Well, I've mailed Jeff about this, but I'm reluctant to *keep* bothering him with foolish newbie questions when I might as well ask them here ;)

 

My NA Zed is running on five cylinders - when this first happened the cat overheat light came on for a bit, but after easing off it disappeared, and while limping home up the M1 I only saw it once more. The engine smoothed out by the end of the journey, was fine the next day, but since then has been running on five constantly. ECU diag gives code 55. Oh, it might also be worth mentioning that I've been running *very* rich recently.

 

From a search, and from Jeff's advice, it's a dodgy connector or spark plug somewhere, right? OK, well I tried disconnecting what I assume are the coilpack connectors, one by one, and the dodgy cylinder is the middle one on the left (looking from the front into the engine bay). This is where my mechanical aptitude runs out and the stupid questions flood in:

 

Coilpack connectors: They're the chunky grey and black plastic connectors on each cylinder, right? I hope I've got this right :S The contacts look clean and shiny, and the connectors themselves are well pushed together. Is that all I'm looking for here?

 

Injector connectors: I'm loathe to investigate these because they're buried under the central cover, and because they have those little wires clips I am no good with. Am I right to think that it shouldn't be these, because of the cat overheat warning? I've not seen the warning light since, but then I've only trundled to the supermarket, taking it very easy - should it be appearing even then, or do I have to boot it to get this effect?

 

PTU: This was replaced a few months back, but it's possible the connections are a bit ropey. Again, I'm loathe to take things off to get to it unless it's a likely suspect. I kinda prodded the rubbers round the connectors with the engine running, and I got a dip in revs, as if I'd lost a cylinder - is this normal? Or could it mean I have a screwy connection and it just happens that only one cylinder is down *so far*?

 

Spark plugs: OK, where *are* these? :confused: In a flash of inspiration I undid the chunky thing next to the coilpack connector (held on by two 12mm bolts), but that didn't free anything, and I couldn't see what else to undo, so I put it back.

 

So, many thanks for any advice you can give. Please remember I am a technical moron, and any explanation or advice should be accompanied by fool-proof instructions on how to identify the relevant part. Sorry to be such a drag :/

If all else fails I'll limp onto the motorway and call out recovery to drag me to Jeff's, but it seems a little extreme for just a spark plug...

This may not be related at all but;

 

I was on way to work the other morning and I pulled up at some lights and suddenly the Z souded terrible, missing and sounding like a V12 and juddering..........

 

........I crawled the 150 yards to work worried.......

 

Got out of the Z, lifted the bonnet, mooched around couldn't see or here anything apart from the really bad lumpy grumble (It had done this a couple of days before but only for about 20 seconds and stopped)

 

I was late for work and stopped the Z and clocked in ;)

 

Went back out at lunchtime with tools and other stuff, I was ready for anything!!

 

Started up the Z and no grumble..... :confused: ....thought WTF is going on then I heard it........

 

.........I had a split pipe, it caused the Z to run lumpy (feel like it was missing) and run rich........it was sucking in air!!

 

 

May be your problem, maybe not but worth a look for cracks and tears in your pipe work around your fuel rails.

 

Matty.

Thx, and for the picture too :) I'll check tomorrow when it's light again, meanwhile wait for more suggestions.

 

I *have* noticed a smell of petrol while messing under the bonnet (and my sense of smell is terrible, so I guess it must be strong), plus at least two pipes have some orangey crust around them where rubber hose meets metal pipe (the rest of the engine bay is pretty clean), as if something's been leaking. Neither of these pipes were specific to the cylinder that seems to be down, but it's worth checking properly, yes... and they might be a contributing factor, at least.

Would the cold weather cause things like this to get worse? The night this happened it was frickin cold, and I was bombing up my *ahem* private test track *ahem* at about 100-110mph (once the engine was warm, of course), so perhaps extremes of temperature like this stress the rubber/metal pipe connections?

 

I couldn't hear air hissing under the bonnet, but with two 3.5" exhausts and a poorly engine, it's unlikely I would. On the "sounding like a V12" issue - heh, yeah, at low revs it does kinda.. when I limped back from the supermarket it was school chucking-out time, and I got twice as many "pwhoar! whadda beast! how fast does it go, mister?" comments as usual. Heh, youth ;)... I was cringing at every chug :(

If your smelling petrol under there get tightening the clips on the fuel lines too.........

 

Best bet would be to change all the hoses under the bonnet for silicon ones 4mm and 6mm (get those from Smithy in Trader section) and also get rid of the fuel rail and and replace that with two braided fuel lines, also from Smithy and at about £65 for them lot it's a good deal!! (I did this and will post pics over the weekend) makes the world of difference IMHO.........plus the braided lines look the muts!........

