runnermedic

Big update here
finally solved 3 years later!!!!

well today i finally fixed this electrical headache !! no more running pump while switch in on pos and now the obd reader works!!!

the culprit in my case was that the po bypassed the neutral safety switch by energizing the starter relay from the efi fuse so thats why the pump never stop priming and the obd port never worked ,so i undo the jumper and it works.
BUT!!! now it wont crank because theres no signal going to the starter relay wich means that maybe the neutral safety switch is cloged with dry grease or maybe the factory alarm which i removed was causing the problem,anyway im taking out the nss and clean it if this dont fix it im going to make a new line from ignition switch to starter relay and its done!!!

right now is starting great with a push button wired to the starter relay but i dont want to have that funky dance to start it.

runnermedic

Finally working great!!
obd port working and starting via ignition switch,perfect!!!

jgard2702

what did you end up doing? I manual swapped my limited with the engine and trans from my sr5, used full engine harness and ecu but im haveing the same issue as you, fuel pump constantly running, and a miss around 3k rpm. I have jumped my park selector switch to get it to run when i initally did the swap, so wondering what you did to get around that. Was a great running engine in the sr5.

jgard2702

what did you end up doing? I manual swapped my limited with the engine and trans from my sr5, used full engine harness and ecu but im haveing the same issue as you, fuel pump constantly running, and a miss around 3k rpm. I have jumped my park selector switch to get it to run when i initally did the swap, so wondering what you did to get around that. Was a great running engine in the sr5.

runnermedic

Check the engine bay fuse/relay box ,someone jumped the fuel pump relay underneath.
i think it was related to the factory security system so it was bypassed,at this date is rare to find one with a working antitheft system thats why almost everyone is jumped.
if the engine has a hiccup check the spark plug boots/tubes they develope hairline cracks arching inside the plug hole.

jgard2702

Thanks for the reply! Will do, i think youre thread has got me on the right direction tho

83

Huh. I have no hesitation issues, but I do have an issue with people always correcting me when I say my fuel pump runs with the key in the "on" position. Aside from the fact that everyone else on this site who replies to threads about when the fuel pump starts running says it doesn't run when in the "on" position, I would have never thought anything of it. Every truck I had before this had a manual fuel pump. I have no "issues", but my fuel pump does run constantly when my key is "on".

runnermedic

it should prime for 2-3 seconds then turn off,if the pump keeps running with out cranking the engine/engine off it nay point to the fuel pump being jumped ,or ignition relay jumped