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Robert
Robert, ASE Certified Master
Category: Dodge
Satisfied Customers: 4157
Experience:  Dodge Master Certified, Dodge Sprinter Certified
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2008 Dodge Charger 2.7. Fully rebuilt engine. New timing

Customer Question

2008 Dodge Charger 2.7. Fully rebuilt engine. New timing kit. Flex plate not broken. Giving P0016 code. Crank cam difference at 1.7-2.3 degrees. Runs excellent. New cam and crank sensors.
JA: Does the vehicle stall at low speeds? Does it sputter?
Customer: No
JA: Are you fixing your Charger yourself? What have you tried so far?
Customer: Yes
JA: Anything else you want the mechanic to know before I connect you?
Customer: No
Submitted: 4 months ago.
Category: Dodge
Expert:  K. Wiggins replied 4 months ago.

Hello, you'll need to start by inspecting the wiring and connectors at the sensors. If those look good next step is going to be to scope them and check for any type of signal drop out. I'll post the complete testing info with diagrams below. If I can help further just reply back.

Customer: replied 4 months ago.
I don't have access to a scope. What is the crank cam difference tolerance in degrees? Is there a relearn procedure that needs to be perfomed after a timing chain replacement?
Expert:  K. Wiggins replied 4 months ago.

Crysler has no given a published spec for any acceptable deviance.. There's no relearn procedure for the crank or cam sensor. On the cam sensor it does matter how it was installed. It should be twisted in until it seats and not pulled down with the bolt, this can cause signal errors

Customer: replied 4 months ago.
The sensor was twisted in after oiling the seal. Any other ideas of what would cause this code? It comes on immediately after erasing.
Expert:  K. Wiggins replied 4 months ago.

If the timing marks are dead on and it's running good, I would look at the ring the cam sensor reads. It might be worth it to have a shop scope them as far as knowing quickly. Double check your grounds for both sensors.

Customer: replied 4 months ago.
Timing marks are dead on. Car runs great. 5v supplies and grounds to ckp and cmp are good. Inspectes camshaft gear and it has no damage at all. Could it be a pcm failure?
Expert:  K. Wiggins replied 4 months ago.

It's possible but not very likely. I'm going to open this up to other experts so others can offeer their thoughts.

Expert:  Robert replied 4 months ago.

Hello, welcome and thanks for asking your question. My name is*****'m a Certified Auto Technician with 29+ years experience. I will do my best to assist you. please keep in mind that I may need to ask questions of you before I can answer. When you reply please feel free to add as much detailed information as possible pertaining to your concern.

Where was the timing kit purchased? Do you have the part number for the timing kit?

It is possible that you have the wrong camshaft tone wheel installed if it came with the timing kit, this is why I need info on the timing kit.

Can you post the last 8 digits of the VIN and the miles on the odometer so that I can do some research on this concern for you?

Keep me posted...

Thank you,

Robert

Expert:  Robert replied 4 months ago.

You also stated that the engine runs good. Have you tried driving it yet? Does the engine rev up easily above 2000 rpm's??

Keep me posted...

Thank you,

Robert

Customer: replied 4 months ago.
Car drives perfect, no problems at higher rpm's. The timing kit dis not include sprockets, just chains, tensioners and guides. Last 8 are 80101802.
Expert:  Robert replied 4 months ago.

It's very possible that there is an nick or slight damage to one of the tone wheel windows of either the Left Cam Sprocket Tone Wheel or the Flex Plate tone wheel. To be sure, you will need to remove the valve cover to carefully inspect the trigger wheel (tone wheel). If there is absolutely no damage, then you will need to pull the trans to inspect the flex plate trigger wheel. If you find even the slightest damage or scratches or slight dents near the trigger wheel windows, replace the affected part...

Keep me posted and let me know if you have any additional questions...

Thank you,

Robert

Expert:  Robert replied 4 months ago.

Hello,

I just wanted to check in with you to see if you need more help with your concern. A non rated question normally times out within 7 days, so I wanted to stay in contact with you to see if the problem has been solved.

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Thank you and thanks for using JustAnswer!

Robert

Customer: replied 4 months ago.
Before I pull the transmission I want to get an oscilloscope and check the signals.
Expert:  Robert replied 4 months ago.

That would be an EXCELLENT idea, make sure it is at least a 2 channel scope so that you can monitor both the cam and crank signals at the same time. This will also help you make sure everything lines up properly as well as finding any stray signal traces...

Keep me posted and let me know if you have any additional questions...

Thank you,

Robert

Expert:  Robert replied 4 months ago.

