Engine/Transmission (1998.5 - 2002) Engine surging at highway speeds

[kevhype0825]

My dad is having an issue with his 02 DRW CTD 4x4 QC auto 47re when driving at highway speeds over 40mph. The truck continually surges and does not clear up until he reduces speed. The truck does not exhibt this surging at take off or at moderate speeds. He intially supected a fueling issue so he changed the fuel filter but that did not help. The truck has 98K miles on it and is stock besides a drop-in K&N air filter. He replaced the lift pump at 70K miles. Could he have another lift pump issue or does this sound like a bad injector(s)?

 

[HBarlow]

Does it happen with cruise control engaged and on slightly undulating terrain or slight downgrade?

It is common for all three I've owned to shift back and forth from fueling to not fueling when the ECM (cruise control) is trying to maintain speed on a long but slight downgrade. The ECM is not very smooth at this task and often slightly overshoots the speed then shuts off fueling to slow.

The speed variation is very small, maybe only one mph or so but the driver can feel the truck throttling then slowing above and below set speed.

 

[kevhype0825]

Does it happen with cruise control engaged and on slightly undulating terrain or slight downgrade?



It is common for all three I've owned to shift back and forth from fueling to not fueling when the ECM (cruise control) is trying to maintain speed on a long but slight downgrade. The ECM is not very smooth at this task and often slightly overshoots the speed then shuts off fueling to slow.



The speed variation is very small, maybe only one mph or so but the driver can feel the truck throttling then slowing above and below set speed.

We drive in a mostly flat terrain and he wasn't using the cruise control when these incidents occurred. The way he explained it was when driving above 40mph, after the transmission shifts into 4th gear, the truck begins to surge erratically. We have done all the inspections of the fueling system that we could think of and there are no warning lights to suggest something failed. Could this be poor fuel? If so, why only under those circumstances?

 

[BoeingDiesel]

Are you sure that what you're describing is a surge and not TC lock/unlock?

 

[kevhype0825]

Are you sure that what you're describing is a surge and not TC lock/unlock?

He does not notice the surging as the transmission shifts into over drive. It usually happens a while after. It is not subtle surging either. It sounds like the engine wants to shut off; RPM's drop significantly.

 

[BoeingDiesel]

Sounds like a fueling issue. New stock lift pump and filter does not automatically mean the VP is getting the proper amount of fuel. Check the fuel pressure; idle usually hovers around 13-psi and under load around 6. Have you checked for codes? A little more info on the truck re; mods, etc. . would be helpful.

 

[kevhype0825]

Sounds like a fueling issue. New stock lift pump and filter does not automatically mean the VP is getting the proper amount of fuel. Check the fuel pressure; idle usually hovers around 13-psi and under load around 6. Have you checked for codes? A little more info on the truck re; mods, etc. . would be helpful.

We haven't checked the fuel pressure yet but we will try that next. This truck is an 02 DRW CTD 4x4 QC w/ auto 47re trans. It is basically stock except for a drop-in K&N air filter. It doesn't show any codes but that is based on us not seeing any warning lights on the dash. We do not have a scan tool to check this truck so it would mean a trip to the local Dodge dealership.



Is there an in tank filter on this truck that could be blocked?

 

[JMetzger]

You can check for codes by turning ignition key on-off,on-off, on. You can then read the codes in the mileage odometer.

 

[kevhype0825]

You can check for codes by turning ignition key on-off,on-off, on. You can then read the codes in the mileage odometer.

Thanks for that info! I never knew such a method existed for these older trucks. Now here is the bad news :{ ... . it is displaying several codes. Here is what I see:



PPCU

P1693

PDONE

PECU

P0216 (I read somewhere this is related to the VP44)

PDONE



Any ideas?

 

[hsmith]

I recall that the P0216 means the VP44 may be on the way out.

