BBSC New SS Box Thread

[KODIAC]

Ok, im going to take a swing at trying to explain why this works they way it does....

Basically you can modify afrs at idle, cruise, part throttle, WOT.

Here’s why I think:

The SS box works by manipulating the MAP sensor voltage....

Now, lets take a minute to understand how the map is designed to work.

The MAP sensor, measures vacuum created by the motor, then relays this information to the ECU. The ECU in-turn applies its set pulse width for whatever MAP reading it gets. All the map sensor is a voltage signal, no more no less... if you up the voltage, it thinks closer to atmoshperic, lower voltage, is more vacumm.

Now if an engine is idling, vac is present, and the ECU applies its given pulse for that level of vacuum. So everything runs fine.

Now lets say we up the voltage a lil, by modifying the coefficient in the black box map a table. Well now the ECU sees less vacuum, so it applies a longer pulse width to make up for the difference.

Well if the engine is still running the same, and we just lie to it, then its gonna go richer or leaner, depending on what we tell it.

Here’s the key, the stock O2s we know aren’t good, and so does the ECU, so as long as you don’t pass the overly rich, or overly lean. The ecu thinks it’s "acceptable" and will allow it to run. Its only when you reach these overly lean/rich conditions that the ECU suspects something wrong, and will perform changes...


This "acceptable" window is where you can tweak things, so at idle, partial, cruise, WOT, doesn’t matter, as long as it’s not overly lean, or overly rich. Now ppl getting CELs, aren’t getting them for overly rich/lean conditions mostly. Usually they get CELs for map sensor voltage too high, or too low. Which we all know how the voltage math works, and the whole 13.8 thing goes.


Now, the reason that the changes work, and have affect has to deal with just how basic this system truly is. It’s a simple look up and reference table.

As a side note, I want to share another fact I've came across. On my del slo, I have a VAFC. Now it can modify fuel delivery, and vtec engagement. Well the fuel delivery is the same way the NSX ECU works stock, and the VAFC controls it the same way the SS box does. It modifies the MAP voltage. I can sit in my car at idle, and take out enuf fuel to stall the motor, or add enuf to stall the motor. It’s instantaneous; cause its basically putting a POT right on the lead going into the ECU. Now the SS works in a so much nicer interface, but doesn’t have the on-the-fly adjustments that my VAFC has, so you cant go sit in your X and lean it to the point to stall on the fly, but you can modify it to the point it will not crank. (I’ve done this to a BBSC NSX trust me it works)

Now, as far as passing emissions goes, you can make the car run similar to stock, and make it pass cause you can affect the values across the board. I have personally tuned a BBSC for better street conditions, and safe AFRs for cruise and idle. It CAN be done. And it will maintain these values, thanks to that basic system it uses.... if it’s between overly lean, and overly rich, it’s "acceptable"

Now lets look at what we are actually trying to accomplish to make it pass.

We want it to run "like stock" so that means a "stock" cars AFR. Well how ya gonna do this??? hmmmm.... how about shorten the injector pulses enuf to make the 440 injectors have the delivery of the 270s that came stock. Now how you ask do we accomplish that.... simple... we just give it a lower map voltage, which makes it choose that shorter width out of its reference table, thus in turn lowering the delivery of the injector enuf to obtain that "stock" AFR.

Now what’s great about this??? Well since you have control across the board, you can now have a great vacuum set of values, that run the car more efficiently, which our tree huggin' friends will hate us less for, and you can have your regular boost values, that give ya that wonderful power when ya need it safely.... This means that the car can be tuned to be more eco-friendly, and safer to drive.


Another topic, the removing timing:

if you lower the map voltage enuf to get the delivery of the 270s, we all know that the stock ECU can pull enuf timing just fine to make it pass. It did it before the SC, so with the same flow rate, it will be fine. Now if you feel the need to pull timing, or just want to, you can pull timing anywhere ya want.... vacuum, boost, doesn’t matter...

