http://www.nc4x4.com/forums/showthre...=35756&page=13


Wife's car was wrecked, so I am using the engine to put in my Honda buggy. It was out of a 98' Accord, had an automatic transmission. I am converting it to a 5 speed, so there are some wires that are not being used. My question is what do I need to do to convert it over to use only the O2 sensor on the manifold? I don't have much room for the CAT nor do I really want to run it, so what kind of computer do I need to nix it?

I am NOT a Honda guy, so take it easy on me with the techincal stuff. If someone wants to do a strip job on the wiring harness and get this thing running let me know. I am in Winston-Salem, NC. I'll pay you...

Thanks

 

wow that looks interesting. i think you question would be in a better place if you post it in the engine tech section. they know all about ecu tuning ang 02 sensor questions. i know that when you take out a cat and put in a test/cat delete pipe, you just weld a bung in the tube and put the 02 sensor in. and i think that if you dont run it, youo know like cut the wires and delete them, it will just throw a check engine light. but i doubt you will have one.

 

I won't have an actual check engine light, but I don't want it to run rich/lean/rough either. If I can just ditch the O2 sensor and it will still run OK that is fine though.

Also wondering how much of an exhaust system these engines need to run good. I am building what would basically be a straight pipe, but I was thinking about putting some baffles in it or something.

 

nice build up!

the second o2 sensor just measures the efficincy of the cat, so if you just put it in the exhaust stream with one of those chepo spark plug defoulers/o2 sensor light fix products in first there should be no problem. as far as exhust goes, they deffinatly want some back pressure, so possibly having stock sized piping, resonator and a muffer might not be a bad idea.

 

Thanks a bunch, I will do that then so I might can get by with the CPU that I already have. Will the Auto CPU work with a 5 speed? I know the auto had all the extra sensors (or solenoids, whatever they were), but will it fault out if those sensors are not hooked up to anything? I remember seeing somewhere that someone said you can jump a wire inside the CPU to make it work with a 5 speed, is this true?

I have an exhaust cutout I am thinking about using that opens with vacuum, that way I can have "dual" exhaust, one side would be muffled with a glasspack or something, the other side would be straightpiped. It is supposed to function with vacuum, when you hit full throttle it opens up. Power wise are they good to be straight piped @ WOT? This would give it some backpressure @ low rpm's which I would think is where it needs it most, but be straight through @ full throttle.

Thank you very much for the help. I'm trying to get this thing finished for a race in March.

 

wow good i came in here, im running my F23 open header with magnaflow hi-flow cat

low-end rpms like under 3000 takes a substantial loss in torque compared to stock full exhaust
when its in VTEC over ~4K full throttle it pulls like a **** though (not sure bout stock comparison)

for this engine i would not recommend straight pipe or oversized piping or glasspacks
i think what would be best is to use stock diameter piping but use good mandrel bends and a twin-loop muffler or chambered muffler

yeah also OBDII is a bitch especially on these cars when you want to start screwing with it and swapping to 5speed

 

i dk about obd2, I did a 5 spd swap on my friends obd1 accord, just left them disconnected, removed the TCU and installed the 5 speed ecu. hacking obd2 ecus are impossible so you would need to get the 5 speed ecu to keep it from running funny.

 

this, in addition to that you may or may not need new transponder keys and ignition for the immobilizer system

 

Downconvert to OBDI

Get a chipped ECU (like P28)

 

Thats the best way to go, lot less hassle.

 

Ok, I am sure I won't be lucky enough for it to work, but I have a 5 speed P75, will it work? Will I need a new wiring harness too (I sure hope not).

So for the exhaust, from what I understand with what 361 Accord says I should be able get a muffler with some decent restriction for the low end torque, but if I do the exhaust cutout that will give me (possibly) some added high end HP?

 

I've got a muffler off a Suzuki Bandit 600 motorcycle that would look good on the buggy, it is a stainless muffler so I don't have to worry about rust either. The inlet is plenty big enough, the outlet is about 1" or a little larger, seems like it would be kind of restrictive, BUT that might be what I need since the exhaust system will be very short, and I won't have a catalytic converter. What are your opinions on this? I am also thinking as vacuum (RPM) builds it will open exhaust cutout and let more exhaust out that way, since the valve opens with vacuum, there is no way to set it at "open" or "closed", it just opens as vacuum overcomes the spring.

The cutout is really nice which is why I want to use it, it's off a Ferrari

Anyone suggest a good cheap muffler that is somewhat small and would work good for this application?

 

Vacuum DECREASES as soon as the throttle plate opens. So you'd want the cut out to be held shut by vacuum, so as throttle into it, the cut out will open.

And as far as the secondary o2, if you want to stay obdII (which in your case there is not reason for) you could do just throw a non-fouler in there. Or even better, screw it and dont run one. It wont effect how the car runs whatsoever. The secondary o2 is only there is monitor the cat. (You need the primary though, just in case I miss read the thread title. Unless you go OBDI and just want to run in open loop.)

If you have a p75, you need an OBDII--> OBDI adapter.

 

I have an adapter, but one section coming from the engine harness does not have any wiring. I am hoping all that section of wires is for is all the auto tranny sensors and stuff.

So the P75 will work with this engine I guess? Will it require any special tuning?

The cutout is shut all the time (held shut w/ spring), it is pulled open with vacuum. I was told it worked off vacuum, not sure how Ferrari made it work on their cars with vacuum??

 

Muffler off the motorcycle is on the buggy, I had to cut it down about 8" but I think it will still give decent flow/backpressure because it was a chambered muffler. Now it has only one chamber which will hopefully create enough backpressure for some low end torque. Turned out really good, I'm not using the cutout now just because the exhaust went so smoothly without it.

I have a friend that's hopefully gonna help with stripping down the harness. I called rywire.com, they will make a harness for $650, thats outrageous!

 

x2 on the chipped OBD1 ECU. If your putting it in a rail/or buggy it should be easy eough to wire. As long as your not putting boost on it or any crazy induction system a stock basemap tune should be good until you can get it tuned.

Here is my obd1 ECU wired to run in an OBD2 chassis.




I have an OBD1 ECU here. Send me your F23 wire harness. I'll chip the ECU and custom wire it for a couple hun...

 

hey i am located near you i will help you out this looks like a fun project. i sent you a pm call me if you want 331 2049 you know the area code

 

How many wiring jobs have either of you done? I'd be happy to pay someone for a good, neat wiring job. I want nothing in the harness that is not related to the engine, just a wire to run to ignition, or any other necessary stuff.

ashb82, I am in Wallburg if you know where that is, you might can stop by sometime.

Thanks

 

I need a pinout for the PCM but can't find a detailed one anywhere. When it's all done I want nothing but what is absolutely needed to make the engine run, if anyone near Winston-Salem wants to do this I can pay, but ONLY if you have experience doing it, I don't want my wiring harness hacked and screwed up. rywire.com wants to charge $650 to do it...