auto vs 5-speed ecu

[BoostFab]

regarding rb20det:

do you guys know what's the difference w/ the auto vs 5-speed ecu, as far as power wise, one might have more agressive fuel curve than the other...??

[Nameless EJ6]

If you search the Skyline forums out there you'll find lots of info on this.

Some say Auto ECU's are better.. I think it's because they are more finely tuned for higher octane or some ****.. don't quote me on that.

[Carl H]

they have a weaker timing map than the manual ecu does so it wont strain the transmission when it shifts.

[Wulfgang]

There's a lot of noise out there about things like this. People say lots of things. For example, if you read the Skyline forums you can find people talking about how much power you can gain by "resetting" your ECU, or by going out and thrashing your car so that your ECU "learns" to drive your engine harder. I'm not saying anyone is wrong or right, but the fact that there is so much discussion tells you that the effect must be rather small, if any effect at all.

But without a comparison of the ROM files, side-by-side, there's no real way to know. Nissan isn't going to tell you, and it is impossible to measure on a dyno (due to the auto transmission).

FWIW, I put a '95 KA24DE with auto ECU in my 5-speed '89 with no troubles. The engine pulled hard, and I was very pleased with the result. Still, only a dyno could tell you whether or not a 5-speed ECU would have pulled harder.

Carl H may have a point, but I would guess that if the ECU does retard timing for shifts, then it would need a shift signal from the auto transmission controller. If you install it in a 5-speed car, then there will be no shift signal, and thus, probably no timing retard either.

[goofynick6]

I have an auto ecu, and I think it sucks, trying to find a manual one. I think it is the cause of some of my idling problems and the reason it likes to stall when I come to a stop, and idle lower.. I've tuned my own fuel maps, it's fast, but I think I'm only tuning one of several other maps that could be changed.

Nick

[Wulfgang]

No kidding... I also had an idle problem with the auto KA ECU. When I started the car, it would want to die. No misfiring or anything, it would just die, like when you turn the key off. Also had that problem when coming to a stop, although I learned to deal with it.

Still, I had no problems with getting power. The car was very fast for a KA.

What other maps do you think there could be? Have you looked at the ROM file in Excel to see if there is any other map-like data?

[goofynick6]

Well, nobody has "hacked" the rb ecu like the rb26 or the sr. With those engines, you can change tps enrichment, fuel vs. water temp, etc. With the rb20, there is fuel, timing, and "idle stabilization" which I haven't messed with because I just found it yesterday.

I did my best to try to hack it myself going by address files from the other engines, hoping they would be similar, but no luck.

I know there's a lot more that could be tuned, just no way to figure out 1000's of lines of hex code.

[BoostFab]

my rb20 is 5-speed, running an auto-ecu...version "23". idle does get lump at stops/neutual. before i didnt have a one-way check valve between the brake booster and the IM--after i put back the valve it helps stablize the idle and not shut down at a stop...but i think the nature of the auto ecu cause that effect on 5-speed setup....

[Wulfgang]

I just looked at the address file, and I see what you mean.

Also, it appears that the 300ZX ECU tuning page no longer exists (but I think I may have copied it.. have to see if I can find it).

[BoostFab]

a possible test to get the 5-speed rom and load it on the auto ecu?

[Wulfgang]

I *think* that would turn the auto ECU into a 5-speed ECU. As far as I know, that single ROM chip holds both program and data memory... meaning that it is the only thing that is different between an auto and 5-speed ECU.

[goofynick6]

Answer this then..

DOes the manual rb ecu use that 2nd switch on the TPS? The tps has the normal .45-4 volt sensor, but it also has a closed throttle and wot switch built in, and my car would stall 10x more often before I hooked it up..does a manual ecu have that?

nick

[Wulfgang]

I do not know about the TPS, but since you have an emulator you could just load up a ROM image from a 5-speed ECU and see how things go.

I may be pulling my EPROM soon and could send you a ROM image then, depending on what equipment I actually end up buying. How did you load your ROM into the emulator? Does it have a reader/burner with it?

[Wulfgang]

Wait, I just realized something else.... I ordered parts to make a Conzult interface (the PLMS one) last night, so I should have that up and running in a few weeks. With Conzult you can just tell the ECU to spit out the whole data space, although I do not know about program space.

[goofynick6]

I have loaded the eprom, and it's not from an auto..it's the only one on the net, I didn't scan my stock eprom, I used the bin file from the net...so it doesn't make a difference really.

Nick

[goofynick6]

I just found this awesome info from the Skyline's forum again (love that place!)

This is what you need to do if using an auto ecu with a manual transmission:

Pin 44 is a nuetral switch earth seek. Pull it to ground through a fuse initially with the engine at normal operating temp. You should hear the engine RPM slow down. If so then remove the temporary fuse and cut this wire about 150mm up the loom away from the ECU. Strip the insulation for about 15mm and join this wire in to the wire of pin 10 or 20 or 50 or 60, whatever is easiest. Solder the joint. Without this terminal pin grounded the ignition timing is way advanced and the idle speed is to high. You may find that you need to undo the things you did to reduce idlespeed. You will also need to recheck the ignition timing.

Going to try this tomorrow and see if it helps!

Nick

[Carl H]

well it is important to have the neutral switch hooked up to the ecu as the ecu retards timing 5 degrees when in neutral.when i timed my engine i always set it to 20 degrees at 600rpm because that would be 15 degrees if the neutral switch was working correctly.also with the auto ecu it is still looking for the auto controler signals which would mean when the car is at a stop the transmission would be in 'neutral' so i would pull timing appropriately.

[BoostFab]

good info, let us hear your result.

[goofynick6]

Well, car runs like total ***...I connected the pin 44 (neutral switch) to a ground like I read to do on the skyline forums, timed the engine to 16 degrees at 600rpms. Then, I reset the ecu, now it the car pops and sputters and doesn't run well.

I noticed the idle did lower when I hooked up the pin 44 to ground, so I'm guess it thinks the car is in "drive" and therefore the timing should goto 15 degrees, so that is why I timed it there..

AHH..I need a manual ecu; this bs is really annoying with the car stalling and idling like $hit.

Nick