Engine Mgt Light (2.2i)

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thomasbrown92
Joined: Tue 05 Feb, 2013 18:55
Posts: 31

  Z3 roadster 2.2i
Location: South Shields

Engine Mgt Light (2.2i)

Post by thomasbrown92 »

Hi there,

Done a bit of reading on here before posting - sounds like a common problem, but just wanted to give you the story to see if anybody has had similar experience.

I've had the amber engine mgt light on my dashboard (not to be confused with the EML light). Car went to main dealer for service and MOT last month and had fault investigated and cleared and was asked to monitor and return if necessary. Two days later warning lamp returned so took car back. They did further tests and carried out smoke test on inlet manifold and inlet pipes with all returned OK.

They advised I fit a new suction set pump on the side inlet manifold. Following a road test, the techies said all was OK and that I should monitor. On collecting the vehicle, I ran it up to temperature. The light returned and is solid - does not go out when engine is cold. c£400 down the drain!!

https://drive.google.com/file/d/1PIYzIX ... Z_rb6/view

Did my own diagnostic test at home today - fault codes are: P0171 & P0174 (System too lean - bank 1 & 2).

Previous topics suggest it could be MAF sensor, but I will add, back end of last year before I laid the car up for winter that there was an eggy pong coming from the car. Few considerations in my mind below - what's everybody's thoughts, please?

1) Could this be faulty MAF sensor?
2) If yes, could this cause a reaction from the cats from an imbalanced mixture?
3) The car recently passed it's MOT - would broken cats/lambda sensors fail the emissions MOT test?
Tom
2001 BMW Z3 2.2 Hellrot Red
2011 BMW 320d M Sport [E92] Space Grey

Mike Fishwick
Joined: Fri 19 Jun, 2009 10:27
Posts: 2054

  Z3 roadster 2.8
Location: Daglan, France

Re: Engine Mgt Light (2.2i)

Post by Mike Fishwick »

Hydrogen Sulphide (rotten eggs smell) is a sign of catalytic converter trouble, which in turn can be due to air leaks in the inlet system, or Lamda probe problems. Take the car to a decent specialist aqnd see what they find. Most dealers do not have a clue about older cars, and are only proficient at changing the oil and filter.

What is a 'Suction set pump' on the inlet manifold? It sounds like peaudo-technobabble . . .
A Z3 is not just for Christmas - it's for life!

mrscalex
Joined: Fri 13 Mar, 2015 09:14
Posts: 901

  Z3 roadster 1.9

Re: Engine Mgt Light (2.2i)

Post by mrscalex »

Mike Fishwick wrote:
Wed 01 Jul, 2020 14:42
What is a 'Suction set pump' on the inlet manifold? It sounds like peaudo-technobabble . . .
Glad you asked Mike. Thought it was just me who didn't know so kept quiet. Smells of BS to me.

I would guess at a vacuum leak, maybe the MAF.
ImageImage
2001 Z3 2.2 Topaz Blue (Trudy) - Keeper rebuilt from a write-off
2002 Z3 2.2 Titan Silver (Cookies) - Keeper rebuilt having been bought with a seized engine
2002 Z3 3.0 Sapphire Black (Peanut) - Keeper awaiting rebuilding having been bought as an abandoned project
Plus Willy, Kodak & Maycee - All 2.2 Sport projects. Yes, 6 is a lot of Z3s :)
Always happy to try and help with spares :)

NZ00Z3
Joined: Thu 23 Jun, 2016 01:26
Posts: 90

  Z3 roadster 3.0i

Re: Engine Mgt Light (2.2i)

Post by NZ00Z3 »

Its a "bmw z3 suction jet pump", supplies vacuum to the brake booster. Google the phase and you'll see what it looks like.

You have the classic lean codes, which are usually caused by vacuum leaks. The smoke test showed that its not a vacuum leak, so lets dig a little more.

Do you have 50 PSI at the fuel rail? There is a test valve on the fuel rail. Lack of 50 PSI could be from a blocked fuel filter or failing fuel pump causing your lean condition.

With a hot engine at idle, look at all 4 fuel trims (2 short term and 2 long term). Are any > 8% indicating a lean condition? Rev the engine to 3,000 rpm for 30 seconds and watch the short term fuel trims. If they reduce significantly, might even go negative, then you have a vacuum leak to find. If they don't change significantly, then we dig deeper as its not a vacuum leak.

Time to look at the MAF.
It should be drawing around 3.6-3.8 g/s of air at idle. If it is like 3.2 g/s or 4.2 g/s then you have a problem with the MAF as we have already eliminated fuel problems and vacuum leaks.

