Thanks,
PCM's are both Refurbs, 1st was junk, but
last two do exactly the same thing, so unless it were the issue of the
security system shutting it down, I doubt it's that, god 1w2v at
injectors, will run a test on the side going to the PCM to ground, but i'm
pretty sure there is none... question is why?
i've unraveled the
engine harness looking for any sign of melted/crossed wires, will confirm
connection on the lines going to the PCM, but doubt it's that cause they
are ALL dead, if only 1 cyl was dead i'd say 1 bad wire...
I see the
cap's on the 12v line too? prob. to stabalize voltage, if bad prob go to a
short...
truck has no security system, just a door lock
clicker, but as I had been reading online, somehow there can be an issue
if you get a PCM that has security turned ON, and install it into a truck
w/o it???
But I have NO idea how any of that functions!
Yes,
plenty of fuel pressure.
Thanks for the
help!!!!
>
> On Tuesday, August 28, 2012 07:04:43 PM you wrote:
>> I'm at my wits end, replaced PCM 3rd time, still no start, no
codes,
>
> Are these new PCMs, or junkyard / refurbs or what? Are they actually
known
> to
> be working? It seems unlikely that you'd have a dead one, and get
two
> identically dead replacements.
>
>
>> all looks good except no fuel signal to injectors, if I spray
>> starter fluid runs fine.
>
> So the fuel pump is running, and you've got pressure at the
injectors?
>
>
>> actually when I prob the signal side of an
>> injector with a test light the truck fires few times cause
apparently
>> the
>> test light is helping it fire the injector since the PCM
>> isn't...
>
> Looking at the FSM, it looks like the injectors get power on a common
bus,
> and
> the PCM controls the ground side. So if you put a meter on the power
side,
> is
> there 12V present?
>
> If I'm reading the schematics correctly, you've got 12V from the
battery
> coming through the "automatic shut down relay" in the power
distribution
> centre.
>From there, it goes through "joint connector no. 2" in the
PDC.
> After
> the connector, it goes to all of the fuel injectors.
>
> On the other side of the injectors, each one gets a line back to the
PCM.
>
> Since you have _no_ injectors, I'm thinking the PCM isn't where you
should
> be
> looking, but on the other side of the injectors where all of that
common
> wiring is.
>
>
>> New Cam sensor, new Crank
>> sensor(Bi^$@# of a time getting old one out!), have 12v at
injectors,
>> and
>> spark...
>
> Hmm. So you're pretty sure that the power side is good, then. And if
you
> ground the injector (like with the test lamp), then it sprays? How
about
> testing it the other way around, if you can? Hook the test lamp to
power,
> unplug the PCM side of the injector, and see if the PCM is
switching
> ground to
> it. That should light the lamp.
>
> Looking further at the PCM, there's a capacitor on the +12V side
of
> things,
> tied to ground. It's not clear to me what that's for, unless it's
just
> providing electrical smoothing. But if that were bad, I'd expect it
to
> either
> drag the +12V down so that nothing worked, or to go up in smoke.
>
>
>> saw few mentions of security enabled PCM's
>> causing similar issues when installed in a truck w/o security?
>> but
>> does that kill the 12v or just the pulses???
>> how do I find out if
>> thats my problem???
>
> Are you referring to the "Sentry Key Imobilizer Module"
(SKIM)? If so,
> that's
> on the steering column (do you have one? or not?), and the FSM
says:
>
> When the ignition switch is turned to the On posi-
> tion, the SKIM transmits an RF signal to the tran-
> sponder in the ignition key. The SKIM then waits for
> an RF signal response from the transponder. If the
> response received identifies the key as valid, the
> SKIM sends a valid key message to the PCM over
> the PCI data bus. If the response received identifies
> the key as invalid, or if no response is received from
> the key transponder, the SKIM sends an invalid key
> message to the PCM. The PCM will enable or disable
> engine operation based upon the status of the SKIM
> messages. It is important to note that the default
> condition in the PCM is an invalid key; therefore, if
> no message is received from the SKIM by the PCM,
> the engine will be disabled and the vehicle immobi-
> lized after two seconds of running.
>
> So I'm going to guess here that this isn't your problem. It says that
it
> disables the engine, but it doesn't say how. But it says "after
two
> seconds",
> and you're not getting even that far.
>
>
>
>
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