Hi team, I converted my 87 16V GTI from the factory KR with K-Jet to a ABF 2.0 with the MK3 Management. Sacrilege.... maybe? However I wanted a car I could jump in turn the key and drive even if it had sat for a year. and the Kjet was becoming painful to keep in good nick I completed this back in 2012 and have relatively trouble free motoring apart from a freak incident in 2013 when a road sign fell off a works truck and subsequently snapped my Accessory belt and in turn destroyed my Cambelt. all this aside, A new head went on and we carried on with trouble free motoring up until recently. The car has developed a very strange issue which so far has only occurred when its warm. but more often then not it will not happen at all. However it is dangerous as all hell if you are trying to pull out in to a flow of traffic it has caught me out twice. When running sometimes the engine decides that its Revlimiter is now 2000rpm at least thats what it feels like, A quick cycle of the key it momentarily corrects itself and then it craps out again, If you persist driving at under 2000rpm for a short time, it then reverts to normal. I am pulling my hair out, I have even held the revs down and grabbed various parts of the loom and manipulated them to see if I could induce the issue. I have replaced the following - Ignition Coil - Brand New - Crank Angle Sensor - Brand New I have had the ECU checked over and had capacitors replaced and dry solder joints repaired. - No Change I have tested the car without the Hall Sender Connected and with the Hall Sender connected - No discernable difference, issue has happened with and without. I have attached two short videos of what has happened. https://youtube.com/shorts/f9tqISqiOX4?feature=share https://youtube.com/shorts/iGmDz32gxPg?feature=share The other notable symptom is if you are exceeding 2000rpm and this issue happens if physically feels like the car trying to pull itself back under 2000rpm, it goes completely Limp! If there is something I am missing, I will welcome a nudge in the right direction. PS I am aware I haven't checked the distributor yet. Not a clue in the world where I can even find a replacement, no local VW shops can get spares for ABFs.
first thing pull the wiring round the back of the inlet to TPS and idle switch, strip all the tape off. if this has never been looked at its likely all split and shorting out. while there bin off the 2 pin plug for the breather heater with the black and brown wires. Another thing it could be is intermittent connection on the fuel pump(s) power or a partially blocked filter perhaps, can you listen with your head out the window next time it happens see if the pump makes any weird noises (or non at all) mine did similar when the fuel pump fuse had burned out the socket due to water damage I also had a similar fault with a faulty ecu temp sensor though it wasnt quite the same, as if I held the throttle it wouldrev up eventually then it would clear around 4k. it got worse and worse though eventually once it happened any attempt to open the throttle would make it stall. At first I did have the exact same symptom though if you cycle the ignition it would fix itself, right up to the end where even that stopped working and the car wouldnt start at all when it felt like playing up anothe rthing you can try though unplug the lambda sensor see if that makes any difference, same for idle switch and inlet air temp sensor
Thank you for the reply Mr Jonny I will investigate your suggestions further! i'm pretty sure the fuel pump is okay. the relay doesn't appear to be clicking and the fuel pump is one from a Mk3 in a Mk3 tank however worst case I suppose i can jury rig some kind of test light to show me the current state of the power feed!
Had similar issue, the pump was working fine but sometimes it wouldn't want to rev past 4k on the highway and 2k rpm if I smash the pedal, turns out it was the fuel pump not giving enough fuel for the engine.
Long shot maybe but my wifes Arosa sometimes cut out during acceleration (just for a moment). At some point it started doing it more often and longer, turns out it was the cranksensor...
Well managed to induce the issue again this morning, after sitting in traffic idling for quite sometime, I noticed the Throttle was very lethargic. I listened out for Relays/Fuel pump, No clicking and the Fuel pump tone was constant, So as soon as I get a moment I will investigate jonny's suggestions and perhaps do a new fuel filter.
A 2000 rpm rev limit, is an indication of a fault managed by the ECU. Please run a scan on the ECU and report what you find. Thanks.
Hey Toyotec, That was one of the first things I had actually done, which led me to sending the ECU off to the PCB Repair shop. VCDS (I have a legitimate one) only ever registered one fault and it was the G145 from when I tried testing the car with the Hall Sender Disconnected. No other faults. not a single one. Which I thought was odd, as I thought the Digifant 3.2 was one of those ECUs that would throw a fault if you scanned it while the engine wasn't running. but perhaps I was getting it mixed up with the behaviour of the MK3 VR6 Engine Management system.
