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Discussion Starter #1
As many people on these forums know, my efforts to campaign the Z33 in SCCA D2D racing has gone on for years. Unfortunately, my last SCCA Majors race revealed a fatal flaw in the ECM. After weeks of preparing, my out lap of qualifying found the HR suddenly unable to accelerate, with revs stuck at idle. Despite replacing (in order) the accelerator pedal (ACC) sensor, ACC relay, checking fuses and grounds and rechecking the electronic control module (ECM), the Z would not wake up. This failure ended up costing me any shot at winning the Majors series for my T3 class.

Now, after a week of puzzling over this unprecedented f(for me) failure, I've found no less than 10 codes coming up on my ECM. Among these are P0605 (internal code module ROM read error), P0453 (Evap [ressure sensor), P2128 APP failure #2), P2138 (APP sensor failure) and P1421 (cold start control), all of which are new codes I've never seen before with this race effort. It appears that neither the throttle bodies or the shift sensor have any effect on this failure. My HR ECM has been reflashed by technosquare and UpRev for race tunes in the past.

My questions for the forum are:

-Has anyone got a positive reference on a service that has successfully repaired a HR ECM?
-Was replacing a Nissan ECM solve multiple operating errors? Besides matching the HR ECM, are production #s and serial numbers critical?
-Does replacing the BCM or other components become a necessity if the ECM is replaced?

The SCCA Runoffs at Road America is my next race and I've got to find the best and most efficient solution. I've searched many, many 350Z technical threads and consulted several sources, but not come to any definitive answers. I'll post here if and when i find one.
 

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Discussion Starter #2
Many thanks to Seb at Speciaty Z and Clark at Jim Wolf engineering for answering my calls for help. Both were helpful in narrowing down the possibilities and potential repair of this problem. it seems like the stock ECM is the likely suspect, and no matter how many men, they can't put humpty-dumpty back together again.
 

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Discussion Starter #3
30 views over three days and not a single response! Nobody has an opinion on this problem?
 

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OK, here's a reply David.

That's it. You weren't expecting more were you? :p

But seriously, any progress? Near as I can tell, you have three weeks before tow-out to RA.... ehhhhh.
 

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Discussion Starter #5
Oh , thank God for you Mic! Only progress has been looking for HR ECMs on fleabay and only finding ones from automatic Zs. The dealer wants over $1500 for a new unit, but my racer's discount from Nissan Motorsports will help. It seems nobody has much knowledge on this type of failure, so I'm somewhat swimming alone here.
 

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Discussion Starter #6
After much swimming, it looks like my ECM is done. Not finding any HR manual ECMs on the market either. I've checked parts yards in Alabama, S Carolina, Texas, Colorado and California, but nobody has a junkyard ECM that'll fit my racecar, Not looking forward to buying a new one, but that may be my only option if I want to compete in the SCCA Runoffs this year.
 

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Discussion Starter #7
After purchasing a new 23710-EV12C ECM from Nissan Motorsports, it still took some careful electronic work to get the TBs to cooperate. Realizing this was a more complex problem than I could handle at home, I ended up taking a friend's advice to take the race Z to my local Nissan dealer and paying for a couple of hours of diagnostic time. They have more resources to track down such a problem. They also needed my spare accelerator pedal assembly and together with reprogramming the ECM seems to have addressed the problem. Next step will be getting the race tune reflashed and drain the tank of race fuel. SCCA Runoffs rules mandate the use of a chemically marked Sunoco fuel to make sure everyone is in the same boat. The plan is to start the 958-mi trip to Road America next Friday and be ready for qualifying October 5th.
 

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Discussion Starter #8
Before the sojourn begins, I put the Z on the dyno the other day to confirm that everything is running reliably at WOT. Good news is the HR will scream right up to redline. Bad news is the output is almost 30 HP down from where it was when UpRev tuned it back in 2011. Not good for a power track like Road America. I went ahead and reflashed the ECM to make sure it had the full 100 octane race tune. The final pull showed the HR had a slight increase and filled in the torque curve, but there were no dramatic gains. Since I didn't have a baseline tune with the SCCA-mandated 40mm restrictors in place, there's nothing to compare it to. SIGH

Not that I have the skills to perform a tune by myself, but I wish I could have devoted the time and effort to make more power, rather than just fix the car. Still, you've got to take the green flag to make the checkered, so that's where I am. Not a good situation going into the Runoffs, but gotta make the best of the cards I was dealt.
 

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Discussion Starter #9
It's Sunday and we've arrived at Road America after a 958-mile tow. My '08 Titan has been a reliable road warrior and the 24' enclosed trailer has been reliable in getting this cross-country run in. Lots to do to setup today and get ready for qualifying on Tuesday morning. Cool and dry today, but no telling what the fall will being this week for our three qualifying days and the Friday race. Race on!
 

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Discussion Starter #10
Despite years of racing experience, and trying every trick and diagnostic in the book, the 2020 Runoffs will go down as a big, fat DNS (did not start) on my race record. Despite having a new ECM and throttle sensor/pedal installed and tested, the Z car lost throttle control during qualifying. Working from dusk to dawn (and with a heady mix of desperation and gumption), we tried logging throttle sensor parameters and found sensor 2 was sending too much signal to the ECM. This was what happened originally at the last race of the season, and while the new accelerator pedal assembly and ECM appeared to be the solution, that was an illusion. To make things worse, now both components may be corrupted and unusable.

Tried to check with local parts stores and found they couldn't get the parts in time for the race. Next, I called Nissan dealers within a 110-mile range about getting the car in, but none had any availability on such short notice. The good news is there are three Z33s and one Z34 in the top ten at the Runoffs with some great drivers to give the marque another National Championship tomorrow. Good luck to all the Nissan drivers at the Runoffs!
 

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Discussion Starter #11
Runoffs updates: while a Z did not win at the T3 Runoffs, one finished third , and three others finished in the top ten at Road America. Congrats to all!
 

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Discussion Starter #12

Here's a link to a SCCA-produced show about the 2020 Runoffs. There's plenty of 350Z action in this professional coverage and yes, other contenders from BMW, Ford, Honda, Subaru and Porsche.
 
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