Idling Issues, Stalls/Fail-to-start, Engine Management Light

[highlander]

Hello,

I asked about this briefly in another post, but I feel I need to bring it out a bit and give it a thread of its own.

My Coupe is idling badly; purely at random, it will idle anywhere between 900 RPM and 1,500 RPM. When it is behaving itself normally, it will idle at about 800 RPM.

Sometimes (VERY rarely), the engine will fail to start the first time I turn the key. It will actually fire up, but instantly cuts out. When it does start, the engine management light comes on and the MFD gives its usual "Engine Anti-Pollution Device Defective" message. The EML light remains on until the code is cleared (but I suspect that, given a number of successful journeys, it will clear itself, as it does on some other cars). The engine also once completely cut out as I was turning left on a busy junction. It started again, first time I turned the key, but I got the EML and the "anti-pollution" message.

Once or twice, I've had an odd shudder from the brakes and the "ESP/ABR System Defective" message flash up on the MFD, coupled with the "ESP" button's light flashing, and the traction control warning light (to the right of the speedo) staying on. Turning off the engine and turning it back on again resolves this. Again, this one is rare and hasn't caused any actual problems (yet).

I'm inclined to think that the bad idle issue and the fail-to-start issue are related. Someone at the Coupe Club mentioned the Idle Air Control Valve, or stepper motor. Steve has very kindly had a look on ServiceBox, and the EW12 J4 engine doesn't appear to have one - not sure how that would work, but from reading various posts on forums for other cars, it's conceivable that the IACV may be part of the throttle body itself.

This might be a bit of a red herring though. The fault may not be with the IACV at all - though even with my limited mechanical knowledge, I can see why it might be the cause of these woes. Is it worth having the throttle body cleaned? Is this likely to be the cause of the poor idling/failure to start/stalling issue?

The car is going to the garage tomorrow for a 12,000 mile service and her MOT. I am going to discuss the problem with the mechanic, but should I mention the IACV/throttle body cleaning as a potential solution? Is that liable to be expensive (i.e. is the throttle body hard to get to / time-consuming to get to)? Would anyone know how much a replacement throttle body would cost?

Any help anyone could give would be very much appreciated, as always

[waue1978]

Don't know if it's any help at all, but I had similar problems with my old Zafira which were solved by either cleaning out the throttle bodies (sprayed carb cleaner while it was running) or changing the EGR valve. Can't say which it was as I did both & the problem went.

[jasper5]

Don't know if it's any help at all, but I had similar problems with my old Zafira which were solved by either cleaning out the throttle bodies (sprayed carb cleaner while it was running) or changing the EGR valve. Can't say which it was as I did both & the problem went.

Yeah, extremely common Vauxhall fault, had this on my son's Astra, cleaning out the throttle body sorts it out for a while, but the EGR replacement solves the problem altogether....for a while at least

Highlander, regarding the ESP light, my 407 did exactly what you described before one of the rear ABS sensors got replaced.

[highlander]

Just read up on EGR, and that is a possibility too - too much exhaust gas entering the cylinder would cause the engine to stall. Not sure if that would cause the high idling though. I'll mention it to the guy tomorrow; thanks Waue1978.

Jasper - are ABS sensors expensive?

Also, if I were to try spraying carb cleaner while the engine is running, where would I actually be spraying it? I have no idea where the throttle body is. I am taking it to mean that maybe I shouldn't be the one trying this, given how little I actually know about all this stuff

[jasper5]

Just read up on EGR, and that is a possibility too - too much exhaust gas entering the cylinder would cause the engine to stall. Not sure if that would cause the high idling though. I'll mention it to the guy tomorrow; thanks Waue1978.

Jasper - are ABS sensors expensive?

Also, if I were to try spraying carb cleaner while the engine is running, where would I actually be spraying it? I have no idea where the throttle body is. I am taking it to mean that maybe I shouldn't be the one trying this, given how little I actually know about all this stuff

Rear ABS sensors are about £68.

