Missfire now won't start
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Marco , edymikis
thank you for taking time out to offer advice.
I have checked for a spark and all appears well. Next i moved onto the diagnostics box. The cap doesn't tell me which pin is which so i don't know where to plug in the LED etc to pull the codes.
Does anyone have a diagram?
Gaz :(
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So it tries to start and turns over but won't fire?
Sound like its trying to fire or not?
Do you have any immobiliser or alarms installed?
Got spark on ALL plugs?
Got fuel pressure?
Got any signs of anything broken? metalic noises when turn over? belts snapped?
Did anything happen before the missfire? hit a bump, pothole, drive through water, any overheating, weird noises?
Whats the inside of the dizzy look like?
What condition are your leads in?
Try and turn it over in the dark with someone watching the engine bay without a torch to check for arching.
Any signs of head gasket failure? oil in water / water in oil?
Have you flooded it? leave plugs out overnight to let it evaporate off…
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Hi UKmxadmin
Sound like its trying to fire or not? A.Sounds like it is trying to fire.
Do you have any immobiliser or alarms installed? A. Yes but seams fine.
Got spark on ALL plugs? A. Checked 3 and were OK.
Got fuel pressure? A. Not sure how to check this?
Got any signs of anything broken? metalic noises when turn over? belts snapped? A. None broken & no funny noises.
Did anything happen before the missfire? hit a bump, pothole, drive through water, any overheating, weird noises? A. I was returning from a 80 mile round trip without incident then about 1/2 mile from home it starting to miss fire/loose power briefly. Parked up then wouldn't start next day.
Whats the inside of the dizzy look like? A. Haven't checked but what should i look for?
I appreciate your help, thank you.
Gaz
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Tried to start the car this afternoon (God it's cold out there) and it fired up and started first turn of the key but died after only a couple of seconds.
I then tried to pull any fault codes. I wired up the LED and link wire then turned on the ignition. The LED lights up and stays on.
What does that mean?
This is driving me round the bend.
Gaz
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Odd question, does it have fuel? Both my Mx3's fuel pumps have gone faulty reporting the wrong fuel level on the dash, took me ages to find it the first time, not so much the second thou lol
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Hi Lori
i put £25 in before doing the 80 mile journey so i am pretty confident it still has fuel in it.
cheers
Gaz
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A mate that has Green Flag membership came around and called them out.
The mechanic turned up and i explained the problem. He attached a booster to the battery as it was partially flat from me trying to start it over the weekend. He turned the key and she fired into life leaving me looking like a right tw*t.
He revved the car and when done gently it was fine but if he booted it the engine coughed and spluttered and nearly died.
I drove the car for approx 20 miles and again if i gently rev it and ride the clutch a bit it was OK. The problem occurs when trying to pull out at junctions etc when the engine is under load it tries to die.So again i would like to know if this is something someone has experienced?
The Green flag chap suggested that it was "Over Fueling" but again i'm not sure what that means or how to cure it.
I would appreciate any help with this.
Gaz :?
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Your engine will be running too lean due it pulling more air in through a split rubber air pipe from the air filter box to the TB. Wrap loads of strong duct tape around it and you will find that it will idle fine. Check the pipe for splits, common problem as they are most likely the original and they perish over the years.
Also take off and clean any breather pipes from the PCV valve on top of the front rocker cover, gummed up one cause running problems.
HTH
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Hi timorridge,
thanks for that i will have a good check of the air pipe. Can you tell me what you mean by TB?
Gaz
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Throttle Body, the 3 pronged fork that sits on top of the engine where the rubber pipe connects. Assuming you have a 1.8 engine?
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If you don't know how to test fuel pressure then best you don't try and do it. Its starting now anyway so its getting fuel.
To check dizzy take off the cap and look for any obvious signs of corrosion, burning or wear. Also remove all leads and check contacts for signs of corrosion.
