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Old 03-16-2019, 04:06 PM
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Shade Tree Welder Shade Tree Welder is offline
Grumpy Bastard
Join Date: Jun 2004
Location: Kankakee County, IL
Posts: 20,392
Default Dodgy Engine Rebuild (318 / 5.2L)

Initial email

The Dodge is broke dick and I am at a loss for WTF could be wrong...

The kid was driving it home a few weeks ago and it all of a sudden starting
running really poorly. Sound like the timing chain jumped a tooth, but it is
not that...

Okay what we have done to this point. Just keep in mind that nothing we
have done up to this point have made anything better or worse. Also with
it running like shit it has no power and will die on us.

1. Replaced the timing chain, but the alignment marks were all good even
with the old chain was had worn a little bit and was loose.

2. Checked fuel pressure, spec is 35-45 psi; it is running at 46 psi with the
engine running at the fuel rail

I got an OBD II reader that could communicate with the Dodge, the spark
advance is going from 3° to 28° back and forth like a saw tooth. I have no
trouble codes but it is still running like shit. See Picture.

3. Replaced the camshaft position sensor and the crankshaft position sensor.

4. Tonight replaced the PCM (Powertrain Control Module aka ECM)

With the new PCM, still no trouble codes and still running like shit, like I said
it runs like the timing chain jumped a tooth.

WTF could it be??? BTW 1999 Dodge Ram 1500 with the 318 (5.2L).

Chad: confirmed good plugs and wires? (would think would show up as
a misfire if these were issues)
(Just did a tune up so all new plugs, distributor and rotor, wire are reused
but I doubt that is the issue because it is all cylinders and just happened at
once.) not sure on the 318, but is there an additional crank position sensor
on the bellhousing like on the old 4.0L 6?
Ron: Yes the crank position sensor is on the bell housing; it is the only one,
and it has been replaced with no change in performance.

Chad: No issues with the fuel itself? (reaching)
Ron: It happened all of a sudden, like one second it was running normally,
the next it was fucked up. Doubt it is a fuel problem, good fuel pressure to
the rails so if it was an injector issue I doubt all eight would fail at the exact
same time.

Chad: Vacuum leaks should show as lean codes on the reader.
Ron: Again no codes. All the vents work as they should in the dash, so
vacuum is working at some point well enough, I think.

Chad: All the valves opening/closing as intended (no bent push tubes
(ha ha) or burnt valves that you can tell? Good compression on all 8?

Ron: Again it changed all at once, so I doubt a valve train issue, the time
marks were all in alignment when we dug into the engine.

Ron: I was thinking maybe something electrical but then I should have a
code. No codes...

Chad: Also I remember you saying it happened when it hit a bump... is
there something in the incoming air ducting (foreign material) or a flapper
door, or something, that can move that is obstructing the airflow or moving
to obstruct the airflow under acceleration?

I had a Bronco II that I had a shop swap a 4.0L into from an explorer. they
used dryer ducting as the air hose, and under deep throttle, it would suck
closed and kill it. fixed that with a $15 factory part... smh

Ron: Nothing I can see and it runs like shit with the air filter housing off. as
well but I could be something below the throttle body/intake manifold...

Via Text I chatted with Neal but I can’t get that conversation to copy over

Neal suggested that the tone wheel in the distributor that activates the
camshaft position sensor could be loose. I really thought that might be the
answer. Sadly no, the tone wheel was very secure…

Also he suggested that I check compression and that will be the next step…
Just not likely today, other things need to be sorted out.
1999 Dodge Ram 1500
201,000 miles.
5.2L 318ci engine

I just had a thought as I was posting this, could it be the catalytic converter
that blinded off?

"Prepare to defend yourselves."
-- Sergeant Major Basil L. Plumley, Ia Drang Valley
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