UPDATE! On Misfire & Lumpy Idle

Well I ordered new injectors and fitted them this morning and the verdict is……

Exactly the same!  

The misfire is still there, had the car at the garage to check emissions and they confirmed the missfire is the, my emissions are completely up the wall.

Car was misfiring between cyliners 3 & 4 so had a fiddle and now appears to have moved to 1 & 2??????  The car has a new ditributor cap, arm and ignition leads and still exactly the same…

Its over to you!  All help appreciated as I feel an add in the autotrader coming on if its not sorted soon ha ha

Do a compression and leak down test to check out the state of the engine.
Before that though id do a test using either carb cleaner or brake cleaner in an aerosol form to test for airl leaks.

Run the engine and spray the carb/brake cleaner onto all vacuum pipes and intake manifold joints etc (dont go mad dont want a flaming death now do we?  ).
If youve got an air leak itll raise the engine revs either a lot/little depending on how big the leak is.

Overboost,

Cheers for that, the head has only just gone back on the car after being refurbed so pretty sure there are no leaks?? But will go and check again.

When it was on the gas analyser with normal idle the hydrocarbons were very high, after taking the rev's to about 2000 they drop to almost nothing, raising again when it returns to idle???  Had the idle screw thing out and give it a clean and replced the little rubber grommet on it but still no change!

Hmmmm

I'd check that the warm-up injector and warm-up bypass hose are both doing their jobs right, and not leaking (the injector) or staying open after the engine is warm (bypass hose)

Then check that the acceleration enrichment valve is OK (if you have one - I suspect it's only campaigns and later cabrios that do - but worth a check). It's usually bolted to the side of the airbox/airflow sensor.

Check the earths as well (I'm beginning to sound like a quack doctor pushing leeches as a universal panacea - "check your earths! check your earths! and everything will be OK!).

Have you had the airflow sensor out and given it a clean? Could be sticking, or the idle clip could have been adjusted and mucked things up.

My DX engine got very lumpy when the vacuum hose across to the idle enrichment/stabilisation valve on the left hand side of the engine bay (looking into it from the front) came adrift.

Sounds to me like you need to put your deerstalker on, reach for your pipe, text the indomitable Dr watson and start checking EVERYTHING.

• Listen for vacuum hissing away when the engine's running
• look for disconnected wires/pipes
• Feel for loose connections (electrical and others).

Then when you've eliminated the obvious, what remains, however improbable, is the answer;

[the pixies are doing it]  

Ali Cabrio

OK another Update!

Just been to see someone who hooked the car up to an ossiliscopy (Not sure that is spelt correctly?)

It would appear that the coil is only giving out 9kv, which is apparently 1/2 what it should be, there is also some very eratic switching which I'm told could well point to the ign amplifier??

What are your thoughts??? Does anyone have an Ign Amp the want rid of??  I have a spare coil and will get this swapped soon.

Finally I seem to be getting somewhere!!!

It could be the ignition amplifier, or coil. At least you can diagnose and see the misfire, with the HC reading at idle. Not sure but I think I have a spare TCI, but I won't know if its available for sale until I've finished my car.

Cheers Paul,

I've now put another coil on, seems a little better but still not 100%.

Anyone else got a spare TCI going???

All help appreciated.

The Campaigner said

Cheers Paul,

I've now put another coil on, seems a little better but still not 100%.

Anyone else got a spare TCI going???

All help appreciated.

Hi mate ive got a spare TCI off of a digifant golf, it has the big heatsink on but itll work directly in place of the original.

Yours for the price of postage.

Let me know where to send it.

Overboost

I've sent a PM

Cheers Pal

Did this resolve the missfire? I have a missfire under acceleration when the engines hot in the 1.6gti