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C18XE problems.

Andy

Andy

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Could somebody please help me before I set fire to this POS car.

A few weeks back out of the blue my car started running poorly.
It sometimes struggles to start from warm, misfires at idle and misfires at full throttle. If I feather the throttle it's ok, but the moment I floor it it sounds like a 4 stroke dirt bike upto 3k, then coughs and runs fine.
I flashed the eml a week back and it came up with '19 Incorrect revs per minute signal (crank position sensor) - Incorrect signal, check sensor'.
A cheap new one was fitted, but it made no difference. I bought a new supposed gen one yesterday and fitted it today, again no difference, but now for no f*cking reason the eml has started flashing up '71 Intake air temperature sensor - High voltage' as well, WTF?!

I've just checked the engine loom for any obvious broken wires, but couldn't see anything out of the ordinary, the sensors are all plugged in properly, I even gave them a spray of contact cleaner.

Any suggestions before a reach for mr lump hammer and the car ends up looking like a golf ball?
 
Where would the earth be. The one above the pas side headlight?
 
Tightened the battery terminals, then undid the earth above the headlight and gave it a clean with a wire brush and a spray with degreaser. There's no chance of me getting to the one on the gearbox, as it's completely buried under the inlet manifold behind 20 wires and pipes (bloody 16vs).

After that I thought I'd give the icv a clean. Took it off and gave it a good spary through with carb cleaner. Before, if I quickly jabbed the throttle cable with my hand, it'd splutter then rev. After I cleaned the icv it revs fine by hand.

Or so I thought. Excited that I'd fixed I took it out for a test spin, planted the throttle and it's just the same. Spluttering badly and back firering.
 
Grab a jump lead, put it on the battery negative terminal and the other end, straight onto the cylinder head or block.
This will prove if you have any earthing problems in the loom.

Another thought, is the ECU nice and dry? Also, timing belt correctly tensioned and timed up?
 
Does it run any better with the afm disconnected? I had a similar issue on my XEV but I had that many spares I changed everythin so never narrowed it down :lol:
 
Got this sorted finally thanks guys, turned out to be the coil in the end.

Tried the jump leads and swapping sensors for old ones, checked the timing, found the gearbox earth and gave that a clean... nothing.
Gave it a service and new ht leads, it ran better but was still missing quite badly. No EMLs were flicking up and remembered Tom saying check the coil, so got one from work for 15 quid and now it works fine. :)

Still has a slight miss at idle, but it had that before the poor running so it's back to 'normal' lol.

Thanks again. :thumb:
 
Nice one Andy. Is it definitely missing at idle? I only ask because all the C18XE'd cars I've had (including the current one) idle so low, they sound a bit 'choppy'. Mine sits at around 650rpm and the sun roof rattles :lol:
 
I'm about to go out and work on it, so will report back. :)
 
Rancid_Ron said:
Nice one Andy. Is it definitely missing at idle? I only ask because all the C18XE'd cars I've had (including the current one) idle so low, they sound a bit 'choppy'. Mine sits at around 650rpm and the sun roof rattles :lol:
Click to expand...

Mine starts around 1000k for a minute then settles to around 900rpm.
You can hear it up and down slightly, especially when standing near the exhaust, but the rev counter doesn't move. Stuff like the power steering bottle and the bonnet stand shake a bit as well.

Andy_Mk3 said:
Glad you got it sorted Andy :) I seem to remember you had a misfire on the way to Billing last year and looking like you were close to torching the car :lol:
Click to expand...

Oh yeah I'd forgotten about that, that was the AFM playing up lol.
 
Typical, fix one thing then another pops up right afterwards.

New problem.

I have a REALLY annoying flatspot under 2k revs.
If I floor it from a standstill, it bogs down like the fuel been cut, then picks up again at 2k. If I floor it while cruising in say 3rd or 4th and it's under 2000rpms it kangaroos like a *******, the moment it gets over 2k, it picks up again and runs fine.

It's got new plugs, leads, tps, crank sensor and coil.

