Fault code advice

[NickGold]

I have the classic issue of my 8v 1998 R reg GTI running rough. It will start and and will sometimes idle fine for a few mins and then the revs will suddenly drop off and will stall unless foot is applied to the accelerator and even then this isn't always enough to stop it stalling. Engine will then pick up and for varying periods of time run fine then run rough again and the cycle starts all over again. This happens whether hot or cold. I know there are many many posts about this on here and I had tried to read as many as possible and as a result have done the following:

1. Cleaned TB
2. Replaced ECU relay
3. Replaced Fuel pump relay
4. Replaced fuel pump with second hand one
5. Replaced coil with second hand one
6. New distributor cap
7. New spark plugs
8. Checked vacuum lines
9. Added injector cleaner to fuel

None of the above has made any difference and now when idling (when running rather than stalling!)the car idles at around 1300 revs rather than 900-1000. I have just bought a fault code reader and plugged it in and got the following 4 fault codes which I could use some help in interpreting in terms of replacing an item or it being a symptom of something else being at fault. The 4 faults are:

1. 0513 Engine speed sensor (G28): Sporadic - signal outside tolerance

2. 0518 Throttle position sensor (G69): Static - short circuit to earth

3. 0530 Throttle position sensor (G88):  Static -  open/short circuit to earth

4. 0520 Air Mass/Air Flow Sensor (G70)/(G19): Sporadic - Open/short circuit

I'm actually happy to have the above faults as I was running out of ideas of how to fix! I'm assuming fault 1 requires a replacement part and faults 2-4 are an earthing issue? I did unplug the air mass sensor to see if it improved the running so would this show as the fault 4 above or is there an earthing issue as the fault suggests?

Help much appreciated from this fantastic forum!

[Callum_K]

Engine speed sensor, also known as the crank sensor, is a very common cause of cutting out/stalling issues. The wiring tends to get brittle where it runs close to the engine, and they can fail intermittantly. Make sure you get an OE quality one (though not necessarily from VW) as the cheap ones are poop (one last 2 days for me). Easy to fit as long as you have some axle stands and a jack to support the engine, as you need to remove the frotn engine mount/starter motor to get access.

[dixie180]

Same old Mk3 issues i'm afraid.I had similar with mine and had to have the throttle re-aligned after i had cleaned it out.Had it done on a proper VAGCOM and worth doing m8.Similar problem with crank sensor and worth changing that too.The air flow sensor will show a fault if you have disconnected it.
Good Luck


Rob

[NickGold]

Thanks guys. I'll get a replacement crank sensor, clear the codes and see what happens from there!! I think I may well have unplugged the TPS as well hence faults 2 and 3 so fingers crossed I fit a new crank sensor and all is well.

[dixie180]

Hopefully m8.If not i would definitely get the throttle body re-aligned as it has made a big difference to the performance of my 8v.


Rob

[boneybradley]

clear the faults first and then rescan in a few days. alot of people (inc garages) don't wipe old codes when fixing problems

if the same codes come up then it's time to spend fixing those issues

[NickGold]

Thanks for the advice. Turns out the wiring connector on the crank sensor was split and letting in water. All fixed and working fine. Fault codes cleared and then checked a few days later. Thankfully fault free!

[dixie180]

Good ol Crank Sensor fault  .
Happy Motoring chap.


Rob

[spudboy6]

Sorry to hijack ,

Does anybody know the procedure for throttle body alighnment ? I have access to full VAG COM at work but being a Toyota dealer I have no idea how to use it !

[dixie180]

Go to http://wiki.ross-tech.com/wiki/index.php/Throttle_Body_Alignment_(TBA).


Rob