My saph has developed a misfire under load. It started when I was driving back from silverstone classic in torrential rain.

I checked the three connectors at the back of the engine bay and found a small amount of water in the middle plug. I have left this plug disconnected all week to let it dry out and have also replaced my ignition coil, put in a new wiring loom for it and replaced three ht leads (got three used ones with the car). I have also cleaned the crank position sensor which was a bit gunked up and checked my distributor and rotor arm which both look fine (they were replaced fairly recently).

The car is still misfiring above about 3000 revs, I am going to get a new set of spark plugs and leads but am fairly sure, from reading old threads on misfiring issues, that the cause of this was water getting in to that middle connector, i'm going to spray some wd40 in it to try and disperse any remaining water but after doing this I'm not really sure of the next course of action. Does anyone have any advice that might help me sort this out?

 

set it on fire

ive changed basically everything in my bay and still not cured my missfire

good luck

 

Solder the multiplug connections most people say

 

..How old is your battery?

 

I have now replaced coil, spark plugs, leads and cleaned the crank sensor. I also found a small lake in my spare wheel well and water has got into my inertia switch, don't know if this could cause a problem?

The misfire is not as violent as it was before but I've noticed my revs have started to become a bit erratic, when i lift off the throttle, the revs go up to about 2500 rpm and then drop to the point the car nearly stalls before going back up to about 1500.

I was looking at the cambelt last weekend and noticed the car was a tooth out of time so I have timed it correctly and it now idles better than it used to. I don't think it slipped a tooth though as the cambelt was on tight and there are no signs of damage on the belt and would have thought that the car would idle badly if any out of time valve smashing shenaningans had happened.

I am going to have a bit more of a root about at the weekend, the fuel filter and pump are new but there seems to be a small amount of damp around the fuel filter so I think it needs tightening up.

I have also tested the resistance on each injector and they all read 6ohms and my electrically minded friend has made me a diagnostic tester which I am also going to try (if it works and I can find the diagnostic socket)

If anyone else has anything that might be worth looking at or trying I would be eternally grateful as this is my only car and I've only had it three months and I'm starting to get a bit fed up with it.



set it on fire

ive changed basically everything in my bay and still not cured my missfire

good luck

Very tempting! Cheers mate, I have read about your plight, hope you get yours sorted. Seems like this is a bit of a common problem as there are a lot of threads over the internet. I did find one (for a 3dr) that said to test the coolant temperature sensor and check the wiring loom for the injectors, apparently that can get tight and become stressed when the engine moves under load, might be worth a look if you haven't already


Solder the multiplug connections most people say

That sounds like it is worth a go, cheers for the advice, take it other people have had a problem with that back connector then?


..How old is your battery?

Looks fairly new but I've only had the car about three months so don't know for certain, never had any trouble starting the car even if its been sat a couple of weeks. Some of the connectors to it look a bit scummy though so I am going to take them all of and clean them up at the weekend.

 

Erratic idle could be just a dirty idle speed control valve...or it could be further indication of damage to the loom resulting in an erratic connection. But personally I like to start with the cheap and easy things, like cleaning the ISCV.

Do you get the misfire without boost also? If it comes only with boost, at what level?
Which plugs did you get, and what gap are you using in them?

 

The misfire only starts when I first boost but then will start misfiring at lower revs and idle as well.

I shall clean the ISCV this weekend and try that

I originally had some motorcraft 071s which I gapped to 0.61mm and then replaced these with denso iridium IK27s, I haven't checked the gap on these

 

..does it misfire when you diconnect lambda sonda?

 

Aftermarket ecu with coil on plug and a brand new loom should fix it, I know this costs a packet but his forum fUll of these type of posts. I certainly fixed mine and made it so much nicer to drive.

