The93egg

Ok ive had this idle problem for months now and I cant take it anymore. When i swapped the d16y8 into my 93 hatch (cx, so it was a 8 valve d15) I came upon a idle problem. When at idle my rpms would go from about 1000 rpm to 2500 rpm. I heard a major leak from the intake manifold, so i changed the gasket and it fixed most of the air leak, but its still there. When i spray carb clean in the area the idle drops, so obviously theres still some space there making it leak.

When my friend had the motor in his 2000 civic, he had the codes ran and it came up with a bad IAC valve. So i figured it had to be a combination of both. I just changed the iac valve tonight, and now the revs bounce up and down very quickly from about 1200 rpm to 1500 rpm, very fast. This dosent sound like a air leak would be doing THIS.

Anyway, i ordered a hondata intake manifold gasket, i figured that would fix my leak out of any other gaskets I could buy.

Some other interesting facts are that I am still rocking the obd1 harness with the d15 ecu. So there are some random sensors not plugged in, I am eventually going to get the harness.

So does anyone know wth I should do, or what you think the problem most likley is?

Funanin

By not having certain sensors plugged in, thats most likely causing the ecu to go a little out of its mind. What ecu are you running? Do you have it hooked up to the stock 93 obd1 ecu and harness? Have you tested for codes since you did the swap? To absolutly be sure there is no vac leak anywhere you can invest in a smoke machine. They have gone down in price over the past few years and shouldnt be much on ebay. It is def one of the best tools in my arsenal.

The93egg

bump, any other suggestions?

93EXR

When the idle bumps up and down from 1200 to 1500 really fast like you say- ive seen that happen when the IACV is left unplugged. And yes you should def. make sure everything is plugged in correctly