Timing is based off of sensors again... it works by interrupting and delaying those signals from the cam signals, to make the retard.

Basically stock works by getting signals from the cam sensors, and the crank sensors, and then firing the correct cylinder, when it is ready. To get the retard, we just delay the crank signal a few milliseconds, and BAM there’s your retard. The SS box does this for us... and it will do it at any RPM, and at any vacuum or boost value. It’s just a straight up system... very basic...


As long as the O2s are reading "acceptable" then it really doesn’t care.... it just wants to be "acceptable". Now as far as open loop goes, its expecting it to be rich, but again, the stock O2s aren’t good, so it knows that as long as its not overly lean or rich, then it should be safe.... if it had been designed as a FI car to begin with, rest assured the ECU would use 5wire. But it wasn’t, and as long as we lie to it, it will never know any better. It’s only as accurate as its stock O2s. And Honda designed it with those on, because they could do the job, and safely for a NA car. So for us to go FI, means we have to accept some things we can’t change, like the stock O2s and the way the ECU uses those signals. But it gives us a tunable area, between overly lean/rich. We have to get it where we want.


Well hope that clears up some things, and helps us all to further understand the NSX.

 

[Jason Weaver]

Mikey,
Very well written. Thanks for your input.

 

[kpond]

Andy, et. al,

Regarding my smog experience last year.

BBSC with SS box I had NOx values ranging from 1100 to over 2000 PPM where the allowable max was approx. 1000 PPM. HC and CO% were both in the pass range.

When I bypassed the SS and re-installed the factory injectors, my NOx values were 358 PPM for the 15MPH test and 242 PPM for the 25 MPH test.

Let me know if you need any more data.

 

[true]

Ok, im going to take a swing at trying to explain why this works they way it does....

Here’s why I think:

The SS box works by manipulating the MAP sensor voltage....

Now, lets take a minute to understand how the map is designed to work.

The MAP sensor, measures vacuum created by the motor, then relays this information to the ECU. The ECU in-turn applies its set pulse width for whatever MAP reading it gets. All the map sensor is a voltage signal, no more no less... if you up the voltage, it thinks closer to atmoshperic, lower voltage, is more vacumm.

Now if an engine is idling, vac is present, and the ECU applies its given pulse for that level of vacuum. So everything runs fine.

Now lets say we up the voltage a lil, by modifying the coefficient in the black box map a table. Well now the ECU sees less vacuum, so it applies a longer pulse width to make up for the difference.

Well if the engine is still running the same, and we just lie to it, then its gonna go richer or leaner, depending on what we tell it.

Here’s the key, the stock O2s we know aren’t good, and so does the ECU, so as long as you don’t pass the overly rich, or overly lean. The ecu thinks it’s "acceptable" and will allow it to run. Its only when you reach these overly lean/rich conditions that the ECU suspects something wrong, and will perform changes...


This "acceptable" window is where you can tweak things, so at idle, partial, cruise, WOT, doesn’t matter, as long as it’s not overly lean, or overly rich. Now ppl getting CELs, aren’t getting them for overly rich/lean conditions mostly. Usually they get CELs for map sensor voltage too high, or too low. Which we all know how the voltage math works, and the whole 13.8 thing goes.


Now, the reason that the changes work, and have affect has to deal with just how basic this system truly is. It’s a simple look up and reference table.

Hi Kodiac, I believe you have failed to mention that Honda ECUs possess both short term and long term o2 fuel trim tables. We know you will be able to overfuel the car to the point of death, but also remember that the ECU is always polling the o2 feedback for later calculations.

