N55 tuning issues after ecu unlock.

[matreyia]

Anyone seen these before? Engine half light is on and these codes are up.
Just got unlocked ecu back and reinstalled.

2BF8 Rail pressure sensor, signal: Permanently stuck.

2c72 Boost charging pressure sensor, plausibility, after run: pressure too low.

2D20 oxygen sensor after catalytic converter, electrical: short circuit to earth.

3429 Engine oil pressure sensor, plausibility: pressure too high before engine start.

Car was fine before reinstalling ecu and flashing mhd stage 2 plus.

Any advice appreciated.

Thanks folks!

 

[houtan]

Any updates? Who did the unlock?

 

[matreyia]

Any updates? Who did the unlock?

Still no luck. Client supplied ecu. Not sure ecu is issue. Got the 2 cables mixed and would not start, then corrected cables and started but these errors. Maybe sensors need replacing due to short circuit?

Oil pressure sensor shows high oil pressure even before starting engine so that is an electrical malfunction since high oil pressure is impossible if engine is off.

Rail sensor stuck also damage to sensor evidence. Will replace sensors and try again.

 

[Bnks334]

Oil pressure sensor shows high oil pressure even before starting engine so that is an electrical malfunction since high oil pressure is impossible if engine is off.

This code could potentially be from cranking on the engine for a long time before it fires? Oil pressure builds to 40psi+ from cranking and N55 DME throws a code. This code happens to me frequently if I prime my car for too long with the Accusump before starting it. What does MHD say the actual oil pressure is? should be in the 14.xpsi range.

Got the 2 cables mixed and would not start, then corrected cables and started but these errors.

Do you mean the DME harness? If so, check the pins... might've bent some since I don't think the pin-out is the same on both of those harnesses. Then again, those codes are not on the same harness anyway lol

Check the ground strap on the rear of the engine?

 

[matreyia]

This code could potentially be from cranking on the engine for a long time before it fires? Oil pressure builds to 40psi+ from cranking and N55 DME throws a code. This code happens to me frequently if I prime my car for too long with the Accusump before starting it. What does MHD say the actual oil pressure is? should be in the 14.xpsi range.


Do you mean the DME harness? If so, check the pins... might've bent some since I don't think the pin-out is the same on both of those harnesses. Then again, those codes are not on the same harness anyway lol

Check the ground strap on the rear of the engine?

1. Yeah, the client did crank the hell out of the engine when the harnesses were switched. How do we reset this? I did a fault delete and reset in MHD and unplugged both battery terminals in trunk and touched the two wires together for 30 seconds to dissipated, but the error comes back still...even when the car starts up instantly. So now I just picked up a new oil pressure sensor in case it got fried from the switched harnesses.

2. Yes, the harness first two cable groups got switched upon installation and then was corrected afterwards. Pins are straight like from the factory. Weird thing is, I and other people have made this mistake multiple times and the car runs perfect once we switch the harnesses to the correct spots...so this is a first for me.
However, there was an article from one of the forums that had a guy have the same error of the 2BF8 Rail pressure sensor permanently stuck - because he installed downpipes (like this car did) and then drove it around a long time without installing MHD to mitigate the catalytic converter absence. This client did drive the car for a couple of weeks after installing to the point that the SES light came on. That may be related...who knows.

3. I will check the ground strap again... I didn't even know there was a ground strap...where exactly is this strap? On the left or right side of the battery. I only know of the negative terminal that you take off and put on during sensitive electronic installs.

Thanks to all you guys who are chiming in. I appreciate it very much. I hope I can get this car into action again with all your help and a little luck.

VT

 

[Bnks334]

1. Yeah, the client did crank the hell out of the engine when the harnesses were switched. How do we reset this? I did a fault delete and reset in MHD and unplugged both battery terminals in trunk and touched the two wires together for 30 seconds to dissipated, but the error comes back still...even when the car starts up instantly. So now I just picked up a new oil pressure sensor in case it got fried from the switched harnesses.

The code clears for me. What is MHD reading the oil pressure as prior to cranking? pull up the monitor data.

3. I will check the ground strap again... I didn't even know there was a ground strap...where exactly is this strap? On the left or right side of the battery. I only know of the negative terminal that you take off and put on during sensitive electronic installs.

There is a small ground strap on the back of the valve cover area right near the rail pressure sensor. I forget what it grounds but it came to mind because someone might've disconnected it when pulling the dme? Just a thought...

 

[matreyia]

The code clears for me. What is MHD reading the oil pressure as prior to cranking? pull up the monitor data.



There is a small ground strap on the back of the valve cover area right near the rail pressure sensor. I forget what it grounds but it came to mind because someone might've disconnected it when pulling the dme? Just a thought...

Holy shit... are you serious? OK, I will look for that strap.

