How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Ron Your Own Question
Ron
Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 33423
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
7276279
Type Your Ford Question Here...
Ron is online now
A new question is answered every 9 seconds

I am completely stumped on a 2000 ford with a 5.4 ltr auto

Customer Question

Hey all, i am completely stumped on a 2000 ford with a 5.4 ltr auto 4wd truck. Initially the ECU was bad so i replaced the ECU. Once i replaced the ECU the truck fired right up. I checked the fuel pressure once the vehicle got running an it was low ( after about 45 min of running at idle the fuel pressure would drop to 26 psi). I replace the fuel pump and filter and the truck has an insanely hard start and sometimes no start. Today the truck fired right up and ran great. When i tap the throttle the idle hangs at about 1800rpms for roughly 45 seconds and this happens repeatedly. When I shut the truck off and go to restart it it will either not start at all, attempt to start but not start, or it will take a long time to start. At this point I really need some help getting this thing figured out. If you can help in any way please let me know thanks.The constant fuel pressure is great at idle and key on and off. This morning i came in and went to start the truck and it started right up and ran but the idle was high at 1200rpms. I let the truck run for about 30 minutes then turned the truck off and waited roughly 2 minutes and went to restart the truck. I cranked the truck over for roughly 45 seconds continuously. The truck would attempt to start but wouldn't. Then at about the 45 second mark the truck fired up with a high idle. I am at a loss with this truck. I have been a ford truck for over 15 years and have not ran into this problem before.
Submitted: 5 months ago.
Category: Ford
Expert:  Ron replied 5 months ago.

Hello Bill and thank you for your question,

If you connect your fuel pressure gauge to the service port , what is the pressure readings while the problem is occurring from your new pump?

Customer: replied 5 months ago.
After replacing the fuel pump and filter the pressure at the service port is 36psi vacuum on and 42 psi vacuum off it holds that pressure the entire time its running.
Expert:  Ron replied 5 months ago.

So its also holding when its hard to start?

Are there any fault codes setting?

Customer: replied 5 months ago.
My thoughts are in a couple different directions, one being the the factory anti theft system is failing, of the enertia switch is failing. There is one code for coolant temp p0118
Customer: replied 5 months ago.
the coolant temp guage on the dash cluster is not reading anything
Customer: replied 5 months ago.
the fuel pressure is holding even during the hard starting.
Customer: replied 5 months ago.
It chugs like it wants to start then free cranks and repeats the same things until finally about 30-45 seconds later the truck will start with a high idle.
Expert:  Ron replied 5 months ago.

In most cases if the theft system was at fault the theft light would be flashing and it would normally not start at all. If the fuel pressure is holding steady then the pump is running and that would rule out the inertia switch. Give me a moment and let me look in to the P0118 code for you. It almost sounds like it loading up .

Customer: replied 5 months ago.
It does have a rich unburnt fuel smell when cranking. I received this vehicle from another technician and basically have had to refix a ton of issues that the previous tech left in disarray. but with the current issue i am lost. The hanging idle i feel is related to a bad IAC.
Expert:  Ron replied 5 months ago.

The common cause for the code P0118 to set is in most cases caused by a failing CHT (Cylinder Head Temperature Sensor) and if in fact its bad it could very likely affect the engine starting causing the computer to over load the system with fuel. I would consider replacing the CHT .

Customer: replied 5 months ago.
It is located on the back side of the drivers cylinder head correct, closest to the fire wall?
Customer: replied 5 months ago.
you dont think the anti theft has anything to do with the issue?
Expert:  Ron replied 5 months ago.
  1. The CHT sensor is located at the back of the right side cylinder head. See the replacement steps in the link below. Copy and paste the link to your browser to open and view them.

    https://dl.dropboxusercontent.com/u/104923897/CHT%20JUN%2028.pdf

Customer: replied 5 months ago.
The reason why i ask is because when you removed the key and open the drivers door the theft light on the center of the cluster with faintly flash.
Customer: replied 5 months ago.
How sure are you that this will rectify this issue I am having with this vehicle?
Expert:  Ron replied 5 months ago.

That would be normal , if it flashes fast with the key on then it active but this dose not sound like a theft issue to me and beside there are no fault codes for the theft system which in most cases if it was a problem there would be.

I know if the computer can not read engine temp is will cause the system to be rich. I would sure address the P0118 first.

