EGR PROBLEMS
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Trailering
Joined: Sep 2016
Posts: 23
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EGR PROBLEMS
hello guys
have this issue with my 94 f 150 5.0
the problem im having is the egr valve gets a signal just above an idle opens the egr valve and causes the engine to run rough
ive read that its only supposed to open with a warm engine mine does it cold or warm
just above an idle
no codes what so ever
ever hear of this?
have this issue with my 94 f 150 5.0
the problem im having is the egr valve gets a signal just above an idle opens the egr valve and causes the engine to run rough
ive read that its only supposed to open with a warm engine mine does it cold or warm
just above an idle
no codes what so ever
ever hear of this?
Cargo Master
Joined: Sep 2006
Posts: 2,120
Likes: 390
From: Evansville, Indiana
The EGR valve on the '94 5.0 is controlled by an electric solenoid. The solenoid is powered by 12v from the ECM relay (along with many other components) The valve is opened by the ECM varying the path to ground. It is possible that you have a short between the solenoid and ECM, BRN/PNK wire to pin 33. If not that, then possibly the ECM is processing bad data from the coolant temperature sensor. Check sensor for 15K-25K ohms at 75ish degrees. (does not have to be precisely in this range) If good, check for 5v at ECM pin 7, LT GRN/Y or LT GR/R wire.
I am no expert but I have been into ECMs the last few days. And I stayed at a Holiday Inn Express in Saltio, MX last November..
I am no expert but I have been into ECMs the last few days. And I stayed at a Holiday Inn Express in Saltio, MX last November..
Lead Driver
Joined: Sep 2003
Posts: 7,015
Likes: 208
From: SoCal
One of the things that controls the EGR is the engine load. The EEC determines engine load from the MAP and TP sensors, so if one of those is not working properly (most likely the TP), it could cause the EGR to open at the wrong times.
However, a failing TP sensor can give rough operation as well, and it is a more common part to fail. You can check it to see if its resistance varies smoothly throughout it range of motion. If it jitters at all, replace it.
However, a failing TP sensor can give rough operation as well, and it is a more common part to fail. You can check it to see if its resistance varies smoothly throughout it range of motion. If it jitters at all, replace it.
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Trailering
Joined: Sep 2016
Posts: 23
Likes: 0
went through and checked for shorts in the egr regulator wiring all is good
tps is new motorcraft set at .95 coolant temp sensor was new when i put the new engine in also a motorcraft part
16k ohms at 70-75 degrees 4.78v checked pin 7 thats ok as well
one thing i dont like is fuel pressure at idle is 30 lbs ( new pump new filter) motorcraft pull vac off 42 lbs
inj pulse with between 3.85-4..10 if i pull the vac off the fuel pressure reg changes to 3.55-3.80
im using an otc genesis scanner which wont show me eng load
just trying to figure out what perimeters short term fuel trim should be when up to temp 02 switching from 10-80 back n forth coolant temp 190-195
this truck has mass air from the factory which is at 85-90 at idle
tps is new motorcraft set at .95 coolant temp sensor was new when i put the new engine in also a motorcraft part
16k ohms at 70-75 degrees 4.78v checked pin 7 thats ok as well
one thing i dont like is fuel pressure at idle is 30 lbs ( new pump new filter) motorcraft pull vac off 42 lbs
inj pulse with between 3.85-4..10 if i pull the vac off the fuel pressure reg changes to 3.55-3.80
im using an otc genesis scanner which wont show me eng load
just trying to figure out what perimeters short term fuel trim should be when up to temp 02 switching from 10-80 back n forth coolant temp 190-195
this truck has mass air from the factory which is at 85-90 at idle
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