Octavia Mk II MPI ....intermittent start / stall problem

[Rudi]

So this is a problem that I have literally had for years, although for the last 12 months or so the problem has been more frequent to the point where I am reluctant to use the car. 

 

VEHICLE:  Skoda Octavia MkII, 1.6 MPI (BSE engine)  2011 reg, just under 40K miles done.

 

SYMPTOMS:

 

- Intermittently, the car won't start. The starter motor turns over very merrily, but there is no suggestion that the car is ever going to 'catch' and fire up. If I turn over on the starter motor for long enough (10-15 seconds?) the starter cuts out anyway (that might be normal?).

 

- The problem usually appears from time-to-time when the engine is warm, but I have also had the same symptoms with an attempted cold start (see below).  If I wait - anything between say 5 to 20 minutes - it will decide to start again.

 

- When driving along, the engine may cut out/die, usually at low revs. Then it will refuse to start, as above.

 

- After starting from cold and warming up, I am aware of a slightly rough idle, but it is pretty mild and might just be how this MPI engine idles? Idle is just over 700 rpm when warm, a little faster (and not remotely rough) when cold.

WHAT I HAVE ALREADY DONE:

 

- Taken it on several long runs on motorways. Last one was around 120 miles doing 70 mph for long stretches. On return to my house, the car was running fine. Next morning I drove to a supermarket (10 min journey) and when I had finished shopping (about another 20 mins) it refused to start, as described above. Finally got it going 15 mins later.

 

- Bought a VAG/Audi/OBDII code reader. There were some error codes relating to a lambda sensor.

 

- Took it to my local garage for service/MOT. Told mechanic about the lambda sensor code. Passed MOT, no emissions problems (and, inevitably, it didn't break down all the time it was with the garage). The mechanic couldn't find any other error codes when he hooked the car up. Cleared codes and service light. (The car has now passed three MOTs with this fault not emerging at the time (Sod's law!) nor having an impact on emissions, etc).

 

- Checked the air intakes, and the throttle body. All clear. Air filter was replaced at last service, but these problems were apparent well before that.

 

- Removed and checked (visually) the air intake manifold pressure sensor / air temp sender - looked all very clean and clear.

 

- I have put throttle/carb cleaner spray into the throttle inlet (engine running) on two occasions - used a full can each time; no effect on the fault. Throttle butterfly and chamber look very clean.

 

- Replaced the crankshaft sensor (because it was relatively easy) - no effect. No error codes and no service light on the dash. But the car still intermittently dies / won't start. 

 

Today was typical: took it for a run this morning, did around 6-7 miles without any issues. Got home. Let the car idle for about ten minutes, until the cooling fan came on. Then turned off ignition and re-started it three times without any problem. This afternoon (ie, about 3 hours later, engine cold) went to drive the car again - it wouldn't start (usual symptoms, as described above). Took about 5 mins before it would start, drove it about a mile and a half and it died on me. Then took about ten minutes before I could get it started. Got home, parked up and turned ignition off. Restarted the car three times without issue... Checked for fault codes: absolutely none. No warning/service lights.

 

The garage advised me to run the car until whatever is wrong 'properly breaks' but that just isn't happening, and it isn't practical to use such an unreliable car on a daily basis...

 

Thoughts, anyone....? I'd be very appreciative of any insight, especially if anyone has had similar issues.

 

[Rudi]

Anyone.....?     🙏

[SilverRoomster]

Same sort of problem on our Skoda Roomster - have a look on all the subjects on the forum about intermittent starting problems which I've found helpful.  

[bigjohn]

Lift pump in fuel tank?

 

[stevenc]

I had a similar problem with intermittent starting.  I replaced the main relay in ignition circuit and have not had the problem since.

[Rudi]

Thanks for the responses. Since I first posted, I have (on the advice of a friend) disconnected the battery for almost 48 h. Reconnected it, took it for a run and after ca. 3 miles the car died and wouldn't start, although on this occasion it only took about five minutes before it decided it would start again (whereupon I drove it home - about a half mile - parked it on the drive, stopped it, and restarted it again three times with no problem). Still no error lights or codes. So basically no further forward.   

