R31 Rb30E Cold Start Issue

[SPINR31]

HI all,

So i just recently got a second hand engine installed after i blew my last one up..

all is well except for this really annoying cough/splutter on a cold start just off idle...

if you try and put any load on the engine when it is cold (around 1000rpm) it will cough and splutter to the point of stalling.

i recorded a video so you will know what im on about:

i have replaced:

Leads (top gun)

plugs (NGK)

Air Regulator (off another motor)

i also took the injectors, fuel rail and afm off my old motor which had no issues and it still does it.

if its worth mentioning:

1. Car is a manual conversion (never had issues before)

2. all is fine when it is warm

3. it seems to idle a lil low when cold(around 800 - 900rpm, could be more or less as i have a sticky tacho), but a little high (1100 rpm when warmed up)

[Moodles2]

I'm not sure how R31 ecus work, in a R32 and beyond I would suspect the coolant temp sensor (not the one that feeds the dash cluster, the one that feeds the ECU), when not functioning it might not be going into the cold start map (richer than the normal one).

[StevenCJR31]

i had issues similar to this an adjustment to the TPS cleared it up

[SPINR31]

i had issues similar to this an adjustment to the TPS cleared it up

the throttle position sensor? i wouldnt have any idea what it looks like or how to adjust it

[SPINR31]

i had issues similar to this an adjustment to the TPS cleared it up

so i have tried so far:

1, Spraying crc contact cleaner on the AAC Connector, Both sides of the coil, Air Reg connectors, tps connector......

2. tried having a play around with the tps, fully clockwise it idled lower, didnt fix the issue with the spluttering..fully anti clockwise the issue wasnt any better but it idled higher

3. unplugged afm and it idled like shit, wouldnt rev etc so i know the afm works.

im baffled as to what it is

[StevenCJR31]

how is the ignition coil? if its the original it maybe past its use by date

[SPINR31]

how is the ignition coil? if its the original it maybe past its use by date

that's my guess, it did it in the old car now its doing it in mine.....i might swap the ignition coil and see if it helps

[StevenCJR31]

if its not that then keep trying other similar things, 31s are getting old now and most of them have had the tits revved out of them by p platers and messed around with a lot

[SPINR31]

i changed the coolant temp sensor and played around with the tps, its cleared up mostly, still a little cough but if you let it warm up for 15 or 20 seconds its completely fine