How does it idle? low/high steady/hunting
Check all air hoses for signs of a leak, look for cracks, splits, improper seating, has it collapsed or gone soft etc
Take off air box and VAF and have a good look over the hose going from the VAF to the Throttle body for any splits or cracks.
Look at the plug going to the VAF for any signs of corrosion.
Push the VAF cone in very gently and let it slide back out gently, isit smooth? or does it get stuck/jerky? does it slide back out? it should be spring loaded.
Check that the plastic resonator is fitted properly. (bit that fits to the concertina inlet pipe after the vaf.
Look at the breather pipes, are they clear or gunked up inside?
Look at the throttle body, is it clean or dirty inside?
IF ITS DIRTY it might be worth Looking up how to clean the TB and all bits attached and set them up properly. TPS, Stepper/IAC etc
Check all the small vacume pipes on the inlet manifold for leaks, remove them all and refit.
Check all pipes going to the PCV and also to the EGR.
Thats enough to be getting on with…
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ukmx3admin
wow that is a comprehensive list of things to check.
Looks likely to be a job for the weekend as by the time i get back form work we only have about half an hour of light left.
I really appreciate all your help and i will keep you updated.
Gaz :(
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timorridge
thanks for your help. I will keep you updated.
Gaz :?
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Every thing you have mentioned and experienced gazzoouk
strikes a chord with my nightmare a year or so ago! (do a search on my posts, the one in the newbie bit) I'm no expert! (as recently discovered/proved) lol But Id take a stab at coil/hall trigger unit in dizzy? coil is quite easy to check with a good meter?
Unplug the 3pin and 6 pin plugs on dizzy and check the male/dizzy side.
primary winding resistance should be @20 oC (not today tho!) between the first two pins on the 3 pin dizzy connection (1st is pin closest to ya)
0.49 - 0.73 ohms ?
For secondary, (remove dizzy cap to expose coil post) put a meter between pin 1 again and the recently exposed coil post should be 21000 - 31000 ohms
(21k ohms - 31k ohms dependent on meter range) In these sub zero temps youll prob get lower readings but any readings out of spec maybe point to ya prob?????
The hall trigger/IG unit is a difficult beast to check? I could find no 'base' meter readings to check against anywhere online etc so took plunge and bought a new unit (UKPS) fitted, sorted straight away
:P
Pulling codes did not work for me, I had strange 'ghost' codes of '10' '11' '13' etc, I reset ECU, fitted item, vvvrooom! good to go :P
Not saying for deffo it is that for one moment, but from experience with 2 failed coils and 1 hall/IG unit in 2.5 yrs and virtually mirrored symptoms/issues, worth a check? Hope ya get sorted gazzoouk :o
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Thanks blackmevyv6
thats interesting to read. Now i am again going to sound like an idiot but what and where exactly is the hall trigger/IG unit.
Thanks again
Gaz
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Sorry gazoouk, its all in the distributor body! best thing to do to check everything, is remove dizzy cap with leads still attatched (less chance of mixing up) then remove whole dizzy body? (Two 12mm bolts on dizzy mounting flange on side of front cam cover/ cylinder head). also check the 6 posts in dizzy cap and the center carbon brush ( on one of my caps the brush was burnt away! but still ran ok ish!! ) As mentioned before on here, if everything looks ok in cap best leave rest alone in there? coz after removing rotor it all gets a bit complicated under the next circular black cover where the hall trigger/vanes/ig unit live! if ya dont mark everything with a black pen or something it could get messy on re assembly??? :( best do the meter check 1st then dig deeper ? good look hope ya get there :) kev b
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blackmexyv6
Kev,
thanks for that. I will be having a look at it on Saturday and will let you and all know how i get on.
Gaz :?
