Starting Problem (205gti 1.9)

[Sy_ 0]

Right, I rectified a previous starting problem and the car's been running fine for a 2 weeks. Filled up with Optimax (or V-Power now I guess) and since then the thing has been a mare to start.

 

The morning after filling up took 3 turns (each of 10secs or so) to fire, and since has been getting worse. Now (3 days later) she won't fire at all.

 

Up until now I've been running it on normal 95 unleaded and it just seem strange that the problem's happened straight after filling up with 98 - but could this just be a red herring?

 

There's fuel getting to the rail, and there's a spark getting to the plugs. So I'm pretty confused.

 

Car is a 1993 Kplate CAT GTi, with Motronic injection. Any help much appreciated as this is driving me nuts.

[matty_gti 20]

Could just be a dodgy batch??, you could just try adding a normal 95 ron fuel (normal inleaded) and see if that makes a difference. Unless the dodgy fuel you have in now (if it is dodgy) has damaged the lamba sensor in the exhaust if it has one??

[Ahl 4]

It might be worth checking if the injectors are working. Also check the air flow meter (or map sensor and crank sensor.)

 

What do your spark plugs look like?

[Sy_ 0]

Thanks for the replies on this guys, in response:

 

- I'm pretty sure the injectors are working as there's a fuel smell from the cylinders when removing spark plug, and it has driven around 80 miles since the problem started.

- I checked the AFM pinouts not to long ago and all was pretty much ok

- spark plugs dont' look too bad; generally grey/sandy deposits with some black marks round the edges (possibly from previous overfuelling problem)

 

I'm gonna try draining the fuel tank, filling with 95 Unleaded, running some through with the help of some EazyStart and see where it lies. I feel a bit uncomfortable replacing components when I can't rule out the fuel quality. Will update soon.

 

Cheers.

[t16ryan 1]

Do a compression check free to do ( if ya can get a gauge ) and will tell you alot

[Andrwn8304 0]

Might be down to that contaminated fuel aswell.

 

Take the plugs and put a little drop of old fuel in the pots and try starting it.

[Sy_ 0]

Alright,

 

Update on this: drained fuel tank (to almost empty), filled up with 95ron Unleaded and the problem is still present.

 

Car will start (reluctantly) with Easy Start, but not without it. Once started, runs fine.

 

Does this mean that it's probably not overfuelling? Any ideas greatly appreciated.

[pugrallye 0]

if its starting on easy start its really overfuelling... i mean REALLY, or... you are leaking so much oil into each cylinder (unlikely)

[smckeown 1]

if its starting on easy start its really overfuelling... i mean REALLY, or... you are leaking so much oil into each cylinder (unlikely)

 

as the plugs are dry i'd say the opposite. Could it also be the starter isnt turning the engine over well enough ?

[jonah 1]

Could be an ignition problem (coil, dizzy cap etc). If the spark is weak then it may be struggling to ingite the mixture under compression, but still produce a visible spark with the plugs removed and earthed on the block. Also the battery voltage drops when cranking on the starter which will make the spark even weaker, which could explain why it runs fine once started.

[Sy_ 0]

Thanks for the replies -

 

I believe the starter is turning the engine over fast enough - well it certainly 'sounds' like it is, though it's no proof.

 

How can I go about checking the strength of the spark - I'm guessing my multimeter won't like 16kV?!

[jonah 1]

No don't try using your multimeter!

 

Dizzy cap and rotor arm you can check by eye, clean em up while you're at it, but for the coil your best bet is substitution with a known-good one. A new coil instantly solved a non-start problem on a mate's 309 GTI, and that was also managing to produce a spark with the plugs removed, so I can vouch that coils do fail in that way. Although I can't guarantee that it'll fix the problem in your case...