Doing short term (live manipulation) tuning you are able to rich/lean your mixture by feeding the ECU, but if you drive the car long enough, the ECU will do whatever it takes to return status to a stoich* mixture while in closed loop. For all Honda ECUs I've worked with, the max value before CEL* is 30%. I've never considered underfueling by 30%, but as far as over-fueling is concerned, anything greater then 30% and the ECU will display the check engine light. This data point is backed up by Greddy and other turbo manufacturers by supplying 310cc injectors with their turbo kits. This is the maximum size [((240(stock) x .30) + 72) = 312cc] injectors Honda ECUs can control in closed loop without any additional devices, and without erroring. So while I agree you will be able to drastically minipulate your MAP values to change fueling at idle and not receieve a CEL immiedietly, I would be willing to bet, over time, if you drove the car long enough -- the ECU will apply a long term o2 feul trim and either automatically return the mixture as close to stoich(14.7:1) as it can get, or give CEL.

Some people who may have unplugged their battery or reset their ECU may find that their car has idled strangly for a while and ended up smoothing itself out. By resetting the ECU, you clear the long and short term o2 trim values. My advice(big deal) if you are trying to pass emmisions by leaning out your vacuum tables would be to reset your ECU in order to clear your short and long term fuel trim before taking the test.

*stoich = Air to fuel ratio of 14.7 parts air to 1 part fuel
*CEL = Check engine light

 

[Yellow Rose]

Making Progress

I will be re-activating my FJO with the SS fuel map that I passed with a couple of days ago. The 2.5% reduction of the values left of 0 PSI in the fuel map, yielded a modified theoretical AFR of 15.1:1.

Recognizing the fact the AFR fluctuates rapidly, even at steady-state throttle position, my average actual AFR was 14.9:1. Pretty close the above theoretical number.

With my previous map re-loaded into the SS, my average AFR is now 14.7:1. This was the last version of map that I created with the old SS box, and will be the starting point of tuning with the new SS box. After I fine-tune the AFR curve from 69-8000 RPM (average value of 11.6:1, my target is 11.9:1 like it is from 25-6900 RPM), I will re-dyno to see how much if any HP is gained by removing the ultra richness on the original fuel map that netted 383 RWHP. Afterwards, I will change from 8 PSI to 10 PSI.

Side note - installed the new SS box yesterday, but it is not electrically connected because I ran out of daylight. I failed to budget enough time to remove the harness bar. There was no way I would’ve been able to wiggle the SS box into its new location, which is the cavity to the left of the ECU, near the right seatbelt retractor, had I not removed the harness bar. I ran a nine-pin ribbon cable from the serial port, behind the panels, behind the center speaker, up into the armrest console between the seats. When I want to load a map, it is a two-second task of plugging in the laptop. No more trunk carpet and weatherstrip rubber to mess with any more. I have a boost gauge and there already was 1/8” nylon tubing behind the panels. I teed the new SS into that pre-existing tubing with a compression union. At the other end of the new tubing, it inserts snuggly into the black neoprene hose, which is part of the SS’s MAP sensor. I then wrapped that interface-connection with three tiny zip-ties, to ensure the tubing will not slip out of the hose. Next step is to connect the new wires to the ECU’s wire harness and turn the key. I hope the only smoke we see will be from the rear tires vs from the wire harness.

 

[Yellow Rose]

Finished

When we last heard from our hero, his new SS box was installed but not wired up yet. One hour ago, the ignition key was turned and the engine fired on the first try.

However, my conversion took extra time than others, because, not only is mine an OBD2, but mine is a 1995 OBD2. There seems to be some differences in the wiring harnesses with later year model OBD2's, even the 1996, that is the same 3.0L engine.

The OBD1 cars number the pins in an even-odd-even-odd manner within a harness connector. The OBD2 cars number the pins from 1-8 on one row and 9-16 on the other row. (Note - this is just an example, as the harness connectors do not all have sixteen pins.) To further complicate matters, what one car would use as an orange-blue wire, my car would use blue-green wire. For some reason, Honda changed their pin numbering convention in 95, again in 96 and again in 97-on.

Anyhow, the task was not technically challenging, but it was testing my agility as I was hanging upside down from the garage rafters, trying to fit my hands in a space woefully undersized.

