Technical '89 Panda 1000s runs but won't idle and very hesitant at low revs

[binkenhaben]

Hi
I have a 1000s with 30,000 miles.

Lovely little car and starts fine on the choke.

The problem arises when I try to reduce choke and run normally.

It is very jumpy/hesitant at low revs but pulls pretty well at higher revs.

Also, when I come to a junction etc, unless I use the hand-brake to brake whilst feathering the throttle, it will just cut out and can then be quite difficult to start (which is embarrassing at a roundabout or similar)

I can do most jobs on a car but I am hopeless at diagnosis.

Any ideas?

 

[firstcar-Y10]

Well, some theories to kick off:
1: vacuum advance module on the distributor - disconnect the vac hose at the carb end and try and blow down it, should be airtight.
2: blocked idle jet - floaty crud in the petrol will tend to block this one most often as it is the tiniest hole. Take the airbox off and it's the smaller of the 2 brass jets visible from the top, offset slightly to the right as you look down on it (I think, doing this from memory and it's a while since I've been in the carb) unscrew and blow through or squirt carb cleaner through (don't poke it, you can upset the calibration)
3: Sticky fuel cut off solenoid: wire that attaches to a spade connector on the front of the carb near the throttle linkage. Disconnect the wire & with the engine off but the ignition on touch the wire to the contact and you should hear it click as it pulls out and again as it releases when you break the contact.

 

[dragonwagon]

I'm with firstcar on the vacuum unit - these fail with monotonous regularity. Also, clean the inlet filter in the carb itself as well as change any inline filter that may be fitted.
When did you last look at the HT leads, cap and plugs themselves ?

 

[binkenhaben]

Thank you guys (or girls)

I will try those remedies.

I have only owned the car a few months and I have never changed plugs, points, leads or distributor-cap. Guess I should try some of the other suggestions first though.

Cheers.

Richard

 

[binkenhaben]

Fantastic !!

Sucked on the vacuum hose and found a big split in it.

She is now running as sweetly as a 35000 mile panda should.

Thanks for the great advice.

Richard

Ps have just noticed that there is no spare wheel under the bonnet. Where's the best place to source one? eBay?

 

[Pandateria]

I have an 88 Panda and had the same problem. Same solution - vacuum hose had split. Replaced it. Now running sweetly

 

[binkenhaben]

Interesting. I had great fun driving mine around for a week or two and enjoying how well it was driving. However, it then reverted to the previous scenario.
I havent had much time to look at it since then but I pulled the vaccuum pipe off the vacuum advance yesterday and blew into it and it allowed some air -flow, which must mean that the pipe is leaking again ??? I couldnt pull it off at the carb end in the time available, so wasnt able to inspect it properly. Hope its just a leaky rubber hose that needs replacing. Does anyone know the bore diameter for the hose , to save me measuring it up?

 

[firstcar-Y10]

If you blow that way down the pipe it should flow a bit, it just opens into the carb. Blowing down it into the vac unit is to see if THAT is leaking, as there is a diaphragm inside which splits causing a vacuum leak to the carb, and the advance doesn't work.

 

[binkenhaben]

Thanks grumbleweed. Sounds to me as though the diaphragm has split (not for the first time in my life !!)
Whereas the pipe was previously split, once the unit became subject to sustained vacuum pressure, ithe diaphragm obviously couldn't cope.

Is the diaphragm replaceable or do I need a complete replacement unit?

 

[firstcar-Y10]

Here you go:
http://www.ebay.co.uk/itm/170925993095?_trksid=p2060778.m2749.l2649&ssPageName=STRK:MEBIDX:IT
Genuine Marelli, whisker over a tenner, and when I ordered one a couple of weeks ago it was here in a couple of days even from Italy!

 

[Dragon Man]

and also the pipe is 6mm diameter

 

[binkenhaben]

Ok. Haven't driven the little beauty since September but went ot and started her in the frost yesterday and away she went.

Previous problem was still persisting so I fitted the brand new vacuum advance and sadly, it hasn't made any difference. I was quite surprised when examining the vacuum apparatus that it only seemed to have a few millimetres of travel but I guess that's how they are.

I now need to examine some of the other solutions mentioned above. Blocked idle jet sounds promising. Or maybe the fuel cut-off solenoid.

 

[binkenhaben]

Success !!

Haynes said that the Webber carb contained an in-line gauze filter at the fuel inlet but I couldn't find it, so I couldn't clean that.

I also fancied checking for a sticky fuel cut-off solenoid as mentioned by first car-Y10, but there was no reference to it in Haynes and I couldn't find it on the car.

Instead, I took out the jets and although I couldn't see any blockage, I poked a piece of nylon all the way through both of them. It took a long while to get it all the way through the finer of the two jets, (which I presume to be the idler jet) but eventually I succeeeded and straight away, the little beauty fired up and ran as sweet as a nut. No feathering needed on the throttle, no stalling at lights etc.

Chuffed to bits !!

Thanks for suggestions and help.