Car starts then cuts out immediately

[Gavin Waddell 18]

Hello Telf

 

thanks for your replies they are very helpful, i have actually pulled the loom out of the engine bay so that i could physically and visually check all of the connections, some of them all joon together so i tested them before the join after the join and so on everything seem to be good. i checke earths from each component from the plug to ecu, from the ecu to the ground on the gearbos from the gearbox to the battery. i looked at the afm connection and its a bit dodgy so i will order some new junior timer connectors and repin it to make sure.

 

one thing i found wierd is that i checked the perm VE+ to the tah relay and i get  12v in but on the 2 white wires that branch off i only get 10v?

 

i think i might have a dodgy tach relay will order a new one and also maybe try to get an afm.

 

i would love to borrow an afm amd tach relay, unfortunately because i live in Switzerland they never got this model of 1.6gti,  i brought the car over with me from the uk when i moved over here 17years ago.

 

 

thanks for your help i will crack on to see what i can find.

 

Gavin

[Telf 222 2 Cars]

Regarding the loom, as its removed have you removed all the wrapping on it and looked at the wires? the reason i ask is if you have tested it with the wires unbundled and no longer wrapped tight it may all appear good. when you rewrap you may get a short. --especially if you have perished/cracked insulation on a bundle of wires lying together. 

 

If the loom has all been unbundled can you safely reconnect to the engine and test start it? you may have cleared any short fault temporarily

 

 

ebay have loads of 1.6 AFMs come up - usually around £30 . I'm not really sure its an AFM problem but might be worth a shot if all else fails.

 

 

[jackherer 543]

3 hours ago, Gavin Waddell said:

one thing i found wierd is that i checked the perm VE+ to the tah relay and i get  12v in but on the 2 white wires that branch off i only get 10v?

 

i think i might have a dodgy tach relay will order a new one

Try taking the cover off of the tachymetric relay and looking for dry solder joints, it's pretty common for the joints on the PCB to fail due to vibration and they can be easily repaired.

[Gavin Waddell 18]

Ok will have a look Inside to see if I see anything strange.

[Gavin Waddell 18]

Hey telf once I had unbundled all the wires wanted to start the car but the battery had died will give it a try.

[Gavin Waddell 18]

So went to the car toadaybandntriex to start it with everything unbundled, still no joy . 

Checked +VE at the injectors and they get 10v when I crank.

 

i also did a continuity test on the white wire which supplies power. I fixed the multimeter negative on the battery and tested the wire and got continuity? That shouldn’t happen ?

 

i am going to borrow an 1.6 and 1.9 AFM/ECU from someone local and going to whack them one to see if it is an ECU or AFM fault. 

The thing about the car starting with AFM unplugged bugs me.

 

[Telf 222 2 Cars]

1 hour ago, Gavin Waddell said:

i also did a continuity test on the white wire which supplies power.

which cable is this on the wiring diagram? supplies power to what ? the ECU? the AFM? 

[Telf 222 2 Cars]

if you suspect the AFM and dont have one to hand make sure the wiring is ok. 

 

Carry out a continuity check and short circuit check on all the AFM cables if you havent already done so.

In case you don't know how do this:

 

Disconnect the ECU, AFM,Tachy relay,Throttle switch and Injectors. As per the diagram they all have common connection to ECU and AFM so you want them all out of the check.

 

Do a continuity check between the 4 AFM cables and ECU (as per the diagram)

ECU 7 to AFM 7

ECU 8 to AFM 8

ECU 9 to AFM 18A

ECU M5 to AFM M18

 

multimeter should read zero Ohms maybe 0.01 or 0.1

----------------------------------------------------------------------

Repeat the check to make sure there are no shorts between the AFM wires in the following manner:

 

Attach the multimeter to AFM 7

 

use the other probe to check for continuity on 8,18A and M18 there should not be continuity.

 

------------------------------------------------------------------

 

you can test the other components respective looms in the same way. isolate everything so you get no random readings back through relays etc , test between the ECU and the component then test for shorts between the components loom.

 

 

you've probably done this , not wanting to be patronising if you have but ive no idea if you have much experience with testing cables or not. if so ignore!

