I have a 88' dx hatch with a LS-VTEC and I am currently throwing no engine codes. My question is my car keeps on Idling up for no apperant reason and then it will idle its self back down after about 5 min of idling high. It idles back and forth between 1500 and 3000 but seems to keep a constant 2000 most of the time. My ecu is a JDM pr3. Does anyone know what can cause this. I think my vacum lines may be a bit out of wack. Im going to be fixing this prob this tuesday. But I dont think vacum can cause Idling to be this bad CAN IT?

 

try adjusting your idle nut if its not the vacuum lines. See if where the t-cable goes into the firewall, the little black plastic piece isn't flush with the firewall, if it is, thats broken and you either can adjust your idle nut or you can buy a new one of those

 

check for vacuum leaks.. also it could be your idle air control valve.. or your secondary cold start valve located under the t-body. An easy way to isolate which one it is. Is take off your intake.. keep the car running, and stick your finger in your t-body, you will see 2 holes put your fingers over one at a time, the top one is the idle air control valve, the bottom is the secondary cold start valve (that can sometimes get stuck)

Good luck,
Jeff

 

Thank you guys for the imput.

 

ive had this happen to 2 of my friends cars. it could be two things. your timing on your distributor is advanced. loosen the three 12mm bolts holding the distributor and move it back and forth to see where the best place is.

second thing your car is not on time. my friends car idled at 1700 till we found out the car was off time. we took the timing belt off and used a timing gun, only to find out that we messed up the first time. the timing was retarded and the car idles fine now.

go over the vacum hoses like these other guys told you, if that doesnt work then then follow my steps. good luck with your swap, ls/vtec is going to be my next project. what setup are you running, and what are you reving it up to

 

Ive got a stock b18a bottom end with a jdm pr3 b16a1 head. The head is also stock. I am reving to 8000 rpm with no problem. Dont listen to the bs about the stock bottom end cant handle it. Ive had 2 friends that had the same setup as me and they both had their motors going for about 30000 miles each before they rebuilt.

 

whats the r/s ratio of the 1.8l?

 

B18c 1.58:1
B18a/b 1.54:1

Jeff