2008 150 txrg starts and shuts off constantly

[arctic 1]

Hello guys I hope someone can help,

took my boat out for the season and first trip ran for about 10 min and then died.
Assuming it was water I cleaned everything and still no go.
I have 45 lbs at the fuel rail and seems the spark is good.

I am getting a code 18 TPS on the yds that wont clear.
I changed the tps but still the same.

when trying to start now it fires for a second and then quits



I need help as I don't know what else to do




I need help

[arctic 1]

any input might help

[rodbolt17]

you have other issues.
that engine will run with the TPS tossed in an appropriate EPA dump site.
did you check the REF voltage?
did you check pin to pin from the ecu to the TPS or did you just chunk a TPS at it cause the puter says its bad?

[arctic 1]

what is the ref voltage
also I did just throw the tps at it
also tried ecm on another 150
isc valve is burning hot is this normal?
got fuel coming out of the injectors
spay intake cleaner in the intake and she fires

[arctic 1]

rodbolt,
I don't know what else to do

I have 145llbs compression on all cyls
have 45 lbs to fuel rails
good clean gas
good spark jumps about 1/4 inch
it cranks and tries to fire then dies as were first it would run for a bit and then stall.
If I open the intake and spay a drop of intake cleaner in she will fire right up

I checked vst and all filters for blockage and dirt but turned up clean

took the injector rail off and held in the injectors and cranked it and they all sprayed fuel.

the only things I can see that seems odd are the isc valve seems very hot and also the fuel filter on the front of the engine seems to have pressure is this normal?

[rodbolt17]

unplug the ISC and see what happens.
yes a defective ISC can over current the ECU and burn up ECU,ign coils and other stupid things.
remember the value you see on the yds is simply a request.
the ecu does not monitor a physical ISC position.

[twirk_twirk]

My first thought is you might have a battery that has too low of a Ah rating for your engine. This can cause damage to your electronics if voltage drops below a certain number while cranking engine.

Happened to me with my f115.

This is what the shop manual says for an F150AET:

[arctic 1]

awesome

I think we have it narrowed down to that

can this stop it from starting?

pretty sure it didn't get my ecm yet as I tried it last night on another and it fired right up

if it is not that I am out of options
unless you have any more suggestions

[arctic 1]

rodbolt I forgot to mention I did unplug it and still don't start but can it start without it

and twirk
I will try a new batt but pretty sure mine are fine as I used the last year
but right now I am open to try anything

[twirk_twirk]

I would just check the spec on your battery. If it's within spec then no problem, however I ran under spec'd battery for one and a half seasons before electronic problems started showing up. Swapped the faulty part, and swapped out my battery and poof, problem disappeared.

It could potentially be the root of your problem. Worth a look at least.

$.02

[arctic 1]

thanks for talking to me
been calling all over Canada all day to get no progress brought it to the local dealer today to get charged 300 bucks for me to tell them what to do

[arctic 1]

def will check twirk
tks
and every ..02 works

[twirk_twirk]

The ECM/ECU/CDI controls spark timing (among other things) and engine will not run without it.

That is my understanding.

[arctic 1]

tell me if I am nuts but it don't make sense to have fuel fire and compression but still no go the only thing left is air which I am hoping is caused by the ISC which I will try to get my hand on tomorrow

[twirk_twirk]

Do you have the YDIS software by chance?

If so what does your intake pressure and atmospheric pressure read at key on and during engine idle (if you have those numbers. I know you say you can't start the engine)?