 

 

 

 

Edited April 23, 2020 by Telf

[Gavin Waddell 18]

Not patronising at all, I tried to do a short circuit test but didn’t quite understand how to do it, i didn’t disconnect everything. Will try and and have a look at it this weekend if I can get a couple of hours. 

 

Was going to swap the AFM and écu hoping it would be a miracle cure. But like you said it must be electrical. I’m going to order do JT terminals this weekend so I can change the ones that looked shoddy.

 

thanks for all you help Telf. I’m good at mechanical stuff but electrical is not my forte, it was my dads but he passed 5 years ago, so on my own☹️.

 

i let you know how I get on.

 

thanks again Gavin

[DamirGTI 323]

Reading back a little bit ... said you've got an "Aliexpress" replacement fuel pump inside now ?

 

If so .. i'd be very suspicious about it . People reported all kinds of failure with "el cheapo" Chinese fuel pumps from over pressurizing , under pressurizing , no start , under load misfiring , low power etc. 

 

I've seen internals of these pumps in comparison with a OE Bosch unit (in fact i posted that link over here too) , and the stuff they put inside makes you wonder how does it work at all ... it's cheap made crap ... possibly 1 out of 10 works , the rest are junk .

 

Thus , i'd try with an spare known good OE Bosch pump .. or new one , can still get new Bosch ones . In terms of longevity , safety and overall car performance one must never go cheap with the generic fuel pumps , only well known brands really work as it supposed to and last .

 

D

[Telf 222 2 Cars]

Regards the aftermarket pump I would agree go with Bosch or a well known brand over cheap stuff every time. The pump is after all immersed in your fuel. How ever being as the car is running without the AFM plugged in (badly but still running) I'd worry about solving this issue first .

Edited April 23, 2020 by Telf

[PhilNW 40]

2 hours ago, Gavin Waddell said:

But like you said it must be electrical. I’m going to order do JT terminals this weekend so I can change the ones that looked shoddy.

Thats were my problems were, 

[Gavin Waddell 18]

I get how to do a continuity check, I can check voltage,but what do you set the multimeter too when doing a short circuit check.

going to sound really dumb to you guys but I don’t get what I’m supposed to be seeing? I set the ohmmeter to ohms? And then that’s what I don’t get what I’m supposed to read on the multimeter 

 

cheerfor or your patience I sure I get there in the end.

 

Thanks gavin

[DamirGTI 323]

There's copious amount of resource on the web and youtube , textual and video form .. so you can learn almost anything these days , if you're eager to do so .

 

Do some research on what you want to know/learn , and most important after that - try to do that in practice (only then you'll be actually "learning" , meaning it'll then stay in you're memory , unlike if you're just reading and watching)

 

Also , since this problem last for quite a while now without success/repair , if you do not feel capable handling the electrics - ask for help , someone in your town or nearby who knows how to diagnose and fix electrics (if you're lucky and find an sound guy who's willing to show you "how to" , you'll learn some there too during the diagnose/repair process , that's how we did before the internet ! learning from others and from the books ..)

 

All of us , even the professionals every now and then need and seek assistance of others . Thus noting wrong or shameful in asking for help . 

 

Just saying , not meant to be rude .

 

D

[Gavin Waddell 18]

I get you point Damir, and that is also my way of thinking, if he can doit why not me. I don’t shy away from most hands on things in life. 

  Like you said I will go and have a look on the inter web and im sure I will find what I am looking for. 

The problem has been going on for a while also because as with life other things come up when you get older. And as I like to call it “dad time “ is a bit more difficult to have. But hey that’s life.

 

I will let you know how i get on, I think I have a enough info to keep me busy.

 

thanks again for your help.

 

Gavin 

[MikeC 10]

17 hours ago, Gavin Waddell said:

So went to the car toadaybandntriex to start it with everything unbundled, still no joy . 

Checked +VE at the injectors and they get 10v when I crank.

 

 

I'm having starting issues of another kind, but are you checking the injector signal with a digital meter?

These injectors have a permanent live and are switched on the 0.

I would test the injector signal with an Analog meter, as the signal is too fast for the DMM.

