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Misfire


Weekend Warrior

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Thinking back my Misfire ,I think,only started after my fuel leak.The hose from the regulator to the fuel rail came loose and fuel was leaking out .After I’d fixed it by tightening up the jubilee clips the misfire seemed to start ,could it be related or just coincidence .On a trip out over the weekend on initial start up when turning the key the engine sort of stalled followed by loud backfire ,it then started fine.

Any ideas ?    I want to try the basics before taking it to a garage and paying them to work through a list charge a fortune and tell me it was a loose wire .So what can I check myself ? I assume plugs ,and  leads  what do I check for and how .do spark plugs need torquing up ,if so what setting on 2.0 zetec blacktop 

It ticks over ok at the minute and only seems to misfire under hard acceleration ,if the sun comes out is it ok to keep driving as is ?

Steve

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If it is over fuelling you run the risk of bore wash.  If you ruled out the TPS, then the next step I would do is new leads (or swap them if the length allows it).  Have a look at the plugs and check for gap/soot, and replace them.  These are the cheap options.  Not sure what version of coil pack you use (for Zetec there are two with different connectors), but if it is the old 'mushroom' type, then I have a spare brand new coil pack you can try out before you spend £££.

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Thanks for the reply Quinten I haven’t ruled out anything yet as I don’t really know what to look for hence the post .

is the coil patch the thing with the red and blue wire coming out the bottom ?

what are the symptoms of bore wash ,am I right in thinking you do a compression test to check this /

 

 

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Easy way to check for bore wash is to smell your oil,it shouldn't smell of petrol. 

If it does you run the risk of knackering your engine,as the fuel washes away the oil from the wall of the bores which protects the piston rings and bores.

The starting issues could just be the map needs fine tuning for cold running,the issue is when mappers map a car they only have very limited time to map the cold running,unless of course you leave the car with them for a week so they have lots of cold start time!

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2 minutes ago, CosKev said:

Easy way to check for bore wash is to smell your oil,it shouldn't smell of petrol. 

If it does you run the risk of knackering your engine,as the fuel washes away the oil from the wall of the bores which protects the piston rings and bores.

The starting issues could just be the map needs fine tuning for cold running,the issue is when mappers map a car they only have very limited time to map the cold running,unless of course you leave the car with them for a week so they have lots of cold start time!

Thanks Kev ,The starting issue only happened once the last time I used it ,and the misfire is a recent thing .

ive still got the oil from the last oil change in a sealed container in the garage ,it’s 2000 ish miles old I’m off for a sniff 

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49 minutes ago, Weekend Warrior said:

is the coil patch the thing with the red and blue wire coming out the bottom ?

No, that is your TPS (throttle position sensor).  Just check the screws are still secure on it.

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That thing above (yours will likely be on the back above the bellhousing) is the coil pack (without the HT leads).  Thats the type I have too, so compare it to yours...

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I had a misfire on mine once at high revs turned out to be the crank sensor

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@CosKev  I had a sniff and wasn’t convinced smelt a bit treacly, how strong would it smell ,does 2000 mile oil smell like new oil or would it have a tinge.

First thing I’m going to do is check the plugs ,if they’re soot free does that indicate no bore wash ,is a compression test easy to do and ,if all is good with the compression can I breath easy .

 

Steve 

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You need to check the plugs after a run out when the engine has been upto normal temp,don't look at them after a cold start as they will be sooty.

I would bang a new set of plugs in whatever seeing as you are removing them to look at them,for the price it''s not worth refitting the old ones IMO.

Ref the fueling do you know anyone at a local garage etc with emissions testing equipment? 

If so just pop the car in and ask them to see what the emissions are like at idle as a start point

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How olds the fuel?....  also.  If you need to tighten a fuel hose maybe the fuel line is degraded.   A bit of rubber in an injector would certainly change the running. 

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9 minutes ago, DamperMan said:

How olds the fuel?....  also.  If you need to tighten a fuel hose maybe the fuel line is degraded.   A bit of rubber in an injector would certainly change the running. 

The fuel is never older than the last suny day,the tank only holds £22 quid or so and lasts about a hour and a quarter Ona brisk blat .

It’s a 2013 car so lines new then.

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Re the fuel line repair. I'd recheck that area too, you may have a restriction, or be pulling in air under extreme load?

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  • 3 weeks later...

Just a quick update re the misfire in case anyone is searching through old threads 

Changed the plugs and fixed a wire on the water temp sensor and it’s running better than ever 

I know all cars are different but if your worried sick and thinking the worst don’t panic it’s never as bad as you think 

 

Steve

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Hi @Weekend Warrior. I have perhaps a similar issue to you on a 2.0l Zetec blacktop. You mention a problem on a water temp sender. I am assuming you have two senders like mine, one in the cylinder head between cylinders one and two and another either in the thermostat housing or in the feed pipe?  If so, which one did you have the wiring fault on?

cheers

Bob

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Hi Bob I know sod all about cars ,but as said After all the advice all I did was change the plugs and crimped a wire at the location marked by the red arrow .I haven’t got a clue if I have one sender or two .

 

Hope this helps ,if not don’t worry one thing I’ve learned after a lot of car paranoia is it’s never as bad as you think it is 

 

 

Steve 

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