[Lokidog]

My 1.3 (carb) zook has developed an idle issue today.

After a good run back home on the freeway, it's developed a really low idle. It basically idles just above stalling. In fact it did stall once when I went to pick the kids up from school.

The carby was rebuilt late last year and the zook has been running perfectly up till now. It's too dark now to go and have a good look at the carby etc…
But I'm thinking it could be one of a number of things…

Crap in fuel? (I had a new fuel filter put in with the carb rebuild), So I'm so so whether it's this. Also, I've been running 98 ron for a good while.


Plugs? I just changed them 3 weeks ago, I normally use NGK-BP5ES but a guy at Repco recommended an NGK-BP6ES?? (Not too sure about this number - will check plug packaging to see whether I quoted the correct number)??

Leads?

Any suggestions on the order of sourcing the problem…

I was going to start by checking the carby by looking down the barrels to see if it's looking dirty.

Checking air filter, which should be pretty well clean.

Then plugs, leads and so on… If there is anything else I should be checking out, please let me know.

Thanks Darren

[Lokidog]

One other thing, it still goes like stink. There is no stuttering while accelerating, and it holds its speed. No power loss while it's been given some welly.

[want33s]

BP6ES is the recommended plug for Sierras.. Look at the sticker under your bonnet..
I'd suggest maybe it's the idle jet partially blocked.
If you don't already have one, fit a fuel filter between pump and carby.

[Lokidog]

Blocked idle jet makes sense.

Is there a way of cleaning it out with out having to pull down the carby? Force a back fire by crossing the ignition leads on cylinders 2 & 3 perhaps?

[want33s]

Lokidog wrote:

Blocked idle jet makes sense.

Is there a way of cleaning it out with out having to pull down the carby? Force a back fire by crossing the ignition leads on cylinders 2 & 3 perhaps?

That should do it or start engine and rev hard, then (while still at full throttle) smother carby with a rag until it nearly dies. Repeat 2 or 3 times... Should pull offending article through.

If above doesn't work, remove carby and take out the idle jet and run a piece of wire through it.

[Lokidog]

Thanks Jason.

Not sure where I got the NGKBP5ES from? I'm sure that I've been running that plug for the last 20 years of own Sierras.

[want33s]

Correction...
It says BP5ES on the sticker under bonnet but with unleaded and higher octane the BP6ES is the plug to use.

This explains the heat range thing....
http://www.ngksparkplugs.com/tech_suppo ... p?mode=nml

[Lokidog]

Just did the old crossing leads 2 & 3 over, then turned it over with a little throttle to get it to cough a couple of times. Seems to have done the trick.

Will find out shortly when I do the school drop off!

[Lokidog]

Well the forced backfire didn't work. It was all ok up until the 2nd intersection, then it started to stutter again.

I'll try smothering the carb with a rag at full throttle a couple of times.

[Lokidog]

Whoo hoo. Smothering the carby worked!!!

All is good now. Thanks Jason

[want33s]

Lokidog wrote:

Whoo hoo. Smothering the carby worked!!!

All is good now. Thanks Jason

No worries mate... Glad to help.

[Lokidog]

[suzibob]

How do you no it's unburnt fuel?? Mine does exactly the same things your does in the morn. If I start it for first time later during the day, the effects aren't as bad. I'd say the "un burnt fuel" is probably condensation mixed with soot in your exhaust pipe that is getting blown out.
Probably wooldnt worry about it. To me it's just an initial mixture issue with the denser cold air.

[suzibob]

Also pull your plugs out and have a quick look. This should give you a general idea on your mixture settings if your worried about it. (better rich than lean)

[Ben_Sierra]

Lokidog, mine was similar until a couple of weeks ago. Just tweaked up the cold idle a touch and now its much better...

[Lokidog]

[suzibob]

Look from passengers side at the back of the carby where the accelerator cable goes and you should see a screw facing downish. Pull the accelerator cable around a bit and attack the screw with a flathead. (screw it in a bit)

[Lokidog]

I take it that it's closer to the firewall than the mixture screw, if IRC. Too bloody cold to go outside now. I think us sandgropers are poofs when it comes to the cold!!

[suzibob]

Yep. You have mixture down bottom in middle, cold idle towards firewall, and warm idle pokes out just behind the solenoid. Not the mention your idle up screw at the very front of the carby.

[Lokidog]

I may give it a shot tomorrow morning before I fire her up.
I'll give the screw half a turn, what do you reckon suzibob?

[Cade]

Having the exact same problems with mine

[Cade]

Having the exact same problems with mine

[Fatzook]

Cade wrote:

Having the exact same problems with mine

Cade wrote:

Having the exact same problems with mine

Must be bad if you had to post it twice

[suzibob]

Depending on where your cold idle is now, you may need to screw it a full turn or so. Set it so the car idles between 1500 & 2000 rpms when cold (remember you can only adjust this when the engines cold). I had mine at 2000rpms but the high idle annoyed me, so I've got my set at 1500. Only prob is when its really cold, it wants to stall if I don't hold it revving for 5 secs or so with the accerator. No big deal really. I give it a few mins to then warm a little, then she's drivable.

Easy really... Not rocket science.

[Lokidog]

suzibob wrote:

Depending on where your cold idle is now, you may need to screw it a full turn or so. Set it so the car idles between 1500 & 2000 rpms when cold (remember you can only adjust this when the engines cold). I had mine at 2000rpms but the high idle annoyed me, so I've got my set at 1500. Only prob is when its really cold, it wants to stall if I don't hold it revving for 5 secs or so with the accerator. No big deal really. I give it a few mins to then warm a little, then she's drivable.

Easy really... Not rocket science.

Finally got around to doing this the other day. So far it works a treat!