Also an oscilloscope is ideal for this test if you have access to one.

 

[Telf 222 2 Cars]

12 hours ago, Gavin Waddell said:

but what do you set the multimeter too when doing a short circuit check.

yes use resistance. if it shows zero Ohms that is a short. You can also use diode test - it will beep if there is low resistance.

[Telf 222 2 Cars]

12 hours ago, Gavin Waddell said:

going to sound really dumb to you guys but I don’t get what I’m supposed to be seeing?

as i say use Ohms - you will see zero or as near as damn it. - same as a continuity check. 

[Gavin Waddell 18]

Ok so went and tried a new AFM and écu no go. It was a stab in the dark.

 

tried to start it with everything unbundled still nothing.

 

so I’m going to take the whole loom out of the car and bring it home that way I can visually inspect it better and also do all the continuity testing without latex out on the floor. 

 

Also so enables me to do this when the kids are in bed or playing outside, the car is stored at my parents.

 

will let you know how I get on.

 

gavin

[DamirGTI 323]

Thing with electrics is , you really need to know what you're doing ... especially on modern cars , failing to do so might blow out the ECU and various components .

 

 

 

I suggest you watch all these video series :

 

 

 

D

 

[Telf 222 2 Cars]

On a 205 provided the battery is disconnected the chances of doing any damage continuity checking is the same chance of Elvis returning from the moon. Don't overcomplicate this, the loom is removed from the car , chances of a fluke damaging it -zero. 

 

Maybe a Insulation tester could harm the loom if you have never used one, apart from that no.

Edited April 24, 2020 by Telf

[Gavin Waddell 18]

Thanks for the vid. I always disconnect the battery before doing anything on a car that touches its electrics. 

 

Taking the loom out the car just means I can work my way through it  over a couple of nights , in peace and quit.also easier to fix any problems.

 

once again thanks for your advice.

 

 

[DamirGTI 323]

I wasn't referring to continuity test as particular .

 

To be able to solve this "mystery" by himself , doing by himself with no experience nor help from someone who knows how to fix and diagnose electrics to guide him trough the process the OP must know the basics first .. as with anything else , get to know how stuff works first and you'll be able to fix it being a hair dryer or locomotive doesn't matter .

 

How to perform certain tests , how to set the multimeter for particular testing , how to read the multimeter in order to understand the reading , how to read and understand wiring diagrams , etc. .. so all the questions he's been asking from the start till now to me tells that he's keep on trying to do certain test but doesn't know how to , neither how to interpret the readings he sees on the multimeter if they're right or wrong . 

 

Aside from the continuity tests , if will be needed , how will he perform live tests with the loom connected on the battery and with the system switched on ? plus , there's a lot of different ways to do the same test on electrics , some of them are better/worse/easier/safe/dangerous .

 

"Cherry picking" information here only leads to confusion ... the above series of videos will guide him from the start to finish , all the stuff he wants to know is covered there and is shown in practice with actual testing too .

 

That's if he's willing to do so and learn something during the process .. if not , id pay someone to fix it and be done with it .

 

 

D

Edited April 24, 2020 by DamirGTI

[Telf 222 2 Cars]

any progress with this Gavin?

[Gavin Waddell 18]

So I went through the entire loom with a multimeter, and there is continuity on all the wires as per the diagram you gave me Everything is connected as should be. I received some dodgy terminals inc the ground. 

Went and plugged it all back in tried to start and nothing. I jumped the tach relay to rule that out and nothing. Unplugged the AFM and it started. Not good.

 

changed the coil nothing.

changed the img amp nothing.

changes the écu nothing.

changed the AFM nothing.

 

it still won’t start.

checked 12v to injectors and there’s is 12v when cranking.

 Checked the écu ground and it’s good. Even moved it to the battery direct.

 

what I don’t get is why does it start when I unplug the AFM, technically I shouldn’t start as the écu circuit is open?

 

i may go and borrow a spare loom and see what happens then. 

 

Apart from that I’m stumped, ordered a test lamp, as per the videos Damir posted ( as I watched all of them, very useful). 

 

.

gavin 

 

will keep going at it, I’ll get there in the end.