My Polo Won't Start
Discussion
I own a year 2000 Polo 1.4 16v and it won't start. The first sign that something was wrong was a drop in mpg from around 41 to 37 although the performance of the car felt no different at that point.
However, after a couple of weeks I found it was sometimes reluctant to start when cold. This gradually got worse to the point where it really didn't want to start, but I would always get it going eventually.
Today the bloody thing definitely isn't going to start. I've tried two fault code readers but neither of them will work on this car even though they've worked on other cars, so it looks like the time for guess work and the process of elimination.
I've taken the plugs out and they are wet so I know I'm getting fuel to all four cylinders. I've tested it to see if I get a spark and there is nothing. However, sometimes just as you let go of the key there is a slight spark.
It is the same with all four plugs and the only thing they have in common is that they all run off the same coil rather than having individual coil packs like more modern cars. Should I replace the coil or does anyone have any better suggestions?
Thanks in advance
However, after a couple of weeks I found it was sometimes reluctant to start when cold. This gradually got worse to the point where it really didn't want to start, but I would always get it going eventually.
Today the bloody thing definitely isn't going to start. I've tried two fault code readers but neither of them will work on this car even though they've worked on other cars, so it looks like the time for guess work and the process of elimination.
I've taken the plugs out and they are wet so I know I'm getting fuel to all four cylinders. I've tested it to see if I get a spark and there is nothing. However, sometimes just as you let go of the key there is a slight spark.
It is the same with all four plugs and the only thing they have in common is that they all run off the same coil rather than having individual coil packs like more modern cars. Should I replace the coil or does anyone have any better suggestions?
Thanks in advance
Steve126 said:
I own a year 2000 Polo 1.4 16v and it won't start. The first sign that something was wrong was a drop in mpg from around 41 to 37 although the performance of the car felt no different at that point.
However, after a couple of weeks I found it was sometimes reluctant to start when cold. This gradually got worse to the point where it really didn't want to start, but I would always get it going eventually.
Today the bloody thing definitely isn't going to start. I've tried two fault code readers but neither of them will work on this car even though they've worked on other cars, so it looks like the time for guess work and the process of elimination.
I've taken the plugs out and they are wet so I know I'm getting fuel to all four cylinders. I've tested it to see if I get a spark and there is nothing. However, sometimes just as you let go of the key there is a slight spark.
It is the same with all four plugs and the only thing they have in common is that they all run off the same coil rather than having individual coil packs like more modern cars. Should I replace the coil or does anyone have any better suggestions?
Thanks in advance
And would it not make more sense to locate a diagnostic scanner that does work, instead of just guessing and throwing parts at it ?However, after a couple of weeks I found it was sometimes reluctant to start when cold. This gradually got worse to the point where it really didn't want to start, but I would always get it going eventually.
Today the bloody thing definitely isn't going to start. I've tried two fault code readers but neither of them will work on this car even though they've worked on other cars, so it looks like the time for guess work and the process of elimination.
I've taken the plugs out and they are wet so I know I'm getting fuel to all four cylinders. I've tested it to see if I get a spark and there is nothing. However, sometimes just as you let go of the key there is a slight spark.
It is the same with all four plugs and the only thing they have in common is that they all run off the same coil rather than having individual coil packs like more modern cars. Should I replace the coil or does anyone have any better suggestions?
Thanks in advance
Although if there is no spark, obvious things to check are power to the coil, signal to the coil whilst cranking. If those are good then you could perhaps guess at replacing the coil/ignitor.
But generally check the entire ignition system. And if the plugs are soaked with fuel, throw them in the bin.
Or if those are both cheap, replace them anyway.
If it is the usuall problem with this year of polo and golf it will be the ign switch?
First test for live at the coil with the ign on then again wilst cranking, if the live to the coil dissapears on cranking you need a new ign switch, if you dont have a test meter try a push or tow start.
First test for live at the coil with the ign on then again wilst cranking, if the live to the coil dissapears on cranking you need a new ign switch, if you dont have a test meter try a push or tow start.
tiger.banana said:
Quite common on these is the coolant temperature sensor to fail, giving poor cold starting etc.
Yep, if the ecu doesn't know it's cold the engine won't like starting in the cold.Also, how good is the battery? Does the engine still turn over at a "normal" speed ?
Quite a few batteries that are on their last legs will have had a hard time the last few days. The combination of cold weather & having lights/heaters flat out is tough on batteries/charging systems.
