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Com update and Car work
8 years ago
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Been working on a car for a day or two... and have some very interesting conclusions:
2009 Mercury Grand Marquis 4.6l
Had recurring codes;
p0300 Random/multiple miss
p0303 Miss on Cyl 3
p0306 Miss on cyl 6
p0307 Miss on cyl 7
p0106 Map/baro sensor range
Being a Ford, I suspected the ignition coils and did the normal "Musical chairs" with them. Move the suspected bad ones to a different cylinder and see if the code moves to that cylinder as well. No luck... The codes stayed on the same cylinders.
Injectors! Did the same with those, shuffle them around. No change, same cylinders. The injector harness checked out with a noid light test across all 8 cylinders.
I've ruled out electrical and it was time to test for mechanical. Yay...
Compression test was my next go to, all cylinders were reading normal aside from Cylinder 6, which had 0psi compression.
Just then a though occurred... I'd done almost the exact same thing on the same engine type, and the problem there was a collapsed lifter.
I removed the valve cover and behold, I found the rocker arm had FALLEN OFF the lifter and was laying in the bottom of the head. Well, problem solved. Replaced the hydraulic lifter and the rocker arm, inspect the camshaft for damage. Car runs fine now.
Afterward: I found it odd initially that the MAP/BARO sensor was throwing a code, but after thinking on it, I figured out why. The MAP sensor monitors pressure/vacuum in the intake, and is pre-programmed with a set of parameter values (X-Y reading range) IF there was an intake valve that was not opening (CYL 6), then the computer that is looking for 8 pulses of vacuum will only see 7, thus triggering the code to pop.
The misfires on cyl 7 and 3 were from the fuel pooling at the valve that was not opening and spilling over into the adjoining cylinders (3&7)
It's a pain in the ass to chase 'phantom' codes and problems... codes that pop up because of another issue. But, if you don't get overwhelmed by the amount of codes, and only tackle the core issue (Misfiring) it helps to smooth things out. If they are 'real' codes and not phantom codes, then they will come back after the larger issue is solved. If they are a symptom of the problem, then they will clear out once the problem is solved.
So for future reference, I shall keep in mind that a MAP/BARO code could be an indication of a mechanical valve problem, but only if paired with re-occurring missfire codes.
___________
And now for something completely different...
___________
So far I have 21 commissions to get to, already completed 3.
If you submitted a note, I shall get to you
Doing Commissions:
Send a note and I'll get to you in order!
Feel free to browse through my latest submissions as a guideline for what you can expect to get!
Base price, 15$
Add Char +10$
Send a note to my FA with character ref, description of what you want drawn and so on. If I have questions, I'll note them back.
2009 Mercury Grand Marquis 4.6l
Had recurring codes;
p0300 Random/multiple miss
p0303 Miss on Cyl 3
p0306 Miss on cyl 6
p0307 Miss on cyl 7
p0106 Map/baro sensor range
Being a Ford, I suspected the ignition coils and did the normal "Musical chairs" with them. Move the suspected bad ones to a different cylinder and see if the code moves to that cylinder as well. No luck... The codes stayed on the same cylinders.
Injectors! Did the same with those, shuffle them around. No change, same cylinders. The injector harness checked out with a noid light test across all 8 cylinders.
I've ruled out electrical and it was time to test for mechanical. Yay...
Compression test was my next go to, all cylinders were reading normal aside from Cylinder 6, which had 0psi compression.
Just then a though occurred... I'd done almost the exact same thing on the same engine type, and the problem there was a collapsed lifter.
I removed the valve cover and behold, I found the rocker arm had FALLEN OFF the lifter and was laying in the bottom of the head. Well, problem solved. Replaced the hydraulic lifter and the rocker arm, inspect the camshaft for damage. Car runs fine now.
Afterward: I found it odd initially that the MAP/BARO sensor was throwing a code, but after thinking on it, I figured out why. The MAP sensor monitors pressure/vacuum in the intake, and is pre-programmed with a set of parameter values (X-Y reading range) IF there was an intake valve that was not opening (CYL 6), then the computer that is looking for 8 pulses of vacuum will only see 7, thus triggering the code to pop.
The misfires on cyl 7 and 3 were from the fuel pooling at the valve that was not opening and spilling over into the adjoining cylinders (3&7)
It's a pain in the ass to chase 'phantom' codes and problems... codes that pop up because of another issue. But, if you don't get overwhelmed by the amount of codes, and only tackle the core issue (Misfiring) it helps to smooth things out. If they are 'real' codes and not phantom codes, then they will come back after the larger issue is solved. If they are a symptom of the problem, then they will clear out once the problem is solved.
So for future reference, I shall keep in mind that a MAP/BARO code could be an indication of a mechanical valve problem, but only if paired with re-occurring missfire codes.
___________
And now for something completely different...
___________
So far I have 21 commissions to get to, already completed 3.
If you submitted a note, I shall get to you
Doing Commissions:
Send a note and I'll get to you in order!
Feel free to browse through my latest submissions as a guideline for what you can expect to get!
Base price, 15$
Add Char +10$
Send a note to my FA with character ref, description of what you want drawn and so on. If I have questions, I'll note them back.
This isn't the first story like this I've read recently. Someone had a problem with his Mercedes 380SL that turned out to be a rocker arm falling off. weird.
*Edit* The oil pressure itself can be a problem too, though that would manifest across all the upper valve system, wear, heat ect. In this case it was the single part that caused the fail. It's endemic on the 4.6 ford engine...
This thing had no electronics aside from the very strong sparker. It seems to me that the lesson from both of these stories is to always to a thorough inspection of the mechanical systems that the electronic systems are only smart enough to manage properly when they're operating correctly.
I like writing space suit porn and I really enjoyed reading Tom Clancy's submarine porn. I think I'll have to figure a way to add some space ship mechanical porn to my sci fi writing … if I can avoid sounding like Star Trek EPS Conduit Porn.