When I fitted my oil catch tank recently, I removed all the associated vaccuum pipes from the cam cover and throttle bodies. I replaced the throttle body ones. All was initially ok and the engine ran fine, but the last 2 times I have started the car, the idle goes straight to 3000 PM and stays there untill the engine is warm!
I have checked the EMERALD idle settings and they are all fine, circa 1000 RPM, so I am wondering what is causing this problem?
Without pre-empting the audience answer, my thoughts are an air leak somwhere in the TB’s… or the wheel speed sensor as per the problem it sometimes gave the MEMS ECU?
Air leak mate, on the engine side of the throttle butterflys is my guess
Sean, do you recall the nickle plated steel vaccuum pipe that took air from the cam cover and ran the full width of the TB’s, feeding dirty air via 4 ‘nipples’ (CALM down Rob!) in each TB.
Someone suggested blocking each of these off with a srew into some new pipe. I have interconnected each pair with a ‘hoop’ pipe. Do you reckon this is this OK?
Cannot understand the air leak as all the vaccuum pipe work is new! and worked fine when installed!
Yeah what you have done sounds OK. Could you have an inlet manifold gasket leak? To test this spray WD40 around the inlet manifold gasket while the car is running. If it coughs and splutters you have found the leak.
Just to confirm you are not running an idle speed control valve are you?
Yeah what you have done sounds OK. Could you have an inlet manifold gasket leak? To test this spray WD40 around the inlet manifold gasket while the car is running. If it coughs and splutters you have found the leak.
Just to confirm you are not running an idle speed control valve are you?
Sorry mate, but where is the ISCV?! Is it the big bugger on the base of the block that takes the filtered induction feed from within the air box, and another pipe, or is it the one on the LHS of the TB rail?
All this started after I used some TB cleaner and sprayed it in and around each TB with the engine at 1500 RPM. Cleaned them a treat. I have made sure they do close fully too! I would be surprised if there was a leak as the gasket is only 8 months old…
Another thing to try is the balance of your throttle bodies. Back in my K series days I got my engine back from its umptenth Erland rebuild and the throttle bodies were so badly out of balance that the engine actually misfired.
The idle speed control valve is on the inlet side of the engine mounted on the block below the inlet manifold. It will have a couple of rubber pipes going in and out of it. They are a good thing, but they can stick open, which could lead to your high idle speed.
The idle speed control valve is on the inlet side of the engine mounted on the block below the inlet manifold. It will have a couple of rubber pipes going in and out of it. They are a good thing, but they can stick open, which could lead to your high idle speed.
Thanks muchly Sean
Now all I need to work out is if it is sticking!!!.. and if so how to fix it!
… and it says the ‘IACV valve position may be reset… with the ignition on and mobilised, by pressing the throttle fully and slowly 5 times’ I will try this!
I am wondering if I inadvertantly ‘reset’ it whilst cleaning the TB’s when the throttle was being depressed in such a manner?
So, whats so good about this IACV! Seems to me that just taking the whole thing off and blocking up the lower feeds to the TB’s would avoid llots of hassal? I could live with having a slightly lumpy/sluggish engine when cold as I dont give it beans till very well warmed up anyway!!
Has anyone here removed their IACV experiences positive or negative?
Anyway, thanks for the really good steer Sean… I think this IACV will be the reason…