Link to video:

 

I drove for 45 minutes with no problems, then stopped, turned off the car and when I tried to turn it on again it did like this. Outside temperature around 6 C, dry weather. Replacing the coolant temperature sensor does not make any difference. On the video I didn't touch the throttle, but if I keep the gas pedal half way down, it'll die while revving up more then on the video. If I have full throttle while turning the key it'll rev to max before dying. So for a few hundreds of a second the car gets fuel and ignites, but the it's like the ECU says NO MORE FOR YOU and kills it.

 

Twice before it has happened and letting it rest for >3 hours fixed the problem those two times. Now I've let the car rest for >4 hours.

 

Please help.

Edited 9 March, 201610 yr by Ludds

Welcome to the forum!

The video doesn't help much. You took the time to blur the registration number of the car in front, but the audio is very poor.

There are many things that could go wrong. Fuel related (pump, filter, injectors), ignition related, immobiliser related, etc. My question is; other than trying to start the car, what did you test? You have full access to the car. We are not wizards to tell you exactly what is wrong. We can only guess and make a list in order of failure probability. What will you do then? Buy parts till the problem is solved? If you want to repair the car yourself, you must have basic engine testing knowledge, a decent set of tools, a VAG-COM scanner, and a service manual.

I've replaced the coolant temperature sensor with a new one, but that didn't do any difference. I've looked for broken hoses and I've checked the air filter. I've also tried to push start the car. A diagnostics tool is on it's way from ebay. What confuses me most is that the two previous times when this happened, the problem disappeared by just having the car rest for some hours. Imagine a normal start sound, but when you see the tachometer start turning down, the motor shuts off.

 

Regarding the blurring, I would want someone else to to it to my car and it takes approx 20 seconds to do it. Being new to the forum doesn't mean that I'm new to the internet. And regarding the "what will you do then", what would you do?

 

Thanks

When you turn the ignition key to on, you should hear the buzzing of the fuel pump inside the tank for 2-3 seconds. If that doesn't happen, the fuel pump is dead / dying.

 

One other thing you could do to confirm a fuel related problem is to uncover the throttle body, spray some carb cleaner or similar in it for 1-2 seconds then immediately try starting the car.

 

If that doesn't start the engine for longer than before, you need further digging. We'll get it from there. How many miles has your car?

 

Being new to the forum doesn't mean that I'm new to the internet.

Then I guess you know that the most annoying thing on YouTube is watching videos took with the phone held vertically like for a selfie. Our PC monitors and our TVs have landscape format screens. Just my 2 internet cents.

Thanks for your prompt reply. The car has around 146000 km (~90700 miles). There's a buzzing sound for 2-3 seconds when I turn the ignition on, just as you say. The sound goes off when the airbag lamp is turned off. I'll try to get some carb cleaner today. If the car starts before I've done anything (haven't tried to start it today), is there anything I should check before turning it off then?

 

Best regards

Intermittent failures are the hardest to diagnose. It is very possible the car will start before doing anything. That would bring us to square one in terms of diagnosis. You can't do much if the car is running well. The condition your engine has is called "intermittent no-start when the engine is warm". From your description it looks the next on the list is an immobilizer issue. But for now, let's hope the car will not start without doing anything. If it starts, all you can do is to have the carb cleaner handy for the next time.

Guess what? The car started today before I did anything to it. When it started, the idle was bad and the tachometer was at 900 +- 200 revs. After driving it 5 metres, the idle went stable on 700 rpm. I turned it off and on and it worked fine. While it was running I looked under the car and saw some exhausts coming out from what I think is a loose connection in the first bend on the exhaust pipe. I believe it's after the lambda sond though?

According to your description the exhaust leak is after the lambda sensor.

Regarding the start / restart condition, the cold restart was not an issue before. Let's see what happens in a warm restart situation. You have to gather as much data as possible when the car will not start. Disregarding the fault and hoping "it will fix by itself" is a big mistake. The car will refuse to start usually when you'll need it most.

Edited 10 March, 201610 yr by RicardoM

So the next step is to run it hot and then troubleshoot. What should I try and look for? Actually the motor was cold when I started this thread. Then I tried to start it several times every hour over a five hour period.

I drove for 45 minutes with no problems, then stopped, turned off the car and when I tried to turn it on again it did like this.

From your description the engine was warm, You stopped it, tried to start, no luck. Only after the engine cooled down a few hours later you could start the engine. So make up your mind or try to be more specific. The more accurate data you provide, the better advice you'll get.

 

So the next step is to run it hot and then troubleshoot. What should I try and look for?

I thought I was clear. Wait for no start. Remember the carb cleaner spray advice? Then check for strong spark. The have a look at ECU connectors, throttle body connectors, MAP/IAT sensor connector. Use WD40 on them. Look at MAP/IAT sensor itself, check for no oily residues. Hook up the VAG-COM scanner, key on, read coolant temp, air temp, air pressure, throttle body data.

Cannot tell a lot from your video. (sound too por) I don't know in detail the ign type on the 1.3 engine. If the rev counter dropped to zerro before the engine stopped it's possible the hall sender it's the cause....someone with a felly with that engine will be more helpful.

If the rev counter dropped to zerro before the engine stopped it's possible the hall sender it's the cause.

I wouldn't have missed that on his video. The ECU and crankshaft sensor look OK. The behaviour of the engine during start-up is very similar to an immobiliser fault. Personally I prefer to get to that conclusion only after I eliminated all other causes.