If you can get some recordings of the scope results and are having a hard time deciphering the signals, I may be able to help diagnose this if you can post the information here. I'll review it and let you know my thoughts...

Click Here for Document Upload Instructions

Thank you,

Robert

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Customer: replied 3 months ago.
I'm trying to upload pictures of the oscilloscope reading. Is it possible to upload from an iphone?
Customer: replied 3 months ago.
Here are pictures from the cam and crank signals. The crank spikes erratically every 4 revolutions on the third or second window after tdc. What could cause this? I have a video of the flex plate from the ckp sensor hole and there is no obvious damage.
Expert:  Robert replied 3 months ago.

It is possible that the tone wheel on the flex plate has excessive radial runout causing the sensor to not get a good signal intermittently. You would need to either pull the engine or transmission to inspect the Flex Plate more carefully, just replace it or try playing with the airgap for the crank sensor.

I've found in the past that even though the crank sensor is not adjustable, you can either slightly grind down the sensor where it mounts at or add a thin shim to play with the air gap to see if you can get a better signal.. Try bringing the sensor a bit farther from the flex plate first to see if things get better, if that doesn't help, then grind down the sensor mounting area a bit and remount it and see if things get better. If neither solutions help, you will have no choice but to pull the eng or trans for close inspection of the flex plate.

Keep me posted and let me know if you have any additional questions...

Thank you,

Robert

______________________________________

Please keep in mind, If I haven't clearly answered your question and you need additional info, please don't hesitate to ask "before" you Rate my Answer.

Remember, RATING is REQUIRED to credit me for helping you!

A "One Star" or "Two Star" rating does not automatically result in a refund so if you would rather have a refund, please reply and let me know BEFORE rating and I will submit a refund request with Customer Service on your behalf...

This site operates on the honor system, meaning I only get paid with a "3 Star" rating or better. Once you are satisfied with my service, please "Rate". Remember, you have already paid to use the site, all the rating does is allow the expert to be paid for his time. Expert Payment comes out of the fee you paid to use the service. Thanks in advance for a "5 Star" Rating.

Customer: replied 3 months ago.
Here are pictures of both signals at the ecm connector. Do you see anything that might indicate what's wrong?
Expert:  Robert replied 3 months ago.

Now both signals seem to appear good.

Are you still seeing the P0016 when you were running this scope pattern?

If you have already verified that the timing chain was installed "In Time" then I would have to conclude that you may have a faulty PCM. That would be the last thing left, especially since you state that the engine runs great.

With a current P0016 and actual problem with the timing system usually causes the engine to not be able to rev over 2000 rpm's. The fact that it runs good and revs over 2000 with no issues leads me to believe you may have an internal PCM failure incorrectly reporting a p0016 code...

Keep me posted and let me know if you have any additional questions...

Thank you,

Robert

Customer: replied 3 months ago.
It drives perfectly until the coolant temp goes to 160. At 160 degrees it throws the code P0016 and the stability control light comes on. When that happens, it doesnt go into over drive. If the car is turned on with the engine hot, it immediately throws the code and turns on the stability light.
Expert:  Robert replied 3 months ago.

Have you checked the codes in the ABS system? The codes setting for the Stability Control may give us a clue as to the problem. With this new info, I suspect a wiring issue causing both problems. Something comes on at 160 that is likely backfeeding causing the P0016 and the Stability Control light to come on at the same time..

Keep me posted and let me know if you have any additional questions...

Thank you,

Robert

Customer: replied 3 months ago.
Found C121C on ABS module, torque request signal denied.
Expert:  Robert replied 3 months ago.

Have you checked the cam and crank sensors using the scope when engine is hot as well as on a cold engine?

Customer: replied 3 months ago.
I didn't notice any difference
Expert:  Robert replied 3 months ago.

The first time you posted pics of the scope patterns, they were bad, the second time you posted them they were good. What was different between these two different instances??

Expert:  Robert replied 3 months ago.

Also, I need to know where you purchased the cam and crank sensors??

Customer: replied 3 months ago.
Cam and crank sensors are the original ones. I also have a cam sensor from Autozone that gives the same scope readings but I removed it. The first scope readings are amplified but they're are basically the same patterns with the same engine conditions and same sensors.
Expert:  Robert replied 3 months ago.

Your original question states it has new cam and crank sensors.

At this time, since the CRANK Sensor was the one that has the dirty signal, and a new factory one has not been tried, I recommend to replace the Crank Sensor with a NEW Crank Sensor purchased from the DEALER.

Don't go aftermarket such as AutoZone as many of these are known to be faulty..

Keep me posted and let me know if you have any additional questions...

