Developed A Misfire Whilst Sat

[number2301 1 1 Cars]

The latest annoying problem on my 1.9 GTI which has been off the road for 3 months now is its developed a misfire. Now its just been sat so surely nothing could have broken, and last time I drove it a couple of weeks ago it was fine. But I started it after doing some work on the brakes to test them and its misfiring terribly from idle all the way through the rev range and will stall if I leave it for long.

 

At first I thought it might be due to having virtually no petrol in it (last trip to the petrol station was aborted due to a driveshaft noise) so stuck a few litres of super unleaded in from a can.

 

I'm completely stuck because I know very little about cars and am learning it as I'm going along, and I haven't got as far as engines yet!

 

I was planning on starting with just a normal service, oil filter, plugs, air filter, maybe fuel filter depending on how it looks and see how it goes from there. But does anyone have any tips based on how it happened?

[notamondayfan 44]

HT leads? could have moisture if its been sat for a long time. give em a squirt of wd40 and see if that improves it.

[Simes 248 2 Cars]

I've got a missfire too happened in a similar way, it's sort of documented on an ignition amp thread, athough my missfire is between 2700 - 3300 and once warm and when it feels like it.

 

It sounds to me like you may have a dodgy HT lead. I'd first of all unplug and replace each lead (one at a time) to ensure a good connection is made. See what happens there.

[Tom Fenton 1,526]

How long had the fuel in the can been sat there? Petrol does go stale after a while, if it has been sat a while a tank of fresh fuel may well perk it up again.

[number2301 1 1 Cars]

It was fresh fuel from the petrol station as I thought exactly what you said, that the little fuel there was in the tank had gone off. A few litres worth would be enough to sort it out though surely?

 

When you say spray WD on the HT leads, I assume you mean take them off at one end, quick spray, then same at the other?

[Anthony 1,000]

Take the dizzy cap off and see if it's damp inside - that's a favourite trick of cars that have been sat parked up for a while.

[number2301 1 1 Cars]

Update on this, its had £20 worth of fuel, a good long run, a set of spark plugs (not new but in good condition from a 1.0 Micra) and just today a new distributor cap and rotor arm.

 

The run cleared it up a bit, then the plugs made it a bit better again but its still missfiring really badly and massively down on power. The missfire seems to be worse under load, as in accelerating, but it seems alright when you're just cruising along.

 

Any idea what the next bit to check should be?

[dcc 855]

check the oil, if its milky, could be a headgasket.

 

only changed the ECU on my car, and my headgasket went! (sometimes the strangest things can bewilder me)

 

my symptoms were the same as yours.

[Wallby 39]

I had the same sort of problem as this. On mine there was a bad connection between the leads and spark plugs as there was a build up of soot.

[kate205gti 4]

best bet is get someone to come over with a running 205 1.9 and swap a few bits

 

start with leads, dizzy cap and arm, then try AFM and ignition amp, check all the electrical connections to the AFM, coil, etc.. in case any have corroded

[Alastairh 47]

First off. Run proper plugs for your car.

 

If its under load missfiring. Change the coil. Worth cleaning your earthing points aswell.

 

Al

[maturin23 10]

Mi Mi16 developed a misfire after not running for a couple of months.

 

Racked my brain and swapped out a few parts with no positive result.

 

Next weekend I fired it up and gave it some revs - after about a minute or two the misfire cleared up, suggesting to me it was probably just moisture.

[number2301 1 1 Cars]

Right plenty to go on there cheers, I figured since the plugs didn't really make any difference they could be doing any harm but I'll get them swapped over. Its done a good 40 miles since I got it going again, so unfortunately I don't think its just moisture somewhere

[Guest cooper205]

sounds like a possible coil problem to me(almost certainly lack of/ weak spark), also when you changed the ht leads did you change the main coil to dizzy cap lead?

[Smudgey1985 0]

hate to be the bearer of bad news but sounds like headgasket to me

[number2301 1 1 Cars]

Haven't done the HT leads yet, I'll have a session of swapping bits over when the weather clears up a bit and see how that goes. Otherwise my next thread might be about headgaskets!

[luggy 13]

Had a similar issue with my conversion, it would missfire really badly sounding like a trabant, running intermittantly on 1 and 2 cylinders, everything was know good because they were removed from the donor vehicle which was running well. Swapped everything over for spares which I had to get the donor running in the first place, still no joy, replaced AFM things did improve but it was running constantly on 2 cyls.

 

All spark plugs were removed and checked for spark with corresponding lead at dizzy which were fine, plugs on cyl 2 and 3 were wet. Replaced spark plugs now it runs fine.

[munster 0]

I was just about to make a new thread until i saw this..

 

I have just returned form a drive my MI, and it has developed a real 'mis' or hesitation at 3 - 4 k revs.

I then had what sounded like a back fire.. Below 3k its fine (idles and starts no probs)

 

Recent HT leads and plugs. Could it be this muched talked about Igniton Amp?

 

Could someone provide a picture of what/ where it is?

[munster 0]

well i had a closer look and it appears i have an Intermotor coil and Igniton amp. Which from reading another thread on here, they seem to have a bad rep.

 

what is this single wire going to the coil?

 

http://i268.photobucket.com/albums/jj33/ka...r1/Image000.jpg

 

It is down to the bare wire where it joins the moulded black part, so im hoping this might be the cause.

Edited August 8, 2008 by munster

[munster 0]

Turned out to be the Ignition Amp.

The intermotor one i had only lasted about a yaer then..

Edited August 9, 2008 by munster