Cold start problems

[TimGti]

Yeah, they are somewhat worn

Redex is a good shout, I'll pick some up later and stick it in. Might even have some in the house already I think.

[alexperkins]

Economy should improve now!

[TimGti]

Economy should improve now!

That would be nice. Might stick some redex in the S3 too, some more economy out of that wouldnt go amiss

[TimGti]

Well, been for a 30 minute drive. Car starts ok again now, but engine check light has returned within a few miles.

Under acceleration 75% of the time the car feels like it might be starved of fuel. Instead of smooth and steady acceleration, in starts to accelerate, but then holds back briefly before continuing to build revs (kinda 1/2 second smooth, then 1/2 second holds back, on a continuos cycle) almost like the fuel supply is lacking or an Injector is clogged. This makes for a very jerky acceleration!

The same codes (+1) have returned:
16684 (Muiltiple misfire detected)
16685 (Misfire Cyl 1)
16688 (Misfire Cyl 4)

Gonna clean the leads tommorow and stick redex in. Do the leads ever need replacing at all that you've heard of ?

Beyond that, Wikiross suggests it might be injector or fuel pressure related? Not quite sure where to start it thats the case

[alexperkins]

Leads last 50-60k in reality and should be replaced on the service around 60k for optimum output and stability of voltage.

Thats interesting. You might have a faulty coil pack you know

[TimGti]

Do you have coil packs on the GTI then? The symptoms would point to that, but ours is a 2001 without coil packs!

[alexperkins]

All the polos have electronic ignition (DIS) since the start of the Mk5

The lack of power could also be down to a blocked fuel filter, a vacuum leak, dirty throttle body, ignition timing out - theres alot lol

You say you had the G28 sensor - thats interesting. You are reffering to the crank sensor on the back of the block? When that fails, you get similar problems

Id try redex, and giving the throttle body a full cleanout with carb cleaner, plus squirt all the HT leads at both ends

[TimGti]

All the polos have coil packs (or it can be known as a DIS) instead of a mechanical distributor

Ah right, I assumed there werent any as they aren't above the spark plugs like all the 1.8T's I've had. So is there still 1 per plug/cylinder & they are located at the opposite end of the leads to the plugs then? Wish I'd looked earlier when it was light now. Can I still replace them individually?

I replaced the camshaft position sensor G28 to the right hand side on top of the block. Wiki does say the problems Im now having might relate to the G40 sensor though (back of the block I believe).

[alexperkins]

You'd normally flag a fault

The coil pack is integral to the DIS on the polo just to make life difficult

You have a 1.4 16v 75bhp then?

[TimGti]

Its a 1.4 8v (60bhp) Match.

So just to clarify, the coil packs are within the Dis? By this I assume its the 'distributor cap', ie directly at the end of the leads? So are there 4 coil packs, that can be replaced seperatley?

I cant quite picture how it looks/works when they arent on the plugs end like on the 1.8T's Ive had! Sorry for all the questions, I'm so unfamiliar with this engine!

[alexperkins]

fair play.

Aye its an integral coil inside the DIS (its not a distributor pack, as it is a distributorless igntion system ie DIS lol). The unit is replaced as a whole and no you cant replace the integral coils seperately - one new unit.

[TimGti]

Ahhh I see. Is that one new unit including the leads aswell do you know?

Knowing the amount of issues Coil packs give on the 1.8T platform, its very likely to be this. Symptoms are the same, even down to the engine management light flashing under 'juddery' accleration.

[alexperkins]

No the leads are seperate lol

Aye 1.8Ts munch coil packs like nobodys business. Yes it could be that, but try the cheaper options I suggested first lol you may find it fixes it!

[TimGti]

Went and squirted/ cleaned both ends of the leads today with Wd40 and refitted, cleared the codes. After a 10 mile test drive to the petrol station (where I added some Redex for good measure), it seems to have worked. Smooth acceleration and no EML up as yet

I'm not holding my breath just yet until Ive driven it more, but its looking good!