R32 GTST RB20DET Crank no start - Tomei ECU?

[Tim32]

Recently bought an R32 drift car as a father son project. Was running rough a few days before we saw it, have a video of it, sounds like a vacuum leak somewhere. Not running when we got it though. We went through some basic diagnosis, fuel pump is priming, injectors are pulsing, but no spark. Checked all the grounds we could find, swapped out all the fuses for new ones, still no go.

Got an auto-electrician out on the weekend, tried to crank, no crank!!!!! Traced it back to a dodgy battery terminal, once he replaced that we had crank back. There was a lot of wiring from previous things installed on the car that he removed to clean it up and he fixed up some earths and other wiring, but still no spark.

He opened the ECU and it looked OK except for a little dark spot near a capacitor, after testing it a bit more he came to the conclusion that the ECU is probably the issue.

So next step is to find a replacement ECU.

The factory ECU is 23710-04U01 MEC-R126 27C256 (#22) and thats the one that is currently in it.

There is one on Marketplace at the moment near me, however it a 'Tomei tuned' ECU. Can I use this? or has this been mapped to something in the previous car and if I just drop it in it could damage something?

Thanks

 

[GTSBoy]

Tomei and other Jap tuning house ECUs generally are just a stock ECU with a burnt EEPROM in them, with the maps changed to remove some fuel under load and add timing. Sadly, they generally assumed 100 octane Jap fuel, which means they frequently caused engines to detonate to death when used here.

You can probably still Nistune it, which would be the only sensible way to run a stock ECU anyway, particularly for drift, as you are going to want to put a safe and decent tune in it. The stock tune is "safe" but not "decent", as it has quite ridiculous "rich and retard"  in the upper right corners of the maps. Not as bad as on RB25 ECUs, but still, AFRs of ~10 at high load is not the way to make power.

[Tim32]

OK I'll pick up a stock ECU and go from there. Thanks for explaining that, appreciate it.

[joshuaho96]

1 hour ago, GTSBoy said:

Tomei and other Jap tuning house ECUs generally are just a stock ECU with a burnt EEPROM in them, with the maps changed to remove some fuel under load and add timing. Sadly, they generally assumed 100 octane Jap fuel, which means they frequently caused engines to detonate to death when used here.

You can probably still Nistune it, which would be the only sensible way to run a stock ECU anyway, particularly for drift, as you are going to want to put a safe and decent tune in it. The stock tune is "safe" but not "decent", as it has quite ridiculous "rich and retard"  in the upper right corners of the maps. Not as bad as on RB25 ECUs, but still, AFRs of ~10 at high load is not the way to make power.

IIRC a lot of these Japanese chip tunes tend to have epoxy all over the ROM chip because they didn't want to make it too easy for their maps to get dumped. If the board isn't ruined by all that then Nistune is a pretty easy way to get a map figured out if only to reset timing/fueling for local fuel quality.

[Duncan]

I'm not familiar with how a Nistune physically looks, but if I remember from your other thread it has an aftermarket turbo...therefore it is very likely your current ECU already has a nistune on it as the standard factory one is unlikely to be happy with a bigger turb.

I think it is unlikely the tomei one is any good unless you can confirm your can nistune it before you buy it....maybe check out what they look like physically. I guess it should at least confirm if the car starts and runs but basically any of the japanese fixed rom tunes are pretty much worthless these days

But, depending on budget and what you want to do, an aftermarket ecu is probably a better choice long term, things like powerFC are very cheap these days for example, or a link/haltech etc plug in would give you better flexibility/features/protections/logging

[Tim32]

Yeah got a factory one on the way, just really trying to get this thing fired up. I looked up what a Nistune ECU looked like and it definitely didn't have the extra board soldered into it, so must be a stock ECU I guess?

I am thinking it had an aftermarket ECU at some point and was removed to use somewhere else and they just put the stock one in when they sold it or something.

Link/Haltech are probably where we are headed I think.

[Duncan]

Pretty poor effort from the seller, unless they were clear the car would not run as supplied.

I don't think the car will run properly, if at all, on a standard ECU. Apart from anything else you should confirm if you have standard injectors and that the air flow meters wiring is connected.

And I suspect your ignition issue might be masked by the ECU issue too, so the troubleshooting is going to be difficult.

Perhaps you could ask the seller what ECU it was running previously, I was assuming Link or Haltech as they make plug ins and you didn't mention the ECU wiring had been messed with

[Tim32]

Yeah he was clear that it was not running. He's not the one that did any of this, he didn't have it very long and just lost interest in fixing it up. I'll hit him up to see if he can find out what ECU it used to have.

