molegti, Here is a simplified summary diagram that shows the relation, in terms of connectivity, between the Hall CPS -G28, Digifant ECU J169 and the T28a round connector. You can use this to help debug your CPS. I should add the earth from pin 3 ( "-ve") is also attached to the shielded cable that wraps pin 2 ("0" signal return) and pin 1 ("+ve" supply). This is better illustrated in tshirt2k's post 28 by the dotted lines around current track T3c/2 and 1 of G28.
Okay it's get frustrating I've unwrapped the loom and there's no damage to the crank sensor wiring. I've also wired up pins 1 and 23 on the ecu and confirmed the 12v at pin 67 so its been produced by the ecu and not a short in the loom. I've also pulled the ecu out of its case and there's no indication of any burned components. While I understand this doesn't mean it's good it's the same story on both ecus and it appears too functional to be broken. What's the normal symptoms of a failed ecu? Just a theory could this be the immobiliser. It just strikes me that the ecu making 67 high would be a fairly effective way of blocking spark and fuel. I understand it should let the engine run for a second but at what point does it reset?
Mole, have you hooked up a VCDS? It's three wires, an OBD plug, a $14 USB adapter and when we had this issue I wish this was first and not last on the list (Our SEAT ABF 95 was a lime green signal wire) Our ECU failure gave no indication that the ECU was bad. Continuity tests, voltage tests, undoing looms was all part of a wild goose chase, ultimately resolved by a new ECU/Immob/Ignition switch/Steeering column. RJ,Toyo,T-Shirt are here to bounce ideas and get a lot of awesome feedback, it would have been impossible without their help and I want to thank all the ClubGTI members for their help, but seriously, go straight for the jugulars and confirm your ECU is good to go by connecting the diags. I wasted 3 months of my life, hurt my back hunched over the engine bay and spent $$$ testing components when I should have accepted that the ECU comes before the engine. Unfortunately as Golf's weren't on my resume, I struggled and in hindsight executed diagnosis using the wrong method. If you are certain the crank sensor and coil are good, if the ecu and ignition system** good then it should at the very least spark. ** Note that with the ECU, the Immob, Keys, Steering column and Ignition Switch were also bundled as one package. Whether a fault may occur in these components that would prevent the ECU from signaling the coil the others may know. Just my 2c worth...
Thanks for the input vcds has been plugged in and the only fault codes I get are the crank sensor, which could just because its not running and engine start blocked by immobiliser on occasion. I have an immobiliser box and key which are matched and now 2 ecus which produce the same issue. I couldn't agree more on the feedback I've had and the reason I posted on this site rather than another one I'm a member of is due to the wealth of knowledge here. Most of the information I gleaned to do the conversion came from here and the reason I'd not posted before despite been registered a while is that I've never had to. The fact that 2 ecus will prime the fuel pump and talk to vcds makes me think there good despite what I'm seeing at pin 67. I could hold out for a matched set I suppose but they tend to attract a premium and a) im skint and b) megasquirt isn't that expensive.
if it was the immobiliser the car would still fire for a few seconds then cut out so would say it may be a faulty crank sensor, they can be faulty out of the box too, the one I bought from ebay was. the one I have now is from here: http://www.vwsonline.co.uk/car_parts_bristol/037-906-433a.html
I know its just the thought of spending money replacing parts I don't know are faulty. I know a faulty crank sensor is the usual suspect but it doesn't explain what I'm seeing at pin 67 which doesn't seem right. This suggests both ecus are faulty but then they'll both gladly talk to vagcom. I think I need to find an auto electrician who can verify the ecu. Oh and just to confirm I've verified that 33 is connected internally to 1 so there would be no need for a separate earth.
Update: in my vain attempt to avoid spending money I've tried a bit more testing. I'm starting to think this 12v at pin 67 is a red herring. If pin 2/ 67 is connected momentarily to earth the fuel pump runs, tap it replicating a running engine and the pump runs continuously. Seems we're falling edge triggered. However still no spark although I have verified the ignition wiring is right by unplugging the ecu and shorting pin 8 on the loom. It could be that my signal isn't good enough for the ecu but ill try and test the crank sensor tomorrow.
True but I'm too feeble to turn the engine over with the plugs in and I didn't have a thin wall socket to get them out.
It was the crank sensor who'd have thought it? None of the tests I did showed any difference between the good one and the bad one!
Yes thanks to all that helped. Proves rjs point that crank sensors can be busted out if the box and also the old adage buy cheap buy twice. Despite a flustrating few weeks I've learned an awful lot about the wiring for an abf conversion. Pretty sure I could do another loom with my eyes closed . I hope it doesn't put anyone off either the wiring really isn't that bad even into ce1 as it turns out my loom was fine straight away. Toyotecs guide is spot on so if the info provided by rubjonny.
