Hi, first post, hope you can help. So took my 1.6 diesel Octavia Mk 2 estate (60 reg) for annual service, full one. Day after service glo plug warning light comes on, goes into safety mode.  Turn engine off, starts ok, no warning light. After driving for half an hour, light on again, plus engine warning light. Took back to garage. Diagnostics suggest fuel pump issue. Garage tests car, conks out completely on short test run. Replaced fuel pump filter. All seems fine. Set off on long journey from Essex to Glos. After an hour, glo plug light comes on, goes into safety mode. Stop at services. Restarts, no light. An hour later, light on again. Drive very gingerly back next day, 150 miles, no light. Back to garage. Fuel pump very dirty with debris like sand apparently. Fits brand new fuel pump. Tests, all fine. Returned to me. First time I go to drive it, engine is totally dead as if immobiliser is on. (Didn't notice light at this point.) Turn off, lock with remote, unlock. Starts fine. Ten minutes into journey, glo plug light again. Pull into to return home, engine dies. Won't start as if immobiliser on (fires but immediately dies). Try six or seven times, finally starts. Limp home, no warning lights. Dropped back at garage.

Another symptom seems to be that when you take your foot OFF the gas, it slows much more quickly than you'd expect. I may be imagining this but I don't think so.

 

What the hell is going on? This has now being going on for three weeks. Any guidance I can give my garage as clearly the fuel pump wasn't the issue. Why would the immobiliser kick in if it's a fuel related issue? Some weird electric fault somewhere. Thanks sooo much for any suggestions. Cheers

Edited 9 February, 20179 yr by SimonCambridge

Sounds like at some point some dirty diesel was put in the car to cause sand like substance. Most likely when you filled up the fuel tank at the garage the fuel level was near the bottom and sucked up some rubbish. Garages tend not to bother with cleaning the fuel tanks as it is a costly exercise.

Regarding the immobilser issue. If you have had a new fuel pump fitted and it worked fine before it was fitted. Id say the issue is with the new fuel pump not supplying the engine with fuel. Take it back to the garage as there might be an install issue or a loose connection etc.

Thanks for your response. Yes, our only local petrol station is Tesco and I've heard some terrible things about their diesel not being up to scratch compared with BP or Shell's. Maybe that's the cause of the debris.

Just went to the garage, car wouldn't start at all this morning, seems like no fuel getting through at all today, just starter turning over but not firing, so yes my immobiliser thought is a red herring as you say. Just need to find out what the fuel pump issue is. It didn't work fine before the new pump, it worked fine before the service! So had another filter, then the whole new pump but symptoms persist as described. I can't imagine that anything they did during the service or MOT would set this off, could it?

The car needs scanning with VCDS to get the proper fault codes.

 

If your local garage is guessing or using a generic fault code reader he might find himself going around in circles - at your expenses.

 

Once you have the codes you can use this fault finder...

 

http://wiki.ross-tech.com/wiki/index.php/Category:Fault_Codes

Hi Silver (or is it Hi Ho Silver?), would a local service garage be likely to have VCDS? I don't know what that is?

 

VCDS is a fault code finder that used to be called VAG-COM and is bespoke for all VAG cars (Skoda, SEAT, VW & Audi etc.).

 

It is therefore generally found in most VAG specialists but all good independant garages will have it.

 

It is possible for private purchase too, a lot of members on here have it. Find someone close to you. The currency used is generally beer tokens...

 

 

Edited 9 February, 20179 yr by silver1011

OK. I have no idea whether he has this, I'll check obviously. But that's amazing that people are prepared to offer their scanning services to forum members. Thankyou!

Apparently the specialist auto electrician the garage uses has VAG COM so thanks for the heads up.

Well, we've now replaced the fuel pump relay which was apparently shorting after the pump replacement. So hopefully this will solve the whole issue. Just posting this in case other owners have similar issues. 

sounds promising.