I own a 2001 Ford Excursion with the 7.3. I Super Chip'ed it about four years ago.

Approximately 1 year ago, the engine started to display a disturbing behavior. Sometimes its pronounced, other times it's hardly perceptible.

Between 1200 and 1600 rpm, while maintaining a steady speed, it jumps, surges, and hestitates for no particular reason that I can ascertain. It won't behave this way any other time, except at a steady speed between the above mentioned rpm's.

I do recall when I first noticed it (but that doesn't necessarily mean it's when it first began). It was very shortly after I had changed oil with a Valvoline 15w40 synthetic. My mechanic (not a Power Stroke expert) thought maybe the oil I picked had screwed something up. So he changed it back to Motorcraft 15w40 conventional oil. The problem improved, but the problem never fully disappeared. I have ONLY had the oil changed ever since with the Morotrcraft 15w40 conventional.

I just had the oil changed a few days ago, again with the Motorcraft, and the hesitation seems more pronounced than before I had it changed. WEIRD!

This is making me crazy, and I can't find a Power Stroke expert (outside of a Ford dealer and the confiscatory prices they charge. What's more, depending on the dealership, they'll turn their nose up at a chipped Power Stroke and take joy in voiding the remianing warranty, and then refuse to work on it) who can diagnose and fix this problem.

Is it something to do with the oil, or was that just coincidence? Has anyone experienced this before? What is going on?! What's the solution?! PLEASE HELP!!!

Pat Hurley
Fort Lauderdale, Florida

 

You are not the first to experience this problem. I've not had it but know there are many possible causes. All the way from a VSS to a failing throttle pedal assembly. Hopefully someone who has fixed this will chime in. In the meantime I will attempt to look it up for you in the shop manual.

Stay tuned.

 

Might it be the Camshaft Position Sensor starting to go?

 

I dont think so I am going over the shop manual like Tenn is now. It kinda feels like an airation issue but that is usually in the higher rpm ranges.

Here are the preliminary checks for surge while cruising
Perform the following preliminary checks:
Confirm brakes are not dragging
Confirm transmission and axle fluid levels
Confirm transmission and axle tube are not "cooked"
Check for oil in coolant
Check engine oil level
Confirm oil change within 8046.5 km (5000 miles), (5632.6 km [3500 miles] if severe duty)
Check Air Filter Minder
Check MAP sensor hose for holes, blockage, or disconnection. Confirm correct MAP sensor.
Check intake manifold system for leaks
Confirm acceptable SAE oil viscosity and API rating of oil. Refer to operator's guide.
Check fuel quality. Refer to Section 4A or Section 4B, Diagnostic Subroutines.
Confirm proper dipstick part number
Check for sufficient clean fuel
Check for an intake restriction
Check MAP sensor hose
Compare loaded weight of vehicle with performance expectations

Tenn did hit on one possibility, Do you ever notice it with the cruise control on?

 

Thanks Alan, I'm just checking to see if you bailed me out as I am stuck poking around in there like always. An interesting but unrelated thing I came across in there is:

A stuck-closed regulator valve (possibly caused by debris) will cause high fuel pressure for a short time until the pump fails.

This makes me wonder about the life of our stock pumps with after market regulators at higher pressures. While the safe threshold is 30-80 psi, and I don't think anyone is running anything above 80. I would guess increased operating pressures will decrease the lifespan of the stock fuel pumps.

Back to the topic. Most of those don't sound like what I would suspect. Curiously injectors are not on the list. Surge issues during cruising would be more evident than during accelleration if it was a minor issue due to the fact you're on the loud pedal unless it was a bad problem. A lot of those checks it seems to me would appear across the board.

 

Tenn check the "AG" Symptom chart 7 Injectors are not far down the list. And fuel pump inlet restriction is only about halfway down

About 90% of the preliminary checks are across the board but there are some pricey possibilities and i wanted to make sure an easy and inexpensive one didnt get overlooked

 

I see that, along with ICP and IDM tests, fuel pressure testing, aerated oil as well as even possible CPS, or CMP as referred to in the manual, possible contact on the timing disk. The others we don't really want to consider such as egine wear or piston/valve leaks. There is a lot of EBV leak and malfunction stuff too.

 

At the risk of trouble, here is the list of AG 7 checks:

AG6 CHECK FUEL HEATER

AG8 CHECK COLD CMP CLEARANCE (CMP CODE PRESENT)

AG9 CHECK CMP CLEARANCE TO TIMING DISK

AG12 CHECK FUEL PUMP PRESSURE

AG13 CHECK FUEL REGULATOR <o></o>

AG14 CHECK PUMP INLET RESTRICTION

AG15 CHECK FOR AERATED OIL

AG16 CHECK SOURCE OF AERATED OIL

AG17 INJECTION CONTROL PRESSURE TEST <o></o>

AG18 CHECK FOR LOW IDM POWER

AG19 CHECK LUBRICATION PRESSURE

AG20 KOER ON-DEMAND SELF TEST<o></o>

AG21 CHECK PRESSURE BALANCE

AG22 CHECK FOR LEAK SOURCE <o></o>

·Remove valve cover on cylinder head with higher IPR reading.

