12 replies to this topic

[klivins]

Long story short - cant start it. There's spark, there's fuel.

 

 

Short story long:

Its 500 kms or so after a major rebuild . been fine, have tweaked the carb a bit.

it was slow to start in colder mornings. Then one day it didnt. After a battery charge it did.

And now, sitting in the garage, I cant get the thing running.

It just splutters from the carb, even with the spray start gas.

I 'dont think' its ignition related - its a megajolt, and gives spark.

I did clean the carburettor, readjusted the float - it was a bit off.

I checked the valves.

I even tested the compression. Although the readings are low (75 psi) they are even across all 4 pots. I think low readings are because engine is cold, and cheap old chinesium gauge I have. I will try to borrow some better gauge and check again.

All I got is odd puff of smoke from the carb...

Anyone can have an idea, of what I have missed?

[klivins]

There is a video

https://youtu.be/cQL-Sd_pErw

 

[Ethel]

It's certainly having a good go at igniting something.

 

As it's got wasted spark ignition, it's not impossible some wiring has got mixed up, try swapping the plug leads from side to side on the coil pack. i.e. swap 1&4 with 2&3

[sonscar]

Firing on wrong stroke and/or valves not closing would be my shout.Be methodical and try to avoid guessing.75 PSI is bordering on too low to start if it is correct.Steve..

[klivins]

It's certainly having a good go at igniting something.

 

As it's got wasted spark ignition, it's not impossible some wiring has got mixed up, try swapping the plug leads from side to side on the coil pack. i.e. swap 1&4 with 2&3

I'll be damned... Swapped leads, and it started. BUT HOW!!! The leads are impossible to mix, I have made them correct length according to their position, years ago! They now dont match! And I have marked them 1 to 4 with a marker.

I dont understand, and I'm gutted, having spend 2 DAYS drooling at the thing and doing god knows what. Yet, im happy it f**ng started!

As it goes, its always a tiny bit of human error. Makes a good laugh afterwards!

 

edit: I now do recall, that I did mark the leads after one such incident some years ago. It now seems to me that for unknown reason the Megajolt or Motorcraft EDIS module looses some data and swaps over the ignition sequence from one pair of spark plugs to other. Could it be related to low battery voltage while cranking? just a thought.

Edited by klivins, 05 October 2021 - 11:58 AM.

[sonscar]

You didnt move the wiring to the coil at all as this alters the firing order.Just a thought.Steve..

[klivins]

You didnt move the wiring to the coil at all as this alters the firing order.Just a thought.Steve..

What do you mean? I unplugged the coil pack, and then plugged back, yes. But I think I have done it before. This ignition sits on the car some 9 or 10 years now.

[sonscar]

Is the plug for the coilpack handed so it can only go one way?.The coil has a live feed(center) and a 1&4 and a2&3 side which it earths.Reversing the plug changes the firing sides.The plugs usually have some form of tang or shape to prevent this.Steve..

[klivins]

No, its a one-way plug. cant put it other way round.

[klivins]

I now do recall, that I did mark the leads after one such incident some years ago. It now seems to me that for unknown reason the Megajolt or Motorcraft EDIS module looses some data and swaps over the ignition sequence from one pair of spark plugs to other. Could it be related to low battery voltage while cranking? just a thought.

 

[Ethel]

There are a number of other things to mix up apart from the plug leads, depends what you've had in bits,or put together. The coil pack has one +ve supply that's grounded by a couple of wires through the Edis module 1 wire for each pair of cylinders. The timing is taken from the tooth wheel, could it have been flipped or rotated 180 degrees?

 

The Edis has a limp home mode, suppose it's not impossible it was deliberately set up wrong (anti-theft?) and corrected in the MJ's configuration. Not too likely, but it could mean the MJ isn't working, but something to think about if  it lacks performance.

[sonscar]

Millions of Fords did not start firing on the wrong cylinders randomly or the whole world would have been walking at some point.Just a thought,Steve..

[klivins]

Thats the thing giving me insomnia. Mechanical things were not touched, in fact, all I did was oil change and some refurb of the bling, and carburettor cleaning / adjustment.