Expert:  Ron replied 5 months ago.

If you would like to run the pinpoint to verify, I can send you the steps.

Expert:  Ron replied 5 months ago.

See the pinpoint test steps in the link below for the CHT.

https://dl.dropboxusercontent.com/u/104923897/P0118%20Pinpont%20Jun%2028.pdf

Customer: replied 5 months ago.
to my knowledge the IAC, Crank sensor and cam sensor are on a loop. That when one fails it can cause an issue like this. Is that true since the idle is hanging like it is?
Expert:  Ron replied 5 months ago.

The IAC is an actuator which only controls idle speed and allows air to by-pass the throttle plate on start up. If you crack the throttle while the problem is occurring dose it start any easier?

Customer: replied 5 months ago.
No it does not. It wont change a thing.
Customer: replied 5 months ago.
is there a way to jumper the CHT to make it start with it disconnected? For instance disconnecting, running a jumper wire and between the connections to verify the sensor is causing the issue?
Expert:  Ron replied 5 months ago.

Then I think you can safely rule it out. If I was there working on this, I would start first with the one known issue and that is the code P0118. I would run the pinpoint test to verify the CHT has failed and replace it so the code clears and see if the problem clears. The computer has to know engine temp or its going to cause the system to be in open loop all the time which causes a rich condition. I would not jumper it. I would check the signal out of it.

Customer: replied 5 months ago.
ok i will start there and get back to you. Thank you.
Expert:  Ron replied 5 months ago.

Your very welcome, Im here if you need me.

Customer: replied 5 months ago.
what is the best way to access that sensor. There is a ton of components in the way
Customer: replied 5 months ago.
The CHT that is
Customer: replied 5 months ago.
Expert:  Ron replied 5 months ago.

The instruction call for removing the converter Y pipe and the air conditioner deflector shield.

Customer: replied 5 months ago.
ok, so i just the y-pipe removed and this engine has not CHT on the back of the passenger side cylinder head
Expert:  Ron replied 5 months ago.

Are you sure this is a 2000 year model?

Customer: replied 5 months ago.
I feel that the entire issue is related to a bad temp sensor for the ecm due to the raw fuel smell. I feel that at start up that it is getting overloaded with fuel causing it to not start. I however i can not locate the sensor. Production date of this truck is 05/00
Expert:  Ron replied 5 months ago.

That the only place it should be on the from 1999 and up. on the 1998 engine its located under the intake on the cylinder head. See it in the link below. If you find it there then the engine has been changed.

https://dl.dropboxusercontent.com/u/104923897/CHT%201998%20Jun%2028.pdf

Customer: replied 5 months ago.
what i am seeing is the CHT is located under neath the intake manifold on the flat portion of the cylinder head
Customer: replied 5 months ago.
There is no coolant temp sensor in the themostat housing in this truck either which is very unusual.
Expert:  Ron replied 5 months ago.

Your 5.4 uses a CHT which takes the place of the ECT.

Customer: replied 5 months ago.
I realize that, i think though since the CHT is not on the back of the passenger cylinder head that it is under the intake manifold
Expert:  Ron replied 5 months ago.

That would make me think the engine has been changed.

Customer: replied 5 months ago.
I am on the same thought process, since the CHT is not in the back of the cylinder head
Customer: replied 5 months ago.
on this engine you can see where there in wiring going underneath the intake manifold to a sensor besides the knock sensor
Expert:  Ron replied 5 months ago.

Well have a look and see if in fact it under the intake. It sure sound like that is the case.

Customer: replied 5 months ago.
i am going to grab my scope and see what i can see and get back to you in a few minutes
Expert:  Ron replied 5 months ago.

Okay. Im here if you need me.

Customer: replied 5 months ago.
ok, so i removed the alternator to access the what i believe to be the CHT at the font portion of the drivers side cylinder head. Here is a picture of the sensor please verify that this is the CHT
Customer: replied 5 months ago.
part number on the sensor is F65F-6G004-AB.
Expert:  Ron replied 5 months ago.

Thats the right location and the part you holding looks to be the right part. Once you have the intake off, make sure you take a good look at the wiring to it for any signs of damage due to it location.

Customer: replied 5 months ago.
I did review the wiring pretty thoroughly, pulling the loom back the wiring looked good and intact.
Expert:  Ron replied 5 months ago.

