[JR2]

I have an 03 7.3 Excursion. It seems to have split personalities. One day it will run like it should and the next it will be a dog. On the doggie days it seems slow, does not accelerate very well, on the good days it runs like all the other 7.3's I have driven. I have no way to check for codes (yet) but it does not throw the check engine light. Any one ever have a problem like this?

I have not found any events that cause the doggie days or good days. Warm or cold, fuel tank full or empty, weather cold or warm. It just seems to be happy some days and crappy some days.

I have limited 7.3 tinkering experience, but if you give me ideas I will do what I can.
I also don't have gauges on it yet, but that is in the works.

Thanks,

John

 

[coldair]

I just did the DIESELSITE fuel line mods that eliminated the factory check valves and my crappy mode finally went away.I found a very large piece of rubber like a part of a gasket, and boy those check valves are very restrictive. on the down side you have to be very careful accelerating out of a turn as it has a tends to slide sideways spinning the tires when it hits second gear /ubbthreads/images/graemlins/biggrin.gif /ubbthreads/images/graemlins/biggrin.gif

 

[vettejeep]

Only a possibility - and not the only possibility - is the EBV valve. Mine stuck with similar symptoms to yours. If you had a pyro - then it climbs real fast & much higher than normal - I could not climb small hills at more than 45mph with a small tow w/o getting far into the red on the pyro. No check engine light either.

I 'fixed' it by exercising the EBV valve with a tire tool - I was a looooong way from any type of shop at the time.

I'd bet there are a bunch of other possibilities & this is only one thing to check of many.

Best o' Luck,

 

[JR2]

Thanks for the ideas I will look into both very soon.

any one else have any ideas??

 

[drdenny1]

What fuel line mods? Did you do the regulator?

 

[coldair]

I had the regulator but upgraded to the whole kit with the marine grade regulator, the dahl 100 filter, the new intak mods , fuel cooler and the hose kits the got rid of the check valves

 

[JR2]

TTT for more input????

 

[coldair]

have you checked out what I had said? I added a in the cab pressure guage on mine and my fuel pump is not up to snuff

 

[JR2]

No I have not checked anything yet. I am out of town working for another few days. I just wanted to see if anyone had any more ideas before I get to town and try to sort it out.

Thanks,

John