 

Well I don't worry about splitting hoses now, specially as the ones under there are 12 years old, and have been subjected to all sorts of temp ranges and I'm sure they all would have started to go.........

 

The V12 noise isnt good from insode the car!! :eek:

 

Matty.

...using the picture as a guide, if you look in front of the red circle you'll see a coil pack. it should have 2 bolts holding it down. Remove the electrical connector, remove the 2 bolts, prise up the metal top so that you can get hold of it, and lift out the coil pack. You'll see its a transformer on top of a spark plug rubber connector.

 

Then, if you look into the space the coil pack has left in the engine, you'll see the spark plug. Keep looking, it's a long way down.

 

You'll then need a spark plug socket of the right size (smaller of the 2 common sizes) attached to a long enough bar to be able to reach down and unscrew the plug.

 

Now you can check the plug for damage. Sometimes the electrodes at the end of the plug can wear - but this is unlikely on your car as it most likely has platignum tipped plugs which last forever.

 

More likly is that there's some rubbish stuck between the surfaces of the electrodes preventing the spark - although I've never seen this other than on an old Fiesta.

 

If the plug looks ok, place it into the coil pack, re connect the coil pack and place it onto the engine in a position where the metal part of the plug makes good contact with the metal of the engine.

 

Get someone to turn over the engine and watch for a spark from the spark plug. If you see one then you've got problems.

 

If you don't then suspect the coil pack. To test this remove a ''good'' coil pack and repeat the test. If you get a spark then the original coil pack could be faulty.

 

...from here I'm out of my deapth, but it's the natural starting point.

 

good luck

 

Jack

Smart, good info, thx :) Yes, this was where I suspected the plug might be (under those two 12mm bolts), but I obviously wasn't rough enough trying to get it out (plus I didn't undo the connector). I'll try and borrow a socket off my mate so I can get this checked tomorrow.

 

It's the outside metal of the plug that needs to make contact, right? And do I need a mate, or if I start it myself should I be able to see it sparking as the engine runs?

 

If there's a spark, then that means I've got injector problems or something serious, yes? And if there's no spark then it must be the plug (which I can check visually), the coilpack (for which I can do the test you suggest), or the coilpack connector (which looks fine)? What about the PTU idea? Is it unlikely only one cylinder would go down if the PTU connections were dodgy then?

 

Anyway, I've got some good ideas for what to try tomorrow now, thanks, and at last I know where the plugs are :)

OK, here's an update :):

 

I tried swapping coilpacks around, and the dead cylinder stayed the same. I tried swapping sparkplugs round (they looked pretty brown, but basically fine), and again the dead cylinder stayed the same. The coilpack connector looks fine, clean as new, and the wires going into it seem fine.

 

I couldn't find a mate willing to spend a coupla minutes helping me check if there was a spark, but the smell of fuel I mentioned before is definitely strongest round the exhaust, so this implies the injectors are working, and that I'm almost certainly just lacking a spark, right?

 

Don't think I can hear air hissing under the bonnet, but it's hard to tell with all that noise going on. I tightened the one pipe I could find that had crust round its joint, checked every fuel line I could see for visible splits, and sniffed for petrol to no avail (like I said, my sense of smell ain't that great, but I can certainly smell it round the exhausts, very strongly).

 

So, any more thoughts here? I'm guessing a sensible next step might be to check the electrical signal from the coilpack connector, but I haven't got a multimeter to hand, and I don't even know what signal I should be looking for, or which of the three connections to use. Any other signals I should be checking if I *do* have to scrounge a meter?

 

And finally, is it worth pulling the PTU connectors off and having a look there? Chasing the wiring, it seems like there's alot to go through between the coilpack and the PTU, and I've got no idea how directly the PTU connections correspond to specific cylinders.

 

Really, I don't know if I'm missing something stupidly obvious here, sorry if I am :(

Had the same problem on my TT. Traced it down to the wiring. Got an auto electrican to look at it as the wires seem to dissappear into lots of dark places! After two days and £150 got the car back and has run perfectly ever since!!:D Turned out there were several wires that had gone brittle probably due to the lack of air flow caused by such a tight fitting engine. Unless your a wiring expert i would suggest you take it to a good auto electrican. Good luck

Thx mate :) It's going to Jeff's for a once-over tomorrow afternoon, so with any luck he can confirm exactly what it is (didn't want to go to a non-specialist because they could easily turn round and just tell me it's the PTU cos that's the only thing they can think of).