I will monitor AFR for a few days with the 8 PSI pulley. After the holidays, we go to the 10 PSI pulley. I have MB's expressed permission to do this. Say, did I mention that I talked with him on the phone today? Twice. My target timing at redline will be +/-18°BTDC, as confirmed with a Honda data scanner.

There is one puzzling thing, though. You know how when you rebuild an engine, you have a few bolts left over? With the new SS box, I have an extra wire. An orange wire. An orange wire that can pulse an auxiliary end-device.....such as an electronic boost valve. Now who said I can't make HP-TQ like a turbo?

Forgot a very important closing note - thank you Kendall, Larry, Bryan, Romeo, Chris, Bruce, Mike, Sean, Devin, Charles, Mark and Mark for your help / comments.

 

[kpond]

Hi Andy,

You can do me (and presumably others) a big favor by letting us know what SS timing table values will yield your desired 18 degree timing. This alone would be very valuable to a lot of us with OBD1. You see, we don't have the ability to measure as you do with an ODB2 + scan tool. The sooner you could do this, the better. I am becoming concerned - especially after Sean's post on another thread, that I (and others) may not be pulling enough timing to have desired safety margins.

An addititonal piece of information and potentially as easy to get for us would be the effect of SS timing table values to actual measured timing. As you remember, we are still wondering if this is 1:1 or potentially 1:2 - big difference!

Thanks in advance Andy for any light you can shed on these questions.

Oh, as long as I'm askin' for stuff (it is that time of year isn't it?), you also have the ability to look at long and short tern fuel trims - again, something else us OBD1 boys cannot do. I would be very interested in what the fuel trims set themselves at for a given set of SS map values in the non-boost range.

Thanks a lot.

 

[Yellow Rose]

I may be plugging in the scanner this weekend, not sure yet.

Before loading the map into the new SS box, I doubled every cell value in the timing map. Holding down the CTRL key and dragging the mouse's cursor across the table's heading, I highlighted all columns. I then clicked on the "change by" button and entered 100%. Presto - 2x all values.

While I have not dyno'ed or data logged, the car feels a bit stronger. Perhaps it is the placebo effect or perhaps the new box is doing a better job at controlling timing, and as Sean and FX have said, Honda engines respond well to timing changes.

Regarding LTFT and STFT, what should I be looking for? If I recall correctly, the trims should be a close to zero as possible.

 

[kpond]

Andy,

On fuel trims, yes, we are looking for the lowest numbers. I have always suspected that our non-boost SS values have contributed to larger than normal fuel trims which will make tuning under boosted conditions harder. I don't believe anyone know precisely how the ECU factors in trims in open loop but the concensus is that they do play a role.

Regarding timing, the general rule of thumb is to start out on the retarded (on a dyno) and then start "lessening" the retard while watching HP numbers rise. There will come a point where reducing the retard will no longer have a positive effect on HP. (Presumably, this is close to the point where add'l reduction will cause ping and/or knock.) Anyway, once this peak is attained, you can then back off a couple of degrees to provide a safety margin.

Again, this is a very genral tuning guideline. Anyone with more precise, NSX-specifc experience, please chime in.

 

[Yellow Rose]

Confirmed

I will be borrowing the dealership's Honda data scanner this weekend. While I have not seen it in action, the tech says it is configurable to read the NSX's ECU, not just Accords, Civics, etc.

Three variables that I will be looking for are (a) total timing up to redline (b) fuels trims (c) intake air temperature.

Does anybody else have other data requests? Then again, I may end up scrolling through the scanner's menus and reporting back everything that I see.

Until Sunday.

