gran racing
Super Moderator
Yeah I'd pay you to do something that could be tuneable.
Un-tunable ECU's
- Thread starter Joe Harlan
- Start date
Jeremy Billiel
New member
Dave - Joe and I are on the same page. From my understanding the ECU is not all that much different than OBD1 in that you need to desolder the stock chip, solder in a new socket and tune. There are 2 ECU OBD0 programs out there. I agree this is very niche and not mainstream, but it should be able to be done. What is the ECU code name for the preludes?
Can you take a picture of the guts of the ECU? This will determine what typs of chip it is.
See this link
http://www.pgmfi.org/twiki/bin/view/Library/ChippingOBD0PM6
or this
http://www.pgmfi.org/twiki/bin/view/Librar...ppingAn88-89ECU
Joe Harlan
New member
The ECU for the prelude Dave has is a PJ7 Dave's car has a distributor and Vacuum advance if my info is correct. The ECU only controls fuel mixture at that point and has no timing control Timing curve is analog weights and advance (old school easy to work with) I think at this point you could use hondata to read the OE fuel map and factory rev limiters. You should be able to replace the main memory chip and program the new fuel curve ect. Now I think what I have to ask is. Has anyone with these cars that can't be programmed even been to the dyno to find out what they need or if they need anything that can't be done already? Because the rules would not let you change the Distributor in any car I am not sure how MOtec is gonna be worth the money on these older distributor type applications when you look at the money to value ratio..
Anyways Dave I am looking into it a little further and when you send me the photos of your ECU board it will tell me more.
Joe
Anyways Dave I am looking into it a little further and when you send me the photos of your ECU board it will tell me more.
Joe
bamfp
New member
The problem with the Prelude, Accord and the CRX's of those years is the injectors are patch fired. The dist. only has a TDC and crankshaft position sensor. The 88-91 CRX's added a camshaft position sensor. That is why you can chip those cars and not the earlier ones.
Blake Meredith
Blake Meredith
Joe Harlan
New member
Greg I can open both style boxes tomorrow and post photos of them. The technosquare link I posted has photos of the boards that I am thinking of.
Marty sorry you don't get my logic but there are several pages to figure it out from. This stuff is not plug and play and it figures out how to run on its own. To take advantage of the dollars spent you have to spent it twice in dyno time and a programmer. There is nothing cheap about inexpensive
shwah
New member
I don't know about any of these rules in discussion destroying IT either way. Over time the way we handle such items probably will have an impact, and some sort of consistent direction will help this, but I feel that the ITAC is working hard to provide that consistency.
Some guys can't find a decent differential, or bushings, or air dam, or strut brace, or fill in the blank for their chosen car. They have to design/build or pay someone else to do that too. The car you pick is the car you have, warts and all. If there is no chip tuning available, that is one of the downsides of that car. It may not mean it can't be done, and if it can't you can probably use other methods to get the fueling right anyhow, but it means it hasn't been done.
The actual tuning will be the real expense of an aftermarket ecu, unless you have access to a free dyno.
JimLill
New member
I am looking at 9.1.3. D-1-a-6 on page GCR-295 (2007)...
Am I correct that the inside of the ECU box is "open". Can I do anything I want inside it. I mean if I "invent" a JimDribble PCB that fits in there, it's OK?
The CIS-E on a 8V A2 VW doesn't do much fancy, but it's worth a look.
Am I correct that the inside of the ECU box is "open". Can I do anything I want inside it. I mean if I "invent" a JimDribble PCB that fits in there, it's OK?
The CIS-E on a 8V A2 VW doesn't do much fancy, but it's worth a look.
lateapex911
Super Moderator
yup...have at it. Your device can include whatever sensors or widgets you want. You won't be the first to stuff in a full EMS conrtroller, a TPS and a MAP sensor, though......thats out there now.
Joe Harlan
New member
Stevel, actually the later 240 ECU requires a daughter card to handle the additional processor of the OBDI ECU....I have modified both styles and will post pics later. I have not done and NX and would like to see the differences if you wanted to share.
this thread is proof that keeping the stock ECU and only allowing reflashing or rechipping isn't going to keep anybody from doing anything. What is the purpose of making folks work around the stock board? (really... I'm asking) This creates inequality and furthers the gap between those that have the money or technical prowess and those who do not. Some folk's comments smack of protectionism and others sound like they're out to keep the rule as an avenue for profit.
ahhh... I don't know about that. There are performance computers that can be mounted to the windshield with a suction cup and run off the cigarette lighter for power that contain a two axis G meter and with nothing more then an acurrate car wieght input can calculate horsepower for less then two hundred buck that are amazingly accurate and repeatable. Cheap data acquisition systems (less then $700) with g meters built in can calculate horsepower. Wide band O2 sensors are cheap. Every town has a drag strip near by. And there is always the seat of the pants dyno! Actual tuning is the greatest expense, but that expense can be made monetarily or with one's time and systematic record keeping. (same as chassis setup)
Megasquirt isn't simple, but there is a huge user base and tons of documentation. Not so for the typical guys (insert brand here) stock ECU. Some cars it will be harder, some easier... inequality. Yes, we all pick our horse, but if equality is easy to obtain, why not let it be so?