Don't spray the carb clean with the engine running.

Take off the Rubber pipe going from the air flow meter to the throttle body (the pipe from the air filter) and spray carb cleaner around the butterfly inside, then wipe it up with a clean cloth, you should see it run out as a black mess.

[highlander]

OK, the Coupe is off getting her MOT and 12K service now. It was too dark outside to do anything with the throttle body myself, but I've passed on the suggestion to the garage; the mechanic certainly agreed that it would be the likely cause.

He said he'd do the MOT first, and would use the emissions test there to work out whether the idling issue would be down to the throttle body or EGR, and would take it from there.

I'm now like an expectant dad waiting on THE PHONE CALL. I really hope she passes with flying colours.

[Captain Jack]

Good luck!

[highlander]

Bah

Coupe-less for tonight (picking her up tomorrow), and will be seriously out of pocket AGAIN.

MOT failed due to excessively corroded brake lines (to the rear brakes), a damaged "suspension item" (I think he said it was the track-rod end, or something; will find out tomorrow), and a missing pin from one of the rear brake calipers.

£40-ish for the MOT
£150-ish for getting the repairs required to pass the MOT done
£150-ish for the full annual service

AND, they ran out of time today before even looking at the throttle body - they said it'd be another £50-ish to do the work on that. Will need to wait til the end of the month for that one, I reckon

At least the emissions test was no sweat, so possibly not the EGR valve causing the bad idling/stalling issue.

Feckin' cars.

[Gary406]

£150 for service

what does that include ?

[highlander]

I'll get a full list tomorrow

I'm not sure I even want to think about it, but I know it will at least include a complete oil change, air/oil filter change, and a complete set of new spark plugs (this figure also includes the labour costs and VAT)

[steve_earwig]

...and a missing pin from one of the rear brake calipers

They certainly went over that with a fine tooth comb Next time dress like a tramp...

[highlander]

... and it gets worse: the advisories

I have:

Corrosion (but not significant weakening) on the front subframe
Corrosion (but not significant weakening) on the rear subframe
Corroded join on one section of the exhaust
Slight leak of exhaust gas coming from the exhaust system
Play in one of the front anti-roll bars
A sticky bearing on the front suspension strut (something like that, the advisory sheet is in the car and I can't honestly bring myself to look at it again)

The exhaust I know is a good excuse to upgrade to a Powerflow system (:cheesy:) and the suspension issues are reasonably easily solved I guess, but I'm worried about the corroded subframes - that's major structural stuff, that - so I've asked over at the Coupe Club what they reckon I'd be looking at there in terms of cost of refurbishment or replacement.

Sometimes I really hate cars.

[steve_earwig]

It just sounds like they found as many deviations from brand new as they could in the hope you'd be paying for them to take their wives to Australia this year. You went wearing a suit didn't you

Rust on an exhaust join? That's just preposterous because most exhausts are just made out of mild steel and rust is all they're good at. If it was blowing significantly (read that as "in reality") they'd have failed you on it. Wait for it to fall off, then get a Flowerpoe.
I'd check out the corrosion on the brake lines, that could actually be a real issue. Doubtful though, given the rest.
Both subframes on my D8 were covered in surface rust, they didn't show any sign of weakening but you can give them a scrub with a wire brush and a dollop of underseal if you're worried about it.
Anti-roll bars might be a traditional drop link.
Sticky bearing - top bearing? It's the only bearing on a strut, unless you count the doesn't exist bearing

[Welly]

Corroded subframe justs need you, and a pair of axle stands, a nice warm day, some goggles and gloves, a wire brush, a tin of under-seal.......you get the idea

Just get the bits done that it fails on and leave the rest until you can afford to etc - maybe tackling some stuff yourself? a sussy top-bearing is cheap but a bit of a faff to get to.

I think the garage are being a bit OTT here, I mean, "corrosion to exhaust join" you could look underneath any car in the street and see that

[Welly]

Oops, pretty much what steve said