Levin AE101 4AGE Silvertop 20V rev hunting while idling

2fas4u · Post by **2fas4u** » Thu Dec 23, 2010 10:30 pm

hi, part own a 93 levin with silvertop ae101 20v engine. in the last months, the rev started bouncing up and down like rev hunting while idling. It only seems to do it when the engine is running at its normal operating temperature when car's running but sitting there in traffic or at the lights. engine temp never exceeded past half way on the temp gauge. there's a crack in the plastic upper tank but have seal it so it's not losing pressure. have even replaced spark plug leads to thicker ones as well as the airflow meter but not much luck. couldn't afford $30 bucks per spark plug so i got the cheaper NGK alternative, don't mind having to replace sooner but this new set was put in a thousand ks ago if not less.

Did some googling and someone mentioned about a dirty ISCV (idle speed control valve) but i have no idea where the heck that is. anyone come across this and fixed it? also does anyone know how much it roughly cost to redo the timing cos i think the timing is abit out. Any other ideas about this bouncy idle issues? merry christmas. thanks in advance. p.s i did do a search on the forum before i asked but can't seem to find anything.

andyztouring · Post by **andyztouring** » Fri Dec 24, 2010 7:46 am

Clean the inside of the throttle body,usually fixes the bouncy idle.

RedMist · Post by **RedMist** » Fri Dec 24, 2010 8:28 am

Vacuum leak. Check all vacuum hoses. If nothing is obviously aged you can use the good old CRC trick.

OMG so shiny! · Post by **Dell'Orto** » Fri Dec 24, 2010 10:25 am

Or an ECU fault. Cant believe you didnt find my thread, it covered basically every issue there could be :lol:

2fas4u · Post by **2fas4u** » Fri Dec 24, 2010 7:04 pm

thanks for all the replies,
andyztouring: how do you clean the throttle body? and what with?
RedMist: will check for vacuum leak, what's the old CRC trick?
Dell'Orto: what's the link?

and by the way, wish you all Toyspeeders a very happy christmas and new years. drive safely if you going on road trips to be with your family.

OMG so shiny! · Post by **Dell'Orto** » Fri Dec 24, 2010 7:09 pm

viewtopic.php?t=76931

cozmoid · Post by **cozmoid** » Fri Dec 24, 2010 8:22 pm

2fas4u wrote:thanks for all the replies,
andyztouring: how do you clean the throttle body? and what with?
RedMist: will check for vacuum leak, what's the old CRC trick?
Dell'Orto: what's the link?

and by the way, wish you all Toyspeeders a very happy christmas and new years. drive safely if you going on road trips to be with your family.

You can buy a throttle body cleaning kit from repco.
To check your timing is ultra easy like a 15 minute job.
Quite likely your idle control valve as it controls your idle depending on engine temp which sounds like the problem.

Good luck and Merry Christmas

andyztouring · Post by **andyztouring** » Fri Dec 24, 2010 8:56 pm

I clean the throttle body with a rag and petrol or paint thinners.1 car I took the throttle body off the engine and cleaned it with a cleaning brush and petrol,then blew air thru all the vaccum outlets.Worked a treat.

blindnz · Post by **blindnz** » Sat Dec 25, 2010 6:36 am

andyztouring wrote:I clean the throttle body with a rag and petrol or paint thinners.1 car I took the throttle body off the engine and cleaned it with a cleaning brush and petrol,then blew air thru all the vaccum outlets.Worked a treat.

^^This^^ i had idle hunt turned out to be a piece of gasket cement stuck in one of the waterlines that goes to the throttle body...

Next time ill be a bit tidyer with my gasketing