Hello, ive been using this forum for a long time now and it has helped me keep my truck running for 5years now. This is my first post so please forgive me if i post in the wrong place. Anyway, the last couple days my truck( 1997 f150 4.6l) has been having startinv issues. At first it would just turn over and not start then the battery would die. So i bought a new battery and yesterday now its starts sometimes but when trying to start it while its ttuning over it stops then starts turning and starts up. Then i drive whereveri am going when i get back in to start theres nothing.its not turning over at all but when i turn the key there is a loud single knocking noise coming from behind the dash near the passenger floor vent. Actually there ate two noise from the same area, one when i initially trun the key and another when i release the key. But after just sitting there doing this it will finally turn over and start. Can anyone please help me with what this is, there are no codes being thrown besides my dreaded P0401 which i cant seem to get rid of either. Ive changed every part that has to do with the egr system and cleaned the throttle body replaced vacuum lines and still the code. But anyway any help i would be greatly appreciated. Sorry for the long winded writing.

 

next time the truck does not start check for power at the starter when your turn the key to crank. how your gas mileage lately no froze bound engine accessories. check system voltage also.

 

My gas mileage has dropped alot but i assuming it was the p0401 i have a bad sputter or surge because of it. I have had that code and chasing it for almost a year now

 

You have a cable from battery to start relay.
A cable from start relay to starter.
You have a ground cable from the battery to the starter area.
You have a starter. The starter could have worn brushes.
The issue could be any of these items on a truck of this age.
You have to inspect all of them for an issue and tightness and make some tests.
Good luck.

 

which issue would you like help with. if the no crank no start issue check power and ground at the starter when you try to turn the engine. just because you have a code present does not mean it has anything to do with the problem. is your truck a automatic or standard

 

Ty for your reply. I will check thise things today it was pouring here yesterday. So what is that clunking noise coming from the bottom of the dash when i turn the key. Its not a continuous clicking its just one clunk.

 

Sorry carguy i did not see your post. I would like help with the both but can we start with the starting issue. It did it again this morning..starts up fine drove into work stopped to get coffee then nothing just a clunking sound from bottom of dashboard. Got to work checked all connections and seem to be tight and corrosion free. I have power to starter. With just me its hard to pinpoint it seeing how you have to be turning the key for it to happen.

 

ok I see what you mean its pretty hard to do the power check while cranking the engine. these older ford starter used to have issues with internal grounding of the starter. the clunk you here is probably the starter solenoid on the starter if its engaging then the contacts in your solenoid could be poor and its getting power but not the starter. as suggested you could have a lot of internal starter issues but usually you just replace it. make sure the engine turns freely when it will not start by hand. but the power measurement at the starter during cranking are very important along with your starter ground but it sounds ok have you tried lightly tapping the starter with the wood of a hammer. also when you check for power make sure it when it will not start.

 

Hmmm, i really dont know how to explain it. You know the noise you get from your ac unit when the blend door changes positions. Thats the type of noise i hear but obviously the blend door doesnt have anything to do with starting. It is definitly.not coming from outside the truck. It is coming from inside behind the dash board around the glove box area. Am i just hearing a resinent sound? The other day it took atleast 50 turns of the key before it just started like nothing was wrong. So i was able to really hear where the noise was coming from. I do have a some mechanical knowledge but i have never heard this sound before.

 

do your dash lights or head light dim down when you try to crank the engine and it will not crank. usually most all power is drawn to the starter so if you tried to switch hvac controls on or off roll a window down it would not do it until the starter disengaged. I had the exact same truck as you and it would make a clicking noise from the dash and when the blend door broke it made a thud sound from behind the dash. do you notice it when the truck cranks. have you jumped the solenoid to see if it will start

 

Now im second guessing myself, lol its so hard because i just went out and tried to get it to do it and the truck started every dag on time i tried maybe 30 times and couldnt get it to do it. I dont get it..im so confused

 

No it only makes the noise when it wont start.

 

I do hear a click but its the relay in the fuse box not the clunk i hear from the dash cupholder area.

 

is it heat related try a hot test drive and shut it off see if it will not start these issues really get you thinking and annoyed. is your hvac turned off

 

No nothing dims, still have all lights dings everything works