 

[true]

I would like to mention something else regarding tuning with SS Box or any other type of 'piggy back' ECU system. I was going to mention this in my previous response, but did not deem it relevant because of the State Emisions testing procedure. (Will automatically fail if your CEL is on) One thing I would guess you SS tuners are fighting with is non-repeatable A/F results over time under part throttle conditions. What a number of tuners have been doing for the past few years is very simple -- interrupt the o2 feedback signal to the ECU. The only issue as far as emisions are concerned is that you will get a CEL, but it will not impede your tuning or engine performance whatsoever. Some CELs will put the ECU in limp mode, but disabling an o2 sensor should/will not do this.

Before I was tuning with a full stand alone this was my method and it proved to work very very well. (In my opinion as good as you can do with a piggy back hack utilizing the oem ecu.) It allows you to tune without the ECU trying to adjust your changes while you are making them on the fly. After the engine warms up with the o2 signal disconnected, it will emit a check engine light. At this point the OEM ECU is effectively running fully open loop. If you can nail your low load/cruise A/Fs at 14.7 reconnecting the o2 signal wire will re-enable closed loop operation and you will have a very reliable part throttle mapping. I have found it much easier to do this in the past to get a rock solid closed loop operation off a piggy-backed OEM ECU. This is the same type of tuning anyone with a stand-alone would generally do. Map the entire range statically running open loop, then switch on o2 feedback or closed loop operation (if ECU permits) to run at low load.

Also, if someone wants to give it a shot, simply unplugging the o2 sensor's connector won't cut it. The OEM sensors are heated and will fail if left in the exhaust stream without heat being properly applied. If you interrupt the ECU signal wire, the heater will still warm the sensor properly. Just an idea if someone wants to give it a try. I'm certain it will give better and more reliable/repeatable results then adjusting cells while running closed loop. Good luck.

 

[sjs]

Great tip True, but I would think it is a simple matter to go one better by sending the expected voltage to the ECU so it thinks you are at 14.7, then do your part-throttle tuning. It might be best to pull the fuse first to clear all trims.

 

[ncdogdoc]

that is a very interesting idea, but I could swear when my O2 sensor on my 95 died, the ecu went into a limp mode, including lowering the rev limit, etc. I realize this is on an OBDII car, but it would be important to know the difference.

 

[true]

...I would think it is a simple matter to go one better by sending the expected voltage to the ECU so it thinks you are at 14.7, then do your part-throttle tuning.

Sjs, I don't quite understand what your theory is here. Are you saying design a device to feed the ECU a fixed voltage? As you know, this is not how the o2 closed loop feedback system is designed to work, and I don't understand the benefit. The o2 feedback loop is like on on/off switch with a rich/lean cycle etc. If you are lying to the ECU and telling it the mixture is always stoich, I don't believe you will have reliable results. The fact is, it is still in closed loop and would be trying cycle something. This, to me, sounds like it would be trying to keep a decent o2 feedback loop with its eyes closed. Also, I don't think you can, for example, feed it .5volts and assume it's stoich unless you had that particular o2 sensor's data sheet. Maybe I misunderstood -- clarification?

In the past I have simply tapped an off/off switch onto my o2 signal wire to turn closed loop on and off at will.

ncdogdoc, good point -- I will admit not to have tested with an obd2 car, but I would imagine it would have the same results. I forgot about obd2; give it a shot!

 

[sjs]

Sure, I understand how the typical closed-loop works, but I'm making a few guesses.

1. The base maps are very close in closed-loop range just like they are in open-loop, and other trims for IAT, baro, coolant temp, etc. will continue to do their work. I think this is a very safe guess.

2. Although the ECU "hunts" by constantly adding and removing fuel as the mixture swings back and forth between rich and lean, there is a very narrow "sweet spot" where it does not see the need to do either.

Number two may be wrong, but if you monitor the voltage from a standard sensor it is not an instant switch, and I'm hoping the there is a voltage around .5 where the ECU does nothing. Do you know this to be untrue? It would be simple enough for Andy to test with a variable power supply, a volt meter and that nifty scanner. Splice in the voltage source (a flashlight battery and a pot would probably do) and slowly adjust the voltage looking for a point where the closed-loop trim is zero.