If you get out some graph paper and plot air use in g/s against rev's, you should see a straight line. If its not a straight line, then its definitely the MAF

thomasbrown92
Joined: Tue 05 Feb, 2013 18:55
Posts: 31

  Z3 roadster 2.2i
Location: South Shields

Re: Engine Mgt Light (2.2i)

Post by thomasbrown92 »

Thanks very much for your responses - as you can imagine, I feel quite frustrated with the main dealer!

Wow - now that's a scientific response NZ00Z3! Apologies for further questions, I am not mechanically minded in the slightest!

1) Would a tyre pressure gauge work at the fuel rail to check the fuel pressure?
2) How do you suggest I measure the fuel trims, please?
3) How would I measure the air intake at the MAF?

Thank you again for such a thorough response - the knowledge on this forum never ceases to amaze!

Cheers

Tom

NZ00Z3 wrote:
Wed 01 Jul, 2020 20:58
Its a "bmw z3 suction jet pump", supplies vacuum to the brake booster. Google the phase and you'll see what it looks like.

You have the classic lean codes, which are usually caused by vacuum leaks. The smoke test showed that its not a vacuum leak, so lets dig a little more.

Do you have 50 PSI at the fuel rail? There is a test valve on the fuel rail. Lack of 50 PSI could be from a blocked fuel filter or failing fuel pump causing your lean condition.

With a hot engine at idle, look at all 4 fuel trims (2 short term and 2 long term). Are any > 8% indicating a lean condition? Rev the engine to 3,000 rpm for 30 seconds and watch the short term fuel trims. If they reduce significantly, might even go negative, then you have a vacuum leak to find. If they don't change significantly, then we dig deeper as its not a vacuum leak.

Time to look at the MAF.
It should be drawing around 3.6-3.8 g/s of air at idle. If it is like 3.2 g/s or 4.2 g/s then you have a problem with the MAF as we have already eliminated fuel problems and vacuum leaks.

If you get out some graph paper and plot air use in g/s against rev's, you should see a straight line. If its not a straight line, then its definitely the MAF
Tom
2001 BMW Z3 2.2 Hellrot Red
2011 BMW 320d M Sport [E92] Space Grey

NZ00Z3
Joined: Thu 23 Jun, 2016 01:26
Posts: 90

  Z3 roadster 3.0i

Re: Engine Mgt Light (2.2i)

Post by NZ00Z3 »

Hi

Yes its a detailed approach that is very useful at avoiding the "let throw parts at the car" syndrome.

1) There are fuel pressure gauges available cheaply.
2) Don't know what scanner you have, but most will display fuel trims, might be in the PID section. Might be in the analogue section.
3) See answer to 2) above.

If you are unsure of doing the testing, see if there is anyone in the forum close by you with diagnostic gear that may be able to help you. I'm in the South Pacific, so can't drop by to help.

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colb
Joined: Sat 05 May, 2012 22:46
Posts: 672

  Z3 roadster 1.8 TU
Location: Newport South Wales UK

Re: Engine Mgt Light (2.2i)

Post by colb »

NZ003NZ's reply is very detailed on what you should be looking at to resolve this. Mates 2.2 had high fuel trims and EML lit up, smoke test I did on it revealed airleaks on the inlet side from rubber componants around the sucking jet pump, this was replaced with some hoses which buttoned that side up. Further smoke test carried out then revealed further air leaks from around No4 spark plug well in the cam cover which we didn't see before the inlet side was sealed with the new parts. Having sealed that side it increased the pressure inside to findthe cam cover leak point. Stripped the cam cover off and detailed inspection revealed cracks in the plastic around No 4 plug well. The plastic had gone hard and brittle and was starting to crumble around the crack that had developed. Sourced a used good cam cover and fitted that with new cover gasket and plug well gaskets that fit in the centre around the plug wells. Old gaskets were hard and brittle so needed replacing to ensure a good seal. Once all back together ran a smoke test and confirmed no leaks. Started the car and scanned it with live data after clearing the lean codes. Viewing the fuel trims they were dramaticaly reduced to normal levels. Prior to fixing these leaks it was adding 20% more fuel as the exhaust sensors were picking up the unmetered air that was getting in through the air leaks. If your Maf is suspect then replace it with either Bosch or Seimens oem brands do not buy cheap pattern parts, they seldom work or last long, been there done that, you end up paying twice.
Take your time when smoke testing, pay particular attention to things like the dipstick tube bottom seal area where the dipstick enters the sump, they can fail and cause air leaks. All rubber intake bellows and every rubber vaccum pipe on the engine for splits or cracks as well as the cam cover and its gaskets need to be checked. As others have said to check fuel pressure you need the right tool for the job do not use a tyre pressure guage.
I would do another smoke test, I reckon your garage have missed seeing something, if you were near to me I would have done it with my home made smoke kit, it works a treat in finding air leaks.
Colb
1999 BMW 1.8 Z3
2003 BMW 2.5 Z4
1998 Honda Deauville NT650V

thomasbrown92
Joined: Tue 05 Feb, 2013 18:55
Posts: 31

  Z3 roadster 2.2i
Location: South Shields

Re: Engine Mgt Light (2.2i)

