Idle problems

[CivTec91]

I got a 94 Civic DX, I just recently dropped in a 94 Civic EX engine. The only problem I'm having is with the Idle. When you first turn it on it idles around 3 grand, if you let it sit for a while, or give it a little gas the idle speed will then drop down and fluxuate between 1 and 1 and a half grand. Me and my dad tried re-using all sensors and everything from the old engine and wiring harness and still no luck...so if anybody has any suggestions i'm all ears. Thanks!!

[mr poo]

try resetting the ecu.

[CivTec91]

Already tried resetting the ECU...disconnected that and the neg. battery terminal...still nothing.

[Accord Man]

Do they have different ECU's??

[CivTec91]

No, they are different ECU's since the stock DX is not a Vtec, and the stock EX is a Vtec.

[Accord Man]

Then I guess it may be an incompatibility between one or several of the sensors and the ECU..


One of my friends had the same problem. He put a b16a in a 90 Civic si hatch..
One of the sensors was making the ECU go nuts..



did you try with new sensors?

[SWIFT]

94 dx is not pre-wired w/ vtec wires (unlike the 92's or early 93's) so make sure all the vtec wires are hooked up right to the ecu(you did wire it, right?). also,you will notice that the plug harness at the engine bay are missing some wires (blank). those are the vtec wires you need to hook up..goodluck.

[slowEJ6]

helms manuals are gods gift to mankind.

[slowEJ6]

following could cause erratic idle.

Vacuum leak
leaking EGR valve
clogged air filter
fuel pump not delivering enough fuel to injection system
leaking head gasket
worn timing belt and/or pulleys
worn camshaft lobes

have you replaced the spark plugs/wires?

[CivTec91]

Well, turns out that the guy that put the engine in put some vaccum hoses in the wrong spots on the idle valves, so thats all fixed. Thanks for all your help!