No emls have popped up or anything, and I'm now running out of ideas and patience.
 
Sounds annoying as you've already done all the obvious stuff. Is it getting enough air and fuel? Fuel filter and air filter clean?
 
New k&n apollo kit and fuel filter done when the plugs were fitted (full service).

Right, I'm seriously peeved now. Swapped the apollo for the old k&n cone, as I seemed to remember it started flat spotting (may have just made that word up) after I fitted it, and it's fix the flat spot. :doh:
How the bloody hell can a brand new enclosed ram air fliter cause that WHAT THE VERY F*CK! That is so bloody ANNOYING. Well that was a nice waste of 200 quid! :mad:
 
I might have imagined this as a sort of placebo effect, but, on an n/a engine, ive found, the closer the air filter is to the inlet manifold, the more bottom end power I've had. And the longer the air intake pipe (after the filter) the more top end power I've had.
This was always on c14nz though. I don't think these had an afm iirc. I experimented with longer pipes as apposed to the k&n whacked straight on the inlet top box. As you do when you're 17.

P.s I just learned what iirc means. Thanks google
 
Andy_Mk3 said:
Stick to a standard drilled airbox and panel filter, much less hassle. Induction kits etc have never proved to be any good on these things.
Click to expand...

I remember savage telling me to stick to the panel filter, but I figured an enclosed filter would technically work the same way. It is pretty much the same principal except the apollo's a cone in a box and the standard's a panel, I've had a k&n induction kit on it for a while and it ran fine with that. I don't bloody get engines sometimes, they're just like women, so fudging temperamental.

edessex said:
Can you find a 'fault' with the Apollo and return it?
Click to expand...

I'm not the type to return something if it involves boxing stuff up and sending it off again, but if it's a shop I can get to then it's another story. I'll just swallow the cost, chalk it up as another fail of many and put it to the back of my mind.
I don't think they'll accept it anyway as it's gotten pretty scratched from being in the engine bay for a couple of months. Tbh I'm not MASSIVELY bothered though, I think I'll probably just put in storage and stick it on something else whenever that is.

TomVauxhall said:
I might have imagined this as a sort of placebo effect, but, on an n/a engine, ive found, the closer the air filter is to the inlet manifold, the more bottom end power I've had. And the longer the air intake pipe (after the filter) the more top end power I've had.
This was always on c14nz though. I don't think these had an afm iirc. I experimented with longer pipes as apposed to the k&n whacked straight on the inlet top box. As you do when you're 17.
Click to expand...

If this was on my 1.4 I wouldn't have any issues, this dumbass engine just has too many sensors on it lol.
Tbh it felt good above 2k after the flatspot. Compared to the panel and induction kit I had on it, it was nice and smooth right up to the red, and on a motorway it'll properly fly. It was just that stupid flatspot that ruined it all, the tw*t.
 
Last edited:
Hey guys.

Still got this annoying flat spot (7 posts up). :mad:

I've been thinking about finally getting this sorted lately, and I was pondering a few things.

1. Could a dying alternator cause running problems?
Sometimes if I flash the headlights or switch on the interior light, the revs dip slightly, which is making me think the alternator or battery could be on their way out.

2. Do these engines have MAP sensors?
I recently flashed the EML with nothing coming up, but thought I'd check the vacuum pipes and started wondering about the one connecting to the MAP sensor (I'm not 100% if there IS a vac pipe leading to the sensor, I'm just going by my old 1.4 which had one) but couldn't find the sensor.
There's a little black block thing with a couple of vac pipes going into it sat behind the coil, but it seems a bit too small to be a MAP sensor to me. :noidea:

3. Could maybe one of the sensors be knackered without showing an EML (is that even possible)?

I don't feel like spending a butt load of money ordering every single sensor we stock at work without being sure it isn't something easy or cheap first.
If nothing comes up I was thinking of sending it to an auto electrician to check circuits etc, as there could be a break in the loom somewhere maybe, but again that could get pricey.

Any help or suggestions appreciated guys. :)
 
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