Hondata s200 install, d16y8, idle issues

[SQLBoy]

Hello everyone, I just had my Hondata professionally installed and dyno tuned. Wow, what a difference in power. 8HP and 10ft-lbs over my baseline without the Hondata.

Now for the problem. I have a p28 with a ODB2-A harness to ODB1 harness converted (genuine hondata) and D16y8 engine.

One problem I noticed was that the idle speed was all messed up when I got the car back, idling super high and hitting the max idle limiter. The only problem is I don't have a 5th gen Helms manual and doing the 6th gen procedure to reset idle just stalls the car. I basically just turned the screw in a quarter and that made it much better. If anyone has a link or the factory instructions on setting the idle speed on a p28 let me know.

Next problem, I'm not sure if the service connector is working to set the timing. The led comes on but the timing mark is jittery. When I used to set the timing the timing mark was really solid.

[Hondata]

The quick way: with the car hot unplug the idle valve and check that the idle speed drops below your target idle (should be around 700 rpm for a fairly stock engine). If you engine still idles high, then either you have a vacuum leak (more likely) or the ECU has the idle output stuck high (less likely). If you idle drops almost to a stall then the problem lies in the ECU tuning. You need to reduce the target idle setting and possibly the idle control valve duty cycle in RomEditor.

[SQLBoy]

I can't pull the IAC, it stalls and I can't get it to stay running without the IAC plugged in. I tried evey step in the helms manual.

I'll check for a vac leak, its possible they forgot to hook something back up. Thanks for the reply.

[Hondata]

If the car stalls when you unplug the IAC then you don't have a vacuum leak.

[MasterKwan]

When you pull the IAC connector, the engine's supposed to keep running so you can set the base idle. He's saying that when he pulls the IAC it doesn't. Sure that means he doesn't have a vacuum leak but, it doesn't address his problem. Why can't he set base idle?

[Hondata]

Expanding my last answer: If the car stall when you unplug the IAC then there is no vacuum leak, so increase the amount of air bypass until the car will idle (barely) with the IAC disconnected. If the car has continued to idle high with the IAC unplugged then the problem would have been a vacuum leak or too much air bypss.

[misterdude]

with age the idle valve gets gummy inside and starts to stick and cause a high idle too and sometimes surges.

[SQLBoy]

Only the IAC is brand new, started happening right when I switched ECUs, and the tbody was cleaned less than 3 months ago.

Another thing that happens now is when I start the car, it can barely keep itself alive and will stall unless I manually give it gas, this will last for 6 or 7 seconds too.

Is there anyway I can use datalogging to troubleshoot this? It seems to be getting worse.

with age the idle valve gets gummy inside and starts to stick and cause a high idle too and sometimes surges.

[Hondata]

If you have the ROM file, post that and I'll look at it. Otherwise I suggest going back to the tuner.