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2000 7.3L miss and it is not the CPS!

5K views 29 replies 6 participants last post by  klhansen 
#1 ·
Hi! I'm really hoping for a little help here!
As the title implies, I have a 2000 PSD 7.3 / F350 Automatic that has rather quickly started missing. It seems to only do it when idling. If I touch the throttle, it goes away and sometimes it goes away on it's own. I can't tell if it is a miss which then makes the engine speed up next time it fires or what it's doing for sure. I changed CPS's and no difference at all. The wiring harnesses all LOOK good on the outside of the valve covers. It does this with and without any type of tune. The only DTC is P0603, something about an active memory. I read this with a Bully Dog GT that it came with, though presently no tune installed. This all seemed to occur out of the blue and no connection to anything I have touched. It does it mostly when it's warmed up.
I THINK I attached a sound clip. It is in a zip file and should play as an mp3.
Thanks, Dave
 

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#2 ·
The easiest thing to do would be to run a cylinder contribution test. Once you narrow down which cylinder is acting up, you can explore further. If it was electrical, it would throw a code. It could be a fuel injector, cylinder compression, or one of several other possibilities.
 
#3 ·
Thanks for the reply! I have the diagnosis check-up coming tomorrow or the next day. I also meant to say that the truck doesn't smoke at all when it has it's problems. I have no reason to suspect anything mechanical, but I have been around way too long overlook the obvious. She cranks very good and has plenty of power.
There's a guy local out here that is quite good!
 
#25 · (Edited)
Did you ever get the results from the diagnosis at Henry's?

History of your posts:

Unplugged original ICP sensor and it ran smooth unplugged.

Changed out the ICP Sensor with a new one and it ran good for a while and then went back to having issues.

Unplugged new ICP and it ran rough unplugged also and then plugged it back in and now it runs smooth.

.
 
#5 ·
I just did. That almost sounds like the romps. I wouldn't be surprised if the ICP sensor is the issue. Unplug it and see if the idle smooths out.
 
#6 ·
OK! I'll give it a try tomorrow. It's about 26* outside right now. To be clear, that is the sensor that screws into the HP oil gallery in the head? Is that what the ICP sensor would control? I have a Bully Dog GT and it reads the HP pressure and it SEEMS to read roughly what it should from what I have read. Per the gauge, it seems like it idles with around 700 psi or so, and then it climbs right up to around 2000 psi and higher when running down the road.
But if it were incorrectly reading pressure, it would also be incorrectly read on the BD tuner and the ECM / computer with respect to actual pressure, correct? In other words, the truck would have no way of knowing if it really was the right pressure other than what the sensor told it, right? The pressure could be way off and the truck wouldn't know it if I am understanding things.
Thanks for the assist, by the way!
 
#7 · (Edited)
Yes the ICP is on driver side head screwed into it and read pressure of the oil in the head. By unplugging it, it will set the PCM to default mode witch is 750 psi (I think)

IMO don't trust the reading on the bully dog, i had bad experiences because i was counting on those reading but they where off.

(Don't forget to put the truck back to stock before troubleshooting it might be the BD who giving you trouble)

Again IMO after you fix your problem, get rid of the BD and get a chip with custom tune, good set of gauges and AE for troubleshooting


Sent from AutoGuide.com Free App
 
#8 ·
OK! Bingo on the ICP Sensor!
Unplugged and it smoothed out instantly. Does this for sure mean that is the problem, or is it masking something by making the thing run in a 'limp home mode' or default?
However, I was fully assuming there would be no reading of HP oil on the Bully Dog, but it was still reading and changing per rpm and load.
How can it do that with the ICP Sensor unplugged? Where else would it be getting a reading from? Per all the pics I have seen, it is the ICP sensor I unplugged and the CEL light came on of course. Is the BD tuner just guessing?
I have heard there are better tuners out there than the Bully Dog but it came with the truck, so it got put on just to try.
I did completely remove the BD tune from the truck as well.
Thanks for the tip on the ICP Sensor!
 