 

[kevhype0825]

Yeap, I am beginning to think the VP44 is on its way out. I have found several articles on the Internet describing the P0216 code and symptoms similar to what he is experiencing, they all lead up to VP44 replacement. I have also found several other fuel pressure diagnostic tips to try before we make the final verdict.

 

[JMetzger]

I would put a fuel pressure gauge on & check the fuel pressure while driving. It might show good at idle but under load you may not have enough pressure.

 

[kevhype0825]

I would put a fuel pressure gauge on & check the fuel pressure while driving. It might show good at idle but under load you may not have enough pressure.

What is the ideal pressure in both situations?

 

[JMetzger]

The factory service manual says a min of 10 PSI engine running. I know when I had the factory lift pump mine would idle at 12 to 14 PSI & WOT would run around 12 PSI. Anything less then 5 PSI is trouble for the VP-44. I had 5 factory lift pumps, they were so unreliable you never knew where the pressure would be. Today it would be allright & in 5 min it would be at about 5 PSI then back up to 13-14 PSI. They were nothing but junk & caused a lot of VP-44's to fail. With my FASS HPFP 95 I idle at 16 & WOT is around 14 PSI.

Jack

 

[kevhype0825]

The factory service manual says a min of 10 PSI engine running. I know when I had the factory lift pump mine would idle at 12 to 14 PSI & WOT would run around 12 PSI. Anything less then 5 PSI is trouble for the VP-44. I had 5 factory lift pumps, they were so unreliable you never knew where the pressure would be. Today it would be allright & in 5 min it would be at about 5 PSI then back up to 13-14 PSI. They were nothing but junk & caused a lot of VP-44's to fail. With my FASS HPFP 95 I idle at 16 & WOT is around 14 PSI.

Jack

Thanks Jack. We are going to run some fuel pressure test later this week. I'll update this thread with our results. We are also going to have the codes cleared. Weird thing is the truck drove fine yesterday.

 

[mhenon]

Thanks for that info! I never knew such a method existed for these older trucks. Now here is the bad news :{ ... . it is displaying several codes. Here is what I see:



PPCU

P1693

PDONE

PECU

P0216 (I read somewhere this is related to the VP44)

PDONE



Any ideas?

The 216 code is the VP44. You'll probably have to change it out before long. Mine went a few months with the code but eventually had to be pulled. Good luck.

Mike

 

[blacksheepdiesel]

Have the codes cleared at Autozone and then check again in a couple days to see if any codes show up. The ones on there now could be from a good while ago.

Also, it could be that your APPS is going bad. If you have a friend with a 2nd gen with same type of transmission (manual or auto) that does not have symptoms then swap his APPS in your truck for a test drive to confirm your APPS is good or not. If you need an APPS then pm timbo here on TDR for a less expensive aftermarket APPS.

Godspeed,
Trent

 

[kevhype0825]

Have the codes cleared at Autozone and then check again in a couple days to see if any codes show up. The ones on there now could be from a good while ago.



Also, it could be that your APPS is going bad. If you have a friend with a 2nd gen with same type of transmission (manual or auto) that does not have symptoms then swap his APPS in your truck for a test drive to confirm your APPS is good or not. If you need an APPS then pm timbo here on TDR for a less expensive aftermarket APPS.



Godspeed,

Trent

We are having the codes cleared by our local dodge dealer later this week. Thanks for that suggestion.



I apologize for this... ... but what is an "APPS"?

 

[kevhype0825]

More bad news....

Well... we had the codes cleared yesterday and they came back shortly after driving the truck. #@$%! Could it be possible that the VP44 is not getting enough fuel due to a blocked in tank filter of some sort?

 

[Beast2B]

APPS is accelerator pedal position sensor (like a TPS on a gasser vehicle). more likely a failing or failed lift pump, but there is a mesh screen in the tank at the fuel pick-up point that can get plugged up with crap, especially if the truck sits a lot or you got some bad fuel. did you get a VP44 inlet fuel pressure yet?