i'd like to change my obd2 ecu to an obd1 for various reasons (hondata down the road...speed limiter removed...no 2nd o2 sensor). are there any side-effects??? i removed my 2nd o2 sensor and my ecu is throwin that code. when i change the ecu with a conversion harness, will the light just go out? also, will i still be able to pass emmissions when i slap my cat back on? or is the obd2 required for that? thanks...

 

the OBD1 ecu won't check for a secondary O2 sensor, correct.

As far as OBB2/OBD1 for emissions.

MY state (connecticut) for all vehicles after 96 (OBD2) just do a scanner test no sniffer.

Now, if they can't get the scanner working, I theorize that they'll think it's user error and just put the car on the sniffer... Joe average worker will probably just assume the computer screwed up somehow....

And you should in general pass emissions with a turbo and a cat.

This user is not a HAN authorized vendor. For the general well-being of our members, his blatent advertising will not be tolerated in this forum. ~1stGen.

-PHiZ

 

is there a way to remove the speed governor in obd2??? i was told flat at "no" a couple times. that's really depressing me now, cause i seem to lose a lot of races because of it.

 

in general what you would do is take the VSS line, which outputs a frequency, find out what the maximum frequency before speed limiter, and design a circuit that "clamps" at that frequency, until it goes back down...

It's not easy. But it's doable, I know one guy working on it, he's from like the netherlands ro somehing, he calls it a "speed limit defencer" I don't know if that is common parlance, or if it's common on other vehicles.

OBD1 speed limiter can be pushed as far up as 158MPH.

-PHiZ

 

If all you need to do is set a maximum frequency that is allowable to pass, you could design a low pass filter circuit to control the maximum frequecy that pass. This is just a combination of a capacitor and a resistor, but they must be the correct value to get the right cutoff frequency. Now after this cutoff frequency, I suppose you want the output to stay at the max value that is under the cutoff. I'm not sure how you'd design that, but it should not be too difficuilt with some research.

cutoff frequency: fc = 1/(2*pi*R*C) i think.

Jon

 

Why do you need to remove the governor? When are you ever going to take the car that fast? Honestly with your setup the simplest thing to do would be to ditch your MAP bypass and FMU, get 450 cc/min injectors and set the V-AFC to -40% trim across the board until you can have it tuned on a dyno.

Honda motors are reasonably forgiving of loose tuning (i.e. they'll run without blowing up but still can benefit from being dialed in, which is why all of this MAP bypass + FMU stuff works in the first place) and the ECUs--even the OBD-II ones--work on a simple speed-density principle which is simple enough to not get all out of whack when used with piggyback fuel controllers.

 

Even though a circuit like i mentioned would be interesting to try if the VSS behaves like previously posted, it would be much easier just to upgrade to stanalone or chipped ecu. I've just bought a hondata system and it removes the speed limitor and can raise the max rpm if desired. This is because the car is being built for a full race setup. Like Mr.Fat said, in most cases it's not worth the trouble to remove the speed limitations that govern your car- especially if you haven't done many mods or aren't very hardcore.

 

I'm really not a fan of emulators and EEPROM chips like hondata uses. If you're going to drop the cash, go with something more complete, like the AEM EMS, which has more adjustibility than you'll probably ever tap into, and doesn't require anything more than a laptop and interface cable. You can't say the same for hondata. Not to mention the EMS is designed to plug into your car without ghettofabulous back-date conversion harnesses.

 

I think that the hondata system is definitely an option since i does cost less than half as much (~$400 compared to over a grand) even though it may not have the tuning capability. It does have advantages over the vafc I had installed previously and many similar tuning options as the ems. What is wrong with eeproms? They do the job. If there is a need for me to upgrade, I will consider the ems.

 

You will have a plenty reliable setup and it will be much simpler using your V-AFC to run higher flow rate injectors, an upgraded fuel pump, and no more MAP bypass or FMU. You'll need to buy the injectors and fuel pump to really do anything productive with the Hondata anyways and like I already said your V-AFC is more than capable of getting everything dialed in on a dyno as long as someone that knows what they're doing is in charge of things.