Electrical problem...End of my Tether

[Ray1965 10]

Being having starting problem lately. The car has an intermittant starting problem.

I have fitted a new fuel pump relay today, as i was told it was this at fault but this has not cured the problem.

The car will start several times then will just turn over and not start then you try it say 2 mins later and it will go.

I have ruled out the immobiliser as it lets the car the car run for a few seconds then cuts out this is the normal thing i believe?

Don't know if it could be the after market immobiliser at fault or could it be alarm related? I have no idea where the alarm is wired to where it is in the car.

Could it be the fuel pump itself?

I have bridged the fuel pump relay to test the pump and it does work when this is done.

I'm getting to the stage where i'm running out of ideas and need some expert advice and hands that can cure this really annoying problem i love the car but i'm falling out with it really fast.

[Jim 2]

I would imagine it's not likely to be the fuel pump.. I figure that would either work, or wouldn't.

 

The aftermarket immobiliser is a possibility I would think.

 

Is there any pattern to the behaviour? Can it happen with the car stone cold (like first time you use it on a morning) or does it happen after the car has been used / is warm / is partly warmed up?

[fendervg 32]

Fuel pressure regulator?

[Jim Bowen 1]

Have you been able to scan it with vagcom to see if its throwing up any faults?

[easypops 8]

Ignition switch?

[Sean_Jaymo 0]

Crank sensor? They don't show up fault codes sometimes when they're bust.

[fla 9]

Change ecu relay 109

Ray don't lose hope there are some extremely knowledgeable and helpful people here who'll help get it sorted.

[Dox 23]

Spark

 

Fuel

 

Compression

 

Timing

 

If you have the above the engine should run, whats missing when its not starting?

 

Is the non start when the engine is cold / hot / both?

[Ray1965 10]

Firstly cheers for the replies.

The ignition switch was renewed a couple of weeks ago. (had fault then)

The fault happens when the car is cold, warm, and hot.

Will be scanning the car with VAG com as it is not starting now so should show a code / fault, i hope.

I bought a new fuel pump relay as i said. Dont want to be buying another relay for nothing again tbh. I'll ask about to see if anyone is local to me possibly might be able to borrow a ECU relay as mentioned by Mr Fla. I will give mine a test to see if it working ok.

As Jim said will look also to the alarm immobiliser.

Fuel pressure reg. where is on the car and how to check it's ok?

Crank sensor anyway of testing this?

Thank you all again.

[Roger Chatfield 0]

Vagcom... Gotta get it scanned or else you just guessing.

 

Same thing happened with mine, intermittent starting, vagcom told me it was the cps sensor, changed that and all was good.

 

Shame you are not closer as I would scan it for you, look at the vagcom thread on here or put up a post asking for help.

 

Good luck mate,

 

Rog.

[Ray1965 10]

Cheers for the offer Rog, will get it scanned. Then give an update.

Edited April 2, 2015 by Ray1965

[robrado974 1]

Hi Ray , the fuel presure regulator is at the end of the fuel rail . If you remove the fuel pipe and crank the car you can see if it spurts fuel , just remember when removing it, it will be under presure and could spurt out , mind your eyes !. I dont think you can test the regulator ?, it maybe worth getting a second hand one to test if it is at fault . My non starting thread will be of use to you .

[Ray1965 10]

Cheers for that Rob, i will try what you said. The car will not start now so i will be scanning it with VAG COM first to see what errors etc i have got.

I'll keep you posted.

Edited April 3, 2015 by Ray1965

[Sean_Jaymo 0]

I still think it's the crack sensor. No way to test though. They don't always pop fault codes either. The wiring insulation breaks down over time and with the wiring right next to the bottom of the block, The heat won't help the situation.

[Ray1965 10]

Just put car on Vag com.

Results are very strange ones as follows:

The VAG COM firstly couldn't get a response from the engine controller.(No response from the controller).

