Mk2 polo breadvan won't fire cranks and backfires up carb

[mikeywinkle]

Hi everyone I am in need of help fixing my mk2 polo, a couple of weeks ago she broke down down the road from my house with a horrible crunching noise, towed it home and did a quick inspection to find that the crunching sound was the drive pin on my distributor snapping stopping the rotor from spinning, so having another spare broken dizzy I pulled the drive pin off that one and repaired my current one, now rotors spinning again, and got spark at all plugs, not the strongest spark though just a dull white one even when being jumped off my girlfriends mums rover, but she still won't start, when I turn the ignition it just cranks over and backfires out the carb, sometimes with a pop, other times just a mist of petrol spraying out, I've cleaned carb twice now, and tried easy start in the intake which just results in more popping out the carb
Any advice appreciated as I'm stumped for ideas
Cheers sorry about the size of the post

[composimmonite]

Timing out. Simple as that. Set up per the manual to get back to how it was before pin broke. Loads of on-line instructions if you haven't got a manual.
Hope that sorts it out.

[mikeywinkle]

I don't have a manual but I don't see how the timing can be out when I only removed the dizzy? Or could the dizzy it's self be out of time? I swapped the leads to check if it was 180 out and it stopped the backfire and showed no sign of starting at all

[steveo3002]

crank the engine over with a socket on the bottom pulley until the pulley marks line up for tdc top dead center , you can confirm this if you want by poking something clean in the number 1 (cambelt end) plug hole and checking its at the top of its travel

then loosen the dizzy and turn it until the notch on the housing lines up with the center of the rotor arm

that should be close enough to get it running , once warmed up it needs fine tuning with a strobe light

[mikeywinkle]

Also I read on clubpolo that it could also be symptoms of a dodgy Hall sender in the dizzy? Is there a way I can test to be sure?

[steveo3002]

******or have the dizy loose and a mate ajust its position until it starts while you crank it

then strobe light once its running

[mikeywinkle]

Thanks for that the cleared that up but I have another issue, I already tried setting to tdc with a socket and it'll only turn about 90 degrees and locks up? Can crank it past with the key but then can only do another quarter turn?

[steveo3002]

it will go stiff as the compression builds , take the plugs out or eat more pies

[mikeywinkle]

Also I did tipex a mark across the dizzy to the head before I removed it in the first place so I could replace it where it was so it's sat exactly how it was before it broke down?

[mikeywinkle]

Ah okay will be because I had the plugs in when I tried then

[mikeywinkle]

I'm off to go reset to tdc and line up dizzy like you said and see what happens cheers guys, will let you know what happens

[steveo3002]

tipex should have made it close enough to start

report back if all those marks line up

so it needs to be #1 piston(cam belt end) at the top , lower and cam pulley marks lined up , and the rotor arm notch too

[Roy Royson]

I had this problem, check your HT leads are in the correct place and the firing order is correct before you start messing with the timing.

[mikeywinkle]

Okay so set to tdc, rotor is pointing at plug 1, piston is all the way up, all times up okay, still no fire, firing order is definitely correct 1342

[baggabones]

Definitely (IMO) a timing/plug leads swapped issue.

[mikeywinkle]

I've just been out and checked all that I can assure it's not, though I did notice that my rotor arm seems to be rubbing on the dizzy cap contacts, could that be to do with it? I'm guessing that's the reason for week sparks, got a few caps and arms so gunna test some different combinations see if it makes a difference just waiting for the battery to charge as that's decided to die now too

[mikeywinkle]

Okay I put a different cap and arm on, the one that was in the must've been for a golf cos it was slightly bigger, now it keeps trying to fire and dying, but I think I've found the problem, the vacuum advance isn't sucking, so am I right in thinking that means its getting too much air?

[steveo3002]

shouldnt affect it when cranking , the vac comes from the engine running so could be about right

[mikeywinkle]

Hmm well it's seems to be trying to fire, keeps popping as if it's gunna start but wont quite manage, plus mists fuel out carb, though I guess that's just the unburnt fuel, also noticed my carb Base rubber bit is pretty tired, but seems unlikely that it would just start causing an issue now

[mikeywinkle]

I'm thinking of buying another dizzy and chucking that in see if it fixes it as I know someone selling one, but it's sparking so seems unlikely that the problems there, it all times up, I can only think now it's like too much air just catching and dying