Jarcar fuel adjuster - some probs

[predator]

I know this may not be the best place (but where else?). Does anybody have a close up of their completed, and *working* Jaycar DFA from top ??

When I first built it, despite being fairly careful, I stuffed the polarity of a diode, which ended up blowing a transistor. Anyhow, so bought another of the same from jaycar, soldered it in, and still not getting any success. Key points I've measured with the multimeter - and getting voltages to various parts - but without a voltage diagram included, can't tell what the values should be in a working circuit.

The handcontroller backlight connects up, but i am just getting a sort of flashing effect, but no display on it. The LED on the DFA lights up and it "clicks" on. The controller is a lot simpler, so more convinced that the DFA is stuffed, rather than the controller (much simpler circuitry). Its a hard one, as its possible another component is stuffed internally, but how do I tell?

I've tried both a standalone 12V power supply.. (old PC powersupply) and connected to my car, and same result.

Whilst I have checked the schematic and my competed version 10 times and cannot spot any differences, an actual high res photo would help a lot, so I can pick off all the right parts and match to mine.

Checked all solders, redone a few that were maybe a bit sus. Don't really want to toss it in the bin without having even tried it Really do want to give it a try, as I'd save for a rb20det PFC, but in the end I am swapping to RB25 and would have to onsell it again to get the rb25 PFC.

Any help appreciated..

[xRHETTx]

Is the DFA the one where one of the links is shown is the incorrect position in the photo/on the PCB? Maybe it the IEBC, i made them at the same time and cant remember.

How do you tell? Go through with a multimeter and test every solder and link, and triple check everything else... good luck.

[predator]

mmm... but check what? lol.. I have checked the resistance across the resistors, that is all fine and easy to do.

Check the voltage values of the I/C's.. that would be nice, if I knew exactly how they worked or the exact voltage you should be seeing across each pin at a given point but I don't.

I went through the calibration procedure.. feed in 5v.. checking voltage across TP2.. checking output voltage while adjusting the variable resistors till it was 5V... Checked output signal... its outputting 5v. It seems to be "partly" working.

grunt

[RB30-POWER]

In the assembly instructions about 5 pages worth, there is a page that list voltages from various IC chips. It also shows where the IC's should have continuity (be joined).

Using that diagram is how i solved one of my problems which was an intermittent operation fault.

I found one of the links didnt have continuity, i checked the links after i didnt measure the correct voltage that the diagram showed.

I've just pulled out the instructions, the diagram you should be fault finding with is on Page 117.

Hope that helps.

[CEF11E]

my DFA works 100% i have installed and tested it here is a photo 4 u.

Just be patient. its a difficult project especially for a novice like me, but in the end you will get it working.

and the results will be well worth it.

[CEF11E]

Quick questions for those of you who have tuned you car with the DFA.

How long did it take you to tune it on the dyno?

did you do a power run, look at the AFR's and then tune in view mode? or did you tune on the fly? (this sounds scary to me)

did you disconnect the oxygen sensor while you were tuning?

[predator]

RB30-power: ok, have page 117. I will see if that can help

Thanks heaps CEF11E for the large photo, I will study that in detail.

Thanks for the help guys.. hopefully I find something.

It didn't seem too hard to assemble and the soldering, etc was fairly easy (have done a bit before) compared to some things, but obviously I have missed something small which is preventing it from working.

[MANWHORE]

That's what makes these things so annoying. It's the fact that one small component or link can be missing or in the wrong place which makes the whole thing not work.

I'm not saying that this is you Pred coz you have experience, but i noticed that in the Jaycar EBC and DFA thread, many people were jumping on the bandwagon because of the cheap and attractive price realising that they couldn't build one and get it working.

[xRHETTx]

They are really not that hard to make, as long as you are careful and check everything with the diagram etc.

That said, it is easy to stuff it up, especially the soldering, its quite fiddely. Go through all the solder joints with a multimeter checking for continuity. Anything on the same metal bit on the PCB should be joined together. I found one of my early solders didnt work (luckily i improved as i went along.)

[MANWHORE]

I don't mean that they're hard to make as such. Just follow the instructions and it's like baking a cake. EXCEPT, it is so easy for things to go wrong.

Solder Joints may look ok, but not contact well, wrong components, faulty components etc, components in the wrong place and many other examples.

I was just saying that it's fiddly and it's not as easy as it seems.

As an example, I have quite a bit of experience with electronics, and I made the jaycar ebc perfectly, but it did not work. Turned out the problem was I had used the wrong cable even though the plugs were the same.

[predator]

I have soldered a few things, ps2 chips, etc.. the soldering part isn't that hard part.. I even did first year electronics in Uni (fat lot of good that did though )

I checked all the voltages on the diagram and even they seem pretty much to spec, all resistors have been checked for resistance across each via multimeter. Have resoldered many connections.. The LED is lighting up. I am getting 5V at TP2 after adjusting the variable resistor, apply 5v at source, etc.

I'm half giving up diagnosing as I've spent hours on it.. and buying some replacement parts to try and swap in. First time I put it together, diode round the wrong way... popped a transisitor. Replaced that, and still no go - so must be something else, possibly inside one of the IC's has fried.

Thats a good point re the cable - I used the grey 25 pin cable provided from jaycar and that was recommended as part of the group buy.. Hope its the right one???

Now its really just pissing me off, and when something pisses me off enough I don't stop until I've beat it :Pimp2:

[xRHETTx]

Maybe if you can have someone else look at it? You know what they say about fresh eyes etc.. well i cant really remember but often if youve looked at something a million times you just miss things.

Maybe have another look at your handcontroller? If your pretty sure the DFA is right, perhaps your handcontroller is the problem? Maybe use someone elses handcontroller and see if it works.

[rob82]

I would try re-populating the board. If you've fryed the microcontroller then your stuffed, unless you can get the same controller with the correct program.