Thank you for the replies.
I'm sure the battery and starter are ok as they turn the engine over at a decent speed.
I changed the coolant temperature sensor when I first started having problems, but that made no difference. Wouldn't coolant temperature sensor problems mean too much or too little fuel rather than no spark?
I've checked I have power going to the coil and it is there both with the ignition on and when cranking.
I've tried new spark plugs and that made no difference.
We tried push starting it without success.
The stuff about the ignition switch is interesting as I hadn't heard that before, but power to the coil doesn't disappear when cranking and push starting it failed so surely it isn't that?
I've got an old Anglia 105E that I've rebuilt and modified and I thought that was a pain in the arse but at least I don't have any trouble working out what is wrong with that.
I'm sure the battery and starter are ok as they turn the engine over at a decent speed.
I changed the coolant temperature sensor when I first started having problems, but that made no difference. Wouldn't coolant temperature sensor problems mean too much or too little fuel rather than no spark?
I've checked I have power going to the coil and it is there both with the ignition on and when cranking.
I've tried new spark plugs and that made no difference.
We tried push starting it without success.
The stuff about the ignition switch is interesting as I hadn't heard that before, but power to the coil doesn't disappear when cranking and push starting it failed so surely it isn't that?
I've got an old Anglia 105E that I've rebuilt and modified and I thought that was a pain in the arse but at least I don't have any trouble working out what is wrong with that.
Steve,
A car from the '50s, like your Anglia, is like letters written in stone compared to even an ordinary car from the '90s, like the Polo.
As mentioned above, all cars since the early '90s had "On Board Diagnostics" OBD, that can be scanned and read by the appropriate software, revealing codes that point to failing of malfunctioning components.
The OBD connector on your Polo is here: http://www.outilsobdfacile.com/location-plug-conne...
The first was "OBD" but by the time of the Polo Mk3, "OBD-2" was in use, more detailed.
A range of cheap OBD2 readers are here: https://www.amazon.co.uk/s/ref=nb_sb_noss_1?url=se...
You can even get an OBD2 app for your phone: http://www.androidcentral.com/test-driving-obd2-re...
One that gives you more than just the codes is handy, but this site (there are others) will look up the code for you: https://actron.com/code-lookup
Good luck!
John
A car from the '50s, like your Anglia, is like letters written in stone compared to even an ordinary car from the '90s, like the Polo.
As mentioned above, all cars since the early '90s had "On Board Diagnostics" OBD, that can be scanned and read by the appropriate software, revealing codes that point to failing of malfunctioning components.
The OBD connector on your Polo is here: http://www.outilsobdfacile.com/location-plug-conne...
The first was "OBD" but by the time of the Polo Mk3, "OBD-2" was in use, more detailed.
A range of cheap OBD2 readers are here: https://www.amazon.co.uk/s/ref=nb_sb_noss_1?url=se...
You can even get an OBD2 app for your phone: http://www.androidcentral.com/test-driving-obd2-re...
One that gives you more than just the codes is handy, but this site (there are others) will look up the code for you: https://actron.com/code-lookup
Good luck!
John
The problem I have is that I have two fault code readers but neither of them work on my car.
The first is an orange U480 one that cost about £10 which I've used loads of times to fix other cars, but if I try it on mine "Linking Error" is the only thing I've ever got out of it.
The second is an ELM327 Bluetooth one that works with the Torque app on your phone, at least it works when I use it on other cars but says "Not connected to ECU" when I try it on my Polo.
I know that doesn't necessarily mean that every fault code reader will fail to work with this car, but unless/until I find one that does, I'm in the same position as when working on the Anglia but with many more things that can go wrong.
The first is an orange U480 one that cost about £10 which I've used loads of times to fix other cars, but if I try it on mine "Linking Error" is the only thing I've ever got out of it.
The second is an ELM327 Bluetooth one that works with the Torque app on your phone, at least it works when I use it on other cars but says "Not connected to ECU" when I try it on my Polo.
I know that doesn't necessarily mean that every fault code reader will fail to work with this car, but unless/until I find one that does, I'm in the same position as when working on the Anglia but with many more things that can go wrong.
Steve126 said:
The problem I have is that I have two fault code readers but neither of them work on my car.
The first is an orange U480 one that cost about £10 which I've used loads of times to fix other cars, but if I try it on mine "Linking Error" is the only thing I've ever got out of it.
