Dreaded P1390 Code (Wiseman Advice Needed)

[DSMOCTANE]

-Long Story Short: My father and I have rebuilt my 2g Eclipse ground up with a fully rebuilt/overhauled stock 420a motor. The head and block were checked and plained by a professional machine shop. Upon getting the car back on the road, I had my CEL flash before me within about 10 minutes of driving. Using my OBDII scanner, I discovered I had a P1390 code. After extended research, I had learned that the code stands for one or more skipped teeth with the timing. After taking apart the entire timing cover assembly (What a Mother $%#$#%) we noticed that the timing was off kilter less than a full tooth. We put in a new belt and tensioner and corrected the timing. With the timing now correct, we started the car up and it sounded better than ever before. Smoother idle and less vibration. Ten minutes later the CEL came showing the same code! (P1390) This has me so baffled now and its become a nuisance for us. I had even installed brand new camshaft/crankshaft position sensors. Any wiseman takers for advice? Can the ECU be programmed to possibly relearn the position of the crank using a Dealer Scanner Tool?

P.S. Compression test shows 200 pounds in all four cylinders!!!!!!

 

[BoostedPhoenix]

Yes the dealer scan tool has a cmp/ckp correlation relearn procedure in it, though it SHOULD take more than half a tooth to set this code.

 

[dsmspickdad]

Under idea situation it should not set the code. However we have experienced this problem with new crank and cam sensors. Especially with Borg Warner; we now use Mitsu Parts only.

 

[DSMOCTANE]

The problem had persisted before those two sensors were changed. Cylinders #3 and #4 are rapidly fouling plugs and the car is eating oil. Like I said before, each cylinder shows a solid 200 pounds of compression. I had a brand new MSD Blaster coil pack and thought that it could have been defected, but the problem continued even when I put the OEM coil pack back on. Considering the timing job was redone using a new belt and hydraulic tensioner, could it be possible the ECU needs relearn the new position in order to run and fire correctly? I am not exactly sure how much the machine shop had taken off the block and head, but may want to look back into our receipts. Who knows if thats giving me my problem..

 

[BoostedPhoenix]

If the marks are lined up they are lined up, that means cylinder 1 is at TDC and the exhaust cam is in the right spot reguardless of how much the shop planed off.

I say this because during my rebuild I figured out that somehow I was not paying attention when I installed my new crank sprocket and I put it on backwards. I ended up with the timing marks off by two teeth and the engine ran perfect, very noticable lack of power and the belt wanted to crawl to the outside of the pullies which is how I figured it out, but the point is that it never set a code and I put 50 miles on the engine with it like this, and it never set a code.

Did you look close at the cam magnet and make sure the screw was tight by chance ?

 

[DSMOCTANE]

-That was the next possibility I was looking into, however I feel as if I had forgot to mention something really important. This 420a head and block have come from another Eclipse. I am wondering if the variables are not being assigned properly since the ECU was tuned to my original 420a motor. I went to Mitsubishi today and explained to them my situation. The tech guy had printed out an interesting read on this code which I am hoping is the piece to the puzzle. Below is word for word from a Mitsubishi Motors Medic Update Tech Talk Article:

"DTC 1390 PCM Relearn - 1996 - 1999 Eclipse 2.0L Non-Turbo 420a Engine. DTC P1390 is designed to set it the timing belt skips one or more teeth. The PCM does this by comparing the timing relationship between the crankshaft position (CKP) sensor signal and camshaft position (CMP) sensor signal. Since component dimensions vary slightly from one engine to another, the PCM must "learn" the normal timing relationship for its engine. A PCM does this the first time it runs an engine, and then stores the resulting calibration value in its EEPROM memory for the life of the vehicle, UNLESS ITS IS LATER COMMANDED BY A SCAN TOOL to "RE-LEARN" the value. The calibration value will remain in the EE PROM memory even when the batter is disconnected or discharged.

-Replacement of certain components can change the timing relationship between the CKP sensor signal and CMP target magnet, CKP sensor, cylinder head or block, and camshaft. If it is then necessary for the PCM to relearn the new timing relationship to avoid the possibility of setting a false DTC P1390. THIS CAN ONLY BE DONE WITH A DRB-III, Chrysler's scan tool."