It may not work, but then again it may, eliminating problems with throwing codes or going into limp mode.

 

[true]

Originally posted by sjs

1. The base maps are very close in closed-loop range just like they are in open-loop, and other trims for IAT, baro, coolant temp, etc. will continue to do their work. I think this is a very safe guess.


Yes.


2. Although the ECU "hunts" by constantly adding and removing fuel as the mixture swings back and forth between rich and lean, there is a very narrow "sweet spot" where it does not see the need to do either.


I don't think this is the case.

I'm hoping the there is a voltage around .5 where the ECU does nothing. Do you know this to be untrue? It would be simple enough for Andy to test with a variable power supply, a
volt meter and that nifty scanner.

Actually, I don't know it to be true, or untrue. According to the graph below, it doesn't appear that there is a 'sweet spot'. The sensor output curve is nothing near linear, or even bell shaped; it's very strange. I have used this graph before as an example and will do it again. Notice at how many voltages the ECU could believe it's stoich.

Here's my take on what really happens:
I don't believe there is a single voltage that really is a sweet spot as you mention. According to some of my very reliable sources, the resolution on the Honda ECU is only 100mV. This, to me, means that the ECU really doesn't know the differnce between .501v and .599v. This is a pretty big sweep on a 1v sensor. I believe the constant rich/lean switching creates an
'alternating current' type amplitude graph basically giving a constant average of stoich (in the middle/.5v) when running properly. These are my thoughts regarding the subject.


At any rate, the reason why I don't think your method would work well is because it will continue to record a totally incorrect short and long term fuel trim during tuning! I suppose if it was happy with a constant .5v and recorded both 0% long and short term fuel trim you could double reset the ECU again to clear those tables... The fact is, it would take a pretty good EE or Honda engineer to disassemble exaclty what the ECU is doing in closed loop as far as recording goes and adjusting goes-- this is why I feel disabling the entire loop would be the safe/proper hack.

 

[Larry Bastanza]

My impression is the same as True's. I was thinking if you left the 02 voltage at one side or the other of 14.7 the ECU will continutally update the fuel quantity to get you back to the other side, then give you a "rich" or "lean" 02 code. In the case of OBDI, you will just get a 02 code, since it does not decern rich from lean.

I have been trying to think of a way to get the ECU stuck in "open loop" all the time. This is the way, in my mind, to tune the best in the vacuum range, with the SSBox. Get it as close as possible, then close the loop. (True, is this where you are going with interrupting the feedback to the ECU? If so, please comment on "how")

I think in the case of Andy's emissions issue, the base tuning in the vacuum range made it difficult for the closed loop mode to manage. Once he got the A/F closer to 14.7 in open loop, by the leaning he did, the closed loop mod kept it correctly in range.

This to me is just like Kpond going back to stock injectors. It is a case of the base map keeping things closer from the get go.

Also just an FYI, I am working with a company called "Auto Enginuity" who has developed a hardware/software combination OBDII Tool. If has all coding, COMPLETE logging INCLUDING TIMING and it is available for $229. It will not help our OBDI situations, but seems like a nice cost effective tool. Still doing my homework.

www.autoenginuity.com

My $.02

LarryB

 

[true]

I have been trying to think of a way to get the ECU stuck in "open loop" all the time. This is the way, in my mind, to tune the best in the vacuum range, with the SSBox. Get it as close as possible, then close the loop. (True, is this where you are going with interrupting the feedback to the ECU? If so, please comment on "how")

Yes Larry, this is precisely what I am suggesting. As far as 'how', its as simple as disabling the o2 sensor signals as I mentioned above. I took a look at the manual, and this is what needs to be done on an obd1 NSX:

ECU PINS:
D14 - Front o2 signal
D16 - Rear o2 signal

There are several options on how to interrupt the o2 signal output.