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Hi gazzoouk
another side effect of 'one' of my failed coils, was while trying to start while cranking, there was no evidence of her trying to fire, ie 'NO' occasional 'thum' in:- zze…zze...zze...thum...thum...zze...zze...zze...zze...thum...zze...zze...zze..
zze = sound of starter thum = a spark at a plug? strangely I only got an attempt to fire on 'releasing' the key from start position to run (ignition on)??? for about 3 seconds I got thum..thum........thum.thum...thum...........stop! My father (domestic electrician) commented something like "thats crossover current from one set of windings to other, either primary or secondary has failed/shorted/open circuit and other can't build up/maintain current in its windings or enough to maintain a regular spark output!" :( Dint mean much to me but on that occasion I aquired a coil unit, fitted, reset ecu, linked TEN and GND, started, ran til fan cut in, removed link, test drove for 10 miles, sorted ! :P (for about a year til hall/IG unit failed?)
Its your initial statement about "80miles or so in RAIN" that rings true with me! electrics and water? mmm :?
If ya do take dizzy off completely? and it all looks like it should under cap etc? try sticking the whole thing in oven at 80. oC for ten mins or so (no higher or longer tho) get ya gloves on and re fit it sharpish and see if itll run? it might need some heat into it? NO? try opposite end of temp test? in freezer for a hour? :shock:
Is the bonnet nose to bumper upper lip garnish/seal (20mm wide rubber strip that follows bonnet nose contour) intact on yr vehicle???, rain+80mph air pressure+ a failing seal? directly backwards from that is dizzy to center right and alternator to lower left and frnt 3 bank of plugs?
When ya did LED, did ya also link TEN and GND at same time? if ya just jumped TEN and GND with LED! it prob would just light up and stay on????
Pull codes its: 'LED+' lead in B+ (battery12 v) , 'LED-' lead in FEN (fault engine)
then on yr jumper wire its one/any end in 'TEN' (test engine) and tuther end in GND (ground/earth) all tiny sockets in 'DIAGNOSTIC' box! turn key to on (dont try to start) LED should light almost straight away for approx 4 secs then either go out (no codes) or flash to display codes eg.. dar...dit (11) or/and.. dar...dit...dit...dit...dit (14) or/and.. dar...dar...dit (21) etc
if there are code/codes they run a sequence and then repeat anyway! time for a marker pen and paper! I did capital 'I' for long flash and lower case 'i' for short flash for about page and a half?? space em out on page and youll soon see codes and the repeat sequence???? tint easy but worthit if ya do have codes?
(NEVER 'DRIVE' WITH JUMPER AND LED IN DIGNOSTIC BOX!!!) safest way is "lid on nothing in it, bonnet shut no tools under it!) before a drive!I hope ya not daunted gazzoouk Ive gleened all my knowledge off UK-MX3
theyre a great bunch on here X all infos here ,somewhere and its free :lol: feel for ya and hope ya back 'in love' wi ya mexy soon I will log in tomoz for a peek :D kev b
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Kev and all
I got hold of a multimeter to test the dizzy;
primary winding resistance should be @20 oC (not today tho!) between the first two pins on the 3 pin dizzy connection (1st is pin closest to ya)
0.49 - 0.73 ohms ? I Measured 0.50 ohms.For secondary, (remove dizzy cap to expose coil post) put a meter between pin 1 again and the recently exposed coil post should be 21000 - 31000 ohms
(21k ohms - 31k ohms dependent on meter range)I measured 0.600 ohms.
would this be the problem? I still seem to be getting a spark as i pulled a plug lead and fitted a spare plug and got the Mrs to crank the engine whilst i checked for a spark and it seemed fine.
Also whilst i had the dizzy apart i cleaned and dried the points etc. I checked all hoses for signs of splits or leaks and again all appear fine. I removed all spark plugs and cleaned them. I did not that all were wet will fuel.
I recharged the battery re-fitted and attached a booster pack that i have borrowed (as this is how the Green flag chap got it going) but it just didn't want to start.
I re-did the LED test and again the LED just stays illuminated.
I am really getting p#@@ed off with this as it ran so well prior to this and to top it all it's just started snowing.
HELP
Gaz
