Truck wont start.

Asked by Debbie_Fox Jun 26, 2018 at 08:58 PM

Question type: Maintenance & Repair

1989 f150 4.9l, truck died & will
not start now. Ive chkd the
basics & replaced. Fuel pump is
coming on, not sure if its holding
enough pressure tho because I
turned key on & off few times to
build pressure & then started it
up but only ran for a few
seconds & died. Now it wont
start again. I havent chkd the
EGR, that is next but how do I
clean it if dirty? Truck has been
running great until this with no
problems. Will a fuel pump turn
on even if its going bad or do
they just quit at once. HELP
please. Do i need to chk any
lines any where else like vacuum
lines?

2 Answers

7,365

They usually just go out but can slowly die also. Fuel pump relay can cause issues too, jump the slots in fuse box with a short piece of wire (12- 16ga) that correspond to terminals 30 & 87 on the relay, this will power up your fuel pump and tell you if the relay is the problem or not. Check fuel pump with a pressure tester and check for volume also, if you can pump 1 liter/1 quart in under 30 seconds you should have enough volume. Your fuel pressure specs should probably be about 33 at idle and over 40 at cruise (or with the vacuum line off the pressure regulator) but dont quote me on that you should look it up to be sure. Your egr would have to be stuck mostly open to cause your problem, cleaning doesn't always work anyways but blocking it off with 2 new egr gaskets and a piece of tin/ thin sheet metal will aid in either proving/ eliminating it as a problem

7,365

Fuel filter, thats the first thing you should suspect, unless it's brand new, replace it.

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