Jumping & misfiring

[Pete126]

Having spoken to some one helpful on ebay selling the condenser and re read the description in the Haynes the 1985 onwards is a 'Marelli electronic rotorless' and pre 1983 is still a Marelli though.

First time i have heard of that one </* by the look of your coil and year you should have the std marelli dizzy. electronic ignition was never fitted to 126's imported into GB.

[Pete126]

A little more info.

If your dizzy has the plug leads coming out of the top with the HT lead in the centre it should be a Marelli S152A

The other two distributors that are used on the later models are the Zelmot 3459A and the Marelli S314A these have no rotor arm and just a flat top, Both these use the waste spark coil with both plug leads coming from the coil to the spark plugs.

All 3 distributors use a .25 mfd condenser.

[Worm]

Thanks Pete, it looks like the Marelli S152A is fitted to mine then.

How can you check that the condenser supplied is doing .25 mfd what ever .25 mfd means. Prehaps you could explain to an unlearned one [-/

[Pete126]

You may find this link informative it explains what each component does in the ignition circuit [-/

http://autorepair.about.com/cs/generalinfo/a/aa052502a.htm

[Worm]

Thanks Pete, a good read.

Yesterday i put the carb back on and no surprise that the car still jumps as everything looked ok on the fuel pump and carb. I removed the coil after the test drive, as this was my next port of call and found it was too hot to handle but to be fair everything in the engine bay is hot to touch  in comparison. Anyway i remembered someone had mentioned the insides of the coil may be loose, so i was going to see if i could strip it down and take a look. What i did notice is that when i shaked the coil there sounded like there was liquid in it. I removed the centre screw where the HT lead connects and a small amount of this fluid (10ml) came out when tipped upside down. Is this normal The coil has Zelmot written on it too. And that was as far as it came to bits. :undecided2:

[Darrell]

The coils normally have oil in them. Perhaps yours is knackered.

If you are down my way I have one you can try

[Worm]

Does anyone know what the resistance values for the primary & secondary windings in the coil are for the Zelmot as the Haynes only state the Marelli and Martinetti coils!! not a Zelmot one. Then i can check to see if my coil is indeed duff :undecided2: (PS thanks for your kind offer Darrell)

Think I've figured it out as it has 'BE 200 B' also stamped on the coil top too so i assume its that same as the haynes manual as it calls it Marelli BE 200 B in which case my primary coil reading was 3.6/3.7 Ohms and should be 3.1/3.4 at 20 degrees Celsius and the secondary winding was 7460 Ohms which fell within the 6750/8250 Ohm range as sated in the Haynes. I bench tested the coil  as per the link below. So i will order a new coil and post up the results

http://autorepair.about.com/od/troubleshooting/ss/coil-test-ohm.htm

[Worm]

 :cry2: put new coil on today must admit i put the orange and black on same terminal and it would not start and the wires were well hot and starting to smell then looked at the pic i took of the coil earlier  : and wired it up correctly, hope i havent buggered the new one , it still jumped around when driving. It seems to do it on the flat under load just before changing up a gear and up slight hills under load. Coasting at 1/4 throttle no problems though. I took the fuel pump line off again and watched the flow of fuel from the fuel pump, there is a good strong flow but does have some air bubbles in it which i assume is normal for a vintage set up as the carb takes what fuel it wants and sends the rest back to the tank so the bubbles shouldn't make too much of an impact? Apart from changing the spark plugs and leads which i dont think will help im at a loss, Any ideas anyone, as i want a reliable car to drive. </7

[thepuddlejumper]

I have air bubbles originating on the petrol tank side of the fuel pump indicating air is being drawn in at the tank, this is causing problems under full throttle and trying to maintain high speeds for a long periods .  Runs OK at low speed but can get jumpy when the throttle is pushed down, need to back off to keep it going then runs ok untill more throttle is required.  Air should not be entering the system.  I am on the look out for a new or good feed/return/float to resolve the problem. Can you see bubbles in the pipe between the tank and pump? if so use a petrol can with a tube fitted onto the inlet side of the pump start it up and see if you still get the air bubbles.

Ralph

[Worm]

I have air bubbles originating on the petrol tank side of the fuel pump indicating air is being drawn in at the tank, this is causing problems under full throttle and trying to maintain high speeds for a long periods .  Runs OK at low speed but can get jumpy when the throttle is pushed down, need to back off to keep it going then runs ok untill more throttle is required.  Air should not be entering the system.  I am on the look out for a new or good feed/return/float to resolve the problem. Can you see bubbles in the pipe between the tank and pump? if so use a petrol can with a tube fitted onto the inlet side of the pump start it up and see if you still get the air bubbles.

Ralph

Thanks for your reply . Sounds like we have the same problem. My fuel tubes are not transparent enough to see if bubbles are originating from tank side of fuel pump. I guess i can rig up a length of clear tube between the two if i can find suitable connectors. Assuming the bubbles are being generated the tank side before they enter the fuel pump, how can you eradicate them. Also what do you mean by good feed/return/float is this what is in side the fuel tank which draws the fuel in?

[Worm]

Strange.. i tested with a clear tube either side of fuel pump and there were no bubbles at all. So upon reassembling on the inlet to the fuel pump i used a different clip just incase is was drawing in air previously. Test drove it but still jumps. oh bother will i ever get it fixed as i am running out of ideas  I wonder if adding an additive to the fuel whether that will help, probably not but clutching at straws time. HELPPPPPP!

[thepuddlejumper]

It's the fuel/petrol tank sender, can get 500's ok but they don't have the fuel return.

Ralph

[Worm]

I see.

[midvillesb]

Just to bring this thread to a conclusion, I bought Worm's 126 last month - it had been standing outside since the autumn but fired up first time and being the brave/idiotic soul that I am, I drove it the 20 or so miles home during the rush hour on a Friday evening and basically it wouldn't go much above 30 or under any sort of engine load without stuttering/losing power until I backed off the gas and started again.

There didn't seem to be any crap in the fuel lines, points and condensor were new and set up right and the petrol pump seemed OK but it was obviously fuel starvation - anyway, that just left the carb and I suspected a dodgy float.  So, I got a reconditioned carb from Poland off eBay (highly recommended - £50 and it's like new), fitted it this weekend and the car is now as sweet as a nut!  I'll post a proper update once I've got some other jobs done.

[green-fly]

I'm sure worm will be really pleased for you after pulling most of his hair out for months bless him!!  .  .
Interesting thread guys, who was your eBay seller midvillesb?..glad you got it sorted, what year is it? enjoy it!