SOMETING HAPPENED, IP ADVANCE ?

[MrMarty51]

Last evening, turned the key to run, waited for glow plug lamp to extinguish, I fired up the engine.
Upon starting, the engine did a funny little hickup, the SES lamp illuminated and the engine went to a faster than normal idle.
It used to idle at 650 RPMs and it now is idling at 750.
I can not get to a code reader until after the parts stores open, about 7:30.
Just thought I would throw this out there in case anyone has had similar experiences nd wht the remedy might be.

 

[JayTheCPA]

Getting codes is a good place to start

Aside from the idle change, the description seems to match a TDCO re-learn.

 

[MrMarty51]

Getting codes is a good place to start

Aside from the idle change, the description seems to match a TDCO re-learn.

Do they automatically do that from time to time ?

 

[ak diesel driver]

Not supposed to. Never changed on my 96 but it has on my 99. Still scratching my head over that one.

 

[MrMarty51]

I`ll get to the parts store as soon as they open in just a little while, gettum codes and check back in. LOL
I do hope it is nothing major.

 

[MrMarty51]

I started the truck for it to warm up a bit before driving to the parts store. The idle was back to normal just above 600 RPMz.
P0251 was the code. I cleared it and the truck is running just fine.
When I did a search for code P0251, one of the first to come up was an old thread from here.
I hope the code does not come back, if so I will try replacing the optic sensor before condemning the pump.
Here is the thread.
http://www.thetruckstop.us/forum/threads/p0251-injection-pump-cam-code.2486/

 

[ak diesel driver]

for testing purposes with the engine off unplug the optic sensor, start the truck, it will take an extra long time to start and when it does it will be in limp mode. If it starts that tells you the crank sensor is working. do the same procedure but unplug the crank sensor to test the optic sensor

 

[ak diesel driver]

might just need to do your magic on the connectors too.

 

[MrMarty51]

for testing purposes with the engine off unplug the optic sensor, start the truck, it will take an extra long time to start and when it does it will be in limp mode. If it starts that tells you the crank sensor is working. do the same procedure but unplug the crank sensor to test the optic sensor

I will have to give that a try, if it ever trips that code again.

might just need to do your magic on the connectors too.

Yeah, I cleaned all the connectors at the back of the engine, just never messed with all them connectors arounf the IP. Guess I should not leave a job only half, or less, done. LOL
Guess I will run the truck in and get after those connectors too, seeing as how I am not working today.

 

[MrMarty51]

Several startups later and the code has not yet returned. Put about 60 miles on the truck yesterday and it ran as good as it always has.

 

[WarWagon]

Fuel quality can affect the sensor. Air in fuel is a big one. Any fuel additives that you are running? Verified lift pump working?

 

[MrMarty51]

Fuel quality can affect the sensor. Air in fuel is a big one. Any fuel additives that you are running? Verified lift pump working?

I have been fueling at the Cenex and using their RoadMaster fuel, they sell a lot of that.

Running with the Stanadyne diesel fuel additive. Poured from a bottle with the measurements and sight on the side, always put in according to how many gallons I figured it will take.
I`ll have to check the lift pump, It was new just before I bought the truck, I looked at it a while back and seen the brand name but dont rememer what it was, It is an aftermarket and I am believing it is one of the better ones.