Have a early 99 450 sd. Surges at idle enough to stall out. Sometimes if I play with the throttle it will smooth out for a few minutes then start again. I have replaced the icp censor twice just in case the first one was bad. Replaced the ipr. Replaced the cps. Dropped the tank cleaned the filters. Replaced the fuel pump. Replaced the ebp tube. New oil motorcraft. Truck ran good befor it started never even had to plug it in during winter. I checked as many wires as I could. Did not find any bare spots. When the truck starts it will sometimes die at the bottom end of the surge. While it is running if I trip the fuel cut off it stops surging and ideals like normal for a wile. Bought a bidirectional scan tool. Dose not work I'm assuming because there is only 7 pins. What would be making my truck do this.

 

[QUOTE=dougelehman;19819078]Have a early 99 450 sd. Surges at idle enough to stall out.

There is a fuel pressure regulator at the fuel bowl (on return side I believe). That is a common enough problem that there are several posts about this - namely change it when you have a chance before it turns into a prob. As others will mention, hooking a pressure gauge on the bowl would indicate if oscillating pressure is the culprit.

 

Howdy. Welcome to FTE!

There are still a lot of questions surrounding your issues which will need data to correctly move forward.

Have you checked the fuel pressure? I know you changed the pump and cleaned the screens but it could still be FPR related or fuel bowl stand pipe. Here’s a link to an easy method to check. https://www.ford-trucks.com/forums/a...4&d=1592859516

Your issue really puts me in mind of some recent threads on here regarding ICP. My first thought was bad IPR but you state you have changed both of these. First off, around here everyone will say you need Motorcraft parts for these particular items. Now if the truck acted exactly the same with both then we will assume it’s not related to a possible bad replacement part. But it could still be in the wiring. Your best bet is to get a monitoring tool so we can see what the truck is seeing. There are some dongle choices in this thread. Most folks will end up going with forscan for the software side. https://www.ford-trucks.com/forums/1...d-q-and-a.html

Both of those links came from the tech folder “sticky” thread located at the top of the forum. Take a look around in there for a wealth of information. https://www.ford-trucks.com/forums/1...-7-3l-psd.html

 

RacinJason I agree with everything you said...but unless the OP has access to a Live Diagnostic Scanner..( I have a Snap-on MT2500 and AutoTap and Autoenginiuty with their laptops ..all work good....The Snap-On and the AE have the best tests...Injector Contribiution and Buzz Test...Also the Snap-on Read IDM codes the others did not ... I have re -done UVC harnesses a few times due to Bad idm's ...Both my Trucks have very new wiring becuase of this issue......trust me ....3 things a Diesel needs to run .... clean Air.....fuel and the Compression Ratio of the Engine specified by the Factory....Thats It ....Hey I am a 2 Stroke Big Block Guy at heart...BUT I have embraced Diesels..... i love it .....Only difference was the scanners and 3/4 drive set of tools ..on the repair side ..I always had Heavy Trucks...Haul the Bikes to the Track....

 

Actually AE is old tech. If you have experience with ForScan you'd realize it does the tests you bragged about AE being able to do

As to curing the surge, have you tried it without the ICP plugged in? Have you unplugged the fuel bowl and replaced fuse number 30 under the dash?
Have you cleaned all the sensor plugs with electrical contacts cleaner?

 

I did not brag about anything ....Most of the tests I did were with the Snap-on...With the other stuff you could modify your test screens when you were recording live data....to realize what the parameters are and what they should be... Why is that bragging ? Just because I did actual tests ?
My Trucks run like a T444E is supposed to .....I am trying to help the OP... AND what is wrong with old tech ? did it stop working all of a sudden ?
Nobody Told Me ....

 

Well I apologize if I missread your words. However by you saying
"but unless the OP has access to a Live Diagnostic Scanner..( I have a Snap-on MT2500 and AutoTap and Autoenginiuty with their laptops ..all work good....The Snap-On and the AE have the best tests...Injector Contribiution and Buzz Test...Also the Snap-on Read IDM codes"

You stated you were in disagreement with ForScan as being a "live diagnostic scanner" and implying it is not able to by stating:

"With the other stuff you could modify your test screens when you were recording live data....to realize what the parameters are and what they should be."

It sounded as tho you had not used ForScan, otherwise you would know it can do those tests as well (along with the GEM codes and tests, ABS codes and tests and flush procedure, and calibrating the speedometer for different gears or rims) as well.


At just $5 for the app and around $30 for a Bluetooth reader, or the free version of the app that uses a usb to laptop connection, it is much more affordable for the casual DIYer coming here for help than the very expensive AE or SnapOn which does the same tests and data logging for 200 times the price

Old tech may still work, but it's way too overpriced compared to the new days of smartphones and tablets


Not trying to offend. Just stating facts

 

I was not disagreeing with anything..... and never said that Forscan was not able to do it ....I was just saying what I use ..I fix all of my vehicles myself ..Including my Kawasaki Superbikes...Expensive to me is relative... a Ferrari is Expensive ..... My ELR KZ1000R is expensive...My FORD Trucks..Not so Much.....But I put expensive parts in them...I always Install the Best Parts.....And have the Diagnostic Tools ...and they run like clocks.....always reliable..every day ...I have never used Forscan..why would I ? All the stuff you mentioned is easily calculated with grammer school math ....I rebuild Laptops as a hobby ......AND Nothing is Free ....

 

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