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7.3 Romps When Warm...No Throttle Response

6K views 9 replies 3 participants last post by  Pullnpray 
#1 ·
Hello to all of my fellow Powerstrokers out there!
Luckily, I haven’t had many problems with my 99 7.3, but now I have an issue that renders my truck not drivable. So to the forums I go…
After the engine is warmed up, it starts romping…just like when you first start it in cold weather. Also, there is NO throttle response. It will run fine after it cools off 30 minutes or so. I had to use the truck yesterday and it worked out ok, because I never let it idle down. When I had to stop, I put it in neutral and kept the revs above 1500 rpms. So the problem appears to be related to loss of oil pressure to the injectors when the oil is warm and thinner. By keeping the oil pressure up with reving the engine, I’m maintaining enough oil pressure to fire the injectors. By the way, I let it idle all the way down after I made it home and once again, the engine started romping with no throttle response.
My new Auto Enginuity scanner should arrive today. This will be the beginning of my Powerstroke self education course and hopefully before too long, I’ll be able to talk the talk with you Powerstroke gear heads out there!
Any suggestions as where to begin looking with my scanner would be greatly appreciated and thanks in advance!
 
#2 ·
I received my AE scan tool today. I had limited time play with it. The only readings it's showing is RPM, Manifold Pressure and Vehicle Speed. Where's all of the sensors that should be on the drop down selection list?
By the way, I did start the engine and it does display the RPM and Manifold Pressure readings.
I'll get back on it a little later.
Any ideas?
 
#3 ·
The Ford Enhanced package will not activate. I've re-entered the activation code several times and rebooted computer while connected to the vehicle. I guess I need to give AE a phone call.
 
#4 ·
ok...got my scanner working. I'll post the results later.
 
#6 ·
Here's a 45 second video clip of my AE scanner readings just at the time the engine started romping after it was warmed up.



Just in case you can't see, upper left is ICP Pressure, upper middle is ICP Duty Cycle%, upper right is engine oil temperature, middle left is engine RPM, middle middle is fuel injector pulse width MS, middle right is # of trouble codes.

By the way, the engine idle very smoothly when the ICP was unplugged.
 
#8 ·
Fixed!

As it turns out, I had a fuel leak from the fuel bowl plastic cover. Once I torqued the fuel bowl cover to stop it from leaking and thoroughly cleaned the ICP wire connector and ICP sensor with electrical cleaner to remove the diesel fuel, the truck runs fine. I ran the truck really hard to get the temps up pretty warm and so far so good. Not to say the problem won't reappear. But at least I know to just unplug the sensor so I can drive it home if it does happen again.
Thanks for the Help!

P.S. This fuel bowl cover leaking fuel has been a problem before. I replaced the original one due to it being cracked. Is water freezing and expanding in fuel bowl during the winter?
 
#9 ·
If you don't periodically drain the bowl of water/diesel, I guess it could :dunno:

fyi, unplugging the ICP sensor of course keeps the sensor from reporting any data to the PCM. Since the PCM needs that sensor, it just substitutes it's own value for the missing data. Just a safe, default number. That way all subsequent decisions based on ICP can be made. Just in case you didn't know.
 
#10 ·
i have a problem just like this...however i cleaned the connection on the ICP, and even tried unplugging it and now my truck wont start at all. I get no smoke or anything. Its lke something told the PCM to stop firing the injectors.

Any ideas?

For the record i have 1/2tank of fuel with supplements in it, full fuel bowl with new filters, just topped off oil and replaced the CPS. I started it with all that done, minus the new CPS, and it fired up wonderfully. warmed up great. Shut it off and went to sleep, when i went to start it in the morning after bring plugged in all night, it just cranks. then replaced the CPS and nothing changed.
 
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