Rough idle when warm?

[Gambit]

coil is fine, you only use 3 out of the 4 terminals.

Over run cut off should all fit nicely but its tight & fiddly!

you can test your over run cut off valve & throttle closed switch easily. with the engine running, manually open & hold the throttle (around 3k rpm) then with a small flat head screw driver press the throttle closed switch - you should hear diaphram operate, revs will then plummet before immediately lifting back up

for the 3 temp senders below dizzy around water outlet:-

red/yellow wire = dash temp gauge
red/green wire = ISV
blue/white wire = ECU temp signal for timing advance

all 3 senders wires can be swapped about. so if you know the dash gauge works, then use that for ECU and try it for a bit etc

just use oil temp reading in meantime

[pullafacial]

Hi Gambit, thanks for that.

Just spent another couple of hours reading and I've convinced myself that it's the over run valve connecting pipes. They're really loose and I wouldn't be surprised if it's leaking air there.

Would this cause the erratic idle when the engines warm and reduced fuel consumption?

I'll take the trusty wd40 to work tomorrow and have a play at lunch time.

If it is leaking there, thought I would get jubilee clips whacked on to seal it.

Thanks again

[Gambit]

Yeah if it is letting in unmetered air then yes it will effect idle.

Decent tie wraps will give you a tight fit on pipes. Cheaper and handier than jubilee clipping everything. Then once you find an issue then jubilee clip it!

Just rule out things one by one, and take note yourself so you can go back over things and spot potential things you may not have checked

Youll get there in the end, they are pretty simple engines to work on.

[pullafacial]

Hi Gambit,

This morning I cable tied all pipes on the over run valve.
I also disconnected the engine breather pipe from the side of the airbox (which emits a fuelly smelling smoke?)

Seems to run much better now, when I change gear the revs were almost going up slightly when I put the clutch in which seems to be fixed.

Also, although tickover is still slightly lumpy, it's nowhere near cutting out like it was.

I did find a small air pipe which is disconnected down the back of the engine which I'm not sure where it should go, I'll post a pic...



Basically the pipe I'm pointing to connects under the large plastic pipe that connects to the throttle body. It also t's off and isn't connected to anything.

I guess my next two questions are:

1: should the breather pipe be emitting fuel smelling smoke and can I run it with that disconnected?
(Wondered if a fuel chAnge may help this?)

2: do I need to worry about that small pipe down the back of the engine that isn't connected to anything?

As always, thanks massively for your help!

[gazareth]

that could be the pipe that's meant to go your mfa on dash clocks. try blocking it of and see how it runs. there should be 4 wires going to your coil. 1 12v feed/2 wires to ignition module and 1 wire to rev counter.

[gazareth]

check your oil to see what colour it is? if your engine is overfueling badly your oil will be grey and watery.

[pullafacial]

Thanks, I will check that out.

Scrap what I said earlier though, just been out for a longer run and it still idles like a dog when it's properly warmed up!

[gazareth]

oh there is something else I was meaning to mention. maybe the fifth injector is stuck open. in which case unplugging it wouldn't make any difference to engine running, you could try unplugging it then take it out of manifold and get someone to crank engine while you check it. there should be no fuel spraying out of it with it unplugged whether engine is hot or cold.

[Gambit]

Does your overrun valve have its vacuum pipes all connected? That one looks like its the one that runs to the t-piece just behind overrun valve

you can run the car with the breather disconnected but you need to plug the hole in the airbox

[pullafacial]

Over run valve is all connected ok. This is connected to the same place the over run valve connects to just under the big rubber pipe that goes from the air box to the throttle body.