Thanks for your words. Today I found that there was verdigris in the connector, red circle in picture, and after giving it some 5-56 the motor ran just fine and kept doing fine despite several cold and hot starts during the day. What does this connector do?

 

My little Felly got her oil changed today and since I couldn't get new spark plugs today I cleaned the current ones for her. By the way, there was too much oil in the engine before I replaced it today. According to the instructions for use, excess oil is burnt automatically, but how could there then be excess oil in the engine?

 

Thanks

That would be the combined MAP/IAT sensor I was telling you about (see photo, items 7 & 8). Manifold Absolute Pressure and Intake Air Temperature. If the VAG-COM scanner arrived, check for errors. Note down the errors then erase them.

 

According to the instructions for use, excess oil is burnt automatically, but how could there then be excess oil in the engine?

Yeah, excess oil is burnt automatically, but with a price. Clogging the cat. As for higher oil level, read this topic.

500 km later she did it again. I put some more 5-56 into the verdigris connector and scraped it clean with a knife without success. Since I was in a hurry I had to abandon the car, but I bet it will run fine when I start it again. It was dry weather and the car had been unstarted for six hours.

Did you get the VAG-COM scanner? Look for errors. Could be more wiring problems. Sometimes the wires look ok, but tugging and bending them might reveal problems. Like Alan had with a connector here.

The scanner hasn't arrived yet (last delivery day is April 13th). I will do a more thorough check on the cables for all connectors. How strong are the signals in those cables? Are they sensitive for soldering? By the way, I haven't really looked, but where do I connect the VAG-COM scanner to the ECU?

How strong are the signals in those cables?

What do you mean by strong signals ??

 

Are they sensitive for soldering?

Again, I don't get it. Cables sensitive for soldering??

 

By the way, I haven't really looked, but where do I connect the VAG-COM scanner to the ECU?

Near relay/fuse box, looking up you'll see a 16-pin socket.

I started the car a few times without problem. Then cleaned the spark plugs and checked the MAP sensor. After putting everything back together the problem was back! Now I've disconnected the MAP sensor and it idles just fine. The map sensor was moist when I looked at it (the resistor). Broken maybe?

So disconnecting the MAP sensor while cold (cold enough not to show on temp gauge) got it running. I drove around the block and the throttle response was pretty bad. Then I reconnected the MAP sensor when turned off, and it started fine with normal throttle response. Now the engine is hot and it starts both with and without MAP sensor.

A faulty MAP sensor and a bad wiring could have the same effect. Do you prefer to buy a new sensor just to find out it was the wiring? I don't recommend buying parts blindly. But if you are in a hurry and a new sensor is cheap... it is up to you.

Ok, it happened AGAIN! But this time at least it was when I was going to leave home and not the other way around like the last times. I tried to systematically start the engine with and without every connector/sensor I could find under the hood that is somehow connected to engine. When some of the connectors were disconnected, the engine didn't even rev up. When disconnecting the coal canister and starting the engine, it smelled a lot of petrol. I haven't found any damaged cables either.

 

It's dry weather and ~19 C (for the record).

 

Is the rpm gauge supposed to show >0 rpm when start engine is running?

Edited 4 April, 201610 yr by Ludds

Is the rpm gauge supposed to show >0 rpm when start engine is running?

Of course. Doesn't the engine rotate when cranking? In fact mechanics use this behaviour to diagnose if the crankshaft speed sensor is OK. A faulty sensor is a no start condition. I'm not saying you have to buy for sure a new sensor. It is possible, but not certain. If only you had the VAG-COM scanner...

 

Did you try spray some carb cleaner (as indicated) into the throttle body then immediately try starting the car.

Yep, I've tried spraying cleaner into the TB before start. No difference. I'm thinking that the engine revs up on petrol steam from the charcoal canister, is that possible? If you check my video in the beginning of the thread, you can see how it behaves. I did a little research on Youtube though, and from what I could find, the tacho gauge doesn't show anything when the start engine runs (for example

). I just went out to the car to try and see if it had repaired itself, but it didn't start (~12 C, dry weather).

 

I measured some connectors with the ignition turned on. Most pins either has 0, 5 or 11.75 (battery) V. Also I found a few milliliters of water in the fuse box, down at the spare fuses. None of the connected fuses nor relays were wet. Neither were any of the engine related fuses broken.

 

I just want to say that I'm very grateful that you take your time helping me. Hopefully this thread will be useful for other people too.

Also I found a few milliliters of water in the fuse box, down at the spare fuses. None of the connected fuses nor relays were wet. Neither were any of the engine related fuses broken.

This is a very important observation (I've marked it in red). Moisture in the fuse box is a recipe for all kind of random, weird, unpleasant things. A no start is one of them. Moisture and electricity don't mix well at all. Corrosion, bridging, short circuits, etc. I have a few photos for you to look at to see for yourself what water in the relay box does. In case you didn't know, under the relays and fuses there is a stack of plates with thick metallic traks acting as a high-current multilayer PCB.

 

Here is one plate in pristine condition. Tracks are intact, shiny, no corrosion. no signs of heating or arcing.

 

Here is the same plate from another car that had water in the fuse box. You can see signs of electrolytic corrosion, bridging, and arcing.

 

 

Finally, here is what happens in the end when smoke starts filling the dashboard...

 

So my advice is to remove the fuse box, dismantle it, clean it thoroughly, and put everything back. WD40 is very good to clean corroded parts. Clean / reseat all pins of fuses and relays.