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[Tony H]

Hi all can  anyone tell me if Tech 2 or for that matter any diagnostic machine will detect a dis pack fault on an Omega or other cars?

TIA
Tony

[TheBoy]

Indirectly it can help. But it won't say "The DIS/Coil pack is shagged, replace it".

On Omegas, for pre DBW cars, it will likely say no faults, even though there is a chronic misfire. In this scenario, check the HT side of things if the trims/MAF look OK.

On DBW, it'll likely suggest which cylinder is misfiring, though you still need to use common sense to ascertain if fuelling, HT or bugger engine.

[Tony H]

Had a miss fire for a while now. lumpy idle, no miss on slow acceleration, misses on moderate acceleration, floor it and the miss clears, but when the throttle is backed off the miss reappears. New plugs and leads fitted seems to improved a bit but still missing any advice would be greatly appreciated. P.S. could this be caused by a faulty dis pack?
 

[zirk]

Posting your Engine Type and Year might help together with any Fault Codes.

[Andy H]

On cars with one coil per plug (ie facelift Omegas) the diagnostics can often be used to switch off individual coils to aid diagnosis. I think Tech2 can do this 

[Tony H]

Posting your Engine Type and Year might help together with any Fault Codes.

2.5 2000 

[zirk]

Posting your Engine Type and Year might help together with any Fault Codes.

2.5 2000 

?

[omegod]

Hi Tony, I recall my 3.0 behaved like this when the DIS pack was on it's way out , I have diagnostic stuff and am in Huyton but work most weekdays in Bootle if you want it plugging in, as TB says it may record a misfire but not much else   give me a shout, Jon   

[Tony H]

Hi Tony, I recall my 3.0 behaved like this when the DIS pack was on it's way out , I have diagnostic stuff and am in Huyton but work most weekdays in Bootle if you want it plugging in, as TB says it may record a misfire but not much else   give me a shout, Jon   

P.M sent 

[Tony H]

Posting your Engine Type and Year might help together with any Fault Codes.

2.5 2000 

?

Had a local garage plug it in to his machine I don't know what type or how good it is but it was not a Tech 2. I came up with three fault codes a transmission an 02 sensor an one more that I can't remember but the bloke said it would not cause a miss fire.

[Andy H]

Posting your Engine Type and Year might help together with any Fault Codes.

2.5 2000 

You can use the paperclip test on your engine Paperclip test & pedal trick to read the codes but I don't think that ECU is capable of telling you much about the ignition or misfires.

I had a misfire on a 2.5 several years ago. After dicking about getting the codes read and looking for a complex cause I did some basic maintenance - I changed the spark plugs - that fixed it

[Tony H]

Thanks for your reply Andy  , but as stated new leads and plugs fitted but has not fully cured the problem.

[Diamond Black Geezer]

Never forget that more than one thing can be the cause of a problem. I've found that in the past with a poor idle, it was three separate things which were causing it. Hope you get sorted soon

[Marks DTM Calib]

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.

 

[TheBoy]

I too would be going with deeper investigation into HT side...

[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

 

[tigers_gonads]

Got a pfl  Maf here for beer money plus postage if needed but as the 02 sensor was mentioned, what's it look like on live data 

[JamesV6CDX]

Missing under load still suggests HT issue, to me.......

[TheBoy]

MAF on 2.5 will either work or not, so doubt its that.

What state are idle and partial load trims?

[Tony H]

Missing under load still suggests HT issue, to me.......

Just clarify when the go peddle is "floored" it pulls like a train.

[Marks DTM Calib]

Missing under load still suggests HT issue, to me.......

Just clarify when the go peddle is "floored" it pulls like a train.

Hence the need to look at learnt values as WOT means open loop operation 

[omegod]

Missing under load still suggests HT issue, to me.......

Just clarify when the go peddle is "floored" it pulls like a train.

Hence the need to look at learnt values as WOT means open loop operation 

Hi Mark can you expand on the above pls

[TheBoy]

Missing under load still suggests HT issue, to me.......

Just clarify when the go peddle is "floored" it pulls like a train.

Hence the need to look at learnt values as WOT means open loop operation 

Hi Mark can you expand on the above pls

As said earlier, what are the idle and partial load trims for both banks (so we need 4 figures)