Surging Issues - Not Typical Cold Start - In Gear When Warm

[Scully Motorsport]

Hello, looking for some help with an issue here.

I purchased a 177k mile 2013 2500 mega cab with 68RFE a month ago.

It, of course, did not do it on the test drive or anything, but I picked it up from a few states south because I wanted a clean truck, and on the way home, it got a nasty surge when it was good and heat soaked.

I would pull up to a light, which surged and lunged like 300 rpm.

The truck was bone stock, and I did some research, and many forums said a software update or aftermarket tune fixed the issue.

I was planning on deleting anyways, so I did that a few weeks ago with a double R/MM3 setup.

The truck is excellent to drive now and everything, but the surging issue is still there but very different.

Before, the truck would surge and surge consistently and never stop.

Now it mostly just does it in reverse, which is super annoying with a trailer, and if I am sitting still, it will level itself out after six surges or less.

If I am trying to inch forward or backward, it's still super annoying because it will surge nonstop if i do low-throttle inputs in short bursts.

I did not delete EGR, throttle valve, or anything if that matters.

I have done a lot of searching on the subject, so I have come up with some facts:

• VGT requested vs. actual is rock solid, and my exhaust brake works fine, so I do not think it is a turbo issue.

• Scan tool says no water in fuel or recent history

• I have also been watching requested rail vs. actual rail closely while it surges, and they seem to be as close as they can be. Ordered rail pressure surges with the idle surge, so something tells it to surge. It will surge coming to a stop at a light, shifting into reverse, or if I touch the throttle a tiny bit from a stop and then let off. I will add TPS to that mix to ensure TPS isn't acting goofy, but I am pretty sure it is not.

I was hoping Itoget some help on what to look at next.

This is as far as my search has taken me.

What scares me is if I take it out of gear, it smooths out quickly.

I don't see how the trans or converter can cause this, but who knows.?

At the same time, I did the delete it.

I also did trans filters and fluid change.

Thank you for any help you can give.

Joe

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[17_G56]

I've heard of this issue before, and I'd bet you'd resolve it by replacing the Fuel Control Actuator.

It mounts on the back of the CP3 and can cause surging issues as a sign of it's failing.

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[AK Bob]

Check the exhaust pressure sensor and tube for soot restriction.

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[Scully Motorsport]

Thank you, guys, for the quick reply.

I will start with the free suggestion, and then that actuator is not too expensive to try next.

There is no pressure on the low side when the truck is off, right?

I can pop that thing out, correct?

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[AK Bob]

Thank you, guys, for the quick reply.

I will start with the free suggestion, and then that actuator is not too expensive to try next.

There is no pressure on the low side when the truck is off, right?

I can pop that thing out, correct?

Correct, there is no pressure on the exhaust pressure sensor with the engine off.

Since the fuel rail pressure is commanded high and low when surging, I would start with that.

If there is no blockage, it could be a bad sensor.

You could also try the free WD40 test on the FCA to see if it’s sticking.

See the attached video.

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[Scully Motorsport]

Yea, I meant on the FPA if there was pressure or not.

I took the exhaust pressure sensor off with the line on my lunch, and it was clear.

I will look at the data and see if the sensor readings seem reasonable.

First, I will probably try this WD40 test since that thing is easy to get to too.

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[AK Bob]

Yea, I meant on the FPA if there was pressure or not.

I took the exhaust pressure sensor off with the line on my lunch, and it was clear.

I will look at the data and see if the sensor readings seem reasonable.

First, I will probably try this WD40 test since that thing is easy to get to too.

No pressure at the FCA either with the engine off.

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[Scully Motorsport]

The FPA WD40 test cleaned up the idle, so I will replace that.

Thank you, guys, again, for the quick responses.

I wish I had asked earlier! I hope this is nice and searchable now.

The last question is, is it necessary to do the 200$ bosch replacement actuator, or would you like a cheaper Dorman version to be okay?

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[AK Bob]

The FPA WD40 test cleaned up the idle, so I will replace that.

Thank you, guys, again, for the quick responses.

I wish I had asked earlier! I hope this is nice and searchable now.

The last question is, is it necessary to do the 200$ bosch replacement actuator, or would you like a cheaper Dorman version to be okay?

Great news!

I would go with the Bosch.

Hopefully, others will chime in.

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[17_G56]

The FPA WD40 test cleaned up the idle, so I will replace that.

Thank you, guys, again, for the quick responses.

I wish I had asked earlier! I hope this is nice and searchable now.

The last question is, is it necessary to do the 200$ bosch replacement actuator, or would you like a cheaper Dorman version to be okay?

When it comes to the fuel or fuel system on a Diesel, that is the one area I don't cheap out on. $100 saved now can turn into thousands of $$ later. JMHO, I'd agree with AK Bob and go Bosch or even OEM if you can swing it.

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