2004 Fx4 5.4. The truck starts fine every morning and if I start it immediately after shutting it off but if it sits for 10 minutes or several hours it either sounds weak or struggles and cranks long but always starts. It does it everytime its warmed up and driven and then parked. Plugs,cops and a ton of other stuff all 6 months old including fuel pump and refurbished injectors. Sometimes it starts even stranger with what appears like almost no cranking but an instantaneous start. Driving me nuts and can't be good but I can't seem to find anyone with the exact problem. My bluetooth scanner shows good fuel pressure but I have'nt done a leak down due to no schrader valve on the 04's and can't find a fuel pressure adapter to bypass. I guess it could be something other than fuel such as starter or ???????????? Don't know how to track this down. Any ideas of how to diagnose this? Thanks

 

I have this same problem. Well it seems to come and go. About 3 times it would go thru its crank cycle and not start hit it a second time and fired right up. FPDM, Fuel pump, coil boots, plugs and a few coils have been replaced. I have no misfire that I can feel or that the computer can read. Right now it hasnt been doing it.

 

@Tommy J


Have you, or can you check live data on fuel trims with your scanner? If an injector is not closing good, it will usually cause negative fuel trim on that bank. The PCM (not knowing which injector), will respond to the rich O2 reading on that bank by choking down on fuel trim. If that's the case - the only way I know to narrow it down, short of removing the fuel rail/injectors) is careful inspection of the plug tips on that bank for signs of rich running. Both are a PITA.


----- Edit (additional thought)


If you can do a Mode 06 diagnostics test with the scan tool, over rich condition caused by a leaky injector might show up in misfire counts for that cylinder.


Hope this helps

 

Frustrating is'nt it. It seems like a fuel problem. Why else would it start perfect every morning after sitting over night although my other symptom of the weird crank and instantaneous start makes me think otherwise. I too replaced the FPDM and fuel pump, all cops and plugs. Never throws a single code. I had a slight hesitation around 2000 rpm while driving that I thought I fixed with a new MAF sensor but I think its back. Don't know if thats related or not.

 

Yep, have removed new plugs twice for inspection due to a hesitaion I was having and had the whole fuel rail out to put the refurbed injectors in a while back. I even popped the driver side fuel rail up and turned the key to on to look for leaks if this method is even accurate. I think my blutooth pro torque shows fuel trim but I"ll have to admit Im not a super tech guy so I don't always know what Im looking at. Even if I pulled th injectors I dont know what Im looking for other than the obvious such as bad o ring etc. I thought I bought decent ones from a reputable place but I know nothing is a sure thing. The truck also never seems to have the power it should either. I mean its ok and does get up tp speed but its just my gut feeling but its new to me and different feeling than my 99 was so maybe its normal, I dont know. It also has new cats and 4 new 02 sensors. I"ll try to interpret some of my readings if I can. Thanks

 

@Tommy J
IMHO you have far & wide the best scanner out there to monitor critical engine operations. Its ability to "scan" the ECU for responses and add custom parameters IDs and gauges is awesome. I have ran a complete scan on my 5.4L and found over 200 parameters that can be configured and monitored with Torque - in addition to the standard stuff Torque displays. I've been "hacking" the thing trying to develop a complete PID list for the 5.4L.
A couple of useful dashboard screens that might be helpful with diagnosis of your symptoms is shown in post https://www.f150forum.com/f12/normal...3/#post4209216
Be sure to check the checkbox "use separate dashboard layout" in your Vehicle Profile first. THEN download/install Ford PID's before setting up any custom dashboard screens.

 

Thanks, Im still tring to figure the pro out and will check into the forum

 

Have you tried a new crank sensor? A near dead crank sensor can cause long start.

 

Are you able to put one in without taking the ac compressor off?

 

I actually bought one a while back but it looks like I have to lower or move the ac comp. Would a bad one still allow me to have a perfect start every morning?