I have a jdm B18c swap. Reason for my post is I got a harness and civic computer, with program similar to Mugens. My cars tach stops working after it hits vtec, around 6000 rpm. What is strange is that it works when rpms come under 6000. when using my stock ecu tach works fine. I also have a bouncing idle from 1100 to 1300. I know about the two wires that have to be spliced together to make tach work. the manufacturer and myself are stumoed. He has made many of these harnesses and ecu for people on this board. I post this in this forum because its a '97' JDM type R motor, and Im converting obd2 to obd 1. I assuming many of you have made that switch when swapping ecus or getting hondata. Anyone else have this problem or a solution for it. Manufacturer offered to refund all money, which is fine, but I like the way the car runs with this ecu. BTW, no CL or anything strange but tach and idle. Thanks in advance!

 

https://honda-tech.com/zerosearch

 

I have a specific problem that I did not find thru search. Sorry to hassle you guys with a question, but I cant find answer to tach not working in vtec. If you could suggest the thread, than that would be helpful. To tell me to search does not solve or help me, because I did that. Thanks

 

Man, that's pretty specific...betcha don't even know yourself if that was mentioned before or not! Next time, don't bother telling the guy to do a search for something like that

 

if no one is going to help you, try at http://www.hybrid.honda-perf.org , im sure someone there has your answer and will help.

 

without the wiring diagrams.. no idea. Do you have a VAFC installed? if so does it read the RPM correctly? etc?

 

dude come on that is a very specific problem, you need to do a search on obtaining some mannor's.

 

No vafc, completely stock internals. Just have I/H/E and CAI. Just adjusted idle and no more bouncing of rpms. So cant figure this out. Tomorrow Im going to try ecu on OBD1 car and see if his tach works. Its a civic with 95 GSR swap. I have already sent back and manufacturer replaced harness. Im not mentioning his name because he has been helpful and understanding thru this. He also offered to refund all money plus shipping costs if I am not satisfied. Computer was tested in his type r and tach worked fine. HMMM no CEL, car runs strong, fixed idle, what is it!. Im confident the harness was done properly.

 

I'm sure K did the harness correctly as well. My current guess is a bad sensor or something is focked on the wiring harness.. but that's just my guess.

 

Well, he replaced the original one and sent me a new one? If you mean the stock one, its works with stock ecu?

 

errrrrrrrrrrr.. I meant the main wiring harness.. for the motor.. not the OBD2->OBD1 conversion harness.

 

How would I check that. Is there specific tach wire. Im assuming it would come from distributor. I know about the crank angle position sensor on new versus old. 97 are on the distrubtor, while 2001 is on crank itself. But that doesnt explain why it would work perfectly with stock ecu. I think your explanation would add up if it happened with both ecus. Well, thanks for your replys Dominic.

 

There is a tach wire. RPM signal, not sure which wire it is in your application though. But even then, it's weird that it's cutting out after 6k.

 

Well checked ecu in a civic with 95 gsr motor in it. The tach worked fine in that car. Also checked blue tach wire and it seems to be working. I guess the only other test would be to find a 2000 or 2001 gsr and see if tach works in that. Anyone have any comments or suggestions on how to rectify. This is a total stumper.

 

I have a 2000 GS-R.. not that it helps you much in PA...

 

Anybodt have any clue whats going on?