Po452

[mongocanfly]

Ok.. I'm still in a no crank mode on my swapped 03 5.3 into the IH
Thought it was plugged injectors..
Went thru the whole cleaning process..Got it back together
Still no crank.
Thought it could be fuel pressure ,Ruled that out with a gauge on the rails...
its sitting right on 58psi
So I hooked a scan tool up and its showing a po452 code
Which is fuel tank pressure fault.. which according to a search means loose gas cap
Which I dont think will keep it from starting..
And it also could be fuel tank pressure sensor, which I dont have..
The back ground
I changed the intake to a Holley 300-136, mounted the maf and throttle in the carb position
I basically copied everything that dayj1 did on his cat skinner build
I can pour a little gas thru the throttle, and itll fire right up and run that gas out
When I try normal cranking, itll hit every now and then, but never cranks
Any ideas?

[Accelo]

"I'm still in a no crank mode on my swapped 03 5.3" My comments are assuming you mean "cranks but doesn't start."

You can pull the fuel rail and crank the motor with everything hooked up. Visual confirmation that everything is working correctly. I had purchased injector pigtails from Ebay that were pined incorrectly. That was a PITA to find.

Silly questions;
Did you get the VATs removed from the computer?
Are all the grounds connected?
Does the fuel pump come on for 3 second and then quit when the key is turned on and the motor not started?
The one that gets the most people is there are two computer connections, one is powered all the time and the other is 12v when running.
The motor temp sensor has to be hooked up and working correctly.

The code is “Evaporative Control System Pressure Sensor Low Input.” Typically the computer's ability to set this code is also removed when the ECM is programed for a transplant.
Cheers

[mongocanfly]

(My comments are assuming you mean "cranks but doesn't start.")
it will crank and run, as long as i pour gas in it by hand...guess i should have said no run mode


answer is yes to all of the following...

(Silly questions;
Did you get the VATs removed from the computer?
Are all the grounds connected?
Does the fuel pump come on for 3 second and then quit when the key is turned on and the motor not started?
The one that gets the most people is there are two computer connections, one is powered all the time and the other is 12v when running.
The motor temp sensor has to be hooked up and working correctly.)

[Richard]

Not sure if any help but here is something. In my PSI harness there are wires that need constant 12v and one that is swtiched. It is noted that the most common no start/run problem is the switched 12v wire. Indicates the wire must have 12v during crank and run.

[mongocanfly]

ive got the constant 12V and the switched 12v
to clarify..it will crank, it will run...if i pour gas in it the throttle
i think its just not firing the injectors , but im not sure if the po452 code is why.. but thats what pops up on the scanner
the engine ran fine in the donor truck...i heard that happen before we pulled it..
i may need to call the tuner guy that unlocked my ecm and see what he says...hes real busy though ,and hard to get ahold of

[Richard]

Guessed you probably already had the switched 12v. Depending on where you are getting it from, pointing out on some ignition switched sources the 12v goes away in the crank/start position.

[Jason Banks]

P0452 you need to tune out to not turn on the CEL/MIL. It would not prevent you from starting. I'm assuming you don't have the whole evaporative emissions system and this is a swap vehicle. Sounds like you don't have HP Tuners? Or have you not had any programming done to the computer?

If you suspect injectors are not firing, you could first check and make sure you have battery positive at all of them. They are negative/ground triggered from the ECU.

If you have battery voltage at all of them, to test the negative trigger, it is easiest to use an "injector noid light".

[mongocanfly]

yeah, from reading, i kinda figured the 452 wouldnt keep it from cranking
no evap, no hp tuner, the only thing done to the ecm is the basic unlock and base tune..
was planning on the dyno tune once i got it mobile
testing for 12v at injector was my next step, just havnt had time..
all the PSI grounds are hooked up, and i have double grounds on engine to frame to cab.. ive got extra grounds

[mongocanfly]

Ok...finally got a chance to check for 12v at the injector..
It was hard to get anything into the injector plug, but I managed to get a small wire Into it..
And checked with a fluke ..Switch on and I have 12v at the injector...
I only checked one that was easy to get to..
So I've got 12v there, so I assume they all have 12v..
I wish I had something that would fit the plug so I could check to see if I get a ground while cranking

[clay68c10]

You could use a short piece of wire the right size and an alligator clip meter lead end. Maybe a paper clip would be a close size. Just don't go too big or you'll stretch out the pins.
If you have a Hz (frequency) function on the Fluke it should read. Otherwise it probably won't, the ground pulse is too fast.

Ideally a noid light is your go-to in this situation.

[mongocanfly]

I've got a noid.....somewhere...couldn't find it last night, that's why I used the fluke..
Didnt think of a paper clip...good idea..I'll get one and try that.. now...where is my noid?????

[mongocanfly]

I think my noid lights got loaned out and never made it back home.. so I ordered some new ones..
They showed up in the mail today... Injectors not firing ...no time to troubleshoot for a few days

[Accelo]

It appears the ECM is not grounding the injectors. Could be wiring or?

[mongocanfly]

Yeah, 1st chance I get I'm gonna check all the connections..gotta work next 9 days so itll be a minute