So aftermarket ECUs don't use the MAF sensors?

[GTSBoy]

1 hour ago, Tim32 said:

So aftermarket ECUs don't use the MAF sensors?

It would be possible to set up some aftermarket ECUs to use the AFM, but many can't at all and almost everyone takes the opportunity to throw the AFM in the bin. Not having an AFM makes a lot of things easier, like turbo inlet plumbing, dealing with reversion and BOVs and so on.

[morboost]

I looked at your engine bay pics and couldn't see this

 IGNITION / IGNITOR MODULE - ptu 

goes on your coil cover that seems to be missing, splitfire state: This kit DOES NOT replace the OEM ignitor chip.

 

[morboost]

also you wrote spitfire coil packs if you ment splitfire they should be blue not red, I typed in red rb20 coil pack straight china $189

[joshuaho96]

2 hours ago, GTSBoy said:

It would be possible to set up some aftermarket ECUs to use the AFM, but many can't at all and almost everyone takes the opportunity to throw the AFM in the bin. Not having an AFM makes a lot of things easier, like turbo inlet plumbing, dealing with reversion and BOVs and so on.

The reversion issue is very real if you decide to go without any BOV. Or if the OEM bypass valves decide to stick closed from age. I have heard this badly impacts the resulting tailpipe emissions. The hot film MAFs are supposed to fix this by only measuring airflow in one direction.

Edited March 27, 2024 by joshuaho96

[Tim32]

@morboost Yep it has an ignitor like that, its just not mounted properly, it's just flopping around up the back, so will have to mount it nicely... Good pickup on the coils, they are SuperSpark SSCP-RB1 (https://www.streettuned.com.au/shop/uncategorised/super-spark-coil-packs-rb20det-rb25det-rb26dett-a31-r32-r33-gtr/) Are they OK???

 

[GTSBoy]

14 minutes ago, Tim32 said:

they are SuperSpark . Are they OK???

No. No they are not. Coils in any shade of the rainbow other than the OEM black and the official blue of Splitfire are to be regarded with massive suspicion. Some of them work, many of them are very cheap crap. Impossible to tell between them until it's misfiring on the dyno.

There are people who swear by a particular rainbow brand, including those Supersparks, saying that they ran well for them. Those are the lucky people who managed to get a whole set of 6 good ones. Many other people got 3 good ones, 1 bad one and 2 really bad ones. Bought another set, got some different split between the possibilities.

It doesn't matter these days, because no-one in their right mind would use stock format coils on an RB, now that you can buy massively strong and good quality pencil coils and conversion kits for ~double what a set of Splitfires cost. I have Splitfires and they are fine for my power level, but if they start to play up I will be putting R35 coils in.

[Tim32]

Thanks so much, that's good to know, they'll probably be the next thing to replace by the sounds of it.

Thanks a lot for the detailed info and taking the time, really appreciate it.

[morboost]

if this was more modded (i suspect it was as it has the pwr catalog on it) and somebody has thrown a stock ecu, cheap coils they may have also thrown a china maf in it so double its a real nissan maf the copies look close and is a green label for your application.

[Duncan]

23 hours ago, Tim32 said:

Yep it has an ignitor like that, its just not mounted properly, it's just flopping around up the back, so will have to mount it nicely...

You need to check that the earth ring near the ignitor is properly earthed to the head, from factory the ignitor and coil earth are part of the coil pack cover mounting, and you won't get spark unless it is properly earthed.

[Dose Pipe Sutututu]

Opportunity to convert to R35/370Z coils, those coils are more trouble than anything else.

OEM (including R35/370Z) or Splitfire are the only sensible options.

In the past when I was a broke lad in my 20s, I bought brand new colourful (won't mention the colour, but it's similar to my skin) looking coil packs and 2x actually came DOA! Ended up buying used Splitfires and instantly fixed my misfire issue.

[Tim32]

OK here's the MAF, I am assuming this is the original???

Thanks @Duncan I'll double check that earth.

Sounds like Splitfire coils are definitely next on the list.

[morboost]

heres a china one like i said they are close, i think you will be good to go when you get the stock ecu and crank it over I personally would have a timing light on it when you go to start it unless you have pulled the timing cover already and all the marks line up, if it has adjustable cam gears they are tight and the cas is sitting were it should be.