#11 · (Edited)
If you choose to stick with OEM :ford: then I just priced the ICP at AutoNation Ford White Bear Lake for $133.

There are some cheap after-markets but I have read those are a crap shoot.

Also, its important to inspect the pigtail connector to the ICP. Its common for oil to find its way into this connection from a failed ICP (very high pressures) and if oil is present in the pigtail then it needs to be replaced as well.

Good luck.
 
#10 ·
Not sure how the BD take is info but it is not accurate at all. I ditched it and bought a hydra chip with PHP tunes. But if you want a programmer I think the edge is a good one (never use it myself)

For ICP if I remember the best one are Aliant buy not sure, i bought one of ebay 3 years ago for 60$ and im surprise it still good


Sent from AutoGuide.com Free App
 
#12 ·
OK then!
So to be sure if I unplugged the ICP sensor and it instantly smoothed out, does that definitely imply it is bad? For the price of one, I would like to be as sure as possible.
Was that Alliant brand sensor purchased over the counter or mail order? I need to get one locally if possible because my truck decided to do this when my car is down and the license tabs on the truck are due, along with an emissions test (of course, why not?) in a week and a half so it will be that Alliant brand or down at Henry's garage.
Would one from a '95 PSD be the same? Come to think, I could trade the one from my other truck before I sell it. At least just to try, I guess.
 
#14 ·
That makes perfect sense to me. That is exactly what that hombre is doing! It acts just like as you say that almost misses once and the very next time it fires seems like a 'harder hit' that I can hear, just as in the sound clip I sent in! It explains why the scanner / programmer is still 'reading' HP pressures. That's the one that threw me off. I figured that the computer had a default pressure that it would use, but I didn't figure there would be a way to see it on the scanner.
So that being said, is there an accurate way to read ICP, short of installing an actual gauge? Or, is it that important to know as long as it is running OK?
Thanks to all, by the way!
 
#15 ·
The gauge is the only way to verify actual pressure.
 
#16 ·
Got it! Those threads for the sensor, are they something called 'JIC' threads as in hydraulic fittings? I actually have a hyd. pressure gauge I have used for my tractor hydraulics and I suppose I could just 'Tee' that in? The gauge is good for 5000 psi which should be plenty I assume.
So, another question:
Does the HP pressure change only with RPM, or is it load dependent? I don't think I have a hyd hose to bring the gauge into the cab, in other words.
Don't mean to drag out what I am sure is a simple subject, but I like to know exactly how things work!
 
#17 ·
Yes - the PCM modulates HPOP pressure depending on the load of the engine. Its basically an indirect way of increasing fueling. Increased pressure and increased injector pulse width increase fuel. Fuel needs go up with increased RPM and even more with increased load. The 5000 psi gauge is perfect for this, but I'm not sure its necessary. Swapping the ICP sensor after the test you already ran is an acceptable practice.
 
#18 ·
Alrighty! I just got done drawing blood trying to get the one out of my other truck. I'd just have to put it back so I'll go find a new one then! Actually, the whole thing seems pretty ingenious in the way it works. Lots to go wrong I suppose, but they seem to be pretty reliable! I just remember the first time I looked under the hood and realized there was no throttle linkage - or an injector pump like my 1st oiler had (which I really did like, I have to confess!).
Thanks for the pointers. I'll post how it all works out!
 
