Fluctuating idle

[marcus1875]

Hi guys,
probably really simple this one, just changed the inlet gaskets, put everything back together and now the idle isnt constant have checked everything i can think of, all the parts are on as before and nice and tight but the idle drops to around 200 then jumps to 1000 falls to 200 and jumps back to 1000 ad naseum. Any ideas.
Video on youtube search for tvrmarcus1875
dont know how to link a youtube video.
cheers guys
marcus

[Rockettvr]

Sounds like hunting. Usually air leak some where after AFM. Must have a gasket that hasn't sealed properly.

[mrzigazaga]

Hi Marcus...As said it could be an air leak..Did you use gasket sealant on the inlet manifold gasket as the end near the dizzy has cork strips on it and is known to leak there after its been torqued down..Ideally you need a good spreading of sealant there..Ziga

[marcus1875]

i did put sealant on, damn it, bet i should have waited for it to cure/set before starting it up. blast
marcus

[mrzigazaga]

marcus1875 said:

bet i should have waited for it to cure/set before starting it up.

Possibly...

[marcus1875]

Possibly...I'm an impatient fool.

[mrzigazaga]

Thats a probably then......Im in the club of no patience..I would make a terrible doctor..Ziga

[wild rover]

Sounds like air leaks at the manifold. Try rtv sealant it works every time for me.

[marcus1875]

Well thats a job needing redone tomorrow.
Must remember to stop once refitted, cup of tea and a fag, then start it up.
cheers guys
marcus

[Solitude]

Apply it.......let it "half set"


then join it.......

leave it for a few hours.


Kick the dog

start a row with her indoors

drive off in anger...........

[marcus1875]

Well, i resealed all the gaskets. Of to the pictures with the kids so i'm not tempted to start it too soon.
Should be set by tonight right?
marcus

[marcus1875]

That didn't help.
Although at least i know the gaskets are correctly fitted now.
I've maybe split a hose, or something so I'll double check all these again, can't do it tomorrow so Saturday will have to do.
Anyone think of anything obvious i may be missing?
cheers
marcus

[V8 Fettler]

Spray inlet hoses, plenum joints etc with Easy start, idle speed should increase if there is a leak.

[mrzigazaga]

Hi Marcus..As i understand it you have a carb set up...If it was the old plenum then i would say check the cold start plug as mine did the same thing a while back..Other than that it must be a leak some where on the vacuum side..Did you fit the vacuum pipe back to the dizzy?...Ziga

[V8 Fettler]

Assumed RV8, but clearly not, my error

[marcus1875]

Hi Mark,
no, i've got injection. You might be thinking of a post i up a couple of weeks where i had been offered a carb engine and i wondered how easy it was to change to injection.
I'll spray with easy start and check everything over....again, and again.
Although smurfs2 was fun!
marcus

[mrzigazaga]

Oh ok...Yes that did confuse me about the other engine..Check the cold start injector plug then..Pull it off and push back on whilst it is hunting..Did you replace the plenum gasket and torque down properly..I recall a while back you was going to adjust the idle..Did you do that?..Have you touched the metering head mixture screw at all?...Check hoses to the AAD and the WUR..Is the AAD functioning properly?...

[marcus1875]

yup, new plenum gasket. didnt know the correct torque settings so tightened them as much as i could with a ratchet. they didnt feel very tight tbh when i removed it though.
i adjusted the idle and mix last year, it all ran fine until i took the rocker covers and plenum of to put my shinny ones on last week which was when i tore a gasket.
it wheezed away after that and started hunting after i replaced the gasket. the wheezing has stopped tho.
not touched the idle or mix this time.
i'll check out the rest on saturday.
marcus

[mrzigazaga]

Hi Marcus...I know this probably is not the case and im not sure if its possible but the inlet manifold gasket has two cork strips that go to the distributor end..Is it on the right way round..Sounds a bit strange that it started doing it after you took the rocker covers off..I will pick the brains of the ford guys tomorrow to see if they have had this before...Ziga

[Grady]

No idea if I'm on the right track, by since Zig said "Ford": Any change it's crud (oil bypass) on the fuel/air mixture plate where the air comes in? Grady