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[Marks DTM Calib]

Resistance is not a great method for checking coils, a test plug with variable gap (upto 40-50mm for modern ignition systems) is the only method that gives a true test of the setup.

The reason being that an important part of the coil is the iron core, it is this that stores the energy in the form of magnetic flux and hence when the core corrodes, the capacity to store magnetic flux drops and the spark energy drops......and in this common failure mode, the resistance values are unchanged. 

[Andy B]

.....The reason being that an important part of the coil is the iron core, it is this that stores the energy in the form of magnetic flux and hence when the core corrodes, the capacity to store magnetic flux drops and the spark energy drops......and in this common failure mode, the resistance values are unchanged. 

How do you remember all this stuff?      

[Marks DTM Calib]

.....The reason being that an important part of the coil is the iron core, it is this that stores the energy in the form of magnetic flux and hence when the core corrodes, the capacity to store magnetic flux drops and the spark energy drops......and in this common failure mode, the resistance values are unchanged. 

How do you remember all this stuff?      

Its basic electrical engineering (first year theory) 

[05omegav6]

I wonder then if the slope does matter, if you are on the flat with a very low tank and than change to a slope will it cut out? All my tests were pretty much on the flat. But even on a hill a bit of braking is going to throw the back of the tank contents forward over the pump, even with baffles.

Makes me think even more that the fuel is electronically cut off when it decides the tank is too low rather than keep pumping every last drop.  On each of the three tests I did when it cut out it went immediately, no spluttering.  I didn't try ignition off and restarting; I wonder if that might reset something.

The estate can cut out parked on a bit of camber if your heading towards the red Takes a lot more fuel than you might think to get it running again, as Albs will testify

[Webby the Bear]

cheers guys  as said i cant comment as i aint learned ignition yet  but thanks for the explanation

as i dont have any updates due to assessments there is something i would like to talk about thats been bothering me in my short learning curve.

that is....

RUSTY BOLTS.

As you probably know i was the proud owner of ralf and after scrapping the old boy im really pissed off i didnt get the cats off and take more stuff off to be honest. however in fairness to myself i own onlythe halfords tool kit (mainly with awfully pointless double hex ring spanners) and a bottle of wd40.

i made a half hearted attempt to get the bolts undone. no chance. especially as i couldnt get the car on stands (i dont trust my stands anymore and am replacing) and it was on a slope 

Anyway....

i want a little step-by-step cut out and keep guide as to how to tackle any bolt.... i think it should be as follows... do you agree....

spanner/socket
penetrating oil then spanner/socket
heat
last resort...angle grinder and replace bolts

but what about in tight areas like exhaust manifolds? 

as per the addition of heat is there anything that you can buy for the ''DIYer''? i have a very good heat gun but im thinking that wont get anywhere near the temp needed.

SO i suppose the topic should be ''what can the diy'er use for heat''?

discuss.

[aaronjb]

Skip the WD40 and use a proper disassembly oil like PlusGas..

For home use your best option is Oxy/Propane - slightly less potentially lethal than Oxy/Acetylene and doesn't require a license to store the bottles. Expensive for infrequent use, though.. really good straight propane torch might do it, but I've never tried.

With limited access a very good HSS/Cobalt bit and a steady hand with a drill is your only real option.. it's annoying, takes forever and some practice!

[Webby the Bear]

Thanks Aaron

if i did want to have a home kit is there one that anyone could recommend?

[Webby the Bear]

by kit i mean blow torch kit to remove rusty bolts 

[Marks DTM Calib]

Look for a Bernzomatic torch and then get either a disposable Propane bottle (hot) or a MAPP gas bottle (hottest).

They can be used for plumbing, heating, brazing etc

[Webby the Bear]

Look for a Bernzomatic torch and then get either a disposable Propane bottle (hot) or a MAPP gas bottle (hottest).

They can be used for plumbing, heating, brazing etc

cheers mark 

are these a good edition to the home worker would you suggest? at least i'd never not be able to remove a bolt again 

[Marks DTM Calib]

Its the next best thing to a Portapack! (which are pricey!).

Plus very useful for general things such as plumbing, fire lighting etc

[Webby the Bear]

cheers mate.

would my heat gun set on high be any good?

[aaronjb]

would my heat gun set on high be any good?

Electric one as used for stripping paint etc? Not even remotely I have a butane torch and even that doesn't get things hot enough..

[Marks DTM Calib]

cheers mate.

would my heat gun set on high be any good?

Unlikely, you need a GOOD blow torch with a controlable flame and at least propane (much hooter than Butane).

[Andy B]

..... (first year theory) 

That was a long long time ago for some!