·With engine idling, look for bubbling around injector bores or oil gallery drain plugs.

·Or, with engine off, attach approximately 689 kPa (100 psi) air pressure to high-pressure oil gallery. Remove injector spill spouts for visibility.

·Look/listen for leaks.

<!--[if !supportLists]--><!--[endif]--> <!--[if !supportLists]--> <!--[if !supportLists]--><!--[endif]--> <!--[if !supportLists]--><!--[endif]--> AG23 KOER CYLINDER CONTRIBUTION TEST
AG24 CHECK FOR BIASED EBP SENSOR

AG25 CHECK FOR EXHAUST RESTRICTION (KOER, DTC 0476)

AG26 EXHAUST BACK PRESSURE OPERATION TEST

AG27 CHECK ELECTRICAL SYSTEM

AG28 CHECK FOR ENGINE WEAR

AG29 CHECK FOR PISTON OR VALVE LEAKS

AG30 CHECK FOR AN EXHAUST RESTRICTION (NO DTC)

AG31 CHECK FUEL INJECTOR OIL DISCHARGE

AG32 ATMOSPHERIC PRESSURE RATIONALITY CHECK

AG33 CHECK FOR BIASED EOT SENSOR

AG34 CHECK EOT SENSOR

 

I seem to remember putting the cruise control on while maintaining an RPM between 1200-1600 and the surging, hesitation remained. As a sidebar, my cruise control is not currently working!

As to engine wear being a possiblility, that isn't it. The engine has 92k on it. I got it when it had 20k, and have babied it ever since with a rigorous maintenance schedule.

As to the other possibilities mentioned, I have to admit that you guys are talking way over my head. I hope you can give me - in laymans terms - some clues I can share with a mechanic. I just don't speak the lingo that well.

I want to clarify that if I am accelerating through the 1200-1600 rpm range, but not staying there, I don't experience the surging and hesitating. Only when I maintain a steady speed in that range only do I get the surging and hesitation.

Could this be the CPS that I read about so often in this forum?

I'm desperate to get this fixed.

Thanks for your help!!!!!

Pat Hurley

 

CPS is a relatively cheaper check to fix. I realize now that my earlier post will be of no assistance to you as it is just the bullets without the routines.

I would suspect you have something relatively minor plagueing you but the devil is in finding it. It is likely an electrical or fuel related issue. Now that is a large order of things to run down. Disregard my last post except for general ideas of what to look for. I am guessing there are no codes? Have you had it checked for codes?

Edit: pull the chip and see what happens. I would suspect the IDM or ICP as this is what is controlling the extra oomph that the chip is telling it to put in there.

 

Is the CPS a part that is destined to fail at some point on the 7.3?

Is it your advice to remove the tuner (it isn't a chip, it was uploaded into the computer by way of the port below the steering wheel inside the cabin)? Before I do that, I'd like to instruct my mechanic to try some other less invasive avenues.

In order of likelihood, can you (or anyone else responding to this) list the top five most likely causes of this phenomenon? I've got to think that someone else in this forum has experienced this exact problem.

Lastly, I don't understand your acronyms... IDP? Please spell it out for me.

Your help is greatly appreciated!

Pat Hurley

 

Will the SC display codes? Yes, as I mentioned, remove the tune and then troubleshoot. As I mentioned before, others have had your problem and fixed it but you must give them time to see and respond.

If you do not have a spare CPS, get one and see. If it does not correct the problem, you need one in the glovebox anyway because they are prone to failure.

Do a search for surge issues and be prepared to read a lot while you wait on those who have had this problem.


Also, removing the tune is not at all invasive. A simple flash tune as opposed to removing a physical chip. Unfortunately, if the tune is worth anything, your truck will seem to run like a dog in the stock tune. Since you bought it that way you will think you really have problems. You will just be checking to see if the surge goes away.

 

Don't know where you got IDP. Injector Drive Module and Injector Control Pressure are the sensors I was referring to and they are the sensors that the computer uses to control the HPO or high pressure oil system that actually drives the injectors when they are electronically activated in order to inject the fuel. These devices, along with a couple others depending on the chip/tune is what are manipulated in order to make power. When they operate beyond their design parameters, they sometimes fail.

 

Is it true that if you have a tuner in your 7.3 that you can't rely on the accuracy of the codes you get from the computer? So, without reversing the tuner there's no way to know what the true codes are?

Since I'm not mechanically inclined, I had a after market guy put the tuner in. I've since moved. Who could I turn to in order to properly reverse the tuner?

I really wish there was a directory of Power Stroke mechanics so I could turn to sombody trusted locally who didn't work for a dealership! Does such a list exist? Does anyone know of a Power Stroke expert in South Florida (name and number, please!)?

I've got to tow my travel trailer across country in early February and I've just got to get this blasted surging/hesitation diagnosed and fixed before then or I'll go nuts.

Thanks for your input and theories!! Keep it coming!

Pat Hurley
Fort Lauderdale, Florida

 

Codes are codes wheather you are running a tuner or a chip but when you go to start diagnosing problems it makes it hard to be sure if the aftermarket device is causing the problem or the actuall part. If it is a tune that was put in you can get a reflash from Ford or DP-Tuner, If it was a chip he put in it can simply be removed.