Well then replace the sensor and see if you can get the P0118 to clear. I suspect if you can you will solve your starting concern.

Customer: replied 5 months ago.
ok i just ordered it, I will get back to you once done
Expert:  Ron replied 5 months ago.

Okay. Good luck.

Customer: replied 5 months ago.
ok, so i replaced the CHT sensor, cleared the codes, started and ran the vehicle to operating temp and then shut it off and it will not re start
Customer: replied 5 months ago.
Customer: replied 5 months ago.
live data on my scanner said ECT was -40 at running temp
Customer: replied 5 months ago.
what is the sensor in the drivers side on the engine block has a c style connector with three terminals
Customer: replied 5 months ago.
found that sensor to be a block heater
Customer: replied 5 months ago.
Need some help my cell phone number is(###) ###-####is there any way you can call me
Customer: replied 5 months ago.
not sure why i am not getting any response at all????
Expert:  Ron replied 5 months ago.

Sorry I was off for the evening. I start work at 3 eastern time.

In order for the engine to start and run you need good spark to the spark plug, injector pulse at the injector and proper fuel pressure , now that it will not start can you check each one of these and tell me which one you are lacking?

Customer: replied 5 months ago.
On restart after initial run to operating temp it seems to be dropping injector pulse and the fuel pump starts to power up irregularly. Meaning it will come on for a second or two then pulse off and on. I can crank it over and it will attempt to start then after about 30 seconds of this it will finally start.
Customer: replied 5 months ago.
I did find late yesterday that the iac is bad
Expert:  Ron replied 5 months ago.

The IAC being bad would explain the Idle hanging, that being said, if the fuel pump is coming and going and you loosing injector pulse I would suspect the PCM and or the connection to it. Both are controlled by the PCM.

Customer: replied 5 months ago.
The pcm was replaced and reprogrammed.
Expert:  Ron replied 5 months ago.

Well if you sure its not defective then I would go back and recheck powers and grounds to it.

Customer: replied 5 months ago.
Ok so i decided to go ahead and pull the fuel pressure regulator off the rail. I applied vacuum to it and it slowly leaks down from 22 to 0 within about 1 minute
Expert:  Ron replied 5 months ago.

In most cases if the regulator is leaking you will get fuel leaking out of the nipple, are you?

Expert:  Ron replied 5 months ago.

Not to mention, a bad regulator would not cause you to loose injector pulse.

Customer: replied 5 months ago.
No, no fuel leaking
Expert:  Ron replied 5 months ago.

In most cases if its not leaking and your pressure is holding like you said then you do not have a bad regulator.

Customer: replied 5 months ago.
I dont know where to go with this vehicle. I dont have a reading at the temp guage at all, and can not locate the coolant temp sensor for the guage. I keep going back to the fact that the factory antitheft is causing the issue
Expert:  Ron replied 5 months ago.

Are you getting any anti theft fault codes?

Customer: replied 5 months ago.
No, no codes
Expert:  Ron replied 5 months ago.

Well in most cases if the theft system has issues it will set a code

Customer: replied 5 months ago.
Well, I'm stumped, i don't know where else to go with this vehicle. I cannot get it to start on the second start up without it taking about 30 seconds.
Expert:  Ron replied 5 months ago.

When it dose not want to start what are you loosing, spark or injector pulse?

Customer: replied 5 months ago.
do you have any sort of instructions on how to bypass or disable pats
Expert:  Ron replied 5 months ago.

Unfortunately the PATS can not be by-passed.

Customer: replied 5 months ago.
Can you get me a wiring diagram of the ecm?
Expert:  Ron replied 5 months ago.

Yes , let me know which circuits your needing and I can send the diagrams.

Customer: replied 5 months ago.
I am looking for the PCM pin out diagram that shows where that factory anti theft connects to the pcm.
Expert:  Ron replied 5 months ago.

The PATS actually connects to the instrument cluster See the diagrams in the link below.

https://dl.dropboxusercontent.com/u/104923897/PATS%20Jun%2030.pdf

https://dl.dropboxusercontent.com/u/104923897/PATS%202%20Jun%2030.pdf

Customer: replied 5 months ago.
im confused hpw does pats communicate with the pcm to disable the fuel syatem
Expert:  Ron replied 5 months ago.

It communicates with the instrument cluster which in turns communicates with the PCM.