  

There seems to be 101 different possible explanations, and without any error codes or 'terminal' breakdowns to work on it seems like it's all really guesswork, so I'm trying to nail the most likely (or easiest/cheapest to fix) causes first. So.....

@stevenc : according to workshop-manuals.com, I've got four relays in the engine bay fuse and relay box but a search for the position of the "main relay in the ignition circuit" doesn't throw up any info. Don't suppose you recall where the one you replaced was..?   Cheers. 

[rojbe]

Hi Rudi,
Although your issue is not identical to what I had, there are quite a few similarities.
See:

Let me know if you need more specific information.
rojbe

[Rudi]

Thanks, rojbe.  I think the biggest difference is that my MPI 'usually' starts from cold OK (but, admittedly, not always...) and the problems of slightly rough idle, engine dying, and difficulty re-starting, generally appear when the engine is up to normal running temperature. But I did wonder about the pre-cat lambda sensor because that was the only error code apparent when this problem first started (the mechanics wiped the code and it hasn't reappeared, but then again there are no other codes appearing either...). Thanks for your input!

[rojbe]

My MPI started fine from cold if it had reached full temperature(needed margin) before shutting down the previous time. If it just reached nominal working temperature(without margin) it was more difficult.

Worst was doing short trips a few minutes after leaving it for an hour or two of cooling down. (Grocery store)

 

When starting from cold it normally ran fine the first minutes, and later on when starting to get warm, the engine ran less smooth. But it never stopped when running for me.

Worth noting regarding error codes: I had quite a few error codes about Running Rich and Running Lean, but engine lamp only lit twice or so during 500 km driving with this issue. 

[stevenc]

On 19/10/2021 at 13:12, Rudi said:

Thanks for the responses. Since I first posted, I have (on the advice of a friend) disconnected the battery for almost 48 h. Reconnected it, took it for a run and after ca. 3 miles the car died and wouldn't start, although on this occasion it only took about five minutes before it decided it would start again (whereupon I drove it home - about a half mile - parked it on the drive, stopped it, and restarted it again three times with no problem). Still no error lights or codes. So basically no further forward.   

  

There seems to be 101 different possible explanations, and without any error codes or 'terminal' breakdowns to work on it seems like it's all really guesswork, so I'm trying to nail the most likely (or easiest/cheapest to fix) causes first. So.....

@stevenc : according to workshop-manuals.com, I've got four relays in the engine bay fuse and relay box but a search for the position of the "main relay in the ignition circuit" doesn't throw up any info. Don't suppose you recall where the one you replaced was..?   Cheers. 

In the following photo its the one with 100 written on it.  This is inside the box to the right of the engine.

 

[Rudi]

Thanks stevenc, much appreciated.

[Looby2411]

Mine is doing exactly the same (probably 18 months) , and is now driving me bonkers as it happens weekly - I am starting to blame the new E10 fuel as it has got worse since using this fuel. 

Over the last few days, the car has developed a new intermittent fault of over revving whilst driving - then appearing to go into limp mode but not actually stalling. The usual problem is the intermittent starting/not starting. It the car doesnt start, I usually have to leave it 10-20 minutes for it to spring back to life (did this last Thursday) - it then tends to give me a week to ten days of trouble free driving, although the last couple of days I have experienced the weird over revving, limp mode feeling whilst driving - if it does cut out whilst driving it has started straight away. You can then throw the enging just cutting out when parked (usually when I am waiting to collect the daughter from school) and after a lot of patience can usually get the car started again.
I work at a SKoda garage, so have had the car on the computer on more than one occassion after the above has occurred and the car just isnt bringing up any faults!! We have changed the fuel sensor relay - but now dont know what to try next! Any ideas/feedback would be appreciated.

[Rudi]

@Looby2411: this sounds similar, if not quite identical, to the problem for me about a year ago. It has since become more frequent to the point where the car is undriveable.  Interestingly, I have only noticed the over-revving when I have warmed the engine up on the driveway and then tried to hold the revs at about 2,000 rpm. With the pedal perfectly still, the revs climb to between 4,000 and 5,000 rpm for no apparent reason. Inevitably, it doesn't do this consistently though. Unfortunately, if your MPI follows my one, your problem will only get worse 😞. What's the mileage on your Octavia? 

