Got a shitty idle with your 4A-GE 20V silvertop?

[The Witzl]

Well for ages i have had a shitty annoying idle that would stall the engine all the time, and has been causing me to pull my hair out chasing it down.
To avoid it, i literally trimmed up the throttle cable, and even then the idle was often around 500rpm

In my attempts to fix it, I tried:
- replacing the ISCV
- Setting base timing again and again
- resetting ecu
- checking idle mixture screw on AFM
- checking and re-setting cam timing
- replacing VVT pulley
- checking for vacuum leaks



..... but in the end.... it was the freaken throttle bodies being all gummed up with crap!!!


So, if ever you have a 20V with a crappy idle, just take off the top half of the plenum, remove the trumpets, and clean the intake ports and throttles with some carby cleaner and a rag.


Now it idles MUCH better.
<end whinge>

[Mr Revhead]

moral of the story: always check the simple stuff first

[The Witzl]

moral of the story: always check the simple stuff first

yeah yeah yeah... thanks for the reminder mr nz smartypants!
I just thought i'd share my mistakes with the community cos i know of at least two other silvertops with the same idle issues.

My idle now isnt 100% perfect, but its 600% better than before - it can actually hold idle and not stall.
Im now blaming the imperfect idle on the worn engine (it blows oil smoke).

[The Last Streetfighter]

I keep meaning to clean my ISCV but I never end up finding it

[The Witzl]

the ISCV is a complete ARSEHOLE to get to.
It's located near the dissy, on the intake side of the head... tucked beneath all the solid vacuum lines.

Its a prick to remove - trust me!
One option to "quickly" clean it is to pop off the input pipe for the iscv and spray carbie cleaner into it... then start the car and spray more carby cleaner into it.

[Ben Wilson]

..... but in the end.... it was the freaken throttle bodies being all gummed up with crap!!!

So, if ever you have a 20V with a crappy idle, just take off the top half of the plenum, remove the trumpets, and clean the intake ports and throttles with some carby cleaner and a rag.

I used to pull mine off and clean them on the mr2 every three months or so, I assumed it was the Haltech hurting things. Apparently not.

[The Last Streetfighter]

The throttles would get most of that crud from your PCV return, no? So catch can it...

[Mr Revhead]

correct

but to work the best you need to set it up so no fumes etc from the crankcase get into the intake. whicch means you vent it to the atmosphere and isnt that illegal over there?

i had mine set up like that as the fumes effect the octane of the intake charge and where i was at the time i couldnt get anything better than 95

[The Last Streetfighter]

Yeah, you still need to plumb it back in to the intake tract for registrable use. But the fumes should make a lot less gunge than the fumes and the crud together. And Karl always runs it on 98 so no real problem there.

[Mr Revhead]

yeah the fumes shouldnt gunge it
they just make em run a little rougher
difference in mine was huge!!

[Ben Wilson]

Mine was gumming up with fuel residue. I was running a catch can and the fuel residue would build up behind the butterflies at cruise.

[c2888]

I clean my TBs a while ago, whilst my idle was fine before, it cleared up a small stumble at very very light throttle.

And if you have a blacktop ecu, you can play some awesome tunes whilst the lid is off

[cambelt]

Do you have to balance the throttles like motorbike carbys , that help the most with shitty idles.
Dave

[The Witzl]

yeah you can balance the throttles as well... i dont have a vacuum gauge, and nor can i be stuffed anymore (it is only my gf's car afterall).

Besides, the engine needs a rebuild before i bother "fine" tuning it.