Dodgy Engine Rebuild (318 / 5.2L)

[Shade Tree Welder]

Initial email

Gentlemen,

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
soooo…

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?

[milomilo]

Seems to me that the timing going from 3 to 28 and back and forth is the reason it is running poorly. Find that cause and I think you are in business. Since you replaced the ECM, I am not sure what else could cause that condition.

[digr]

Catalytic converter could be it all right. What did ya have too pay for the PCM?

[Shade Tree Welder]

Originally Posted by milomilo

Seems to me that the timing going from 3 to 28 and back and forth is the reason it is running poorly. Find that cause and I think you are in business. Since you replaced the ECM, I am not sure what else could cause that condition.

Also the camshaft position sensor and the crankshaft position sensor,
no change in running... This is part of what has me really confused...

Originally Posted by digr

Catalytic converter could be it all right. What did ya have too pay for the PCM?

PCM was $255 Amazon Prime.

[Whitetrash]

Ron, perhaps a direction to look as you chase this. My thought right away is how does the sense the dist. timing and adjust advance.
The ignition timing on your truck is electronically controlled by the engine controller. Turning the distributor does not change ignition timing, but getting it in the right spot is very important. With the timing controlled by the engine control module, you can't set the timing on these engines with a timing light. It's just all over the place.
*
Putting the distributor in the right position on these is called "setting sync". This is best done with a dealer scan tool, but can be done with a voltmeter. You are setting the rotation so the cam sensor (inside the distributor) toggles its signal voltage at the perfect time. It needs to be within 10 degrees of 0 (preferred is 0), if its closer to 20 degrees it will set a code for intermittent loss of cam or crank signal, and if its far enough out it will actually send spark to the wrong pole on the distributor cap, or it will fire to two wires at once. Here is the procedure to set the distributor on your truck without using a dealer scan tool.
*
Connect a voltmeter to the distributor sensor connector by removing the end seal and carefully back probing the connector. Connect the positive lead to the sensor output pin (pin 3, either a tan wire with a yellow tracer or a gray wire, depending on vehicle application). Connect the negative lead to battery ground.
Rotate the engine clockwise as viewed from the front, until the number one mark piston Top (TDC) compression on the vibration damper should line up with the zero degree (TDC) mark on the timing chain case cover.
Continue to rotate the engine slowly clockwise until the V6 or V8 mark on the damper(depending on engine type) lines up with the zero degree (TDC) mark on the timing chain case cover. The V8 mark is 17.5°after TDC and the V6 mark is 147° after TDC.
NOTE: DO NOT ROTATE THE ENGINE COUNTER CLOCKWISE. IF THE ENGINE IS ROTATED BEYOND THE MARK, RETURN TO STEP 6 AND REPEAT THE PROCEDURE.
With the distributor clamp bolt loose and the ignition switch in the ON position, rotate the distributor slightly in either direction until the voltmeter switches between the sensor transition point of 0 and 5 volts.
Adjust the distributor as close as possible to either side of this transition point and tighten the distributor clamp bolt

Someone else on another site was good enough to post this. The computer handles everything, but you have to set the starting point.

[flametamer]

Other than the crank and cam sensors & the PCM, these are common faulty items I found on Identifix:

Distributor Sync
Oxygen (O2) Sensor
Intake Plenum Pan Gasket
Coil
Distributor Cap and Distributor Rotor

The fact that it isn't setting codes is what is interesting to me.

Dt

[toprecycler]

Water in the gas?? Or did someone put something in the tank to mess with your boy?


Sent from my iPhone using ShopFloorTalk

[Shade Tree Welder]

Originally Posted by Whitetrash

Ron, perhaps a direction to look as you chase this. My thought right away is how does the sense the dist. timing and adjust advance.
The ignition timing on your truck is electronically controlled by the engine controller. Turning the distributor does not change ignition timing, but getting it in the right spot is very important. With the timing controlled by the engine control module, you can't set the timing on these engines with a timing light. It's just all over the place.
*
Putting the distributor in the right position on these is called "setting sync". This is best done with a dealer scan tool, but can be done with a voltmeter. You are setting the rotation so the cam sensor (inside the distributor) toggles its signal voltage at the perfect time. It needs to be within 10 degrees of 0 (preferred is 0), if its closer to 20 degrees it will set a code for intermittent loss of cam or crank signal, and if its far enough out it will actually send spark to the wrong pole on the distributor cap, or it will fire to two wires at once. Here is the procedure to set the distributor on your truck without using a dealer scan tool.
*
Connect a voltmeter to the distributor sensor connector by removing the end seal and carefully back probing the connector. Connect the positive lead to the sensor output pin (pin 3, either a tan wire with a yellow tracer or a gray wire, depending on vehicle application). Connect the negative lead to battery ground.
Rotate the engine clockwise as viewed from the front, until the number one mark piston Top (TDC) compression on the vibration damper should line up with the zero degree (TDC) mark on the timing chain case cover.
Continue to rotate the engine slowly clockwise until the V6 or V8 mark on the damper(depending on engine type) lines up with the zero degree (TDC) mark on the timing chain case cover. The V8 mark is 17.5°after TDC and the V6 mark is 147° after TDC.
NOTE: DO NOT ROTATE THE ENGINE COUNTER CLOCKWISE. IF THE ENGINE IS ROTATED BEYOND THE MARK, RETURN TO STEP 6 AND REPEAT THE PROCEDURE.
With the distributor clamp bolt loose and the ignition switch in the ON position, rotate the distributor slightly in either direction until the voltmeter switches between the sensor transition point of 0 and 5 volts.
Adjust the distributor as close as possible to either side of this transition point and tighten the distributor clamp bolt

Someone else on another site was good enough to post this. The computer handles everything, but you have to set the starting point.

I am going to have to read that a dozen time to understand that...

But thanks.

Here is what the advance was doing.

[Whitetrash]

Long story short Ron, that thumbnail looks like a dog chasing it's tail. Beg, borrow,or steal another distributor. My gut tells me something is FUBAR in that distributor. The tutorial is a how to on keeping the components within the design limits of the ECM specifically the dist.

[MetalWolf]

Originally Posted by Shade Tree Welder

Initial email


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?

Ron.
Out of curiosity how did you determine the timing chain is not the issue ???

The timing chain doesn't have to jump a tooth... it can be, A stretched timing chain and that will cause the exact same problem... 99 to 01 were what we call gender years. Dodge screwed with all their better ideals and passed them along... and turned out it just made some issues worse...