +3 degrees of timing. When it rises above 80*F then it retards the timing.

 

As for things hooked ot the PSG. You have a electronic solenoid to control the fuel pin for throttle. Then you have the hydraulic solenoid to control fuel pressure to advance and retard timing. Then the one sensor that sees the cam speed and the fuel temp that's all there is there is no other magic or witchcraft inside the PSG.

 

You can see that sensor here right of the PSG.

 

 

Here is the tone wheel... Look at the mainshaft and you can see the tone wheel for the sensor.

 

[Tim Waldo]

it was the round module that actually was connected to the "tap" wire , when I get the replacement I'll take a photo of it and share, just for clarity.

[Mopar1973Man]

Wire tap hooks to the fuel solenoid lead. Then the tuner will extend the pulse on the fuel solenoid in microseconds. 

[Great work!]

The insulation on the solenoid wires gets old and crumbles then shorts out so the timing contol soleniod doesn't work and the timing goes all the way up to max and it runs really bad.

[Tim Waldo]

Well they finally got back to me, said it was the IAT ON THE PUMP.....  now I am confused because the IAT is not on the pump... tried googling it and couldn't find anything OTHER than the intake air temp sensor that is NOT on the VP44... either way it is in the electronics package that is installed on the pump and I upgraded to a pump with all new electronics....

[Mopar1973Man]

There is no IAT on the injection pump I can promise you that... The only things in that pump are an RPM sense and fuel temp that's all. Externally is the fuel solenoid and the timing solenoid. Nothing else...

Edited March 13, 2023 by Mopar1973Man

[Tim Waldo]

Then based on the way the vehicle ran it had to be the RPM sensor because it would while on the breakout box lope.... like a 360 with a cam in it....

[Mopar1973Man]

This is why I only purchase VP44s from a source that I know comes from a Bosch Certified rebuilder. There is a lot of rebuilders that reuse old PSG and don't recalibrate the pumps. 

[Tim Waldo]

all in all I've been happy with Thoroughbred Diesel, wouldn't have had any issues had I purchased the pump that stated it had new electronics.... Not happy about having to add in a new set of injectors thinking that was the problem... but that was me chasing ghosts...