Starting problems as discussed

**Mattskii** · 20th January 2011, 11:15 AM

Here's a thought....

First off, many many thanks to Dave for all your help yesterday, I thinkwe are well on the way to getting thigs sorted. Didn't start as well as hopes when cold this am, but behaving differently than before. So I've done some more reading.

I have been reading thriough the 14CUX fuel system guide as reccomended (Many thanks for that) and it talks about air/fuel mixtures. On a couple of accosions it mensions poor starting.

I goes over the startup sequence and then there is this line:

One side effect of this system is if air leak develops any where in the inlet system, the engine will start and run for 3-4 seconds and then die.

This is exactly what my car is doing now.

And thenwhen talking about air/fuel it says this:

Problems occur if there is any air leaks anywhere in the plenum feed pipe, plenum chamber seal, stepper motor housing, stepper motor itself, vacuum pipe to fuel regulator, vacuum pipe to distributor, or a split diaphragm in the distributor advance mechanism.

And I thought "Hey, my vac advance is bust" it does not hold a vacuum in the pipe, I just get mouthfulls of air come through it. So could this be the problem?

Is it OK to bung up the pipe to the vac advance and then start the engine?

In the mean time I will be ordering a new vac advance from the suggested supplier this very afternoon.

Thanks again everyone,

Mattskii

**Blknight.aus** · 20th January 2011, 11:33 AM

yep temporarily you can plug every vac port from the engine for diagnostics reasons.

I wouldnt have thought that the thin line from the dizzy would have caused enough leak to actually kill the engine dead, just make it run rough.

**Mattskii** · 20th January 2011, 11:47 AM

I think I left it long enough for the engine tyo be cold enough for this to be a good test. I plugged the tube to the vac advance, it started first time, like a dream. It would never do this when I first got it, not even with a warm or hot engine. Since the work I and dave have done it starts lovely when the engine is warm or hot, but has been cutting out from cold without any input from the throttle. This time is started perfect with no throttle input at all. I will try the same gtest again tomorrow morning when the engine is deffinatly stone cold.

I have ordered my vac advance, should be here in a couple of days. I have been reading through how to change it, seems like something I should be able to do.

**Blknight.aus** · 20th January 2011, 11:50 AM

its not hard to do, just make sure you mark the position of everything on the dizzy prior to pulling it down.

It can be done in situe but is a lot easier if you pull the dizzy...

**Ace** · 20th January 2011, 02:34 PM

Good to hear you are getting somewhere Matt, I admire the methodical way you have approached this and for someone who started out with very little mechanical knowledge you efforts should be commended. Good work.

**Mattskii** · 20th January 2011, 07:33 PM

Thanks Ace. I am getting a bit friustrated though. Seems we are getting somewhere, and the I pop out for a drive, stop at the shops on the way home and it's back to it's old self again, cranking and cranking and cranking before I get any ignition, then fissling out after I let go of the key.

Phhrrrrr! Got it home, engine as warm as it was before, and it starts first time.

This evening, engine still not fully cooled down, and it won't start again.

This morning it started like a dream - as per this thread this morning.

Why this thing never does the same thing twice is beyond me. If there was a pattern I could follow the clues, but this just seems totally random!

**harry** · 20th January 2011, 07:47 PM

Originally Posted by Blknight.aus

its not hard to do, just make sure you mark the position of everything on the dizzy prior to pulling it down.

It can be done in situe but is a lot easier if you pull the dizzy...

hi dave,
i don't think the dizzy needs to be touched at all,
my 3.9 disco is easy as to change the vac advance diaphram without changing anything, so i expect mattski's to be the same,
a little bit of stuff to remove in the top below the cap, but not difficult.
sorry, i'm guessing it is a 3.9 by the reference to the 14cux.

i have often had the problem of the bloody diaphram losing a screw and hanging off the dist. and causing the hard starting.
luckily i have found the rotten little hex head screw in the valley below where it should be.
have fun changing it and enjoy your v8

**Blknight.aus** · 20th January 2011, 08:24 PM

having fat mechanics fingers with the dexterity of high tensile crowbars for me its easier to just pull the dizzy out.

it can be done in situe and if the dizzy is orientated just right its even relatively easy. For me the hardest bit is loosening off and then correctly tightening the retaining screws on the vac unit 20 seconds of work with the paint pen and a few minutes to pull and place the dizzy either side of 5 minutes to change the unit.

I'm also more confident that its been hooked up correctly and those little screws have been done up just right doing with the dizzy out.

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