The second is an ELM327 Bluetooth one that works with the Torque app on your phone, at least it works when I use it on other cars but says "Not connected to ECU" when I try it on my Polo.
I know that doesn't necessarily mean that every fault code reader will fail to work with this car, but unless/until I find one that does, I'm in the same position as when working on the Anglia but with many more things that can go wrong.
That's your problem!The first is an orange U480 one that cost about £10 which I've used loads of times to fix other cars, but if I try it on mine "Linking Error" is the only thing I've ever got out of it.
The second is an ELM327 Bluetooth one that works with the Torque app on your phone, at least it works when I use it on other cars but says "Not connected to ECU" when I try it on my Polo.
I know that doesn't necessarily mean that every fault code reader will fail to work with this car, but unless/until I find one that does, I'm in the same position as when working on the Anglia but with many more things that can go wrong.
The ECU isn't working- disconnected or just broken.
John
tapkaJohnD said:
That's your problem!
The ECU isn't working- disconnected or just broken.
John
Where is the fuel coming from then?The ECU isn't working- disconnected or just broken.
John
Steve, I wouldn't worry too much about the code reader yet, it's probably not going to give you an answer anyway.
Can we confirm a couple of basics -
1) The ignition system is a coil pack with leads that go directly to the plugs? This would mean no distributor/cap/rotor etc and at least three wires going to the coil.
2) When you crank the engine do you see the rev counter lift slightly?
3) If you disconnect the coolant temp sensor and read the voltage on the two wires going to it what voltage do you get on each pin? (with ignition on)
4) Hold a long screwdriver to the body of one of the injectors and put your ear to the other end, get someone to crank the engine, do you hear a ticking noise? If you're not sure try then disconnecting the multiplug off that injector, crank/listen again and see if you notice the difference.
Post up 1-4 and maybe an engine code and we'll see what we can do from there.
Hello Steve and thank you for helping.
1) It is definitely a coil pack. Sorry I confused things by calling it a coil in my first post.
2) No, it remains on zero.
3) I got 4.97V and 0.15V
4) No ticking noise and I got someone else to listen and he said the same thing.
Engine code is AHW
I don't know if this helps but I saw something on another site where someone had a similar problem and they were told to check pins 1 and 3 on the connector going to the coil pack. They said you want pulsed 12V when cranking which I certainly wasn't getting although I thought I'd need an LED circuit tester to see if there is a pulse.
1) It is definitely a coil pack. Sorry I confused things by calling it a coil in my first post.
2) No, it remains on zero.
3) I got 4.97V and 0.15V
4) No ticking noise and I got someone else to listen and he said the same thing.
Engine code is AHW
I don't know if this helps but I saw something on another site where someone had a similar problem and they were told to check pins 1 and 3 on the connector going to the coil pack. They said you want pulsed 12V when cranking which I certainly wasn't getting although I thought I'd need an LED circuit tester to see if there is a pulse.
bearman68 said:
Code reader not working plus no RPM signal suggest ECU is not receiving power.
5v at the CTS suggests that it is.OK, so 1) confirms the type of ignition system, 3) suggests that the ECU is correctly powered up and 2) & 4) suggest that the ecu is not receiving an rpm signal or is immobilised.
It's a bit strange that you are not getting an injector trigger given that the plugs are wet but for now I think we'd have to chalk that up as an anomaly.
It would be worth trying your spare key if you have one but then it's going to get trickier because the next test steps would be to scope the camshaft and crankshaft sensors and interrogate the immobiliser to check if it is happy. This all requires specialist kit.
From memory I think most VWs of that vintage would still have a go at starting on either the crank or cam sensor if the other one had failed which would suggest that it is not one of those two but I think you are getting about as far as you can without spending some money one way or another. I suppose it's always possible that one had failed causing the previous symptoms (harder to start, poor mpg) and then the other one failed some weeks later by coincidence but it doesn't seem very likely.
I'd be aiming for some specialist help before wasting money on parts. By specialist I don't just mean your local garage as most of them won't know how to use a scope and will just chuck the parts at it. A good local mobile diagnostic guy would be the best option if you can find one.
Sorry I can't get you much further, careful basic testing can get to a lot of solutions but it's not all DIYable
You could get the vag tool vcds, https://m.gendan.co.uk/product_VCHU.html yes it costs, but you spend that trying to find the fault
Gassing Station | Home Mechanics | Top of Page | What's New | My Stuff