On a cold start in the mornings car starts and revs drop to like 400 and bounce back up to 1400 up till it warms up a little also Mis fires badly any suggestions what's wrong?

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Bit of a stab but if you've not deleted your sai I'd be having a look at that and the associated pipework. Rough idle is often airflow related and the sai is working hardest on cold start.

Could also be a fuel delivery under choke conditions issue maybe or a few other things but I'd check pipework first for loose connections or splits, focusing on sai.

How does it run when up to temp? Plugs and coils ok? Maf ok?

Coolant temp sensor is always a suspect too.

Indeed! Forgot to mention that one

Coolant temp sensor is always a suspect too.

coolant temp has only just been changed..

 

Bit of a stab but if you've not deleted your sai I'd be having a look at that and the associated pipework. Rough idle is often airflow related and the sai is working hardest on cold start.

Could also be a fuel delivery under choke conditions issue maybe or a few other things but I'd check pipework first for loose connections or splits, focusing on sai.

How does it run when up to temp? Plugs and coils ok? Maf ok?

Sai pump is split when i start it from cold makes alot of noise from the sai only recently started doing it.. only yesterday i was looking at sai deletes.. could the sai delete be dont without doing and n112 bypass or what ever the valve near the dip stick is....

 

plugs have been done like 3 days ago fitted ngk bkr7e, packs need changing but will be doing them on the weekend. and the maf ive unplugged but its still the same..

the one pipe that runs from the charcoal canister to the little connecter next to the fuel lines is split on both ends..

Edited 14 August, 201510 yr by Haych123

Sounds like sai then. I had a hose pop off mine and idle went erratic and on cold start it sounded like a lawnmower. I think the sai can be deleted individually but I think it would make life easier if you do it with n112 as you can then just cut the hoses in that area and get them out the way. There was some good how tos around by Bowders with a map of the engine bay. I only ever got round to doing the catch can and vac simplification so I'm not 100% sure I'm right. Don't forget you'll need a resistor.

Try a pm to Bowders he's the man for this stuff.

If you want to keep an sai I have one on my breaker that's in good working order...

Yep, as said, sounds totally like a noisy / inefficient SAI unit.

 

I only say that because it sounds like my car.

 

On a first cold start, my SAI sounds like a Dyson vacuum cleaner on steroids, lol! And if I try to drive my car immediately after starting, I get similar issues to what you're describing.

 

I KNOW I could either remove the SAI pump and dismantle / rebuild with new nuts and bolts, or better still do the delete that has been described.

 

However, despite being happy to work on my Octy, I actually can't be arsed to go as far as some on here - especially because I have read that doing the SAI delete can be a bit hit and miss with regard to flagging up an engine management light.....and I'm not into that, I like a blank dashboard...

 

SO - I've been doing this for the last 5 years of my ownership with no further problems - I start the car, let it idle for a couple of minutes whilst I faff about stashing my phone, donning sunglasses, selecting tracks on the stereo, setting the climate control, etc. etc. meantime the SAI is wooshing away...

 

Then once I pull away, the motor has warmed sufficiently to not jerk or misfire, as long as I keep the throttle light and the revs below 3k....I have a mile or so round my estate at these gentle settings, cruising round my residential area at 20, 25mph...

 

Then once onto the main road, the car has been running for a good 5 minutes now, the SAI has shut off, and any jerkiness and poor idling / response has disappeared.

 

Sorted?!

Yep, as said, sounds totally like a noisy / inefficient SAI unit.

 

I only say that because it sounds like my car.

 

On a first cold start, my SAI sounds like a Dyson vacuum cleaner on steroids, lol! And if I try to drive my car immediately after starting, I get similar issues to what you're describing.

 

I KNOW I could either remove the SAI pump and dismantle / rebuild with new nuts and bolts, or better still do the delete that has been described.

 

However, despite being happy to work on my Octy, I actually can't be arsed to go as far as some on here - especially because I have read that doing the SAI delete can be a bit hit and miss with regard to flagging up an engine management light.....and I'm not into that, I like a blank dashboard...

 

SO - I've been doing this for the last 5 years of my ownership with no further problems - I start the car, let it idle for a couple of minutes whilst I faff about stashing my phone, donning sunglasses, selecting tracks on the stereo, setting the climate control, etc. etc. meantime the SAI is wooshing away...

 

Then once I pull away, the motor has warmed sufficiently to not jerk or misfire, as long as I keep the throttle light and the revs below 3k....I have a mile or so round my estate at these gentle settings, cruising round my residential area at 20, 25mph...

 

Then once onto the main road, the car has been running for a good 5 minutes now, the SAI has shut off, and any jerkiness and poor idling / response has disappeared.

 

Sorted?!

Classic case of 'driving around a problem', like it. Not sure if the OPs problem is a little more terminal. You're right though the delete can be hit and miss, you can now get purpose made resistors but they're not cheap for what they are.

think im going to delete it only a few days ago i was actually looking at how its done lol

 

will have tp PM bowders and see what we can do with it..

Yeah the guide is pretty good I always meant to do it but didn't get round to it. It's just a question of how it's done individually. Shouldn't be a problem.