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Today, it finally warmed up some, so I started working on the 93 F150 that I bought to fix up for my daughter.
When I first brought in home it started and run, and I pulled it into the shop, and she cleaned it up, and I looked it over a little.
It ran fine with we pulled it in, but when we tried to start it, and move in out side, and it failed to start.
Today I did some trouble shooting and it has 42 PSI on the fuel rail, and has spark. It will start on starting fluid but only until that runs out, then nothing.
So fuel on the rail, and spark, but it seems like its not firing the injectors. I know there is something that triggers them, but I dont know what creates the impulse that causes them to fire.
Do any of you guys know triggers the injectors? I am not sure where to start.
The truck only had 73000 mile on it, and its a really solid truck. I have considered pulling off all the fuel injection, and swapping to a carburetor, and an earlier ignition system.
Probably have to change to an earlier trans as well, and do away with all computer stuff?
Unfortunately this truck falls into an area that I am not real well versed on. We have had several more modern trucks and cars with the 4.6, but autos with OBD2 are a little easier to trouble shoot.
Any suggestions? Thanks so much!
If you turn the key to run but don't engage the starter, does the fuel pump run for a second and then stop or does it run continuously? If the pump doesn't stop there is a problem with the PCM, the timer for the initializing sequence isn't completing so the computer never gets into startup mode where it is ready to fire the injectors. This fault usually occurs as a result of blown electrolytic capacitors that sometimes cause further damage on the circuit board, and the fix is to replace the PCM.
It is possible to pull codes from this PCM as well, it can be done without any special tools by simply grounding the STI pin in the EEC TEST connector in the engine bay, you then turn the key to run and count the flashes on the check engine light. There is a code reader(Equus/Innova 3145) that will take all the guess work out of code reading... and it's not expensive, but if nothing happens when you do the above exercise then that is another indication that the PCM has a fault.
45psi is high for a V8 but too low for a L6. You didn’t say what engine is in the truck. It could be that the computer is not pulsing the injectors but until you use a noid light to confirm that you are guessing.
how long has it sat? how old is the gas?
the current ethanol crap they call gas goes bad real fast, and will really screw up injectors.
i had a truck that sat for 3 months that needed the whole fuel rail, and tank removed, flushed out, and injectors cleaned.
and it still ran like crap for a week until all the crud was pushed out of the fuel system because i did not flush the tank to rail lines.
Thank you all for the help, and information. Today was a typical Monday at work, and I had a few things to do after work, so no progress tonight.
I just went out and check to see if the fuel pump shuts off after a few seconds. No it still kept running for the minute or more, until I turned off the key.
So from the sound of it the PCM must have failed?
To answer a couple of questions. Yes its a 5.0 engine, and yes it has sat for a while.
We will see what else I can uncover tomorrow, and I will report back.
Classic symptom of a failed PCM (computer). Some have replaced any/all leaking capacitors on the circuit board, others were not so lucky or do not have the tools or skillset.
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