It finally happened to me.

I was driving the FC to work on Saturday and made it about 20 miles. I press the loud pedal a little more and then the CEL comes on and car starts popping and sputtering. This can't be good. I also smelled a little bit of electronics cooking. I then decide to get the car back home and made it. This was difficult since mine makes ZERO power until i get into the loud pedal. I made it back and took my truck to work. During my work day, I am thinking about the failure and suspected the TPS, as it's a junk yard one. I got home and went to pull the CEL codes, however there were no codes stored. I then started and ran the car in the driveway and pulled the pressure sensor connector to get a CEL. I shut the car off and went to pull the codes and still nothing stored. This has taken about ten minutes and I am now suspecting the MOP and ECU failure scenario. I then pull the carpet back and remove the ECU and found the MP4501 power transistor smoked. It looks like one of the resistors may have cooked as well.

Has anyone successfully replaced the damaged components in the ECU?

What are the EXACT differences between the N350 and the N351 ECUs? I am aware the N350 is the California model. I just want to know what exactly is different. Components, tuning, etc.

I am going to replace the MOP as well. I just wonder what benefit can be gained by connecting it and tying it out of the way so I can premix? Can the new MOP still fail when tied out of the way? I asked this several years ago and never got a good answer.


Has anyone successfully repaired the S5 n351 ECU after a MOP failure?

 

Wow. This place has sure gone down the toilet. What once was the greatest RX-7 forum is no longer as I remember it. Where are the knowledgeable members? Instead of informative and helpful topics, I see massive response to bird crap. Is that all the forum members around here know any more?


I am truly saddened and will probably delete my account after this travesty.

 

I used the search feature accessible to all including yourself and found this. Page 2 might be of help to you.

https://www.rx7club.com/2nd-generati...-710938/page2/

 

Thank you, I had researched this already and had read the thread linked multiple times in the past. It has some of the questions, but none of the answers I need. It's just like another MOP thread I asked questions in many years ago that no one seemed to have answers to.

As a master level tech, I need to know how when, why and all that. I have to make sure there will be no repeat failures, as I regularly repair other's mistakes. I am NOT a parts changer. The owner gets upset from time to time because I ponder failures quite regularly.

 

It's been slow lately on this board plus some things are too complex for most posters, including myself, so this needs to be taken into account as well.

 

What happened to all the old timers? I wont mention names since I believe its against terms of use, but I think you know most of who I am referring to.

 

Some were run off by over zealous moderators while some set themselves out to pasture along w/some getting out of the rotary business.

 

You have a PM. Hope it helps.

 

Back in the old days, people figured **** out and posted the results in order to help. They also posted experiences and modifications that were cool.

Later people needed help and ideas. They found it with a search.

After awhile, some people whined and were told to search, noob!

Occasionally, someone demands an answer, finds silence, then disparages everyone who hasn't answered.

The End.

 

This is quite beyond the knowledge of most members. It hasn't been directly mentioned but at least a couple of very knowledgeable members passed away.

I would have an electronics place check out the board and see if they're up for replacing the transistor (the resistor should be easier).

Yes, the MOP can still fail even tied out of the way and using premix. The ECU needs it connected so it doesn't go into fail-safe mode (I believe), so yes, with both boards powered, you can still have problems.

Not sure on how to avoid future issues...that's where the experts come in (like an electronics place). Resoldering bad solder joints helps with the CPU and warning lights, but not sure if it'll help here.

 

I've no clue as to the specific differences between the N350 and the N351, perhaps tuning and timing? That would be my guess, considering the strict emissions laws in Cali.

As to your ECU being burnt out: I've personally never seen one repaired. That's not saying it isn't possible or hasn't been done, but in my small window of experience on this forum, I haven't seen it as common.

Your OMP: This must be replaced. It must be replaced with a functioning unit, even if you are tying it off to the side, blocking it off and running pre-mix. The s5 ECU cannot function properly without it and the unit can still go bad after time, taking the ECU out again as well.

