When I’m driving the truck under 50mph, at almost any moment the truck will drop down to less than 1000RPM and will run roughly. The check engine light will come on and will stay on unless I take my foot off the accelerator for about 10 seconds. During this time the engine runs rough and slow and it will not accelerate when I give it some throttle. It especially happens when I come to a stop after driving a little bit. What’s the deal? I’m going to try to post the video.
Whats the history of you ICP & CPS? I had similar symptoms with a failing ICP.
Reading the codes is the best step forward but if you don’t have a scanner you could try unplugging the pigtail from the ICP and look for oily residue. The engine will still run fine with the ICP pigtail unplugged. If running unplugged stops the issue then you need to replace the ICP. If there is an oily sheen in the pigtail connector then you need a new ICP.
Best to use genuine Mototcraft parts based on forum feedback.
Thank you sir, I will check the ICP connector and CPS. I've never changed them out. Earlier I mistyped and meant to write it will drop from anywhere up to 2100RPMs to below 1000RPMs.
Hopefully you can find a Ford compatible scanner and get your codes read. That way you won’t just start throwing parts and $$$ at it.
But I just mentioned a couple things that can help you diagnose until you have access to a scantool that can read Ford codes. (Most generic scanners from the local auto parts cannot read Ford).
Also, if your ICP is the “old” design on the left then it is due for replacement even if oil is not present in the pigtail. Those old style are reaching maximum life and have increased risk of leaving you stranded roadside.
Since I replaced my ICP I didn't have problems for a while, but then the problems resurfaced: loss of power even at high speeds and low speeds and idling. I replaced the ICP again, but it is obviously not the problem since the problems have persisted after the 2nd replacement. I'm thinking it's the fuel screen being clogged or a dying Fuel Pump. What do you think?
My guess is CPS since you never mentioned ever replacing it. Every 7.3 owner should have a spare one in there glove box, since its so common a failure. Does exactly what you mention and is why RT mentioned it. Take a good look at the CPS plug as well. Its known to be an issue as well. The three little squares were the pins go into, if they are not closed, meaning the pins must push them open. Then the plug is toast. If it has black or green or white goo in there too, its toast. A plug and pig tail are cheap, use the whole pig tail to get past the brittle wire at the front of the motor. It gets you all the way up to the fuel bowl. Hopefully your in the US, because the only real good CPS is Fords. Up here in Canada they want 360 bucks for one. Less than half that in the US. Order 2. One for the glove box.
The engine never shuts off completely, it only runs rough with the engine shaking a lot especially at lower speeds and a huge loss of power which makes me think that it is not the CPS. Although I know it wouldn't hurt to replace it.
Check out this link: this is exactly what it's doing.
I changed out the fuel pickup foot inside the tank and the issue didn't show up for three days of driving, but I started it up yesterday after having been running it an hour prior and it immediately kicked back into this. I haven't changed out the CPS yet but I have one ordered and I'm going to replace it on Friday.
So it ran great for 3 days?
Then it ran great for one hour and then it had the return of the issue in the video?
The video appears to show good RPM response immediately after starting but then idles down and stumbles in gear and then in Park.
It doesn’t do any harm to swap out the CPS as long as your new one is either genuine Motorcraft or IH since its only a $40 gamble and every truck should have a spare in the glovebox anyway.
But I think CPS failure usually results in killing the engine.
I sure wish you had access to AE and could monitor various paremeters.
you're right, I wish I had one of those AE things. I'm dropping it off at the shop next Wednesday to get fixed that is IF they can figure out the problem (I've been dealing with this issue for over a year and a half now).
A few updates: drove it yesterday and it was just fine. The day aforementioned in two or three comments ago by me, it ran fine when I started it up and drove it for 40 minutes. When I came back to the truck after it had been sitting for 45 minutes, I tried to start it up without even letting the WAIT TO START light go out and it instantly went into the reduced power (with shaking).
Another interesting thing to note: it's 70-80 degrees out here and the truck has never started on the first crank but it will on the second crank if the second crank is just after a few seconds of cranking it the first time. Could these problems be interconnected?
UVCH loose.
TPS problem.
Various sensors mentioned.
Is it a shop that specializes in Ford diesels? That would be your best bet that they will recognize the issue quickly.
Where do you live?
Maybe someone here can suggest a good shop.
Has to be very frustrating to have had this occur so long. These 7.3’s are usually so dependable I have bought them and immediately driven to AK or FL. Yours should be the same.
I don’t know what they specialize in. I live in Annapolis, MD. I drove it from MD to Nashville and back just over a month ago and it gave me no issues on the road except for once, but it went away.
I had a similar issue but mine got so bad it would actually kill the truck eventually was a bad tps/gas pedal best way to check is to set the cruise control if it drives fine with the cruise chances are it's the tps
BLUF: the problem has been solved. They replaced the Injection Control Module and about $400 later in parts and labor, they truck is running!
I didn’t want to write immediately because it has happened in the past where it will be fixed for a month or two and then all the sudden it starts doing it again. Well those days are over!!
As it happened, he repaired one injector that was sticking and he replaced another one completely and he thought that was the issue— it wasn’t the only issue.So he drove around the truck for about an hour before his computer started getting codes and my truck started acting up.
Thanks for all the help guys!
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