Very Slight Missfire

[djinuk 2]

well , i have finished putting together the 205 i brought with a blown head gasket , plugs and leads are new, i started her up (cam timing may not be bang on as its has a heavy skim) and she started up first time, no missfire, sounds lovely, after about 10 mins of ticking over the top of the engine went very noisty, i turned it off and checked oil was getting to the top, surely enough it was, so i started it back up .. perfect again, so i took it for a drive, oil pressure is in the middle, water temp slowly went up, and stayed, and it ran perfectly, then after 5/10 mins of running a very slight missfire, especially when going slow began, i got the car home 10 mins later (engine warmer) and the missfire was worse, although oil pressure and water were both good so happy there. Ive read up on the forums of so many different things it could be, just wondering where to start first.

 

 

just to add , 2 times on my journey, the oil pressure dropped straight to 0 and my stop light lit up, but before i had chance to pull over it shot back up, so i am hoping thats a loose connection on a sensor somewhere.

 

 

 

the heads had roughly 30 thou of it, however i have simply set the cam timing etc exactly how it was when i took the head off, could this simply be the problem ?

[DamirGTI 342]

Hi !

 

Maybe it's just the moisture inside the dizzy cap/leads/ignition amp. connector etc. ... try spraying this parts with some contact spray or WD-40 ... if this doesn't helps check all ignition components starting from plugs and moving forward to leads dizzy cap rotor arm coil ignition amp ... and try playing with ignition timing - advance or retard a little bit and see if that helps (if the head is skimmed down it could be the ignition timing is slightly out ..)

 

Have you been washing/cleaning the engine with water maybe ?

 

From your description this sounds like coil or ignition amp problem to me ... as it gets worse as the engine warms up ..

 

Cheers !

Damir

Edited January 6, 2008 by DamirGTI

[Sandy 191]

With that much off the head, the cam timing will need adjustment, but usually the symptom is laziness rather than intermittent misfire.

[djinuk 2]

i also have the laziness i think, a slight delay when i put the foot down, but,.. i blamed this on miss fire, tomorrow ill give the ignition parts a run down, . is there any chance you could give me a run down of the ignition amp (where to find it) and the coil

 

also will the cam need advancing or retarding sandy, plus which way is this, towards the front or back of the car

[DamirGTI 342]

i also have the laziness i think, a slight delay when i put the foot down, but,.. i blamed this on miss fire, tomorrow ill give the ignition parts a run down, . is there any chance you could give me a run down of the ignition amp (where to find it) and the coil

 

also will the cam need advancing or retarding sandy, plus which way is this, towards the front or back of the car

 

..adjust the ignition timing first and see if that helps

 

Damir

 

EDIT : see this : http://www.205gtidrivers.com/info/enginelayout.html - the ignition coil is next to the exp. bottle and the ignition amp. is beneath the coil on the aluminum plate (only the Ph2 cars have ignition coil mounted on the inlet manifold)

 

Cheers !

Edited January 6, 2008 by DamirGTI

[205007 12]

i thought the oil pressure and stop light were wired seperatley? seems odd you have both issues without actual loss of oil pressure

[djinuk 2]

not sure, well the head gasket had just been done, so maybe a dry spot in the engine

[Sandy 191]

If the cam timing is out, the ignition will be too! The cam needs to be advanced (turned anti clock at the timing belt end) until the dowel lines up.

[djinuk 2]

sorry a bit confused there, when i put the engine back together i put the cam belt on so that i could get a 10mm dowel both thru the cam at the top, aswell as the pulley at the bottom, its this correct?

[paul_portsmouth 3]

mine seem to be wired together before i did my headgasket my valve stems were that bad the oil kept getting low and as i would go round corners thhe oil light stop light used to come on as it was reaching the pic up

[Sandy 191]

Well if the dowels line up ok, the timing should be right. The problem though is that the Compression ratio will have been increased, retarding the ignition may be necessary to avoid damage.

[djinuk 2]

just realized, earlier i was on about adjusting my cam timing , i actually meant ignition, so please forgive me . tomorrow i am going to take a look, is it worth me simply renewing the ignition amp either way, how much are they ?

 

i didnt hear any pinking so im guessing that is a good sign, so therefore im hoping the dizzy should be correct, which way do i turn the dizzy to advance the ignition timing.

[djinuk 2]

ive just taken a quick look at the wiring on my ignition amp to the dizzy, i pulled the rubber of the plug to see the cables in a bad state and it was full oil oil grease, water , all sorts, am i best to chop this plug out and rewire with spade connectors ? my car has the ignition coil on the inlet manifold , does anybody have a part number for one of these

[djinuk 2]

just spoke to somebody else regarding my missifire , he mentioned that the shims could be incorrect , could this really cause this kind of problem ?

 

At the moment i am just trying to sorce a igniton amp

[Sandy 191]

Check the valve clearances, if they're out, it could be a factor.

[djinuk 2]

i personally would hope not as the guy that did my head was a top bloke and well recomended, but we will see. Tonight i have brought a bosch ignition amp as i removed mine and indeed no paste was evident on it. I am going to fit it at the weekend, and replace my alternator wiring to see if it solves the battery light dimly lit problem, i will then take it out again for another test drive, if problem persists i am going to borrow a known good air flow meter and see if that solves anything.