After turning the ignition on and off several times, the controller then Did respond, as soon as the controller started to respond we noticed the engine would start.

After turning the engine off, then turning the ignition on and off a few times you can tell when the engine is not going to fire as the fuel pump seems to stay on all the time.

When the car is going to start the fuel pump just does a small blip (priming up).

this can be repeated over and over and still end up in the same boat.

 

The fault codes that were stored on the engine are:

17978 - Egine Start Blocked By Immobilizer

P1570 - 35-00 - -

 

And there was 1 fault code stored on the immobilizer:

00546 - Data wiring faulty

27-00 - Implausible Signal

 

Maybe there is a fault with the ECU due to it not responding when its "faulting"???

Can anybody please shed some light on this?

Thanks

Edited April 3, 2015 by Ray1965

[Dox 23]

If youre fiddling with the car unplugging sensors etc then you'll create ghost codes by doing it.

 

Clear codes and retry starting the car to get the true codes

[volksworld13 0]

Try replacing the ecu relay, that would cause a non comm error . And cause it not to start.

[Ray1965 10]

If youre fiddling with the car unplugging sensors etc then you'll create ghost codes by doing it.

 

Clear codes and retry starting the car to get the true codes

 

Hi Dox i had thought of this and did not disconnect any sensors atall. Did the scan and thats what i got.

As i said in my post strange results.

 

it would be nice to have a spare ECU relay to try and rule this out as mentioned. Could i bridge this out to test or is it not possible?

[Dox 23]

Hi Dox i had thought of this and did not disconnect any sensors atall. Did the scan and thats what i got.

As i said in my post strange results.

 

it would be nice to have a spare ECU relay to try and rule this out as mentioned. Could i bridge this out to test or is it not possible?

 

Loads of VAG stuff has relay 109 (MK4 based for example), you can also remove the cover and resolder any dry joints inside

[fla 9]

when you take 109 out and remove the cover, have a look for any pitting between the contacts of the plate on the solenoid. Then when you apply 12v hold the power on for a few seconds then pulse it a little to see that the contacts are held and maintained, then broken and reconnected.

 

Just another thought, have you removed the connector from the ecu and looked at the pins and sockets there in case there is any corrosion? Might be worth spraying it thoroughly with contact cleaner.

[Ray1965 10]

Cheers Mr Fla and Mr Dox, will try what you said.

[Ray1965 10]

Just an update.

I have replaced the fuel pump relay, the ECU relay and still have this intermittent problem.

I had no problems with starting the car all weekend, but today it decided to not play ball.

 

Whilst pulling my hair out i stumbled on a suspect...The Ignition Barrel, ok this is what i have found:

 

When the car fails to start (but engine turns over) i moved the key about in the Barrel, I gave a tap on the barrel itself and it then primed the pump (read post number 15 from me). I am looking at replacing the Barrel?

Anyone done this and where can i get one from?

 

Daft question alert: What is the procedure take my key and a new barrel is matched to my key?

 

I have read on the forum that its ok to use a pattern barrel but always buy genuine VW ignition switches, which i did and fitted a couple of weeks ago.

Edited April 7, 2015 by Ray1965

[fla 9]

yes another typical culprit. The ignition switch is faulty. Its a bit of a fiddle to replace, you will need to bend the end of a star jewellers screwdriver to turn the locking screw literally 10 degrees at a time. Make sure you get a genuine VW replacement, the others are just not made to the same tolerances and will keep you chasing your tail for months.

[Ray1965 10]

Cheers Fla, I have already fitted a VW ignition switch.

It's the Barrel thats gone now i think.

Edited April 8, 2015 by Ray1965

[Ray1965 10]

These will be no good?? as they are not for factory fitted immobiliser https://www.vwheritage.com/shop/corrado/357905855B/ignition-lock-barrel-wtih-keys-t4-09-90-04-98-corrado/?crumbStartPage=1&crumbStartRow=1