Thank you,

Robert

Customer: replied 3 months ago.
I will try a new sensor. What do you think about C121C? Is this related? The diagnosis appears to be very specific either wiring or pcm.
Customer: replied 3 months ago.
Replaced crank sensor with an oem. P0016 comes back as soon as it reached 160 degrees. I ordered an oem crank sensor. I'll try that and let you know. I'm going to measure resistance on the wiring to see if there are any problems there. Do you have a spec for this? Any other suggestions before I replace the PCM?
Expert:  Robert replied 3 months ago.

Hello, Sorry for the delay.

C121C is a "Side Effect" of the P0016. Once you fix the P0016 the C121C should no longer be active.

As for wiring, when you measure from Crank Sensor Connector to PCM Connector, factory specs state 5 ohms would be a maximum acceptable resistance but experience has taught me that you really don't want any more than 1 ohm of resistance. Basically, the closer to zero the better. Don't forget to take into account the ohm meter leads resistance.

Let me know if you need additional info such as wiring diagrams, etc...

Keep me posted and let me know if you have any additional questions...

Thank you,

Robert

______________________________________

If you need additional information, don't hesitate to ask, I am happy to help as long as necessary to help solve your concern. Remember, a "Positive" Rating will not close this question, You can post a reply here whenever you want, even after rating my answer! .

Customer: replied 3 months ago.
Here are pictures of the scope readings with the new sensors. I don't see anything wrong. Do you have something to compare it with? What do you think? Thanks
Expert:  Robert replied 3 months ago.

Those scope traces look good. Is this with the engine below or above 160 degrees?

With this condiiton ONLY happening with engine temp over 160 degrees, Either something is backfeeding into the crank signal circuit that comes on at that temperature OR you have a faulty PCM that may need to be replaced...

Other than that, I would verify that the timing marks are all properly lined up, of course this will require disassembly of the valve covers and timing cover for verification...

Keep me posted and let me know if you have any additional questions...

Thank you,

Robert

Customer: replied 3 months ago.
The timing marks have been checked 3 times all ready. The scope reading were at above 160 degrees with the code active. Is it possible that this code is only monitored at above that temperature and that's why it becomes active when it reaches 160?
Expert:  Robert replied 3 months ago.

P0016 is monitored as soon as the engine starts. The problem MUST be happeinng because of something that is activating at 160 degrees. It may be a good idea to run new temporary wires for the crank sensor for diagnostic purposes. You can start by clipping the sensor signal circuit at the sensor and at the PCM. Run a NEW wire between these points for testing purposes and see what happens. If the same, move over to the 5 volt supply then the sensor ground to see if any of them offer any changes...

Keep me posted...

Thank you,

Robert

Customer: replied 3 months ago.
I rewired the CAM sensor first to the ECM. Do you know if it shares power or ground with any other sensors? It is misfiring and giving accelerator pedal position and vacuum codes. I know it shares a ground with the crank sensor and wired them together.
Expert:  Robert replied 3 months ago.

The Cam and Crank sensors share the 5 volt supply circuit and the Sensor Ground Circuits with other sensors. I was just wanting you to ONLY run the SIGNAL circuit to the cam and crank sensors first BEFORE trying the 5 volt supply and sensor gound circuits. The signal circuit ONLY runs to the individual sensor.

Reconnect everything back to stock then try running only the signal circuit for the cam and crank sensors...

Keep me posted...

Thank you,

Robert

Customer: replied 3 months ago.
Did that already, code came back. I'll try the crank signal next.
Expert:  Robert replied 3 months ago.

Hopefully the crank signal will get better as that is the one that had the dirty signal on your earlier post.

Expert:  Robert replied 3 months ago.

After that, then run the 5 volt supply then the sensor ground. To do these, you will need to cut the wire at the sensor side only then tap in to the circuit near the PCM connector to reconnect it...

Customer: replied 3 months ago.
I did the signal wires first. No change. Then the 5 V supplies and no change. Grounds are done and no change. At this point I think replacing the PCM will be a good idea. What do you think?
Expert:  Robert replied 3 months ago.

If it were me, I'd probably pull the engine or trans in order to inspect the flex plate first. Any time I have personally came across this same scenario, the root cause was never the PCM. One time it was the Flex Plate, the other time, it was that the customer had installed the wrong timing set that had the wrong tone wheel for the cam sensor. You stated that your timing set didn't come with any sprockets, just the chain and guides.

Also, I'm still a bit leary about the condition only happening when temp reaches 160. If all wiring is 100% good, then maybe the PCM is bad.... This is a hard call to make... PCM's are pretty expensive and non returnable....

Keep me posted and let me know if you have any additional questions...

Thank you,

Robert