I have been lurking here for years, but not a lot of posts/responses. 1997 F150 5.4l. Lately they truck will not start when I get in to come home from work. Turns over and just never really catches. If you give it gas during the start process it will run as long as your foot is on the gas. Let up and it dies. I have changed the fuel filter and regulator. Yesterday whaile having the problem I swapped the fuel pump relay and the horn relay, no joy. It finally kept running after I kept pressure on the pedal for about a minute. Am I down to a fuel pump here? When I went to bleed the fuel pump rail for the filter change and the regulator change there was no pressure. I seem to remember pressure there the last time I did the filter change. Fire away, I am open to all suggestions before I have to tear into the fuel pump.

Thanks in advance,
tennfan1

 

Do you have access to a fuel pressure gauge? That you could attach to the fuel rail. Then you could see if its building priming pressure when the key is on engine off.
Quite possible its the fuel pump.

 

I am looking for one now, any suggestions? Also any info on what the pressure should be?

Thanks for the quick response.
TF1

 

How about checking the fuel pressure? Get a guage. You should have about 40 psi in the fuel line much less and it wont work. Thats where you should start.

 

Jethat,
Is that pressure(40psi) at the schrader valve on the fuel rail or prior to the regulator?

JETHAT are you a jet mech?

Thanks,
TF1

 

Yes thats at the valve. I'm not sure of the EXACT range that is acceptable Autozone could tell you that when you borrow the guage. jethat is part of my name.. J. E. Thatcher

 

It could also be a bad or dirty IAC.

 

http://www.summitracing.com/search/?...%20gauge&dds=1

Phil

 

It is lol, -IMO.

Before you do any pressure checks, thro a new filter on there. Unless the one installed has less than 6000 miles on it. Hell, if I was checking pressure, I would start with a fresh one anyway.

A bad Regulator can cause a Crank No Start. That's because they can over pressurize the rail. Keep in mind, -cranking more than 5 seconds continuous shuts down the injectors.

I think it's IAC tho.

 

Regulator and fuel filter have been replaced with no joy. I will check to see when the last time the air filter was changed, can't remember off the top of my head. I would think that if it was the air cleaner then it would not be so intermittent. Also if you give it a little throttle it will run until you let off, then it dies. AutoZ has a pressure checker to "rent" but it was out, I will check another to try and rule that out, truck has started every time since Monday afternoon (5 trips). I will update as I go forward. I do appreciate the responses and ideas.

TF1

 

We told you what it was. Who said anything about an air cleaner ?

You mean an air filter ? No, not the air filter, unless it's plugged.

Like we said = IAC. But do what you must.

 

Easy Jbrew, In my world you would be surprised all the different things people call filters. I read your post wrong, my bad. I will check out the IAC and will give props/update, I had totally for got about this little beast, I did clean it a long time ago when I cleaned the throttle body.

Once again appreciate the info.

TF1

 

Now your going to kick yourself once you find out it is the problem lol.

 

Would not be the first time. Live and learn. I will let you know tomorrow. I seem to remember last time I cleaned it that it was nasty. Lo't of work on the truck lately but still running pretty good for almost 200,000 miles, and cheaper than a payment.

TF1

 

Cleaned IAC valve, not too cruddy but looks better now. Time will tell. Thanks glc, Jbrew, jethat for the help. If this does not fix the problem I will update.

TF1