have a 91 f 150 xlt with 101,000. miles on it.sometimes it will not start ,and if it does check engine light comes on and od light will not work ..also the fuel pump will stay runnin if it does not start.have tuned it up and have replaced the egr valve and thermactor system .the problem still persists.if it does run when check engine light on it feels sluggish like no gears..had transmission rebuilt ,beefed up convertor and all the goodies in tranny.problem is still same...i need help thnx .. bigmicj

 

Have the codes checked first! then get back to us.

 

When was the last time you changed the fuel filter?

 

.i got 114 code and a 116 code.found broken bacumm line on thermactor system replaced it.no code now for it.temp sensor i replaced and code is not on for tht.but i still get no start and fuel pump stays on and doesnt shut off like it used to and check engin light comes on.thnx for ur guys help. bigmic

 

. since i have owned it which is 4 yrs ,i have never changed it but i havent put but maybe 10,000 miles in it it sets alot ,,use it for pullin my boat .thnx for ur help. bigmicj

 

Well change it, just because it doesnt have much mileage, all that sitting causes s^^t to build up in the fuel and clogg that filter.

 

What engine & trans do you have? let me guess, 5.0 & E4OD?

Are those; Key on engine off, Key on engine running or Continuous codes? All need to be checked and noted down for accurate testing. Sorry, should have mentioned that earlier.


Do you have a service manual? Check if the "EEC power relay" or fuel pump relay is staying on, when the problem occurs. That is strange that the fuel pump stays powerd up. I remember that used to be a normal condition with some scanners way back when, but would shut off w/out the scanner hooked up.

Check all of the grounds for the engine controls under the hood and under the dash, this sounds like a broken/corroded wiring or processor issue (just a guess) and may be difficult to diagnose over the internet, but you have to start somewhere.

 

it is a 5.8 liter with e4od.tranny is redone.fuel pump stays on with check engine lite on .with no code scanner on it.when it starts if it gets up to operating temperature it is fine and runs all day. checked grounds and connections ,i am thinkin pcm is my problem..thnx bigmicj

 

A PCM is a rare problem on a Ford, but not entirely impossible, I think I have had to replace one or two in twenty years or so. You still need to get "all" the codes checked and noted, as I mentioned before; KOEO, KOER and Continuous codes. If all are not being checked you will miss something, as all the codes you may have won't show up in every test. Have you tested the MAP sensor?

Did this problem happen all of a sudden, or after something was done?