Edited 28 October, 2021 by Rudi

[Looby2411]

@Rudi Its all very strange, and baffling as the guys at work cant even figure out the fault. I am now of the opinion that I will just drive it until it gives up completely, as I am not too sure what else to do - as this is the only thing wrong with the car I begrudge getting a new one. Mileage is approx 63500. I will not be beaten on my quest to find the fault, so fingers crossed  we can figure it out lol  

[Looby2411]

@RudiWell the saga continues, since Saturday the car has failed to start 4 times (the last time being this morning). I had taken the hubby to work, came home and parked up. Twenty minutes later come to start the car to take the daughter to school and the car wont start.  I have had to leave it today as I needed to get the daughter to school and me to work - thankfully we have another vehicle (VW T5) so today I am a white van lady lol 

 

What we have noticed that when we unlock the car and open the door, we dont always hear the fuel pump priming. When it doesnt prime the car doesnt start - usually starts after 10-15 minutes, today I just didnt have time to wait and see

 

One of the Technicians at work did witness all the non start nonsense the other evening, when I was stuck at work for 15 minutes and thinks it maybe fuel pump - but as the car isnt reading a fault its a complete guessing game. Thankfully work lent me a car for the evening Karoq DSG and I felt a little spoilt 

 

Hubby is trying something at the weekend to test whether it is the fuel pump, so will report back. 

 

 

[Rudi]

Thanks for the update @Looby2411 - listening for the pump priming isn't something I'd thought to do. Not sure if I'm putting 2 and 2 together and making 5, but I've just recalled that I there was a smell of petrol that I pointed out to Skoda about five years ago and they replaced the fuel filter, but I'm now wondering if if was symptomatic of something more fundamental with the fuel system, as the troubles started (very, very intermittently) around that time....  I also note @bigjohn's comment above. I'll have a go at 'listening' for the pump over the weekend and report back.

 

[Looby2411]

@Rudi yes keep a listen out, you should hear it prime when you open the driver door. If mine doesnt make a noise or the noise is really faint, I know I am going to struggle starting it - if not that day a few days later. Fingers crossed we figure it out, as I really do like my car apart from this annoying issue  

[stevenc]

Just out of interest is your power steering on when you are  unable to start the car?   This was one of the wierd side effects of the intermittent starting problems I had.

 

When I mentioned it on here a while ago I was told that this was impossible - the engine had to be running for the power steering to be on. But it was one of the symptoms I was experiencing.

[Rudi]

10 hours ago, stevenc said:

Just out of interest is your power steering on when you are  unable to start the car?   This was one of the wierd side effects of the intermittent starting problems I had.

 

When I mentioned it on here a while ago I was told that this was impossible - the engine had to be running for the power steering to be on. But it was one of the symptoms I was experiencing.

 

I'm sadly old enough to remember when power steering was a mechanical/hydraulic process so the engine had to be running for it to work, but these days I think modern cars use an electronic system? If the power steering is faulty I think that would only become apparent (on the dashboard) after the engine had started and the steering wheel symbol stays illuminated, but I'm not sure if we can therefore conclude that the power steering is 'off' until the engine is started. But certainly, when my car stalls the steering becomes really heavy immediately, which implies there's no power getting to the power steering module when the engine isn't running, even if the ignition is on.

Edited 5 November, 2021 by Rudi

[Looby2411]

14 hours ago, stevenc said:

Just out of interest is your power steering on when you are  unable to start the car?   This was one of the wierd side effects of the intermittent starting problems I had.

 

When I mentioned it on here a while ago I was told that this was impossible - the engine had to be running for the power steering to be on. But it was one of the symptoms I was experiencing.

