Hey folks I have another question,

I just got a new to me 97 powerstroke. The truck has 223,000 miles on it but in great condition. I don't know much about the history of the truck other than it had the trans replaced about a year ago and that it appears to have been taken good care of.
I have been reading quite a few threads about similar problems and have tried a few things but it still seems to have this intermittent problem.

Here is what it does, it runs great under power and will run about 15 lbs of boost under full throttle. When it is in drive and stopped, it seems to idle fine. When I go from drive to park it will idle rough for just a few seconds and the smooth out. The other day I left it running in the driveway for a few minutes and when I came out it with idling rough and had a slight serge. As I drove to work yesterday and I noticed it would surge a little at steady throttle cruising at around 35 mph. Any throttle change and it would smooth out. Today it ran good coming to work.
Here is what I've done:

Changed oil & filter (Dello 400 LE, motorcraft filter)
Changed fuel filter and cleaned FPR screen (it was clogged)
Cleaned recharged K&N air filter.

I was told the truck does not use any oil and it appears to be true.
The rough idle from drive to park is consistent when the truck is warm but the slight surging only happens once in a while.

Any thoughts on this one? I'm still learning all the acronyms so be gentle.

Thanks

 

Well, one of the first things people are going to tell you here is to dump the K&N filter.
Just a heads up for you.


The horrible thing is, I cannot quite remember what the issue is with your truck. It's right there, and its just not coming forward.

 

william, i'm the same way. i remember a problem with the shift range selector or something like that causing trucks to idle weird when shifted from drive to park, but i can't remember!!!!

dixokai, when the truck is "surging" or idling rough at idle unplug the ICP sensor(injection control pressure). it is on the driver side head towards the front of the head. its got a 3 wire plug in it. just unplug it and see if it smooths out. if it does then you need a new sensor and they are $196 at ford

 

Yea, I'm not a huge fan of K&N either but it was already in there so I thought I would use it. My opinion has always been that they are a maintenance item that needs attention and are often neglected, I've seen my share of "dusted" engines with them but if properly maintained they are a pretty good system. Is there something else I should know about them and these engines? I won't hesitate to ditch it if it is in question.

Thanks for the responses Any others?

 

Dusting the turbo can cause a fin to break and quickly destroy an engine. Look at the compressor wheel of your turbo and see if the fins are nicked on the edges. I'm not sure about the other problem. Does it puff a little smoke when it gets rough? Know if the under valve cover harnesses have been replaced? Injector orings still original? If you remove the fuel bowl and the fuel had a faint blue tint, that is one sign of bad injector orings but they could still be bad even if the fuel isn't tinted.

 

I think I was misleading on that last post, This engine is not dusted I just agreed that a non maintained k&n will dust an engine. My intake system is very clean and the compressor wheel is in good shape. I was just wondering if there was some other reason I should ditch the k&n other than they need to be well maintained? Sorry about the confusion.

 

Most folks agree that the K&N seems to allow more crud into the intake tract.

I haven't used a K&N on my diesel. I swapped out the stock air box and filter for a NAPA 6637 (6637 mod) attached to a 4", 45* exhaust elbow attached to the stock intake hose. She breathes much better now.

Have you checked the fuel pressure at the regulator? Normal should be around 40 - 80 PSI at idle. If you're low, search for 'FPR Shim' and you'll get some good information with pictures.

 

Mine does similar things at idle. I'm not sure yet as to the cause. But I'm pretty sure it's inconsistent fuel pressure. I'm going to to go through the system fully once and see what happens. Then go electric if I'm not happy with it. But it certainly could be something else. With an engine with that many miles on it the HPOP could be marginal. Injectors and or o-rings are a possibility.

 

I'd try the IPR sensor that he was talking about.
or ICP, whatever he said.

Anyways.
The thing with K&N filters is, and pretty much all filters, is they dont actually filter very good untill they are dirty.
The holes in the K&N's are so huge they just let dirt go right past.
I tested it on my 95. I sprayed oil in the intake tube to see if it would collect dust, and it did. So i stopped cleaning my filter as much.
With the 6637, you have so much surface area and a tight filter, you'll not have to worry. It's worth every penny.

He wasn't talking about the engine being dusted.
Remember, you have a turbo. it see's everythign that comes though the filter first.

Take the boot off and climb in the engine with a flash light and look at the blades on the turbo.
They should be almost sharp enough to cut you. If they look sand blasted, or have lost their "edge," then your turbo is getting sand blasted by all the dirt it pulls though the K&N.
Not to mention all the leaks from the stock box.

K&N's are awesome filters, but I would never use one on anything with a turbo.
I would buy one for a gasser again though. That filter is on its 3rd truck now.
I baught it for my 91, and moved it to my 95, and gave it to a truck club member who put it on his 96.

 

the deal with K&N's dusting the turbo i think is a combo of the filter letting a little past and the filter box not sealing good enough and allowing air to pass. this is why we automatically do the 6637 to these. check your fuel pressure and the ICP. the fuel pressure regulator is on the driver side of the fuel filter bowl and has a shrader valve on it. it will most likely have a black cap screwed onto it. put a rag under that valve and check the fuel pressure using a cheap tire pressure guage at idle. at idle you want the pressure around 60-70, but stock it should be in the 50's. if it's not in the 50's at least, shim the fuel pressure regulator. so try that and try unplugging the ICP as well. i think one of these 2 things will be your issue. most likely the ICP. let us know

 

OK Thanks for the info guys, I have some more information now. I ran the truck on a Snap-On scan tool and this is what I found. A couple of codes came up.

P1280 ICP circuit out of range low
P0470 exhaust back pressure sensor malfunction

These other codes I don't know what they mean

C19C0
B1C00
U21C0
U3380
U0880

The P1280 may have come from when I disconnected the ICP for testing. When I did that the RPM jumped a little and then seemed to run the same. Another thing it is doing is at a steady throttle it will stumble every 10-15 seconds and then run good and repeat it over and over. No real pattern it's kind of random. It does it when in park at any steady throttle position also. Run good and stumble, lose a couple hundred RPM, pick up and run good. It runs good when under power.

Other scanner results:
HPOP pressure- 580 lbs at idle 2750 lbs wot. (Only had 1/2 block to run)
Boost 15 lbs max (same 1/2 block)
cct showed no faults.

One thing I keep neglecting to test is the fuel pressure. Hope I'll get to that tomorrow.


Thanks for the help so far, any other ideas? Do you think I need to change the ICR? I think that code came from me unhooking it. I'll check it again and see if it came back tomorrow. There is no CEL on. Oh, I think I'll ditch the K&N and go with the 6637 mod.

Thanks folks

 

I only have the P0470 code now, Still waiting to check fuel pressure. If fuel pressure was low I wouldn't be able to make boost at WOT would I? As with most diesels, no fuel, no boost. For some reason the idle seemed to settle down but I still have the stumble at steady throttle. and steady cruising at slower speeds. It's not noticeable at highway speeds (50 mph or up). The other this thing does that I'm starting to think may be unrelated, is when going from drive to park the engine runs rough for just a few seconds and then smooths out (only when warmed up).

 

The 0470 code seems to be an exhaust pressure sensor error. Check it out!