Hard starting at initial startup.

[ORRadtech]

This stops the fuel injectors from injecting fuel during cranking. You may be getting too much fuel during prime/cold start.

Which could be a leaking injector as mentioned above. Although I'd think you'd get a misfire code with a leaky injector.
You may be able to find a leaky injector by pulling the plugs out and borescopeing each cylinder looking for wetness/fuel.

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[blaisa]

Hello; Fuel injection systems tend to have a fuel rail from which the injectors are feed fed fuel. To work properly the injectors, need some amount of pressurized fuel. The fuel pump(s) are made to produce more fuel pressure than the injectors actually need. So, if the injectors need 60psi and the pump makes 80psi some of that pressure needs to be bleed off.
On the fuel rail will usually be a pressure relief valve which can open to bleed off some excess fuel pressure. That excess fuel is sent back to the gas tank to be held and eventually reused. If that valve is faulty it can fail to hold pressure when the engine is turned off. It may allow fuel pressure to slowly bleed off over time (say overnight). When you start the engine for the first-time next morning it takes some longer cranking to get enough fuel pressure built up. Then the rest of the day you may be starting it often enough to keep the fuel pressure up.

Another way pressure can bleed off is a faulty injector.

Where is this pressure relief valve located?

It seems strange that this would be the cause because even if it sits for a week or so it is still hard to start. Sitting that long what extra fuel would seem to dissipate or run down past the rings.

 

[K4fxd]

Sounds like a check valve to me, holding the pedal to the floor turns off the fuel injectors. This might allow the fuel pressure to build faster and it starts faster.

The clue is the fact once you start it, it starts easy the rest of the day. If it was a leaky injector it would start hard all the time.

 

[sk47]

Where is this pressure relief valve located?

It seems strange that this would be the cause because even if it sits for a week or so it is still hard to start. Sitting that long what extra fuel would seem to dissipate or run down past the rings.

Hello; I do not know the location on the fuel rail. On my F-150 it was easy to find.
There is a way to check if the fuel rail has a Schrader type port. ( Will look something like the valve on a tire) A fuel pressure gauge can be attached to that port. Turn on the fuel pump or start the engine. The pressure gauge should show some pressure. It was around 55PSI on my F-150. Then turn off the engine and wait a while. A good fuel rail should hold pressure fora long time.

 

[Cory S]

A good fuel rail should hold pressure fora long time.

It’s not the rail itself that holds pressure after engine off. It’s the check valve in the pump(s) along with the fuel injectors themselves that can maintain pressure after engine off time.

 

[sk47]

It’s not the rail itself that holds pressure after engine off. It’s the check valve in the pump(s) along with the fuel injectors themselves that can maintain pressure after engine off time.

Hello; I do not dispute your statement. To keep pressure both plus the injectors will have to work properly. The valve on the fuel rail, the injectors and the pump check valve will all have to hold pressure.
If the check valve in the pump were the only place holding pressure, then the excess fuel that bleeds off the fuel rail would quickly allow pressure to drop as the fuel moved back to the tank. Modern FI systems have two fuel lines attached to the gas tank. One is a line to move the fuel out of the tank and up to the fuel rail while the other line sends excess fuel back to the tank.

 

[Cory S]

Hello; I do not dispute your statement. To keep pressure both plus the injectors will have to work properly. The valve on the fuel rail, the injectors and the pump check valve will all have to hold pressure.
If the check valve in the pump were the only place holding pressure, then the excess fuel that bleeds off the fuel rail would quickly allow pressure to drop as the fuel moved back to the tank. Modern FI systems have two fuel lines attached to the gas tank. One is a line to move the fuel out of the tank and up to the fuel rail while the other line sends excess fuel back to the tank.

Actually Mustangs haven’t used a return line since late 1998. They went returnless, and still are to this day.

 

[sk47]

Actually Mustangs haven’t used a return line since late 1998. They went returnless, and still are to this day.

Hello; This i did not know. Thanks for the information. Would appear then that the injectors and the fuel pump check valve are the places a fuel system can lose pressure.

 

[ORRadtech]

At this point, without troubleshooting and input from the OP it's all speculation.
I think most of us believe he has a fuel pressure related issue. I suppose another possibility could be a lazy/failing cam or crank sensor, though again I'd expect to see a CEL. Another possible avenue to check would be using a scan tool with active data and watch fuel pressure with that. And that would also tell of any pending or historic codes.
Does he have the equipment or expertise to check that stuff, IDK but without new/more information there's not much more to be said.
I suppose he could always load the parts cannon and replace the fuel pump but that's an expensive path to start down.

 

[blaisa]

At this point, without troubleshooting and input from the OP it's all speculation.
I think most of us believe he has a fuel pressure related issue. I suppose another possibility could be a lazy/failing cam or crank sensor, though again I'd expect to see a CEL. Another possible avenue to check would be using a scan tool with active data and watch fuel pressure with that. And that would also tell of any pending or historic codes.
Does he have the equipment or expertise to check that stuff, IDK but without new/more information there's not much more to be said.
I suppose he could always load the parts cannon and replace the fuel pump but that's an expensive path to start down.

Currently the car is in the paint shop getting the front end painted. The car is definitely flooding itself out. The only code is the Iat sensor but even installing a known good one it made no difference. I too suspect the cps as a possibility mainly because it's a manual and it could be fouled with debris. I will verify that once I get the car back. I have a name brand technician level scanner and know how to use it. Of course the cps will not set a code.

 

[K4fxd]

The car is definitely flooding itself out.

How have you determined this?

 

[blaisa]

How have you determined this?

For example. The guy at the body shop without being told how to start the car went out and cranked the car over repeatedly until the battery was dead. At which time the body shop manager told him what I told him to put the gas pedal to the floor to start it. He connected a jump box to the car and put the gas peddle to the floor and after some cranking it fired up. It smoked like hell at first burning off all that extra fuel but cleared up quickly. Once started it quickly started up at every attempt.

 

[blaisa]

What is the mileage? Spark plugs could cause long startup. Good luck.

Also, do you get any smoke at startup? any oil consumption issues?

86k miles. The only time I have heard of smoke at start up was when the body shop painting the front clip cranked it till the battery was dead then followed my instructions how to start it. Never smoked any other time.

 

[blaisa]

No

What is the mileage? Spark plugs could cause long startup. Good luck.

Also, do you get any smoke at startup? any oil consumption issues?

Idea as to oil consumption due to just buying the car wrecked off of Copart auctions.

 

[K4fxd]

OK. That is more information. Pull the fuel rail, pressurize the system and find the leaky one or 3

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