Sounds about right! :(

When I was reading your original post it made me think fuel pressure. I had a crappy adj fuel pressure reg on my 940 and that would make the car hesitate when accelerating at certain revs. It would also run ok at high revs as i guess it was injecting alot more fuel although it still would of been lean.

When i say it was hesitant, i was almost like the car was getting blown by strong really quick gusts of wind from the front. like it was accelerating ooo errr ooo errr ooo errr!! (this probably makes absolute no sense!)

At idle it could be very fussy. Shutting the bonnet would sometimes make is want to stale!

I would get a second hand fuel pressure reg and bang that on, you might get for free or you could get a lend of one maybe if you ask on here.

Joe

Gadget
 

The detector system to plug into the not-quite-OBD2 port is built. It does nothing. Nothing at all. Next step, test the tester...

At the risk of sounding patronising, you haven't fitted the LED the wrong way round have you?

Other things to check are for very tiny "hairs" of solder where they shouldn't be, for example between tracks on the board, the pins on the plug etc and for any broken or incorrectly connected wires. A common mistake when connecting to a multiplug from a diagram is to connect the wires as viewed from the "plug" side, not as they should be from the "wire" side. When i say common, a neighbour renewed the 7-pin trailer plug on his trailer recently and couldn't understand why it wasn't working correctly. Didn't take long to sort out for him but his head was red-raw from scratching!

Good points - but
 

I was planning on checking all three of those things. I think I have the LED the right way round - leg by the flat on the side being +. I don't think I have any spare whiskers (except my beard) - but will check again, not much spare room inside an OBD plug. I connected to the points indicated by tiny numbers on the PCB inside the OBD plug since the ready-connected ones had sold out. I had to get a magnifying glass to read teh little bathmats!

I think first step will be to put 12 volts directly onto the LED. Next step will be point-to-point checking with a multimeter.

But I am supposed to be working.

Please read before putting 12V on the LED!!!!!
 

Firstly, you have the LED the wrong way round - the flat on the body denotes the cathode or negative terminal. The easy way to remember it is if you hold the LED up to the light, the "small" part of the metalwork inside is the +ve/anode and the large bit is the -ve/cathode which is always next to the flat. I said it was easy to remember, if you look at the electrical symbol for an LED, the bar is the cathode so the larger piece of metal inside represents a barrier to be overcome.

It sounds as if the plug could be a trouble-spot but turn the LED round first. On NO ACCOUNT feed it directly with 12V unless you want a cremated LED! Unless you specifically buoght a 12V LED and are not using the current limiting resistor (1k8 in the diagram, seem to recall you're using 1k5?) then you will fry it as most standard LEDs operate on about 2.0V forward voltage (Vf). That said, you could reduce the 1k5 resistor to 680 ohms to gain extra brightness on the LED.

As for work, it is a 4-letter word no longer in polite use! ;) :D

12v
 

It's a 12V LED. Damn you Mr Google for giving me the wrong info on polarity!

Ah!
 

It might very well NOT be a 12 V LED although I thought it was. So it is probably toast by now, having been exposed to 12 volts backwards.

Ordering a 12 volt one NOW.

However, it turns out a mate of mine has one of the £2000 Volvo code readers and he is getting the screen repaired next week - so he may be able to read the codes for me.

Oops! Considering the cost of LEDs i normally order several at a time, unless i'm ordering a specific LED for a one-off job.
Hopefully the new LED(s) will arrive fairly quickly for you!

Quicker
 

It will be quicker for me to drive to Maplins while on errands tomorrow and save their exorbitant postage charges.