@stevenc i havent noticed, but dont think so no - sorry 

 

[Rudi]

On 04/11/2021 at 15:46, Looby2411 said:

@Rudi yes keep a listen out, you should hear it prime when you open the driver door. If mine doesnt make a noise or the noise is really faint, I know I am going to struggle starting it - if not that day a few days later. Fingers crossed we figure it out, as I really do like my car apart from this annoying issue  

So... not long after your post @Looby2411 I unlocked the car with my key fob and then opened the driver's door and listened. Perfectly audible zzzzzzz-ing came from somewhere near the rear wheel arch, lasted maybe 3 seconds then stopped. Is that the fuel pump priming? Car started fine. Ran it round the block a couple of times (= maybe 1.5 miles) parked up in the drive, stopped the engine, got out, locked the door via key fob, waited a minute or so, then unlocked, and opened drivers door again. No zzzzz-ing, but car started fine. Suspect the pump, having primed the fuel line once, didn't need to do it again so soon after a short run. Tried again after a couple of hours and still no zzzzzz noise, and still car started OK.

 

The car then hasn't turned a wheel for almost two weeks, so I repeated the same experiment today: got the zzzzzz-ing noise first time around, ran the car round the block a few times (= 3 miles-ish) until it had warmed up, stopped, got out, locked door, waited a few mins then reopened. No zzzzzzz noise, but car started OK again. During the 3 mile run the car seemed, as usual, to lose it's initial willingess to accelerate 'briskly' and I am sure had I carried on it would eventually have cut out, again, as usual. Went back to the car 15 mins later: no zzzzzz noise but started fine. So I think all this rules out for me is any problem with the fuel line priming function, which only seems necessary after prolonged inactivity anyway...? 😐

[AnnoyingPentium]

8 hours ago, Rudi said:

Is that the fuel pump priming?

 

I think so. My Mk1 Fabia does the same thing when the door is opened, but only the once.

[Looby2411]

@Rudi , we have noted that the pump wont always make the noise as its already primed, especially when using the car within quick sucession of each journey. I have however added a new fuel pump and filter, and it does seem to run slightly better - doesnt feel as juddery and the tick over has been better, but we still havent recitifed the issue. The car has not started twice over the weekend, and the fault computer has brought nothing up. The problem seems to be that when the car has reached temperature we are unable to start it until it has cooled down slightly. Or once it reaches temperature, it will just cut out on me. I Only nipped to my local Tesco saturday evening,  - came to go back home, and it wouldnt start. Went for another wander round tesco (10 mins) and it started. Only used it twice since, and it started fine, but the car hasnt been up to temperature

 

I have the number for a local VW, Audi, Skoda, Seat speciailist so going to give them a call and see whether they have experience this issue before in any of the VW Group vehicles

 

 

 

[Rudi]

1 hour ago, Looby2411 said:

@Rudi , we have noted that the pump wont always make the noise as its already primed, especially when using the car within quick sucession of each journey. I have however added a new fuel pump and filter, and it does seem to run slightly better - doesnt feel as juddery and the tick over has been better, but we still havent recitifed the issue. The car has not started twice over the weekend, and the fault computer has brought nothing up. The problem seems to be that when the car has reached temperature we are unable to start it until it has cooled down slightly. Or once it reaches temperature, it will just cut out on me. I Only nipped to my local Tesco saturday evening,  - came to go back home, and it wouldnt start. Went for another wander round tesco (10 mins) and it started. Only used it twice since, and it started fine, but the car hasnt been up to temperature

 

I have the number for a local VW, Audi, Skoda, Seat speciailist so going to give them a call and see whether they have experience this issue before in any of the VW Group vehicles

 

 

@Looby2411 That warm-up dependent stall / non-start is *very* reminiscent of what I get (except I go to Sainsbury's... 😉 ). Short runs, just enough to get up to temperature... park up at supermarket, re-emerge 10-20 mins later: won't start... Give it another 15-30 minutes: starts OK. Drive it (from cold) more that 15-20 minutes...car stalls and then won't start. The only thing is, this isn't 100% reproducible: it has failed to start when completely cold (once) and a couple of times the car has restarted merely 5 minutes after stalling. But in general, it really does sound like we are both dealing with the same problem...

 

[Looby2411]

@RudiI really do think we are, I think I have also had one cold non start - but 98% of the time the car has been used and has been at temp for a period of time when it has not started. We are unplugging the temp sensor tonight to see what happens - I will let you know how we get on