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94 7.3 check engine light comes on and goes into limp mode

8K views 10 replies 3 participants last post by  ultimatewarrior 
#1 ·
Have 94 f350 7.3 turbo that when going at hiway speeds and when towing the check engine light comes on and goes into limp mode.Tried plugging a scanner into the plug on the fenderwell and its not getting a reading from the computer. Checked the plug on the fender and it has hot and ground and checked the ohms all looked good.Will only a certain brand scanner work on this model????:dunno::dunno:
 
#2 ·
Many of the 94's have had their computers "reflashed" and updated to the later diagnostics using the OBD port under the dash (and this could be the case with yours). Of course, most generic scanners won't work on that port. You would need one that can monitor the Ford Enhanced parameters. Cheers!
 
#4 ·
my edge tuner plugs right in a works as a great code reader,it gives enough info that u can find whats wrong quickly on the net.Ill tell u now that a weak fuel pump will cause that and wont throw a code.Another thing to try is check your throttle position sensor on your throttle pedal,sometimes they go and wont allow full throttle.Could be many other things but without more info im shooting in the dark.hope this helps and gd luck.
 
#5 ·
Driving around town it doesn't go in limp mode,its when getting up to hiway speeds 60 or faster.I can turn the key off and turn back on and will clear the code but will come back on. Seems like it would be the throttle sensor but why only at certain speeds.Now if i'm getting on it kinda hard while shifting gears sometimes it will go into limp mode.....
 
#6 ·
make sure u dont have any burnt pins on your vc harness plugs,second when it goes into limp mode what does your rpm gauge do?Third,and this is a free fix is check your fpr hooked up to the side of your fuel filter bowl,when you pull them apart you will see a screen,they like to plug up and restrict your fuel.also disconnect your fuel heater on the back of the fuel filter,sometimes when you get on it it vibrates the little needle enough that it touches the bowl causing intermittent fluctuations.this is all no cost options to try before you go throwing parts at it.many other options but try the freebies first.
 
#7 ·
When you say limp mode, what is it doing (something like just idling with zero response from the accelerator pedal)? Since the 94's only have a manual tranny, there's really no limp mode (reduced power on purpose) that I'm aware of. Cheers!
 
#8 ·
Limp mode means no power will barely get out of its own way.....Turn off and on the key and goes back to normal.....jeffygunt I'll try that and see what happens....Patrick it looks like there is a port hookup under the dash between the ashtray and glovebox,will try to mess with it this weekend when i have time.
 
#9 ·
Take a look at the Injection Pressure Control (ICP) sensor connection. The ICP is the sensor on the top front of the driver's side head pointing inward at a 45* angle. See if there is oil in the connection which would indicate an inetrnally leaking sensor. Cheers!
 
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