 

[Twisted Tuning]

This isnt the first time people have gotten the plugs wrong when reinstalling. Sometimes the dme is fine afterwards. But there was two or 3 times that I know of that after having the plugs swapping incorrectly. It kills the DME. Or at least some part of it. Most times it doesnt though. As out of about 25-30 emails I get with the plugs swapped at the DME, DME replacement was only needed 2 9r 3 times.

Viet, as soon as you sent me the screenshot of the first set of codes I new the plugs were backwards.

I do the unlocks on anti-static and stable power source work table so there are no bench flashing issues.


I have also seen people not completely connect and lock in the rear most plug of the DME somehow and that will cause issues.


I will say, that people need to take care installing these DME plugs straight and aligned. As the pins are delicate and very easy to bend. I check alignment also prior to shipping back as an added precaution.

 

[matreyia]

This isnt the first time people have gotten the plugs wrong when reinstalling. Sometimes the dme is fine afterwards. But there was two or 3 times that I know of that after having the plugs swapping incorrectly. It kills the DME. Or at least some part of it. Most times it doesnt though. As out of about 25-30 emails I get with the plugs swapped at the DME, DME replacement was only needed 2 9r 3 times.

Viet, as soon as you sent me the screenshot of the first set of codes I new the plugs were backwards.

I do the unlocks on anti-static and stable power source work table so there are no bench flashing issues.


I have also seen people not completely connect and lock in the rear most plug of the DME somehow and that will cause issues.


I will say, that people need to take care installing these DME plugs straight and aligned. As the pins are delicate and very easy to bend. I check alignment also prior to shipping back as an added precaution.

Yeah, I agree. I don't think it was anything you did. I went back and triple checked the connections and reconnected with smooth action and did a physical pull to make sure they were locked. The pins were all straight also. I think that it is possible that the fuel pressure sensor may have been fried from incorrect voltage from the initially incorrectly installed harnesses on the first two connectors in addition to client driving around without MHD with downpipes installed...who knows, maybe that exacerbated the issue. Anyways, I will install new sensors after work and reset codes and do the battery terminal reset procedure too. Will keep fingers crossed.

The car will run so I would think that the ECU isn't damaged at all. Just need to get these codes cleaned up and rid the car of the check engine light half power.

Keep you posted.

 

[Twisted Tuning]

Yeah, I agree. I don't think it was anything you did. I went back and triple checked the connections and reconnected with smooth action and did a physical pull to make sure they were locked. The pins were all straight also. I think that it is possible that the fuel pressure sensor may have been fried from incorrect voltage from the initially incorrectly installed harnesses on the first two connectors in addition to client driving around without MHD with downpipes installed...who knows, maybe that exacerbated the issue. Anyways, I will install new sensors after work and reset codes and do the battery terminal reset procedure too. Will keep fingers crossed.

The car will run so I would think that the ECU isn't damaged at all. Just need to get these codes cleaned up and rid the car of the check engine light half power.

Keep you posted.

Yea just text me if anything

 

[matreyia]

OK. Car is running strong. I replaced the oil pressure sensor which was bad and the fuel sensor on the rail which was also bad. Then double checked all connections, and disconnected both terminals and touched them for 20 seconds away from battery itself...as per Justin's advice. Then waited 20 minutes and started the car up. No errors, and ran strong. But there is only one code for the rear 02 sensor grounding fault.

"2D20 - OXYGEN SENSOR after catalytic converter, electrical: short circuit to earth."

I will double check the fuses in the glove box as per Justin's suggestion. If fuses are good, then I will let client know to order new sensor.
Everyone has been very helpful. I am glad I am a part of the community.

VT

 

[matreyia]

OK. I checked fusebox as suggested by Justin and there were two missing fuses. I don't know if they were even used but I replaced them anyways. Fuse 40 and Fuse 87 were completely missing. Then I deleted faults in MHD and test drove for 5 miles and checked again. The codes did not come back. So from a slew of errors to no errors over the course of a week. I am glad that the client car is now error free. And running stronger each mile as it adapts.

 

[matreyia]

There is one thing I do notice now... when I put foot on the gas, even very slight slow driving... the engine revs for half a second, then it goes back to proper RPM input... It never lurches or anything...it just slight goes 'vrooom!' and then accelerates normally. Feels like throttle is jumpy. Even after throttle adaptation reset.

It did this after ECU unlock, before and after MHD flash. Is this normal? only a minor annoyance.

 

[doublespaces]

Maybe a YouTube video? Does it appear on a log?

 

[matreyia]

Maybe a YouTube video? Does it appear on a log?

Unfortunately the client didn't buy monitor yet. Will advise him and update soon. It is a real thing, not in my head...I initially thought it might have been. Just a one second or half second pre-motion reving before car starts moving.