Hi:

I'm at my buddy's shop right now and he's having problems troubleshooting a problem with his 2001 F250 XLT truck. The truck is a diesel, with a 6 speed standard and air conditioning. 176,000 mi on the clock.

His issue is this: The truck has an intermittent stumbe (sometimes stall). It's very random. Sometimes the check engine light will come on, sometime it wont. We've attached a snap-on scanner, and it shows no codes at all.

We spoke with Ford and we were told to check for some sort of loose bolt on the back of the fuel filter assembly. It's tight, with no leakage.

Just some more info... we've been enjoying a week of -14F temperatures. Don't know if this is contributing or not.

Any ideas? Neither one of us are diesel savvy either... might be part of the problem

 

Does it just do this when u start it up or just randomly while it is already starting.
Do you plug it up at night or when its not running?

 

I'll guess the Diesel fuel is starting to gel at those temps. Does he add any anti-gel to the fuel? Diesel Kleen in the white bottle would help if it's the fuel gelling.

 

Well, we found out the block heater is cord is toast. We're in the process of replacing it now.

The truck only has the problem then it's already running, never on startup.

Also, we're using anti-gel chemicals in the fuel as well.

Also, just to let you know, the day the truck was really acting up it was -32F that day

But, he also tells me that the truck was also doing this month or so ago when it temperatures were in the low 40s

He also notices that often, but not always, the truck will stumble when you turn the wipers on of all crazy things.

He's threataning to buy a Chevy, but now realizes that that would just never run at all...lol

 

Thread moved to the 7.3 forum...

You'll get lots more answers here

Isn't there a CPS that goes bad?

 

https://www.ford-trucks.com/forums/5...-stalling.html

 

What is a CPS and where is located?

And one more question...diesel newbie that I am, is there such a thing as an IAC on a diesel?

 

What are you refering to on the IAC? we have an AIC - Aux Idle Control (High Idle)

http://guzzle.rbmicro.com/cps.html

 

Idle Air Control solenoid. I'm probobly out in left field.


Maybe another question too. If the CPS was bad, will you always get a code, never get a code or sometimes get a code when we read the codes with a scanner.

 

It might be the CPS going south, my truck has done this once in a while, just driving along, pull up at a stop light and Blagh, dead. Fires right back up though. I would at least get a spare to put in the glove box, just in case. I haven't changed mine yet but I am prepared. Also I don't think you get any code, I haven't seen one on mine, and from what I have read on here I don't think you get one. It has been said on here that to watch the RPM Gauge to see if there is any movement when you crank it, If not then it is a sign that the CPS is going bad, my gauge has never moved during cranking since I learned about it over a year ago, so I don't know. Just my .02.

 

No on the IAC

Sometimes the CPS will set codes P0340, P0341, P0344 and sometimes not. It has to occur a certain number of time in a single drive cycle to set a code so when they are intermittant the code is not always set.

 

Could you be referring to the AIH or Air Intake Heater?

 

No, definitely not. I was trying to make a comparison with a part on a gasoline engine that apparently doesn't exist on a diesel

 

Well gents, the symptoms you are describing certainly sound like we need to have a look at the CPS sensor. We're trying to get the truck to stumble with the scanner on it to see if we get any codes, but who knows if it will act up. It's in a nice warm shop now.

Anyway, since everyone seems to agree that we might not get a code, I'm going to tell my buddy that he should probobly take a look at the CPS sensor. Clean the contact and check for work or frayed wiring to the sensor.

If all looks, good, should I tell him to buy one and try it? I know it sucks buying parts just on a whim, but what you guys are saying sure seems to be what the issue is

 

Hey, they're $50-60 on EBay. Most folks here have a spare. They suck. You cannot really test them aside from pulling them out and re-installing them or reseating and checking for obvious frays in wiring or a bad connection.

At worst, you will have eliminated the most likely culprit and can get on with the troubleshooting and have a spare. Best case, problem solved, and time to get another CPS to have on hand. It definately sounds like the CPS is faulty.