-Luckily for me I am fortunate to know a Chrysler mechanic who has access to one of those scan tools. Tomorrow I will be stopping by his shop in order to give this a shot and see if I can rectify the situation. Theoretically it makes sense that my ECU is not fine tuned to this newly rebuilt motor. Im going to cross my fingers, hope for the best, and post results ASAP!

-Can you tell me where which cam that magnet is supposed to be on and also which side though?

 

[BoostedPhoenix]

Referring to the magnet that the cam sensor reads off of, its not likely loose because there is a nice fat dowl pin that holds it in place but it was just an idea of something to cause it to read incorrectly.

I wish you good luck and a lifetime of patience using the DRB-III, what an ancient artifact that tool is, I had the pleasure of playing with one when I was having a misfire on my wifes car that I just could not sort out (turned out to be some quality walmart fuel causing the problem). But that thing is slow as hell and make sure you use the correct attachment for the car, both of those connectors under the dash will be plugged in when you are using it

 

[Frankie1983]

I got my n/t 420a motor back last week after $1600 , put it in the car on start up it ran the best it ever had. 5 mins in the cel came on and p1390. I removed all the acc and belts rechecked the timing it's dead on, called the machine shop and he said he may have removed to much from the head and i may need cam gears. If this reprogram fixes your car Plese let us know. It makes sense that it would. I don't won't to put 300 in a set of cam gears. I have put 230 miles on it and not a miss or anything it runs great. I hope it works!!!

 

[DSMOCTANE]

I have good news! Luckily for me, I know a mechanic at the local Dodge dealer in my city who had access to the DRB-III scan tool. He had never heard of such a problem before and hadn't used the scanner in almost over 7 years. We got through to my PCM system by selecting that it was an Eagle Talon (which has the same 420a engine as the Eclipse) and got the the menu where the "Re-Learn" option was available. A few clicks on the scanner and POOF... Magic. THE DREADED CODE HAS NOT COME BACK SINCE! I had driven over 100 miles and no signs of the code, nor popping, or smoking as it did before! If it had not been for that little service blog that the Tech gave me at the Mitsubishi dealer, then who knows how long it would have taken me to figure this problem out! It was just a false code being prompted by my PCM due to the variables being set to the first motor. In spite of what others believe, you can not simply unplug your battery or reset the codes with an OBD-II scanner. YOU MUST USE THE DRB-III TO HAVE THE PCM RELEARN THE VARIABLES OF THE CRANK AND CAMS! I believe that this issue was due to the entire motor being replaced which machine work done to the head, block, and crankshaft. If you read the quoted service blog I mentioned above however, a false P1390 DTC can occur if you had machine work done, replaced the crank/cam position sensors, or the cam magnet is not steadily mounted. I hope that this forum post helps everybody that is experiencing the same problem as I had! Good luck to all!

 

[Frankie1983]

Good to know your car is fixed . I drove me grate running eclipes to a shop in town and told him I needed my PCM / cam and crank sensor relearned, he said he's been doing this for 20 years and never heard of this but would try. He pulled it in the shop a hour later I go back there and my timing belt is off !! I'm like what are you doing ! he says it was a tooth off but I fixed it. So I stayed with my car and watched him put it back together on start up it ran like sh## and after he has tried to re time it 4 or 5 times it's still running like shit ! I could kill him he took my car that was running like new and has scrued it up this was Friday at 10 am it's now Sunday and no car. I don't know what to do !!! Oh I did take him a copy of the dodge service Manuel timing procedure , I hope he hasn't broke something it my new motor !!

 

[CarniFreekshow]

I hate to bring up an old thread, but does anybody else have this same issue? I had the camshaft sensor replaced, the crank replaced and the head milled. The car is running great but i get the p1390 cel after about 2 miles of driving after i delete it. I called mitsu and they scheduled me in, i'm hoping this fixes the problem.

I would think this would be a normal issue since our cars are getting so old, most of them would be rebuilt by now.

 

[CarniFreekshow]

I just wanted to reply back and confirm that this resolves the p1390 issue. $89.00 to mitusbishi to get a check engine light turned off.... it's kind of a joke it takes a old outdated scan tool to fix it.

Here's some more info on the situation, i think this error is caused more by aftermarket (non mitsu/chrysler) sensors or parts, rather than milling or decking the head or block.

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