You do have an option, however: the Rtek. If you aren't familiar with them do a little research. For about $125 bucks (about the cost of a used OMP and N350 ECU) you can get a "chipped" s5 ECU that works better and has been coded to allow the removal of the OMP.

 

Besides IceMark, who else passed away?

 

It is very common for the MOP to fail and take the ECU with it. I got lucky when mine died and it didn't brick my ECU.

I bought another OMP, but in hindsight, I agree with tex. Just get an rtek ECU and premix from now on.

 

+1

 

From what I see, Rtek looks like the way to go. I have not ordered replacement MOP yet.

 

Good, because you won't need one with the rtek. Unplug the piece of **** or get a block off plate.

 

I think what he means at some level not passed away so much as simply moved on to another internet forum. Either way, not here to help. Mark was a master at this kind of tech stuff.

 

On point, I've repaired more than my share of circuit boards. Usually you can find physical evidence where the board failed. Something simply overheated and broke a connection.

Look for either a black spot at a connection point on the board (many times a diode that now needs to be replaced) or a part of the board circuit material burned apart (bridge with solder and sliver if wire). Could even be something as simple as a fuse in the ecu box.

But no matter what, as my texas friend advised, do that repair only after you correct/replace what caused the ecu damage in the first place.

 

I was thinking also a guy from Pineapple racing and could swear there were others. But yes, mostly people move on. And not too many tinker to the level of figuring out stuff.

 

If it weren't for my deeply ingrained routine I wouldn't be on here either. I haven't owned a 7 in almost two years now... but it pays to keep the knife sharp.

 

Is this a thread about how to repair an ecu and omp, or is a thread about why everyone on this forum sucks? One day has passed, and this isn't exactly a topic for the average rotary owner. Excuse myself for not answering sooner.

 

"I then pull the carpet back and remove the ECU and found the MP4501 power transistor smoked. It looks like one of the resistors may have cooked as well.

Has anyone successfully replaced the damaged components in the ECU?"

Sounds easy enough to me... the answer is yes. The transistor is 15 bucks, and a resistor is like 5 cents. Spend the chump change trying to fix it, soldering is easy. If it works, come back and say so... maybe it will keep someone from wanking about nobody answering a fairly technical question one day.

 

You can get a second hand ECU and OMP for $100 give or take. Just replace the parts.

 

Yes, I replaced the damage components in my ECU after the MOP failed. Actually I still have some MP4501's sitting in a static bag since when I bought the parts I had to buy 5 so I could probably sell you one for little money if you wanted to try repairing your current CPU.

Unfortunately I bought a used MOP on ebay and about 6 months later that one went out too taking out that new replacement parts I had soldered in. So instead of dealing with that for a 3rd time decided to just go with a Rtek chip that allows you to eliminate the MOP and just premix...been running fine since then.

Rtek7 ECU Upgrade Detailed Information

Also unless you fix the ECU, putting in just a new MOP won't work since the ECU will still think the MOP is bad (due to the burnt components) and keep the car in limp mode. You have to fix the ECU first and then the MOP...obviously don't fix the ECU and keep you're old MOP on as it will just kill the fixed CPU.

Also you won't go into limp mode unless the car is moving, so in the driveway it will seem like everything is okay even when revving to redline.

 

electronics are electronics, you are familiar with them or you are not.

if you have a 2nd similar transistor to the one that let the smoke out then get the numbers off it for reference number for voltage, ohms, amps, and polarity. do a google search and find a replacement or 3 and order them. replacement is as simple as desoldering and resoldering.

whether this will fix the issue i cannot say, i have never bothered to try and salvage a stock ECU. simply replace it, check the engine harness and replace the OMP.

at this point you have to figure out for yourself if a $50 used ECU is worth spending hours of your time and possibly still not getting satisfactory results.


honestly at this point in time i find more OMPs dying than the number of good ones left. Rtek, standalone or simply remove it from the engine, strap it somewhere and premix are your best alternatives.


as for the forum hostility: WAHHHHHHHHHHHHHHHHHHH! someone needs a diaper change, i don't babysit this forum and i will be on vacation next week.