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OPDA issues for 3+ years

716 Views 7 Replies 6 Participants Last post by  LRod
Is there a resident expert on the OPDA issue?

Ive tried everything except for camshaft /pcm replacement

I must have reset the opda position 15 times by now, tried the pin method, tried taking out hole 1 plug and confirming it was out 180, tried clocking it 10 degrees in either direction from alignment

Replaced the crank sensor with new mopar, tried crown sensor, factory sensor, new mopar sensor, cut the plug off the sensor harness incase it was faulty and hard wired the sensor

Resetting codes over and over everytime i think its fixxed the issue comes back, sometimes after realigning it itll run great for a day then go into limp mode and then wont even start

Last time it was running it ran great on the long weekend right after doing the alignment, ran it, shut it off, started it again moved the jeep 50ft turned it off and hasnt started since, ordered a new opda installed confirming tdc compression stroke and nothing

Previously i was getting p0340 and p0344, right now the only codes itll give while cranking are p0038 and p0058 because my downstream 02 sensors are absent but it ran for 5+ years without them its not the issue certainly not a no start issue i bought new 02 sensors and bungs to weld them in but want the rig running first before i goto that trouble

I can see the cam gear it looks fine, and like i said the engine will run for hours when it wants to or not at all when it doesnt want to

Is there a way to completely wipe and reset the pcm? I have a blue driver obd2 scanner with live data on my phone have reset all codes several times but wont start

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Oh wow, you have been diligent trying to solve the problem.

What series of events led to the problem?

I can only think of two troubleshooting possibilities - disconnect the battery for a few minutes to 'reset' the PCM (as much as it can do with a loss of power) or have a tech with the specialized DRB (I think it's called) scan tool to look at the OPDA timing. Could be your camshaft is kaput.
That sounds horrible. I believe that John is correct, a more advanced diagnostic scanner is required to get the setting correct. Maybe a bi-directional scanner has the capability
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Everyone ive seen do it has just replaced the opda and kept the sensor never needed the DBO programmer, trying to call around to see if any private shops have one

Dealers can be pretty unhelpful ill tow it there and theyll look at it for 30seconds say it needs an engine or pcm with no troubleshooting and then charge you 300$ for that

I cant remember what the first sequence of events was because it was several years ago but i believe it just went into limp mode one day and the issue has been ongoing since

I read somewhere that the CPS controls the fuel injection and that the crank sensor controls the spark can anyone confirm if this is correct? And if i can pull a fuel injector and lay it ontop of the valve cover to see if its spraying at all

Might give it a wiff of ether to see if itll pop at all, but i know it a lost spark system so i imagine it can backfire pretty good off ether

The most recent time i drive it was at a mud run event, and the clutch got completely thrashed full of mud and what not i have to pull the transmission anyway maybe i can check and confirm nothing in the bellhousing is causing the crank sensor troubles

Its odd it wont even throw a code for the cam/crank anymore while cranking typically it would always throw a 0340 or 0344

Hesitant to say its the pcm as i can communicate with it and the gauges do work but i dont know exactly how the pcm controls spark and fuel

Anyone know if i can lay the coil rail on the engine with one plug in it and run a ground wire to that plug to check spark? Or will that not work

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Spark is off the crank sensor and both cylinders that are at TDC receive a spark even though one is on the exh stroke. 1 and 6, 2 and 5, 3 and 4 are the paired cyls.

Cam sensor is used for sequential fuel injection. Loss of cam signal causes the PCM to batch fire the injectors and go into limp mode.

Pull the crank sensor and see if it's packed with mud.
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Drb3 is the scanner that was used when these were new. Not many dealers have a working one anymore.
A quality scanner or App is all you need.
I would start with basics. Do you have fuel pressure? do you have Spark. Unbolt the coil rail and gently lift it from the front while cranking. You should hear the spark snapping, As you lift more you may even feel the spark.
If you scanner doesn't show them buy a interface with a App so you can get sensor data. See if you have crank and cam inputs while cranking. You need both.
Crank sensor is needed for ignition and fuel, Cam is need to determine if you are on TDC compression or exhaust.
The 4.0's can be really temperamental with the crank sensor to tone wheel gap. When you pull your transmission look at this closely. If the gap is too much the adjust it down, this can be done by enlarging the hole slightly.
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My clutch was grenaded so hopefully that was giving the crank sensor trouble because ive tried everything i can with the cam sensor

Gonna try a ceramic 6 puck because the luk organic isnt holding up to the abuse

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