 

..does it misfire when you diconnect lambda sonda?
I don't think it has a lambda sensor, its a non cat model

Aftermarket ecu with coil on plug and a brand new loom should fix it, I know this costs a packet but his forum fUll of these type of posts. I certainly fixed mine and made it so much nicer to drive

Got a sinking feeling that I might have to splash out on a new loom but don't really have the money at the moment, especially if that doesn't fix it anyway.
Don't really want to go for coil on plug if I can afford it cause I've just shelled out a shade over Ł100 for new leads and ignition coil.

I've got a few things to try this weekend and next, decided if I can't fix it by the end of the month I might just swallow my pride and take it to a garage. Car's been off the road more than on in the short time I've owned it and just want the damn thing running again

 

Can you drive it off boost? I'm trying to gather here whether the misfire is related to revs or the boost. What gauges have you got, can you see the boost level? What about mixture, or fuel pressure?
You should check the spark plug gap again, mine misfired even on idle when the gap was too large.

Fault finding is easier if you've got a friend with spare sensors and even an extra ECU to try in place of the originals without having to buy everything new. If you had the chance, I'd start by trying the car with another ECU.

 

Unfortunately I have no cosworth powered friends so every part i want to try I have to buy. I'm also not that experienced with mechanics, especially not diagnostics so am relying on reading old threads about misfiring issues to try and fault find (amazing how helpful the passionford lot are!).

I tried the old plugs on original gap, then gapped them to 0.61 then swapped for denso iridium. I'm not sure if it's rev or boost related, will try and figure it out at the weekend. I do have a boost gauge so should be able to tell.

When the misfire started it would only start to misfire when I put my foot down but would then misfire even on idle.

Now that I have replaced coil, leads, plugs, cleaned crank sensor, dried out middle back connector and timed correctly it runs a lot better and will actually rev for a short while before starting to misfire. It starts misfiring under boost but will then continue running rough at idle and nearly dies when I lift my foot off the throttle.

I have recently upgraded the fuel pump from standard to a bosch 044, wondering whether this might have caused the fuel pressure regulator to fail???

I still think it has something to do with water getting into the middle connector at the back of the engine so am going to try cutting the wires and soldering them together. The fact that there was actually a drop of water inside the connector seems to suggest that it must have seeped through the wiring which can't be good, was hoping a ton of contact cleaner and leaving it disconnected for a week in the warm weather would have dried it but it might not have done if the water has got right into the wiring.

Failing that I'm going to get a sensor kit from msd and swap all my sensors and if that fails i'm going to give up and give it to a proper mechanic because it's my only car and I'm getting fed up with the lack of transport (it's seriously cutting in to my fishing time!)

 

Oh the joys of cossies. Puts me right of ever owning one!

 

Have you tried phase sensor timing (dizzy position)........check for correct gap ..0.2-0.3mm..
also it might help to check fuel pressure reg...they are known for broken dia..you can take it out and test it with hand pump..

 

There not all bad, all fast cars have their problems it's just that not many reach the age of the cossie

 

Just to rule out mechanical failure, have you done a compression test?

 

I have now replaced crank sensor, phase sensor, air sensor and coolant temp sensor.

I have also cut all the wires from the ropey middle connector and rejoined. Unfortunately, ford seemed to have run out of brown and red and black and yellow wiring when they put my piece of crap together because all of the wires are colour coded except I have two brown and yellows and two black and reds on one side. To be fair I should have paid more attention when I took it all apart and done one at a time.

I have also taken all the connections off my battery, cleaned them and put them back on.

The car will now not start at all it turns a bit and then just stops trying.

I noticed that there was a smell of fuel when I took my air sensor out and that there was some in the vacuum hose for the FPR as well so I have now replaced this.

Unfortunately I am just starting to get angry with the damn thing so I am going to roll it down to a garage conveniently located at the bottom of the hill I live on and hope for the best.

Thanks for everyone’s help and suggestions.

I have not done a compression test as I don’t have a tester and have spent enough money and time on tools and parts. Think it will be cheaper in the long run to get a professional to look at it.

