Won't fire - wot am i doin wrong this time???

[orangebooboobearcrew]

Hello everyone,

Been trying to get the van going for some weeks now (2.0l petrol Aircooled) after various ignition problems.

Now appear to have resolved the intermittment / lack of spark after replacing the coil with the correct one from Brickwerks, ignition amplifier replaced and hall sensor in dizzy replaced again, with correct one from Brickwerks this time. Also rectified loose pins on multplig coming from amplifier which was causing intermittment spark.

Checked last night a got good regular strong spark on no 1, 2 & 3 - didn't bother checking 4 as seems ok now.

Poured petrol down throat of both carbs (airbox and pipes removed stil currently) and tried to fire up. Tried this several times but no go. I've checked the timing settings as best as I can to Haynes and rotor arm is pointing to no.1 and notch in dizzy body when at TDC so would expect is close enough to allow me to start?

Can't understand - If I've got a spark and got fuel via pouring in carb, why won't it bang? Am I missing something sill or do I just need to persevere? (PS have also refurb carbs with Brickwerks set recently but no sure how this would affect it if fuel going straight through manifold into the head?).

Anyone got any ideas/ point me in the right direction as totally confused now...?

Thanks in advance,

Chris

[nenenaiad]

Hi,

could you explain to me why you are pouring petrol in ?

Dave

[eatcustard]

Dizzy 180 out?

leads in right order on dizzy?

[orangebooboobearcrew]

Hi,

Thanks for responses so far.

I am pouring petrol in as there is not enough power on turn over to the fill the carbs from the fuel pump. This is just to get it going...

I've checked the timing and recently corrected it by 180 as it seemed to be out which I have questionned myself about as to how it could have got out by this much given that nothing has changed? We had a serious misfire before I did all this work and I convinced myself that this had knocked the timing out but 180 felt a bit much!!

I've rechecked that the dizzy drivehaft is showing the smaller segment to the left of the engine (looking from the back forwards) and the larger segment to the right when on TDC as per Haynes. I've checked defo on TDC via the marks on the timing wheel. (I am right in saying there is only 1 tdc on compression per engine revolution? - so if wheel shows TDC that must be right?). I've checked that rotor arm is defo pointing to no 1 lead when on tdc and that rotor arm rotates when I turn engine by hand...

Confused of confused-ville.....

I will go and doulble check the leads again - it's got to be something silly...?

[nenenaiad]

Hi,

Re -"I am pouring petrol in as there is not enough power on turn over to the fill the carbs from the fuel pump. This is just to get it going..."

You should make sure that you have a well charged battery so that that the engine is able to compress the petrol / air mixture such that it can be ignited by the spark. Ring me on 01384 373855 to know more - you are wasting your time at the moment.

Regards


Dave

[VWCamperfan]

There is only one top dead centre mark on the flywheel BUT these are 4 stroke engines meaning the engine turns 2 times to return to where it was, if you like!
In other words, you could be 180 degrees out for the ignition timing. One stroke up is for the exhaust to exit and the other is for the compression stroke just before timing. This is the one you want, the compression stroke.
You may well have to turn the engine another full revolution before No.1 cylinder is at this point.
You will notice the distributor rotor arm only turns half a turn to one full revolution of the engine.

[VWCamperfan]

Hi,

Re -"I am pouring petrol in as there is not enough power on turn over to the fill the carbs from the fuel pump. This is just to get it going..."

You should make sure that you have a well charged battery so that that the engine is able to compress the petrol / air mixture such that it can be ignited by the spark. Ring me on 01384 373855 to know more - you are wasting your time at the moment.

Regards


Dave

Sometimes these engines won't pull up fuel just on the starter motor alone, the pump sometimes needs a little more, quite common with these engines and a little fuel down the carb is common practice on these to kick them into life.

[Buffy]

When my engine died last week it wouldn't fire and it turned out to be the idle stabilisation unit. Disconnected it and viola!!!

There were various other issues, but once we had sorted those the unit seemed to be the only problem left!

[murf]

what buffy said....I by passed idle stabilisation unit and did the trick


murf

[orangebooboobearcrew]

Dear all,

Many thanks for all your responses - help greatly appreciated as ever and some excellent suggestions.

I have now double checked the leads and they are on the correct plugs so not that.

The idle stabilisation unit I have already removed and connected the wires together - this will become a permanent arrangement shortly when I get chance to solder the wires together...

Battery is fully charged - I recharged it the other evening.

Reading the comments - almost certain that timing is out 180 degrees. This kinda makes sense as I mentioned I had previously adjusted this by 180 degrees which I couldn't understand why it was so far out as was running fine before!

Can I just check then, I am now right in saying that there are 2 TDC's via the pulley wheel - 1 when on compression stroke and 1 when on exhaust stroke? Therefore I need to turn 1 full further revolution the put the dizzy back in so it points to no 1 on rotor arm? Sorry I should know this really considering how many times I've done this now but obviously I've still not quite got it have I...

Cheers,

Chris

[VWCamperfan]

Yep, spot on. Give it another whirl, swap the leads over and hopefully you should be ok!

[orangebooboobearcrew]

Brill !

Thanks mate - I'll do it in the morning - if it ever stops raining; it's like the Noah's Ark story in the bible here, ie it seems to have rained for 40 days and 40 nights.

If this doesn't work in the morning, I might turn the van into an ark instead...

Excited now...

[VWCamperfan]

[Mr Bean]

Why isn't someone mentioning the simple process of flipping off the rocker covers and making sure that the relevant spark plug is getting a spark when both valves are closed. Incidentally I am an avid petrol down carb or plug hole on anything from miniature model engines. garden machinery and difficult to start vehicles. Unless you are have the simple process in mind you could flog away for days. Remember you need fuel to burn, sparks to light it and it is all to no avail unless you are on a compression stroke when the spark occurs!
Cheers
Wolfie

[orangebooboobearcrew]

Guys - quick update.

Managed to get out on the van early this morning as we woke to glorious sunshine!!

Quick 180 turn of the dizzy drive / timing - turned the key and hey presto - she fired first time...!

She's running great - let her get up to temp and idling sounds good both cold and hot, no oil leaks, misfires, etc - brill.

Thanks to everyone for helping me (yet again) - I couldn't do it without you

Gonna quit whilst the going is good for today. Next job is just to do quick check on how accurate timing is with my timing gun, then solder the idle stabiliser wires together, as ditched this for good now, then off for a decent length test run. (I've been round the block this morning and all was good).

Thanks again.

Chris