When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
My '95 F150 2wd 300 I6 5 speed pickup with 91000 miles is hard starting. It takes about 2 seconds to start. I seem to notice it only when cold and always forget to check when hot (which tells me it must be starting better hot). Sometimes on cold starts I will let off the starter just a tad too early and it hasn't started, but then when I hit back on the starter if fires right up. It is as if it takes a while to get the fuel to it. Fuel filter is only a few thousand miles old. Plugs, wires, cap, rotor, coil, and air filter are good. Once started the trucks runs like a champ and it always does start. I am wondering if there is a problem with the fuel pumps not coming on quickly enough. Does not seem to matter which fuel tank either so likely it would have to be something that affects both fuel pumps.
INLINE SIX POWER! '95 F150 XL
300 Cubic Inches of Low RPM Truck Torque! And twin-I-beams too!
"Drive a stick young man! There'll be time for automatics when you're old and unable."
I had the same cold start problem on my 87 4.9. I did the whole tune up thing. What finally fixed the problem was changing out the Throttle Body soleniod valve. The soleniod valve was purchase at Ford as an assembly. The cold start problem went right away.
1) Haven't tried to change the throttle body selenoid valve yet as I don't know what or where it is.
2) Turned key to on position and walked around back, but could not hear fuel pump running (also checked with engine on to be sure what it sounds like). Now maybe the clutch must be depressed to get the fuel pump to run in which case I have to repeat my diagnostic with a buddy in the cab.
I suspect the fuel line is depressurized and if the pump dosen't come on until I crank it it would explain the slow starting. The question then becomes, what controls that, the throttle body selenoid valve?
Called a Ford dealer (throttle body solenoid is a dealer item, so says my local parts store). He never heard it called a valve. Said it is a switch. I explained my problem and he said the throttle body solenoid sounds like the culprit, but his computer was not bringing one up for my truck ('95 4.9L, and actually, David, I have an '87 Chilton manual that dosen't show it on yours). Then he suggested the fuel safety shutoff--the one under the dash for shut off in event of an accident. He explained that the safety shutoff actually shuts off every time you shut off the truck and if it is sticking it would give me the same problem. He then suggested a Haynes manual and look in the diagnostic section for the problem to see what it says. Well, that's my next move.
Correct me if I am wrong but the Inertia switch is like a "circuit breaker" and only trips in the event of a sharp blow. I believe the fuel pump relay turns the pumps on to charge the lines then trips out (due to lack of oil pressure signal I think) if the engine dosent start. Your problem kinda sounds like the relay is sticking open.
>Correct me if I am wrong but the Inertia switch is like a
>"circuit breaker" and only trips in the event of a sharp
>blow.
Well that is what I always thought, but this parts guy insisted.
>I believe the fuel pump relay turns the pumps on to
>charge the lines then trips out (due to lack of oil pressure
>signal I think) if the engine dosent start. Your problem
>kinda sounds like the relay is sticking open.
I am going to get a manual and check it out.
>Hope this is helpful
Thanks, It's not like a real problem. It always starts and runs great and three people have told me to just live with it, but it bugs me, especially since the 460 V8 in my motorhome can sit for a month and fires right up.
According to the manual the fuel pump will run for about a second when you turn the key on and then stop (checked, and mine did). So that is not my problem. It notes that some problems can be caused by a leaking pressure regulator valve that could allow a loss of pressure at the injectors. I could see where this, if leaking slightly, could duplicate my problem. The procedure to check it is involved enought that I am not going to mess with it. I'll leave it to the mechanic next time I take it in.
[updated:LAST EDITED ON 24-Sep-02 AT 09:26 PM (EST)]your not alone i have the EXACT problem takes 3 seconds to start but fires up right afterwards same symptoms you have i will check into it too.
Looking back through the posts the pressure regulator valve my manual described sounds exactly like the fuel pump relay that Gasman6674 described in post 5. Maybe the names of these items change over time and design changes.
Anyway Rbrendel (or anyone else who wants to give it a shot), if you are handy in the garage there is a procedure in the Haynes manual for checking this valve. As I recall it involves pulling a fuel line or hooking up to the schrader valve or both and then testing pressure under select conditions, all the while tweaking on various components until you narrow down the problem.