Well, as you may already know, there's pretty much two players in the B13/B14 ECU arena: Jim Wolf Technology, who is a major retailer to the Nissan "tuner" market, and Calum Johnson ("CalumSult") who appeals to the DIY group. Both modify the ECUs with a socket and daughterboard and EEPROMs, and do their own programming; JWT provide cookie-cutter programs and Calum supports user tuning.
I've tried both. I was disappointed in the lack of performance I got with the JWT "100 octane IT" program; on the DynaPack we saw exactly 2 horsepower, and it wasn't repeatable. Statistically, it was zero. I've talked to another IT B13 driver and he reported similar results. JWT "can" work with you on reprogramming; they ask that you run the car on the dyno and send them the sniffer and trace results. Problem is, everytime they do that for you, it's $150. Plus, you have to give them a pretty hefty deposit on the chips and pay for shipping both ways. It's just not a practical solution for the racer.
My foray into the CalumSult realm ended in disaster: I burned up two engines from detonation. However I blame those failure on myself: These maps worked great on the dyno and in autocross, but could not tolerate long runs. The first time I was running 93 octane fuel and they ran fine during a school day (I was instructing) and qualifying session, but after about four laps of constant running in the race it toasted the engine. The second time it happened was a miscommunication between me and my crew chief resulting in my reinstalling the same computer, again with 93 octane.
So what we have here is a comparison of too conservative versus too aggressive, of mass retail sales versus "go it alone, you're responsible for your own tuning." Thus, since mid-year '05 we've been running the stock ECU with advanced base timing (and 100 octane fuel), and the fuel on the dyno really doesn't look that bad. I don't expect we'll be able to get much with tuning.
Following is a photo of one of Calum's setup, which is quite close to what JWT does. With this setup all tuning is done in the software (home-grown) program and is then burned to both chips (I use a Moates BURN-1). This board also supports using ROMulators, where you plug cables into the board connected to your PC, and use the software on the PC to emulate the ROMs. Once you fine-tune the program, you burn that to the chips and then install them. Finally, Calum has developed a design where you can keep the chips in, plug into the box via serial cable, and actually edit the programming in real time. Once I get Matt motivated to rebuild the engine on the NX I'm planning on inviting Calum - who knows how to do the tuning - to join Matt - who knows what to tune - for an afternoon of dyno tuning to see what we can do.
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Joe Harlan
New member
Yep thats basicly all the same stuff I have and have found over the years. Your photo looks like a 95 OBD1 240sx box I have not used that daughter board setup and would like to get more info on that. Now here is the deal, I consider you a pretty sharp person from what you have typed here and other that know you. Here you hae gone through 2 engines in a short period of time learning this stuff. That is it in a nutshell even with open ecu's you still have to program them and understand what your looking art when you do it. I had a box from wolf that was excellent but at one track in one place the motor would detonate. I decomplied the code on that box . There was one small section in the map that had 255 placed in about 6 to 10 boxs in the center of the timing map. A place that you would think the motor would never see we had max timing. Now at that one track in that one place the engin met those conditions. I went looking because I could not explain why I was breaking ring lands on the pistons other than the thing was detonating. Freak deal? I think so but most people don't have a clue how much they are taking on when digging into what is considered the easything to do. When we first did the 350z we lost HP before we gained any.
shwah
New member
Jim - build a microsquirt. Add a frequency to current conversion chip change the injector duty cycle signal to a current for the Differential Pressure Regulator and use the system to build a map for the 'fuel trim' instead of for the overall engine. The flow plate will give you your macro fueling and the ecu will give you the fuel trim, just like the stock system, but now programable.
Of course you get nearly the same result by putting the correct resistor inline with the CIS-E coolant temperature sensor. Basically the oft noted 'fuel enrichment module' that some tuners sell for this system. Tune it on a dyno with a potentiometer, and watch the AFR move at your whim as you turn the knob. Measure the ideal resistance and install a resistor of that value so your toddler son can't change the setting while playing in the car
.The complex system can be tuned to idle and drive like a street car when in the paddock or cold though...
I don't think ignition is as big a deal as people think. Run fixed timing if you like, WOT and 4k+ rpm on the track will be fully advanced anyhow. If you want to make timing curves you can add that functionality with a Megasquirt picking up the stock hall signal and using the stock ICM for dwell control. I just don't know if the Msns-E code works in the micro hardware, so might have to use full size board. Never checked on whether it would fit.
The original subject of this thread was untunable ECUs. Well I think my car falls into that catagory. My car is a 77 Datsun 280z. There is no way to 'tune' my ECU. No epprom to reflash or replace. The whole reason I built this car was that when the 'process' gave the 280z a wieght break, combined with the open within the box ECU rule, I thought this would be a great car. The ECU is as big as a shoe box, I can fit anything. The old electronics are crude, a modern solution would really help. The rule going to rechip or reflash only would hurt me.