Idle help please

[sapper]

Help folks. Idle is mad.
Ive done some work over the last few months and ballsed something up.
Rockers, Plenum, coolant tanks etc have been off for powder coating. Also changed all coolant hoses and power steering pipes. Changed the ignition leads as well.
So I've disturbed quite a bit.
Finally got it back together today and started it up, and Shat myself.

Idle is at 3000RPM and slowly climbing as it gets warmer. And every now and then a nice loud backfire.
Ive checked the butterfly closes, cleaned the stepper and still no change.

What have I done

[PH430]

I think you have an air leak

[Pupp]

Vac hose between fuel pressure regulator and stepper housing off? Another port into plenum open - the one usually teed into the breather circuit perhaps (on the nearside of the trumpet base), often used to take a line to the dump valve or to a MAP sensor on FI cars

[blitzracing]

Do you have the preheat plate fitted under the plenum with all its screws?

[wuckfitracing]

Agree sucking air in somewhere

[QBee]

I thought you had Megasquits (hence stting yourself I suppose) . Please add to my meagre knowledge - why do you have a stepper?

[jojackson4]

You haven't pulled the heater plate of the plenom have you?

There's 2 bolts that brake into the chamber and cause an air leek
Don't ask how I know

[sapper]

QBee said:

I thought you had Megasquits (hence stting yourself I suppose) . Please add to my meagre knowledge - why do you have a stepper?

It was never removed

Edited by sapper on Monday 6th April 20:23

[sapper]

blitzracing said:

Do you have the preheat plate fitted under the plenum with all its screws?

Ahhhhh,
I didn't have.
I'd took it off when I sent it for powder coating. Before your reply Id put it back on but I have a screw missing.

[sapper]

jojackson4 said:

You haven't pulled the heater plate of the plenom have you?

There's 2 bolts that brake into the chamber and cause an air leek
Don't ask how I know

Yes I had the heater plane off. Its back on, with 3 screws, and I'm down to 2000RPM so it seems to be the cause.
Called it a day. tomorrow evening ill find the missing screw (in my toolbox, I hope.

[jojackson4]

You only nead 2

[sapper]

jojackson4 said:

You only nead 2

Which 2 Peter, I have the longer one and 2 short ones.

[jojackson4]

Easy way
Pull the elbow off and shine a torch under the plate open the butterfly and the light will show
You the way

[sapper]

Fitted the missing screw but still idle is at 1500RPM. I cant find any air leaks so scratching my head again. Everything is too hot to work on now so going I'm for a brew and looking for a wall to bang head against.
Any suggestions received with thanks.

[jojackson4]

Have you got any easy Start that will tell you if its a an air leek but make sure your Ht leads
Are not ark Ing

[sapper]

jojackson4 said:

Have you got any easy Start that will tell you if its a an air leek but make sure your Ht leads
Are not ark Ing

Ive got easy start, how would I use it to look for an air leak. Is this a trick of the trade?

[jojackson4]

1
MAKE sure you do not have Sparks /arking from your ht leads
Run it in the dark to check
2 start the car and lightly spray where they maybe an air leak then whate and see if the reves go up if it dose
That's where the air is getting in
Repeat around where you have had it in bits
Not my trick but what has been written on here I read too much

[sapper]

jojackson4 said:

1
MAKE sure you do not have Sparks /arking from your ht leads
Run it in the dark to check
2 start the car and lightly spray where they maybe an air leak then whate and see if the reves go up if it dose
That's where the air is getting in
Repeat around where you have had it in bits
Not my trick but what has been written on here I read too much



Part 1 complete, no arcs.
Part 2 tomorrow. I want to do it now but neighbours have kids and its a school night. Hope I can find a cure before the weekend.

[wuckfitracing]

Hi Mick what did you use to seal the plenum back on.

[sapper]

wuckfitracing said:

Hi Mick what did you use to seal the plenum back on.

Nothing at the minute as ive had it on and off so many times.
Ill seal it tomorrow with hylomar blue before I start looking for leaks with the easy start