91 f150 5.0 5 spd. 110xxx miles.....let see, turn key to start it will crank for about 10 to 15 seconds before running OR after a second or two turn key off and restart it will fire right-away..for a while it was doing this when it was hot after running now it seems to do this all the time..after starting it ran fine...idle was about 750rpm as its allways been timeing is at 10*...have no hits on computer...went and changed distributer cap and rotor, checked plug wires seem to be ok ( about 1 yr old) pulled plugs (again about 1 year old) looked clean (tanish) gaps were .040 ( they closed up????) redid gap to .044 by book specs. disconnected battery to reset computer after 20 min. or so reconnected battery...it started right-away but quite after 2 or 3 seconds (now what)...had to give it gas after starting so it would keep running...after 10 seconds or so the idle stayed at about 600rpm then slowly went up to arround 750 as before...so now after warming up the starting thing is still there...does this sound normal or is there something im not getting...a friend told me ITS RUNNING-DONT WORRY...well i cant live with it that way...any ideas

 

Do you hear the fuel pump come on when you trun the key to run? You should, and if you don't that will cause a delay in starting. The other was probally the computer relearning after erasing the memory. It has to "relearn" the vehicle and how to control it after erasing the memory.

 

yes the fuel pump comes on....i was thinking..several months ago i had changed the fuel pump regulator flooding the motor with to much gas pressure would go as high as 100 lbs at speed...replaced it with one from autozone...after that was told only to use ford fpr as the other brands wont work right...am thinking im getting a little to much gas on start-up....any ideas thanks

 

should not of been so quick in saying the fuel pump comes on with key in on position...still haveing this hard starting problem..cant tell if pump is on so hooked up pressure gauge to fuel rail...with key on no pressure at all..at idle it shows 34lbs...reving motor pressure drops about 2 or 3 lbs...shuting down motor there is no pressure in the fuel rail...so pump is running along with motor but not in the key on position..would a bad pump relay cause this..is 34lbs good at idle....had changed fuel pressure regulator a while ago but not with a ford regulator...need some advice.....thanks

 

my 92 f-150 does same thing, has done it for a while, i don't worry about it, it's never failed to start, but would like to know what causes it...can hear fuel pump kick in initially, but when let off starting 1st time, hear it kick on again

 

I have got the same problem and have been running the truck like that for over a year. Currently I just turn the key a few times and it fires right up. I am thinking it is the fuel pump as I am told there is a check valve in the fuel pump and that is what is bad. When I get around to replacing it I will let you know.

 

NEED TO CLEAN IDLE AIR CONTROLE VALVE!!!!! I have had alot of fords and all of them had done this one time or another and that has always been the problem

 

The pump comes on initially, then if the computer senses no rpm, then it will turn off. Soon as you hit the starter, the pump kicks back on, and when you release the starter and the engine is off, the computer will turn the pump off again.

The fuel rail should hold pressure. Also, when revving, the pressure should increase, as higher vacuum will decrease fuel pressure. There has to be a check valve somewhere that is bleeding off pressure (sounds like it is non existant if pressure drains out immediately).

 

Where is this and what does it look like. Is it right up front on the motor with a pully on it???

 

well went ahead and changed fuel pump relay..the old relay has 4 connections on it while this new one (autozone #mr12) has 5...anyway it works pump now comes on for a few sec. with key in on position..fuel rail wont hold pressure so check valve in pump must be shot..(could there be a check valve in the fuel line)???? just dont want to pull the gas tank just yet......