Ibiza Mk 4 cuts out when warm

[clive]

Old Today, 00
Hi, I've had no luck after trawling many threads in getting a fix to my problem. Ibiza Mk 4 July 2002 1.4S 16 valve BBZ 6L engine cuts out when warm. An afternoon of VAG diagnostics found no faults. Air leaks tested for as well as TBA cleaned, new fuel pump and filter, plugs, coils, etc etc. Compressions spot on and battery fine. Could it be the alternator which is showing below range?

Bit of history - never had this problem until I had a repair following water pump ceasing and causing timing belt to snap. New belt, valves and pump fitted and independently checked to confirm all ok. Piston rings fine. Engine runs great when driven in any gear and at all speeds. Just the cutting out problem persists. I wonder if the water pump ceasing and belt breaking could have caused any other damage unrelated to valves, pistons, etc that would not be spotted on VAG, e.g. Engine coolant sensor or anything that wouldn't show on diagnostics or show a false ok?

Seat master technician spent an afternoon finding nothing and checked for all possible air leaks. He wonders if it is fuel injectors as he knows this engine has a history of this problem. Proving to be a tricky and costly project. All suggestions welcome!

Clive
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[lil3520]

Only problem I had, it was difficult to start when engine was warm in the summer.

Andy

 

[mty12345]

Some sort of earthing or other electrical issue? Did they disconnect any wires when doing the belt etc etc.

 

[clive]

Hi Marty. I'll check with them. The car was parked up 3 months before the belt and pump were replaced so I wonder if that's why they are going down the fuel route and checking the injectors? I'm no mechanic, but I basically think along the lines is it mechanical, fuel or electrical? A lot of mechanical has been done and fuel pump and filter fitted so I was also wondering if it was electrical.
The diagnostics were done by a Seat master technician on a mate basis and could not find anything. Should he routinely check wires and earths? I do wonder if too much emphasis is put on the diagnostic equipment and some basics not done like testing fuel pressure or wiring ......
The car is cosmetically A1 and 60k genuine miles with no history of cutting out so I did wonder if leaving it parked up caused the stalling issue or, as you say, something was disconnected (or dislodged) during repair.
Final thing to add, when it cuts out it's as if I've switched off the ignition so there is no juddering, or noises, etc. When driving there are no misfires. It just stops and starts again when I use the ignition. Gets really tricky in traffic at junctions and busy roundabouts to the point that my wife won't drive it. I'm reluctant too, but on the motorway it's a dream. I haven't checked mpg since repair nor oil, but I will do before I commit to injector work or replacement. But the logic of everything I've said seems to support what you say so I'll chase that first. Does my update make you favour electrical over fuel or mechanical?

Clive

 

[mty12345]

Hi again clive.

Obviously it's pretty hard to say without actually seeing the car but the fact that it cuts out so suddenly and without any noises would definitely make me think that it's electrical rather than mechanical.

When it cuts out, do you still have electrical power to the dashboard/radio etc, or is the car completely dead?

Either way, the first thing i would do is remove the battery and follow the earth/negative cable from the battery back to where it joins the bodywork of the car. (on the leon it's under the battery tray itself, although i'm not sure about the ibiza) Often there is a build up of corrosion there and this has caused similar issues in other cars. Just cleaning the connection and reattaching it will usually cure it if that's the issue.

If you still have full electrical power to the rest of the car when the issue happens, then i would be thinking along the lines of maybe a earthing point for the injectors or part of the ignition system having not be reattached propery when they did the work.

Also i guess it could be something like the fuel pump relay starting to fail and maybe momentarily disconnecting the fuel pump as you are driving.

I'm not familiar with your paticular engine as i've only ever owned the 1.8T, however i know that most of the smaller engines have some sort of idle control valve. If it's only stalling when the rev's drop to idle, then i would also be looking at this system too

I hope that gives you a few points to consider.

P.s are they 100% sure that the timing is correct after the belt change? If the timing was one tooth out then i would take a guess that maybe it would run ok at higher revs but possibly struggle at idle etc.

 

[clive]

Thanks Marty, you were spot on! Problem was caused by faulty wire to cylinder one injector.

 

[clive]

Sorry, meant Matty

 

[clive]

Sorry, meant Matty

Sorry, meant Matty

Hi Marty
I now have a new problem so maybe you can help? On tickover, a cylinder 1 misfire occurs after 15 seconds. I cleared the fault and it misfired again after 15 seconds. I repeated this a number of times and every 15 seconds it misfired!

I uncoupled the egr valve and it doesn’t misfire. Could it be the egr or the injector or something else? Btw the barometric pressure is 25% above norm.

Thanks. Clive

 

[clive]

Hi again clive.

Obviously it's pretty hard to say without actually seeing the car but the fact that it cuts out so suddenly and without any noises would definitely make me think that it's electrical rather than mechanical.

When it cuts out, do you still have electrical power to the dashboard/radio etc, or is the car completely dead?

Either way, the first thing i would do is remove the battery and follow the earth/negative cable from the battery back to where it joins the bodywork of the car. (on the leon it's under the battery tray itself, although i'm not sure about the ibiza) Often there is a build up of corrosion there and this has caused similar issues in other cars. Just cleaning the connection and reattaching it will usually cure it if that's the issue.

If you still have full electrical power to the rest of the car when the issue happens, then i would be thinking along the lines of maybe a earthing point for the injectors or part of the ignition system having not be reattached propery when they did the work.

Also i guess it could be something like the fuel pump relay starting to fail and maybe momentarily disconnecting the fuel pump as you are driving.

I'm not familiar with your paticular engine as i've only ever owned the 1.8T, however i know that most of the smaller engines have some sort of idle control valve. If it's only stalling when the rev's drop to idle, then i would also be looking at this system too

I hope that gives you a few points to consider.

P.s are they 100% sure that the timing is correct after the belt change? If the timing was one tooth out then i would take a guess that maybe it would run ok at higher revs but possibly struggle at idle etc.

Hi Marty
I now have a new problem so maybe you can help? On tickover, a cylinder 1 misfire occurs after 15 seconds. I cleared the fault and it misfired again after 15 seconds. I repeated this a number of times and every 15 seconds it misfired!

I uncoupled the egr valve and it doesn’t misfire. Could it be the egr or the injector or something else? Btw the barometric pressure is 25% above norm.

Thanks. Clive

Hi Matty

Yet another problem. Head gasket blew and car was parked up a few months before it was repaired. It just won’t start. It’s getting sparks from the plugs. Fuel also. Disconnect the injectors and occasionally it fires as it uses the fuel left. Connect the injectors and it gets nowhere near starting. Could there be too much petrol flooding it due to incorrect fuel pressure? Or coolant temperature sensor fault? Dirty egr valve? Nothing showing up on VAGcom except when injectors disconnected.

Clive

 

[clive]

Thanks Marty, you were spot on! Problem was caused by faulty wire to cylinder one injector.

Hi Matty. I’m having the cutting out problem again. My mate had a look and said map reading was 34 kPa when driving but shoots up to 68 kPa when slowing down and reaching 1000-1200 rpm. Once below 1000rpm it cuts out. Does the increase kPa when slowing down mean anything to you? Thanks.
Clive