#19 ·
OK, replaced the IPC sensor and made sure the connector was spotless without oil on it, which it did have due to the old sensor. I have a new plug for it but didn't install it.
Anyway, as expected it ran really nice. Quiet, smooth and lots of power. But then, like flipping a switch it started missing as before only much worse. And now it is noticeable under a load. I unplugged the new sensor and it stumbled and smoothed out, but it didn't go away at all. It was nearly undriveable by the time I got it home even with the IPC unplugged.
Also, it would sporadically smooth out and run quiet. Then instantly stumble and miss along with being very loud and 'rattley' under all throttle positions. With my foot off the pedal, it would try to idle but very rough.
Then the odd thing was when I stepped on the acc pedal at all, it acted like I gave it about 1/4 throttle instead of being even acceleration. If I understand, there is an 'idle switch' in the pedal and the way it acts is that just off idle that switch tells it to accelerate by just touching the pedal
Now I did change oil about 1500 miles back, but I used Dello 400 which I have used in the past on other PSD's with no trouble.
Long post I know, but I wanted to get all the symptoms in one post!
The sound is very similar to the sound clip I uploaded in my first post, only worse by far!
I really don't know where to turn next on this hombre!
Any help at all is appreciated for sure!
Thanks!
Dave
 
#20 ·
OK, replaced the IPC sensor...
Anyway, as expected it ran really nice. Quiet, smooth and lots of power. But then, like flipping a switch it started missing as before only much worse. And now it is noticeable under a load. I unplugged the new sensor and it stumbled and smoothed out, but it didn't go away at all.
How many minutes after starting the cold engine did it start missing?

Thanks
 
#21 ·
I'm going to guess and say about 5 minutes from when I replaced the IPC. But, it wasn't completely cold either. It seems like it started when the oil temp was around the 100 to 110* and it seemed the warmer it got, the worse it got.
 
#23 ·
I just started it up and it still is having problems, though maybe not quite as bad as when I drove it home fully warmed up. Just now, the oil temp was 115 to 120*. Idle is fine, but higher RPM is progressively worse the faster it goes.
 
#24 ·
A short follow-up to the problem: Today I started it up with the ICP sensor unplugged and as expected, it ran pretty rough and missed more the faster I revved it up. For the heck of it, I plugged the ICP sensor back in and the thing now runs like the day it was made! Really annoying and worrisome because I have no idea what was, or is wrong with it. When will it do it again, for example.

I am wondering if it is possible that there was a little chunk of crud in the IPR valve that for whatever reason, cleared out when I plugged the ICP sensor back in? If I take the IPR apart, I wonder if there would be evidence of debris in it? If I recall, there is a screen in them that can be cleaned but is there any other places to clean out that may release more crud?

Anyway, I have learned a lot from the people kind enough to respond to my issues! I guess until it does this, or something else again, the problem is solved. Just wished I knew for sure!

Thanks to all!
 
#26 ·
#27 ·
OK. This is a little late, but I did say I would post the outcome and solution for the problem I had with my truck.
Basically, the ICP sensor was bad and yes, there was oil in the plug / connector as well. I installed the new sensor and after very thoroughly cleaning the connector with starting fluid and elec contact cleaner, I plugged it in and it ran just fine.
During all of this, both with the original sensor plugged in and unplugged, the truck would still act erratically.
The general thought was that it was definitely an HP problem, though not the pump.
After installing the new sensor, it ran very well for a few days. Then, once again it suddenly started in doing the same thing to the point of almost being undrivable. Luckily I was near a parking lot. I left it running and unplugged the ICP sensor once again and it smoothed out. I plugged it back in and it still ran smooth.
So, all of this was the result of two basic problems:
1 - The ICP sensor was bad. It was leaking and sending a false signal (apparently) as well.
2 - I am quite sure there was some debris in the IPR valve that was causing the HP to be very erratic. If there was in fact anything in the IPR valve, it has cleared itself out because the thing has not missed a beat since.

I would like to thank everyone who chipped in with ideas and advice. It would have been in the shop otherwise!
Thank you,
Dave
 
#28 ·
Try running a bottle of archoil 9100 to clean the oil system out.
 
#29 ·
if it does it again, i suggest you change the ICP pigtail. sometime just cleaning do for a bit but it may come back
 
#30 ·
X2. The fact that you've been messing with the ICP harness makes me think that there's an intermittent open/short in the wiring, aggravated by engine vibrations.
 
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