hard start at normal operating temp
Thread Starter
old geezer member
Joined: Nov 2014
Posts: 21
Likes: 0
From: central texas
hard start at normal operating temp
Veh: 2000 Lariat with Approx 135K miles
5.4 L triton
2 WD
Symptoms:
*Starts normally when cold in AM
*Have to crank excessively at normal operating temp or
if the outside temp is warm greater than 70 deg F
*seems like it might be getting worse as the fuel level drops.
Recent maintenance done:
*New fuel filter
*new IACV
*New EGR Pressure Sensor (both rubber hoses had large open holes
at bends.
*New camshaft Position Sensor
*MAF Sensor cleaned
*New IAT Sensor (this completely solved my rough idle issue)
*throttle body cleaned
*Radiator replaced
I have an Actron code reader that gives me all the real time info
on the sensors but I am still trying to learn what all the info means and apply it to fix's as necessary.
Questions:
1-if I get a fuel pressure tester, will there be a difference in readings at:
*pre-engine crank
*Engine crank
*post engine crank 10-15 min after reaching operating temp
2-How would I be able to tell the difference between a malfunctioning
fuel pressure regulator and a fuel pump going bad? Will both of these give me these symptoms?
3-What exactly is fuel trim (long/short) and can I use these readings to assist in diagnosing this problem?
Any help guys would be greatly appreciated...
I've almost got the engine reliable. Once this is done I can move on to
the Emergency brake being inop, leaks in rear window seal, etc...
5.4 L triton
2 WD
Symptoms:
*Starts normally when cold in AM
*Have to crank excessively at normal operating temp or
if the outside temp is warm greater than 70 deg F
*seems like it might be getting worse as the fuel level drops.
Recent maintenance done:
*New fuel filter
*new IACV
*New EGR Pressure Sensor (both rubber hoses had large open holes
at bends.
*New camshaft Position Sensor
*MAF Sensor cleaned
*New IAT Sensor (this completely solved my rough idle issue)
*throttle body cleaned
*Radiator replaced
I have an Actron code reader that gives me all the real time info
on the sensors but I am still trying to learn what all the info means and apply it to fix's as necessary.
Questions:
1-if I get a fuel pressure tester, will there be a difference in readings at:
*pre-engine crank
*Engine crank
*post engine crank 10-15 min after reaching operating temp
2-How would I be able to tell the difference between a malfunctioning
fuel pressure regulator and a fuel pump going bad? Will both of these give me these symptoms?
3-What exactly is fuel trim (long/short) and can I use these readings to assist in diagnosing this problem?
Any help guys would be greatly appreciated...
I've almost got the engine reliable. Once this is done I can move on to
the Emergency brake being inop, leaks in rear window seal, etc...
Senior Member
Joined: Jan 2014
Posts: 1,186
Likes: 63
From: Indiana
Veh: 2000 Lariat with Approx 135K miles 5.4 L triton 2 WD Symptoms: *Starts normally when cold in AM *Have to crank excessively at normal operating temp or if the outside temp is warm greater than 70 deg F *seems like it might be getting worse as the fuel level drops. Recent maintenance done: *New fuel filter *new IACV *New EGR Pressure Sensor (both rubber hoses had large open holes at bends. *New camshaft Position Sensor *MAF Sensor cleaned *New IAT Sensor (this completely solved my rough idle issue) *throttle body cleaned *Radiator replaced I have an Actron code reader that gives me all the real time info on the sensors but I am still trying to learn what all the info means and apply it to fix's as necessary. Questions: 1-if I get a fuel pressure tester, will there be a difference in readings at: *pre-engine crank *Engine crank *post engine crank 10-15 min after reaching operating temp 2-How would I be able to tell the difference between a malfunctioning fuel pressure regulator and a fuel pump going bad? Will both of these give me these symptoms? 3-What exactly is fuel trim (long/short) and can I use these readings to assist in diagnosing this problem? Any help guys would be greatly appreciated... I've almost got the engine reliable. Once this is done I can move on to the Emergency brake being inop, leaks in rear window seal, etc...
Junior Member
Joined: Mar 2016
Posts: 19
Likes: 0
From: NC
I cranked my 2000 5.4 the other day at cold and it ran but sounded horrible so I turned it off. Waited 5 seconds and started it again and it ran fine. Idk what that was but it was strange. A friends of mine said his Ford does that too.
Senior Member
Joined: Dec 2015
Posts: 23,191
Likes: 8,622
From: Utah
After driving it around for a bit, get out and immediately pull the vacuum hose off of the fuel pressure regulator. Watch for a few minutes and see if it starts pissing fuel out of the nipple on the FPR. What happens is that diaphragm gets cracked over time, but still operates as it should as far as regulating pressure. When you shut the motor off, the fuel pisses out into the vacuum line and it causes a flooding effect when you try and start it. The fuel has time to evaporate when it sits and cools off, so it starts normally under cold conditions.
Let us know.
Let us know.