I have a 99 Civic Si and as advised by people on this very page, I went ahead and purchased a chipped p28 ecu with a custom base map. I also purchased the correct jumper harness. This is the link to the ecu I purchased: Advanced Ignition - ECU'S

This is the link to the jumper harness: https://www.amazon.com/dp/B00KB0YV72..._U29XwbWEAFD7Q

Anyways, now for my issues. I removed my stock p2t obd2b ecu and installed this one. I turned the car over and the tach needle fluttered on start and immediately fell to zero rpm. I notice also when I give the car a little gas while in neutral, once the rpm falls down to idle it has a pretty notable hunt before it settles. The idle fluctuates between maybe 800 and 1000 rpm a few times then falls down to idle. My car never did this with the stock ecu. I did some research and found that people found luck in running a wire from the a19 in the ecu to some blue wire in the distributor or something like that? I feel like it's worth mentioning that the tachometer does in fact work. I had no issues after I plugged the stock ecu back in. Any ideas or suggestions? Any input is appreciated.

 

You're issue is separate from theirs.

 

Then what is my issue?

 

So the tach doesn't work properly, right?

With your current set up, you need to run a wire from the ICM to the cluster for the tach work.

Sounds like an idle issue. What CEL codes are thrown?

 

My tach works perfectly fine. As soon as the stock ecu went back in I had zero issues. I found this thread: help wiring jdm cluster to the rpm - Page 2 - Team Integra Forums - Team Integra and post number 19 says something about jumping the solid blue signal wire in the dizzy to the back of the gauge cluster. Will this solve my issue? I assume the hunting idle will be solved with the tach problem since its an issue with the engine speed input?

 

Not with the P28, right?

Likely unrelated.

 

No cel other than the ones from the other thread which don't apply with the new ecu. I have no idle issue or tach issue with the stock ecu. As soon as I hook up the p28 I get a hunting idle for a few seconds and the tach doesn't work.

 

With P28 installed?

Not relevant

Check for CEL codes.

 

The p28 displayed no check engine lights. It would need to be driven for longer than I would feel comfortable without a tach. But I suppose that would be the best way to solve the problem.

 

Does the CEL work? Are codes disabled in the chipped ECU?

Details?

 

Cel definitely works. Codes for the secondary o2 and evap hardware were disabled. Its just a base map for full bolt ons, a two step and a cel shift light at 8k.

 

 

You won't get these codes on an obd1 ecu....

 

Regardless those were the only codes on my stock ecu. And thank you for the diagram. I am going over to my friends tuner and trying to work the problem out. I'll update you asap

 

I recall seeing other people having idle issues when using a chipped ecu. Better make sure that "friends tune" isn't ******* around in there.

 

My friend said he would ask his tuner if he knew how to solve the problem. He wasn't the one who tuned it.

 

Good news. The idle is normal again. I don't know why it was hunting but I just reinstalled the p28 and the idle is seemingly fine. I gave it gas and abruptly let off and it immediately fell down to normal idle. I put a load on it and again it idled fine. I hit the two step and had no issues. So the hunting idle may have just been a fluke thing in initial install of the new ecu. Also the car was warm this time as opposed to cold. Furthermore, I was unfortunately not able to jump the signal wire today. I've decided to leave the p28 in regardless and see if any cel codes appear. I will be back with updates.

 

Solved! I jumped the signal wire from the dizzy to the wire by the drivers side shock tower and voila. The tach works again

 

**** makes no sense, but ok.

 

Tach not working right after ECU Swap - Team Integra Forums - Team Integra

Look at post number 8 for a better explanation.