Digifant 1 Fuel Pump Relay Earth Signal Issue

Yeah I got the original Bosch PN coil on eBay in the post the replacement I got sent was Intermotor and if you were to judge a book by it’s cover... using NGK BP6ET plugs as they are in the manual...they’ve been sooted over a few times now with all this testing Will give the whole system another check over

out of interest what kind of voltage should I be reading at the o2 heater + feed? And across the terminals. I have continuity on the signal wire but not sure if I checked the heater element feed...

 

Great I’ll check for 12v, cheers honestly most of the symptoms point to o2 sensor but the original and the new (aftermarket splice wired) one have the same warm stalling issue.

 

So that’s all good, new coil on and no different, the one thing I hadn’t tested was running it with the CTS unplugged, which has stopped it from over fuelling. I can now get to 80 degrees and it stays in cold start enrichment mode and doesn’t stall.

The CTS itself is a new VW genuine part. The problem I seem to have now is when it signals the ecu that it is all at running temp, it opens the injectors for too long.

I checked the terminals of the CTS connector and getting a stable 5v across all temp ranges.

My thought is to replace all of the ratty wires underneath where the black o2 sensor signal / earth and ecu earth connect. I had tested these wires but looks like despite this and visual checks they may need replacing and re soldering.

Any thoughts on this?? So close now! Thank you so much for your continued help and advice this thread has been an absolute lifesaver and a well or information

 

Co pot was a good shout, I did check it just in terms of power to it and a snug fit / no air leaks and gave it a clean with electric clean spray, and it made no difference. Also saw the eye watering price of a new unit - £272! FML.

Anyway I’ve found the problem now! And it was entirely my bad.

When wiring in my AFR (which never worked and now I know why) in the middle of the night trying to get everything done quickly I cut into the signal wire on the harness side of the connector - not realising that it was a shielded signal cable with an earth around it. They were so green that I had to put new wire in and when I did I just spliced them all together. So, my rich mixture was due to the signal wire picking up earth.

I feel relieved and a bit silly but I have noted that I’m not the only one who has done this so that’s something. The wires are all repaired and all is good and she ran to warm and sat at a nice stoich with no roughness at all. Did this all this morning but a road test after work will be the fun part !!

many thanks for your help and this site has got so much good info on that I’m sure I’ll be back