Ignition amp testing

[KittyCamper84]

hi, does anyone know if there is a way of testing the ignition amplifier? we are having issues with our van and nothing seems to make sense!! we have checked the coil - ok, checked the hall sender - it is showing a change but only 4v to 2v instead of 12v to 0v. is this voltage created by the amplifier? what I really need is a diagram of the amplifier circuit! cap, rotor, plugs, leads are all new. just wont spark!

Any help would be appreciated!! or if anyone is local to Midhurst, west sussex and happy to come look that would be great!

thanks
jeremy

[bigherb]

Where and how are you checking the voltage at the Hall sender?

[Oldiebut goodie]

Is this a case of using a digital meter when you should be using a moving coil one? Just my first thought - back to the petrol guys.

[bigherb]

Is this a case of using a digital meter when you should be using a moving coil one? Just my first thought

Your on the right track.

[mike9009]

Hi

What running problems are you having? My ignition amplifier recently failed. The symptoms we had were the van was just randomly cutting out. To begin with it would be random, but then became more frequent. Eventually I could only drive for about a mile before it would cut out. Once cut out I needed to leave it for about ten minutes or so before it would start again........

Simply change it (£30 from brickwerks) and I have done 120 miles to Weymouth and back without an issue......


Mike

[KittyCamper84]

Thanks for the replies! I tested the hall sensor by removing the dizzy and slowly turning it while measuring the signal voltage. As for the running, we were cruising at 65ish and it spluttered a few times and then cut out. It has got progressively worse since.

[bigherb]

Are you checking with the multimeter between the green wire to the distributor and earth with a digital multimeter?
The hall chip only goes to earth for a fraction of a second a digital meter is not fast enough to measure it correctly all it will do is try to average the voltage. You need to turn the distributor very very slowly until the voltage drops to zero and stop.
Like this. Click to play


If it doesn't drop to zero check the earth for the ignition amplifier is clean and tight on the engine block.

[KittyCamper84]

did a few more tests and found no answers. looked on ebay and bought a powerspark dizzy which gets rid of all the amplifier etc. only £60 and its set up for a dg engine!
thanks for all the help, ill get back to let you know if its fixed!

[ajsimmo]

That should fix it - have fitted powerspark dizzys on a few DGs and they run really well. Two points to note:
The two wires from the dizzy will be too short and need to be extended to reach the coil.
Be VERY careful not to reverse the connections, you will damage the dizzy instantly. Red to the +12v side (black wire on coil), black to the -ve side (green wire on coil).

[KittyCamper84]

All fitted up and no worries. Travelled around for a few days and we are away for the night tonight!! Seems sorted (touch wood!)

[Elsaetka]

Just as an aside to this post, the feedback in this thread regarding the Powerspark Distributor is very positive. I read another forum post about it which was more sceptical, however my inclination would be to go with this post's recommendation, as feedback is from members who have experience of the product. I have certainly never read a post from anyone having to take one back off.

The reason for my interest is because my 1990 DG has required a little re-wiring in the engine compartment, all age related. The connections for the oil pressure switch had corroded, as had the coil and starter connections. Al sorted and re-wired now however....

With the above in mind, I started to think about the Ignition Amp as that too is over 25 years old. I did not know about the Powerspark Distributor until this post came up in my research. My thoughts being, technology has advanced since the T25 was designed and the Powerspark does on the face of it look interesting. I notice they also say it improves MPG, which certainly isnt a bad thing.

Any thoughts would be of interest, plus:
.I note the very important point from ajsimmo regarding the wiring connections, I presume instructions are supplied with the kit. How do you line up the new distributer in terms of the rotational position, (Advance / Retard) does it lock at a particular point? i'm asuming it doesnt need timing up with a strobe?
.Are there any changes to the vacuum advance pipes? I have not had mine to bits for years so just can't remember.

Thanks

[itchyfeet]

yes a powerspark will need timing set with a strobe same as any dizzy.
Single vac connecion same as standard DG.
Personally I would not change unless you have problems.

[bigherb]

The Powerspark is an alternative when the distributor is worn but is not an improvement over the original electronic ignition which is better as it has variable dwell producing a better spark at starter cranking speeds. If the original distributor is working OK keep it as it is tuned to the power output of the engine.

[Elsaetka]

Thanks bigherb,that's exactly the type of feedback i was after. I am very much of the 'if it aint broke' mindset, while of course balancing that against keeping an eye on parts which are getting on, the wiring corrosion obviously concerned me hence my thoughts moved to the ignition amp.

The van actually runs perfectly fine, plenty of power and so smooth you can barely hear it ticking over to be honest. My only remaining concern is the emissions, as it just scraped through last year however it had been laid up for a long time.

I will stick to the origional system, my only other question would be, given the age, is it worth changing the amplifier or carrying a spare?

[itchyfeet]

what did it scrape emissions on? co or hc?