 

The wiring looks solid, but like you say, it disappears into all kinds of tight dark spaces, and you never know what could be going on in *there* :S

Try giving the PTU connectors a good shove around ;)

 

Matty, that pipe is for the fuel pressure regulator - if it leaks, fuel pressure will be higher than it should be under idle and cruise (read as running rich) and lower than it should be under boost (read as lean). The FPR basically keeps the same pressure differential between the fuel rail and the intake runners to ensure the correct amount of fuel delivery.....

 

HTH

 

CheerZ,

 

Andy

Ah, andyduff... was hoping you'd turn up ;)

 

Yeah, I've taken the PTU off, crimped up the contacts a bit, and put it all back - still no joy :( Jiggling the connectors on it before made it sound like another cylinder was going down, but at no point did the dead one kick in. I've not jiggled it since the crimping (lost heart a bit tbh).

 

I gather it's possible but rare for a PTU to fail on one cylinder, so maybe that's it. Jeff will have a spare one I guess, so we can test that tomorrow. Bit of a cop-out if it turns out to be that, though...

Sounds like you may have a broken wire to the coilpack. Have you tried simply replacing the plugs? ;)

Well, I tried swapping the plug on the bad cylinder with the one next to it, but no change to either. Likewise I tried changing the coilpacks round, with similar effect. I'm such a newbie at this kind of thing, I figured that would rule out both components (does it?).

 

The wiring *looks* solid where I can see it, but of course some of it disappears into crevices in the engine block (er..I think). After it emerges it is quickly gatherered up into one of those neat plastic pipes that keep the wiring bundled.

 

But yeah, seems like it *must* be either the wiring or a freak PTU failure. HOWEVER, I've still not checked the injectors (because I'm too fat-fingered to get the little wire clips off the connectors), and I've not checked visually whether I've got a spark (because I have no friends to help me out, and I'm worried about the coilpack rolling off the engine block while I'm at the wheel, or something going wrong that necessitates cutting the engine while I'm messing around in the bay). The exhausts absolutely reek of fuel, though, and there's the whole cat-overheat business, both of which suggest petrol is getting through (I guess the running rich maybe also confirms this?).

 

I know these should be checked next, but I'm too clumsy to be trusted, which is why it's being dragged to Jeff's tomorrow. That way the PTU can be ruled out, and hopefully the wiring can be multi-metered.

Is there anything else it could be that I've not thought of? Like I said, I'm new to all this, so I have a very simplistic view of how the whole system works :S

 

Oh yeah, mention of cats reminds me I meant to check what happened to that thread about de-catting NAs...

Try the following easy steps and you will get to the problem.

 

Spark plugs/ coil packs/ PTU/ ECU - You can test this with the engine running so you don't need a buddy to help.

Check for spark on Cylinder 3 (that's the middle one on the left). To do this unbolt the coil pack but leave the plug in place (otherwise you get fuel shotting out all over the place).

 

Put a good plug (maybe a cheap one from halfords £2, but make sure the thread is the same) into the coil pack and check for a spark. If you get a spark try it again using the plug in the cylinder. If you get a spark it's not a plug or PTU related problem - go to injectors section below.

 

If you get no spark with the new plug, then swap the coil packs and try again. Spark ? Yes = coilpack problem. No = connector/ ptu/ ecu problem.

 

Try swapping the PTU for a know working PTU, if it works then it's the PTU, if it doesn't work then it's the wiring or ECU. Best to get get this checked by an auto electrician. oir you could try rewiring the coilpack connector for a new one.

 

Injectors / CAS /ECU

Ok so we have a spark, then it may be the injector, easy to check this one. mark the position of the crank angle sensor and unbolt it (three bolts 12mm), with the CAS still connected the the harness turn the ignition on but do not start the engine. you should hear the fuel pump noise as normal, slowly turn the cog on the back of the CAS clockwise, you should hear an injector click followed by a swoosh of fuel then the fuel pump fire up, keep turning slowy until you hear each injector fire, listen over the engine for this where the injectors are connected. Can't hear the number 3 injector fire ? if you can't then it's a CAS/ connector / wire /ECU or connector problem. Or it could jsut be a blocked injector, try some injector cleaner in your take for two tanks worth and see if that solves the problem.

 

What's next ?

If you do get a spark and you can hear the injector then you only have one thing left to check !!!!. You have fuel , you have spark you obviously have the air, but do you have the compression ?. Do a compression check on all your cylinders to get an average and see if your cylinder is low in compression. if it is then you need to do a cylinder leakage test to find out what the problem is.

 

If the compression is fine, the fuel is fine and the spark is fine, you obviously missed something because it has to be one of these three "simple" :eek: things :D

 

Hope this help, no really I do because my fingers are bleeding now :(

Just have to say that if the zorst smell of fuel that it's likely that you either have a spark or vavle problem on that cylinder.

