Cold start big idle hunting for 5secs

[jonossiksilvia]

Hi all

Car: 1999 impreza srx hatch Manual 119xxxkms stock standard brought from dealer with 3 month warranty

Problem: First Cold start fast hunting from 700rpm to 2000rpm does this about 4 times them settles to normal idle. Car runs perfect other than this problem

Car has had the following done by crowesport and advantage auto electrical

Cleaned tb and iacv

tried a known good iacv valve

cleaned the afm

tried a known good afm

new coolant temp sensor

Checked for vaccumm leaks

swapped ecus

all wiring and conectors checked. a efi relay was replaced (slightly low voltage)

All sensors parts etc appear to be working correctly when the have their monitors plugged in

Still no change on cold starts after 3 weeks at the above shops.

Car does run tgv on the intake runners straight after the tb

Anyone struck this issues before and it not been the normal parts causing the issue?

At the point of wondering if should ask for my money back but the car runs great other than this problem

hope someone can help. Thanks

Edited May 30, 2015 by jonossiksilvia

[Guest]

Hope dealer paid for the work carried out. Its up to them to get the car to a satisfactory standard or replace it. Did it have the fault when you bought it?

[jonossiksilvia]

yeah i havent paid a cent for any work. it started doing it a couple days after getting it.

Its a really good car otherwise so torn on deciding what to do. hense the post here incase something has been overlooked

[Rosssub]

Does the engine run smoothly when it's revving up to 2000rpm, or miss and splutter as it'

s revving?

Would be keen to check the fuel pressure after one ignition pump prime when it's cold, sitting for a while and bleed out. Then static fuel pressure with the fuel regulator vacuum hose off/fuel pump running/engine off. Then also check the fuel pressure regulator diaphragm to make sure it's not leaking.

[jonossiksilvia]

the car revs smoothly while it does its hunting start.

Thanks Ill will suggest that they look at the fuel pressures. is there a sensor on these so that the ecu does see the pressure?

[Rosssub]

Nah, no fuel pressure sensor at all. Just the pump that primes for 3 seconds at ignition on, then runs constantly when the engines going.

They'll tap in a fuel pressure gauge like this:

http://clubsub.org.nz/forum/showthread.php?45832-Fuel-Pressure

[jonossiksilvia]

cheers rosssub.

[jonossiksilvia]

problem is fixed now fingers crossed. the idle air control valve that they replaced happened to be the wrong one for the car. something about silver sticker vs blue sticker. couldve saved a few weeks labour for them and them paying for a auto sparky.

Cheers all