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[Tony H]

Right well the Motronic 2.8.1 setup on the 2.5 wont detect a misfire.

To test the DIS pack you need a test plug with a 35-40mm gap, then its dead easy to do as they can all be checked using the 1-3-5 bank leads which are easy to get to.

I suspect the lambda fault is as a result of the misfire.

The symptoms described point towards the ignition setup as max volts are needed from the DIS at lighter throttle openings.

Should this read thou? 

[Andy H]

Right well the Motronic 2.8.1 setup on the 2.5 wont detect a misfire.

To test the DIS pack you need a test plug with a 35-40mm gap, then its dead easy to do as they can all be checked using the 1-3-5 bank leads which are easy to get to.

I suspect the lambda fault is as a result of the misfire.

The symptoms described point towards the ignition setup as max volts are needed from the DIS at lighter throttle openings.

Should this read thou? 

No
The voltage required to create a spark in the combustion chamber at 200psi is much greater than it is at atmospheric pressure. Add in the requirement for a big fat spark and a spark of 35-40mm is easily achievable in free air from a DIS in good condition.

[Tony H]

Thanks for that Andy 

[Diamond Black Geezer]

Wow, I never realised that!

Ok, so the 'old way' of doing things would be to stick the HT on the plug, then, with gloves, lay the plug and HT on the block, to generate the circuit. But with the V6 you've got a great big plastic camcover. Are you looking for an exposed bot or whatever as ground, then literally holding the thing 35-40mm away by eye, and then getting a mate to crank the engine, yes? 

[Kevin Wood]

I wouldn't be holding anything on a modern ignition system. They can generate a very powerful spark that will "smart a bit" if it uses you as the path of least resistance.

This is why a test plug is handy, It provides a sensible gap to test the HT voltage, and you don't have to hold it.

[tigers_gonads]

Wow, I never realised that!

Ok, so the 'old way' of doing things would be to stick the HT on the plug, then, with gloves, lay the plug and HT on the block, to generate the circuit. But with the V6 you've got a great big plastic camcover. Are you looking for an exposed bot or whatever as ground, then literally holding the thing 35-40mm away by eye, and then getting a mate to crank the engine, yes? 

No Mr Geezer 

You get somebody you don't like to hold the plug wearing a worn pair of marigolds while YOU crank it over 

[Diamond Black Geezer]

Ahhhh!

Fancy popping over at the weekend..   

[tigers_gonads]

Ahhhh!

Fancy popping over at the weekend..   

I do have feelings you know 

Bastid 

[Diamond Black Geezer]

Ah, don't feel bad, come and have a cuddle 

[Marks DTM Calib]

Wow, I never realised that!

Ok, so the 'old way' of doing things would be to stick the HT on the plug, then, with gloves, lay the plug and HT on the block, to generate the circuit. But with the V6 you've got a great big plastic camcover. Are you looking for an exposed bot or whatever as ground, then literally holding the thing 35-40mm away by eye, and then getting a mate to crank the engine, yes? 

General rule of thumb is 1mm of gap per 1kV of volts......hence a modern ignition system produces circa 40kV so 40mm is working well (if its less than 35mm its goosed).

The old fashioned and very floored method would require a measly 1kV to create a weak spark.....not nearly enough to light a fuel mix on anything even a low compression Land Rover V8 or a Hitler engine in a Beetle

[Diamond Black Geezer]

See, I'd see 'a spark is a spark is a spark' without appreciating the strength of which is a critical factor.

So (again, if I've followed correctly) the test for the coil pack will be to basically run a known good HT, and known good plug from each individual terminal on the coil pack on at a time onto said earth point on the engine. 

[terry paget]

An ignition misfire usually first occurs at full throttle and low revs. My routine on a 2.5 is:
1) fit new plugs;. if I find oil or water in plug holes. rectify;
2) fit new plug leads;
3) fit new coil pack.

[Tony H]

Still having problems any help would be greatly appreciated

[Tony H]

Still having problems any help would be greatly appreciated New plugs ,new lead,new dis pack

[omegod]

Hi Peeps,  I went round to Tony's at the weekend and fitted a new DIS pack, previously all plugs and leads have been changed by a garage and I can confirm all were new.It ran a bit better for a while and would fly when giving it the beans but has reverted to running poorly under load and a little unhappy at idle. I found a split pipe to the plenum which was cut back and is now sealed properly. Looking for pointers as to where to go next, I have a stack of bit's from breakers to throw at the issue. I think it idled better with the MAF disconnected and I have a 2.6 one with a slightly different part number so was going to give this a try first but as said...all pointers welcome ! No fault codes stored either on his 2.5