Hehe thx, that's very comprehensive :D

 

Yeah, I'd not thought about using a spare cheapy plug to do the spark test - doh, nice one :) And I had no idea where to go on the injector side of things :S Hopefully get this sorted tomorrow now, thx again for all the input :)

 

[last second edit: yeah, the zorst *stinks* of fuel - I think it's the right hand one, which also seems to be producing less smoke/vapour. That ties in with the bad cylinder being on the RHS of the engine, I guess :) I'm praying it isn't a valve or compression thing, cos that sounds expensive :S]

With these cars it's usually an electrical fault. It's not like vavles to go on their own, they usually all pretty much go together, pistons on the other hand :eek:.......

 

 

Good luck, if you get stuck tomorrow during the day drop me a mail on stuart.waterman@ants.co.uk, and I'll get back to you straight away (my work address, I try and do as little work as possible until they pay me more LOL).

Thanks alot, I appreciate the help :)

 

Yeah, I'm hanging on the electrical idea - it's been over-fuelling for a coupla weeks since the weather got wet, so it seems likely, I guess :/

Originally posted by baby ice dog

Thanks alot, I appreciate the help :)

 

Yeah, I'm hanging on the electrical idea - it's been over-fuelling for a coupla weeks since the weather got wet, so it seems likely, I guess :/

 

Could it be the damp affecting the AFM? Does an AFM read high or low if there's water in the air intake? If it makes it read high that'd cause overfuelling...

Resolved! It was the darned PTU all along - it had failed on just one cylinder :o

 

I'm hoping the over-fuelling was related to imminent PTU failure - it's been fine until a couple of weeks beforehand. However, this also corresponds to the start of the wet weather, and as I might have mentioned, I sometimes get a chuggy flat spot up to about 3k rpm when it rains (but only after the engine's warmed up :/). So, these might be related and separate to the PTU stuff.

 

I'm gonna clean the inside of the zorsts and watch how fast this tank of fuel goes, *then* start worrying ;)... at least I'm on the road again :)

Originally posted by baby ice dog

Resolved! It was the darned PTU all along - it had failed on just one cylinder :o

 

I'm hoping the over-fuelling was related to imminent PTU failure - it's been fine until a couple of weeks beforehand. However, this also corresponds to the start of the wet weather, and as I might have mentioned, I sometimes get a chuggy flat spot up to about 3k rpm when it rains (but only after the engine's warmed up :/). So, these might be related and separate to the PTU stuff.

 

I'm gonna clean the inside of the zorsts and watch how fast this tank of fuel goes, *then* start worrying ;)... at least I'm on the road again :)

Glad you got it sorted mate

 

Well if the ptu failed on a cylinder you will be getting unburnt fuel coming out of your zorsts. Once the ptu is back up and this should stop the smell. however if you can still smell it in the engine bay then tighen up the fuel lines (just follow them from the fuel filter to find all the clamps).

 

The flat spot may be O2 sensor related. Do you get a slight jumpiness when you are holding the car between 2k - 3k rpm ?. If so it's the O2 sensors mate. Rain into the MAS will cause the car to suddenly loose power and run like kak for another few seconds before the water is evaporated, the car will then run fine again.

Jumpiness..? Yeah, that sounds about right - at 2-3k it's kind of coughy and jerky. When you put your foot down, yes, it runs like kak for a few seconds, stumbley and without much power, then everything clears up. Tbh, I'm not sure whether it clears up because it reaches higher revs, or just because a few seconds have passed - have to try and check this out next time ;)

 

So yeah, sounds like you're right :D Good good, that's the most helpful advice I've had so far on the wet weather stumble (it's tough to diagnose because it's only intermittent). Thanks *alot*, I thought I'd never get that niggle sorted :)

the O2 sensors are bypassed until the coolant temperature reached 70 degrees, then the ECU starts using them.

 

So if the hesitation doesn't happen when it's cold then it the O2 sensors (cost about £100 to replace and takes about an hour with the right tools or 5 days with the wrong ones ;) Quickest I've done both is about 24 minutes :eek: ).

 

The cough and power down will usually happen on hard acceleration, when the induction draws the most air in.

Yeah, it definitely doesn't happen when cold, but it's more than just on hard acceleration, I think. Anyway, sounds likely - when I get some cash together I'll get that done and maybe the speed sensor at the same time (more intermittant dodginess there...) :)

Sorry I probably wasn't very clear there.

 

O2 sensor fault

Cold no hesitation between 2k - 3k rpm

warm hesitation between 2k - 3krpm

 

MAS

Sudden lost of power on hard acceleration

Usually when the ground is wet or it has been raining.

more frequent whenthe car is cold.

Riiiiight, gotcha ;) O2 sensors it is then :) Thanks alot! :D