Cold start sr20det in ae86 issue

[marley4us]

Ok, I figured I would come here and try to get some help. I have searched and read a ton stuff, but I feel like I am at a loss.


I have a AE86 with a redtop s13 SR20det.

Under cold start, it will immediately die out. If you throttle it a bunch and keep cranking it seems to get it to idle, but rough and you have to feather the throttle until it is fully warmed up.

Once it is warmed up, the throttle will idle, but it bounces, from 2000 to about 1500. Some times it will idle ok, but mostly it does this.


It is a stock SR20det red top with B.C. 268 cams. An new external walbro 255.

Fuel pressure is around 3 bar (43.5 psi)

I am running oem 4ac fuel lines to sr20 but it does not seem to effect the fuel pressure.

My I swapped my maf, and even tried un plugging it and re plugging it in while the car was on, and it changed the idle slightly but never solved the issue.

I installed a old greddy boost gauge, and it says I have 500mm/hg or torr (10psi) vacuum, so maybe I have a boost/vacuum leak... but I am not sure....

The orange wire (cold start map) I read about but I am not sure I understand it... I am not using a SR20DET body harness, so info on that might help too


Any help idea's etc. I think this is a common SR20det problem

[s13mikesr20]

i have same prob on my black top mine was tps no getting signal while cold but when it warms up works fine dafuq lol

[Sileighty_85]

Check ECU for codes.

Might be a bad coolant temp sensor.

Of course check for Vac leaks.

Maybe this will help out
http://zilvia.net/f/builds-builds-only/410133-project-sr86.html

[ultimateirving]

That really sounds like a stuck open iacv valve try removing it and cleaning and then resetting the idle putting the SR in timing mode

[mr.nismo.]

Check your CTS, also 43.5 psi is your fuel pressure w/ vacuum? If so that's too much. Should be 37 w/ vac 43.5 w/o. Do you have a wideband?