Misfire

Typical, fix one problem and then another comes along!

My 8v GTI has devolped a misfire under load. On start up its fine, then as it gets hotter the misfire starts. With my foot on the throttle only slighty it runs perfect, and when going down will it will rev no problem. But if I then put my foot down on anything else = misfire & no power.

Please help!

Has the fuel pump got noisier? Could be lack of fuel, could be spark. When was the car last serviced, new spark plugs, new HT leads, new rotor arm, new dissy cap?
More info might help us with you problem...

Dizzy cap and rotor arm are pretty much brand new gen VW parts, spark plugs are probably 1-2 years old. HT leads don't know age. 

All was fine until a few days ago

Id wack a new set of leads on it dude. For what they cost. I had the same symptoms on a different car in the past. The leads were ok under idle and plodding around, as soon as they were put under load they just packed up and wouldnt deliver a strong enough spark.

Chris

http://www.ebay.co.uk/itm/VW-Golf-Mk1-Cabriolet-1-8-15-08-84-07-92-BOSCH-IGNITION-SPARK-HT-LEADS-B338-/181125459559?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2a2beb2e67

x2 mine seems to hit in about 2000 rpm then when you boot it it judders and you can hear the engine struggle like a misfire, it doesn't do it when at a stand still only when under load.

I had new dizzy, rotor arm etc 2 years ago, but didn't do any miles in it. I think I had new leads at the same time.

Been out and cleaned the rotor arm and the contacts on the dizzy cap.

Checked all the leads for dirt all clean and good.

is there a relay that kicks in when you throttle it under load?

Engines I am not good at lol.

Any other ideas?

Did some experimenting on the way home, it will rev fine if I keep my foot only slightly on the throttle. The second I push my foot further it judders/misfires. As soon as I back off the throttle is fine again. 

At one point on the way home I was happily cruising alone doing 60'ish fine with no problems, but as soon as I press the throttle further it starts again. 

I've recorded a video of it, I'll upload it in a minute

sounds the same as my issue Bob…

It's getting me annoyed now :0(

The only isse I had of late was the idle screw unwinding it's self so revs went up high.
Wound it back in again and no issues.
There is an O ring that goes on the screw could it be allowing more air than need be in when accelerating hard.
The air being forced past the idle screw?

Just a thought.

http://www.youtube.com/watch?v=qyI6mty8_Qs

Dont know how to add a direct video on here

About 8-9 seconds in you can hear it juddering and at 23'ish seconds

in at about 37 secs onwards

sounds the same fella

It feels like a flat spot no umph if you put your toe down, but if your gentle it doesn't seem to reach the bit where the engine struggles.

This must be an easy fix? If both of our Rivages have the same issue then it must be a common problem?

I can't even get my head round why mine can accelerate up to 60 with minimal throttle fine, but then judder/misfire with 5mm more of the pedal movement??  

Vacuum/air leak?

just been and took my idle screw out and the O ring is as flat as my locals beer…


It's located just behind where throttle cable goes on the clip. Maybe worth checking yours. Been trying to look for the answer but it appears to be different solutions, IE leads dizzy rotor coil etc. I am sure jelly put new leads on for me when he did the short service for me, only thing I haven't had new was the coil.

What's your petrol gauge on? I am on under a quarter so gonna fill her up and see if that makes a difference. But not noticed this before?

Timing ?

Another good point, but would it just all of a sudden go out of time?

I Don't know when the last cam belt was changed, so it's on my to do list, along with gear linkage kit.

Right I sorted my woes!!!!

It was the bloody dizzy cap! And it's a genuine VW part less then 6 months old!! 

I compared it to my old one that I kept and noticed the coil electrode in the centre was pitted. 

Here's what the old correct on looks like:


Here's what the one I took off looked like:


What would cause this to happen to a brand new cap?



It drives perfect now, 1 lesson learnt here is NEVER throw away parts, they WILL come in handy some day!

I might take it back and demand a new one!

I would mate and tell them you got stranded and lay it on thick