temporary CEL after certain speeds

Hey guys,

Just installed an Edelbrock intake manifold on my D16 and managed to fix all the vacuum leaks however now it idles at 2k rpm when cold and drops to 1.5k rpm when warmed up. I tried adjusting the idle screw to reduce the idle but the lowest it'd go is 1k rpm and the car shakes a fair bit asif its on 500 rpm. Running the car untuned at the moment since I have stock ecu.
Any ideas to reduce the idle back down to close to normal?


After installing my IM and taking it for a drive, when i reach speeds of 35km and up the CEL and Immobilizer comes on simultaneously and it stays on until i turn the car off. When i restart the car, it goes away and the same process recurs. The car seems normal and drives fine so I'm not sure whats going on. All plugs are plugged in (assuming their is no polarity) and everything is secured.

Thanks in advance!!

get the service manual and read how to set idle properly

the method which involves shorting the scs connector, adjusting the idle then unshorting it?

Actually find the problem first before adjusting idle screw as that's more for fine tuning

How did u test for vacuum leak?
Spray carby cleaner all over the flange top and bottom, then throttle body, hoses etc

And test iacv for proper operation, refer to fsm

sounds like a vacuum leak

what TB are you using ?

Using stock TB ECU-MAN and reused the oem gasket.

I tested for vacuum leaks by spraying around the manifold area and seems okay. But I havent tried around tb area. Manifolds got a new gasket and has been torqued.

Prior to changing the IM, car used to idle 1.5k-2k rpm before leveling down to normal factory rpm when its warmed up.

is there enough slack in the throttle cable ?

yep, plenty of slack on the cable

Retard the timing a bit see if that helps

Okay found the problem! A very small vacuum leak which I fixed! Now everything is running fine. Topped up coolant however I'm getting a CEL after reaching 30km/hr. When I restart the car it goes away again until I reach 30km/hr. I'm certain that all plugs are connected in the right position.

I would check the ecu code by shorting the scs connector but I can't find the connector. I looked under the dash and nothing.

mixed up the TPS plug with the MAP sensor plug ?

where abouts is the TPS Plug? Is it in the same position as the one in this pic i found on google?
http://www.dodo-upgrades.nl/imswapd1...n/image016.jpg


Im pretty sure MAP Sensor plug is in the right position. The only other plugs i disconnected was the MAP and another white plug which is attached onto the TB.

Took it for another drive today and when i reached 30-40kms/hr, the CEL and Immobilizer indicators come on simultaneously and stays on until i turn off the car.

Check your ground points on the thermostat housing

found the problem, thermal switch was loose so i had to replug it back, was a pain to get to but managed. Thanks!