pulse measuring to time diesel pump

[photoman290]

i have just changed the IP pump on the bus. all seems to be working well. i have no way of telling if the timing is right as the usual method won't work because i don't have enough info. there should be a number on the pump giving the off set for a dial gauge. this is missing on my pump. the only way to check the timing is to detect the pulse when the injector closes. you can buy kit to do this but it looks pretty simple to reproduce using a piezo mic and a  pre amp. i am ok on that part. i am not  sure about amplifying the signal enough for an inductive timing strobe to  pick up the pulse. any one got any ideas. i could buy one,but would rather try building my own just for the hell of it. the strobes i have used in the past plug into a plug lead so never used the inductive type.

[Julian]

I may be talking out of my backside here ... I usually do, but there are quite a few examples on the web of building a strobe using an Arduino.  Most seem to have a variable frequency and some a variable duration.

I'm far from an expert, but I'd have thought it wouldn't be too difficult to re-code so the lamp is triggered by an input signal.  Most of the samples I looked at just use standard LEDs but again with modification/extra components (SSR?) I'd have thought you could drive alternative lamps.

[photoman290]

good idea, i hadn't thought of modifying a strobe. i can buy the piezo sensor which is the hard part, as a spare from the states. 41 beer tokens. which makes it viable. can check the output with the scope and work from there.

[Julian]

$41 is expensive in my world!  Would these be suitable?  They are a lot cheaper ...


https://www.sparkfun.com/products/9196

https://www.sparkfun.com/products/9199

https://www.sparkfun.com/products/10293

[photoman290]

i have checked  that idea. according to the patent the problem is getting a good clean signal. the design of the the holder for the piezo transducer is pretty important so you get  just the pulse and not a lot of other noise from the engine. i have looked at guitar pick up designs as well. by the time you have made a suitable holder and got a clean signal you could easily have spent the 41 quid.remember the off the shelf one with the strobe is around 130 notes so if i can do the lot for half that i will be happy. of course finding someone with one i could borrow would be a better option. the bus works at the moment so as long as it doesn't overheat i am happy. just like to know if the timing is right as without the timing offset there is no other way to tell. plus if it works it could be a useful resource for other forum members with old purely mechanical pumps.
patent no is here at the bottom of the page.
http://tinytach.com/timing_specs.php

[Julian]

I guess you're right ... that's the difference between looking at things logically and being an out and out cheapskate!