1. Unpin/unplug these pins at the ECU connector using a Honda ECU pin removal tool. (cleanest)
2. Cut the wires - wire-nut or resolder when finished tuning.
3. Tap an on/off switch in-line

There are more options then the 3 above, but those are probably the most basic. I would say #1 is the most ideal as the factory harness is not compromised. I seem to remember hearing that the newer BBSC installations are using an ECU jumper harness so you can tap the SSbox without cutting the oem harness. If you have this, I would probably tap a high quality switch on the adapter harness. I believe this would work well!

 

[Larry Bastanza]

OK,

So I disconnent these two wires, it will generate a CEL, which will probably be 02 front/rear, and will stay in open loop? That is perfect. Should be easily tuned then.

As I thought about this further, essentially what you are doing in the vacuum range is getting the "normalization" right by changing the SSBox map, so you want to run exactly as if you have the 330cc injectors in there.

I know it is not a straight relationship between pulse duration and MAP pressure and it will take some tuning, but this should allow for perfect emissions, and also better drivability.
I am thinking that the drivability tuning is primarily in the vacum range too, so this is the range of MAP values that need to be corrected to insure the best drivability too.

Now I need to get the ignition timing on a graph. I have A/F from the FJO, RPM, and MAP (Honda OEM) on the logging, if I can add ignition timing, it would complete the logging data set.

Idea's on tracking the timing w/OBDI anyone??

Learning more every day
LarryB

 

[kpond]

True, LarryB,

I like True's strategy a lot. I have the jumper harness with my BBSC so it will be fairly staightforward to put a DPDT switch on the two O2 sensors. While I'm at it, I'm going to install a SPDT switch on my ECU wire that triggers the 12V to the fuel pump. With this switch, I can decide if I want to let the ECU handle the fuel pump or if I want to control it with the SS box. I won't have a chance to do any of this for a few weeks though... too many other projects.

 

[Larry Bastanza]

Kpond,

I was thinking the exact same thing about the DPST switch.

In regard to the fuel pump resistor if you do switch the fuel pump, will you have two different fuel maps?

Thanks,
LarryB

 

[sjs]

True, you are probably exactly correct. Of course I am well familiar with the output graph of the stock sensors, but I have also watched their real-world output on numerous occasions and have seen that although the transition is abrupt it is not an all-or-nothing situation. There is a quite discernable slope leading up to the transition, but more so on the rich side than the lean side. (not adequate for tuning under load of course) I guess I was hoping that there would be a point at which the ECU would “relax” and leave things alone until needed. Certainly that would seem ideal compared to constantly and intentionally wandering between rich and lean, but I suppose that the variance is so slight in either direction as to be of no consequence. Too bad though because I take it that simply pulling the signal feed will cause problems on OBDII cars.

All that aside, thanks again for the suggestion!

 

[Larry Bastanza]

Hi sjs,

Yes I agree the OBDII cars will be different, but the OBDII cars at least can have a scan tool plugged in Still doing my homework on a good reliable choice that will give us everything for OBDII cars. I would really love your opinion on the product I mentioned above.

Happy Holidays,
LarryB

 

[sjs]

Hi sjs,

Yes I agree the OBDII cars will be different, but the OBDII cars at least can have a scan tool plugged in Still doing my homework on a good reliable choice that will give us everything for OBDII cars. I would really love your opinion on the product I mentioned above.

Happy Holidays,
LarryB

I have heard of similar consumer-level tools from friends, but I personally have SO little OBDII experience that I'm not qualified to evaluate such a device.

As for a way to log timing (and everything else) in an OBDI car, it's called and AEM ECU. Seriously, by the time you add up all the things it can do (both logging and controlling) without the effort to source and install or invent them on your own, it is an incredible bargain. Have I said that before?

 

[MiamieNeSeX]

Can't all this be resolved with the AEM? I know its more money, but I'm just curious.

Armando