 

What did you replace? The hose? Then you should probably get a new FPR.

 

My Cossie did misfires under boost when the cable from alternator to battery was loose. It obviously also didn't load the battery properly. Don't know if this is the case here though, it sounds weird if it first misfires on boost, and only after that starts misfiring on idle. If you restart the car after that, can you then drive without misfires off-boost?

Is the battery fine, does the alternator load it correctly? If not battery voltage related problem, then it maybe sounds like it's fuel system.

 

I replaced the FPR but haven't tried starting the car with it on yet as I accidentally locked my keys in the boot (boot lever in car doesn't work) and decided that was a good time to give up on the car and go down the pub (found spare set eventually).

I'm thinking battery might be causing me some problems, it's flat as a pancake now and I've been trying to jump start off my mates battery from his xr3 and some heinously cheap jump leads. I've borrowed a battery charger now so going to fully charge my battery and see if that fixes it. Battery seemed fine before as I could leave the car for well over a week with no starting problems, it looks fairly new as well.

I will check the alternator cable, looks like it's seen better days if i'm honest and I've changed the alternator belts recently so will definitely be worth checking to make sure I haven't damaged it further or knocked it loose.

I have until next wednesday to get the car running again before I have to book a recovery truck to take it to SCC on thursday.

Wish me luck!

 

Good and bad news, car is now running with no misfire. However, it is occasionally running lean now and the garage reckon it could either be map sensor or ECU.

I'm running a level 1 Ahmed Bayjoo chip with 18 psi boost and just been looking through my folder of receipts and found out a previous owner bought a 3 bar map sensor. I'm pretty sure a stage 1 is supposed to be a 2 bar but as the car was running fine when I bought it so I'm not sure whether I should be putting in a 2 or 3 bar sensor.

The car has apparently had a 3 bar map sensor in it since 2011 (haven't checked its actually in the car) so I would have thought the car would have run badly when I bought it, not just started playing up now if it wasn't set up for a 3 bar.

Any advise would be much appreciated.

 

A while back my 2wd started playing up, would not idle, kept cutting out when I stopped at traffic lights etc. It was a knackered 3 bar map sensor, put a new one on and it fixed it straight away.
I have had a new engine, fans and fuel pump wiring loom and wasted spark ignition plus all new sensors and it runs like a dream.
Old original wiring looms are are source of a lot of problems on Sapphires.
I have had mine for 21 years and things do wear out just like they do on any other car. I realise it all costs money but you can "modernise" a Sapphire and build reliability into it.

 

check map sensor if its there, the map sensor depends on what chip it is. check you have required voltage from fuel pump.

 

At last! The car is finally running again!

I don't know why people keep moaning about trying to fix YB misfires, turns out all you need to do is replace ecu, map sensor, crank sensor, phase sensor, air sensor, coolant sensor, coil, plugs, leads, fuel pressure regulator, do some re-wiring and leave it off the road for 3 months... easy!

On another note, if anybody wants to buy a kidney I now have one for sale.

Big thanks to saint albans car clinc for repairing my dodgy wiring and getting the car sorted for a phenomenally reasonable price. Highly recommend this garage to anyone.

 

Haha good to see its sorted. Always see cosworth threads now that people are having new looms built

 

Happy days! Got to love the regular breakdowns to keep us up to speed lol

 

Hi James glad to see the Ecu sorted the car out.thanks for the fast payment .

 

Cheers for sending it over so fast, it actually arrived the same time as a map sensor I ordered 4 days before.

 

Glad all is good now..

 

I am afraid that so many Cossies haven't had anything checked or replaced and you need some of the experts to track stuff down and good old fashion money to fix it.

I hope you can now enjoy it. Well done for not giving up on it.

 

My 3 door has suddenly started missfireing at 3k revs, it seems OK when cold then when upto temp it starts to be on 3 cylinders at 3k revs and then gets better after 5k revs, any ideas?