Poor running / loss of power in the wet ??? (91 J- plate 8v Gti - digifant)

[theombudsman]

Hi All,

After giving me ole faithful a spring clean and tidy ready for the summer... .have been getting frustrated with a poor running problem when out in the wet. I have kept my eye on this prob for a few weeks now, but car nearly gave up on me on the m25 yesterday... not fun... foul day...pi$$ed it down...  it pulled through though.

Reckon water is getting in somewhere, but not sure where the problem is. The distributor cap seems dry enough. The leads and coil look dry aswell. Got me stumped

Anyone able to throw some light on this, would be great. It's really odd this problem, as my old mk1 gti which has I understand more or less got the same engine as the mk2, never had any of this tomfoolery going on.

I'd like to have a go at sorting this out myself if poss as I am well skint at the moment.

Here's fingers crossed it's not an awkward problem.

Cheers.

[rubjonny]

The MK1 while the engine itself is pretty similar uses has the mechanical K-Jet injection system, completely different to the electronic digifant system

First thing I'd check is the ECU under the plastic scuttle tray for traces of damp, pull the plug out and clean up all the connections.  Then check the drain holes at either end of the scuttle area for blockages.  Next take the dizzy cap off and check inside it for water/damage. In fact if it hasn't been done for a while you might as well just replace the cap & rotor arm anyway, not expensive   Even if it doesn't solve the problem you have a known good set of spares if you need em later on.

Another thing to do is run the engine at night, reving etc and check for arcing from the HT leads, much easier to see at night.  After all that then start looking at the wiring for signs of damage, particularly any lower down in the engine bay which might suffer from water spray.

[monzablue16v]

Also whilst doing the above get your friendly can of WD40 and spray into dizzy cap and around leads plugs etc. An old fashioned old mobile fixer both my mini and my GTI ran on two cylinders or stalled out or just didn't start moisture gets in ur dizzy cap and stops the contacts working properly try that as it has worked for me many times!
And check your earth straps these can sometimes be affected by serious British weather.

[KKK]

Second that.  Check your gearbox to chassis earth strap - if it fails completely the ECU fries.

KKK

[Veedubgt18v]

also check that the airflow meter flap in the airbox is water tight, mine used to leak and caused crappy running just dried it out and siliconed it back on

[theombudsman]

Dudes.....

Sorry not got back sooner.. thanks for the advice will have a look at that points over the weekend. Good suggestions.

Cheers

[monzablue16v]

let us know how you get on  also the alternator is quite prone to getting wet and can cause problems with some things check all your rubber boots are secured onto the connectors and try taking some off and see if they are corroded etc. Go through your engine with a fine tooth comb! a haynes manual and a can of WD it'll prolly b ok let us know how u get on good luck!