idle problems after first start

[FaNtUm2113]

so after 2 years of rebuilding my motor and car, i finally started it.
the idle revs up to 3500 rpms and then drops and idles really rough. does anyone have any ideas why that could be?

i was thinking maybe a vaccuum leak would cause the high idle but the rough idle im not sure about? possible the sensors just need time to readjust maybe? or could it be a timing problem?

any ideas would be great. thanks for the help

 

[willydsm]

the car is now turbo? correct? next to yr name it say 92 n/t. have you taken it on a test run yet? got normal boost? what psi? check for vac leaks and boost leaks. what maf are you using? check idle air sensor , is it functioning properly? correct timing? all of these things can cause what you are talking about.

 

[GooeyGus]

I know that when I put a new ECU in my car, the idle was all over the place for a couple days, and a few minutes after startup it revved to like 3 grand then would idle around 600 and be really rough. After a couple days of regular driving, the ECU "re-learned" everything and now it's totally fine.


How much run time has your new motor had?

 

[FaNtUm2113]

yes the motor is now turbo, i have not driven it yet because i wasnt sure if it was a good idea with the idle being so high and/or so rough. im using a maf from a 91 N/T. i havent hit boost at all yet iw as jsut trying to figure out the idel first. it has probly only been running for 20 minutes total because i get nervous about the high idle. there is kinda alot of money in there i dont want to blow it up. haha...

how do i check the ISC?

i havent had time to check for vacuum or double check the timing yet.

and it hasnt hit boost yet so i dont think it would be a boost leak.

i was wondering if these cars had to relearn the sensors and everything. im not excatly new to them but some cars are diffrent and this is my first complete rebuld.

hopefull when im off the meds from the surgery i had on wed i can take her for a spin and see if it corrects it self at all.