Post by thomasbrown92 »

Hi folks, thanks again for your knowledge and experience here.

Just a quick update: I popped in to see a specialist (ex-M techie) near me on Saturday. He did a comprehensive diagnostic, using the old port in the engine bay.

He couldn't find anything wrong with it - no air leaks; fuel trims within tolerances; fuel pressure where it should be - all points to MAF (there's a physically printed code on the connector of my current MAF, which the specialist didn't recognise). Last couple of checks for belt & braces, he put the car on the lift to look underneath (always fascinating to see underneath at an indy, especially after having just had my sills and chassis restored and new seam sealer applied - clean as a whistle!) no leaks from fuel filter/pump or exhaust.

He reset the light, cleared the codes, and reset the adaptions. Could be placebo, but I'm positive the car pulls stronger! Within a couple of hours of leaving the garage, the light came back, which he said it may.

Next steps:
- Book back in with specialist as we'll go down the fuel filter/MAF route - assume the best options are Bosch or Siemens?

Will keep you up to date!

Tom
Tom
2001 BMW Z3 2.2 Hellrot Red
2011 BMW 320d M Sport [E92] Space Grey

thomasbrown92
Joined: Tue 05 Feb, 2013 18:55
Posts: 31

  Z3 roadster 2.2i
Location: South Shields

Re: Engine Mgt Light (2.2i)

Post by thomasbrown92 »

Hi folks - quick update on the car. A quick glance at the recent posts column on the home page seems like its the season of engine problems!

Last week, I had the car warming up at idle on the drive and it developed a random misfire (though it started fine). A few gentle revs and it didn't encourage life back into the misfiring cylinder, so I switched the car off, let it settle for about a minute or two then re-ignited. It was back to firing on all six. Gave it good hiding up the coast at the weekend and it didn't miss a beat!

Was out driving last night and under normal load at 25-30mph the engine coughed and cut out momentarily, before coming back to life (kind of like a mini stall).

One thing I should mention is when I went to retrieve the car from winter storage at the beginning of June, I found evidence of mice nesting in external crevices of the intake manifold. They had chewed at a few bits - plastic conduit mainly - but didn't seem to have caused any mainline damage. I'm hoping they didn't manage to find their way into the cylinder head!

Tom
Tom
2001 BMW Z3 2.2 Hellrot Red
2011 BMW 320d M Sport [E92] Space Grey

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motco
Joined: Tue 18 Aug, 2009 18:12
Posts: 708

  Z3 roadster 2.2i

Re: Engine Mgt Light (2.2i)

Post by motco »

If I start my 2.2i and let it idle awaiting the Good Lady it also throws a misfiring cylinder. Start it, drive it is the mantra for me.

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Gazza
Site Admin
Joined: Tue 04 Oct, 2005 20:58
Posts: 9509

  M roadster S54
Location: Romford Essex

Re: Engine Mgt Light (2.2i)

Post by Gazza »

I had a misfire once when the car had sat for months
The battery was flat so I jumpstarted it and let it idle while I gave it a wash.
It developed a misfire so I checked each coil pack in turn to find the dead one.
Ordered six new ones and changed them all.
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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thomasbrown92
Joined: Tue 05 Feb, 2013 18:55
Posts: 31

  Z3 roadster 2.2i
Location: South Shields

Re: Engine Mgt Light (2.2i)

Post by thomasbrown92 »

Hi folks - hope all you're all keeping ok.

Collected my car from my local specialist on Saturday after having replaced the MAF - kicking myself as could have done this job myself, without involving severed fingers! Seems to have cured the engine mgt fault, but while driving home and using indicators and flashing headlights the car cut out momentarily several times (refers earlier post on 30/07, pasted below), but regained power without having to turn the key in the ignition. Clocks revert to zero and dashboard lights up like Xmas tree!!

After getting it home and parking on the drive, I went to put the car in the garage and the car wouldn't start. The engine was firing, but wouldn't catch (tried 3-4 times). I waited 2-3 mins, then tried again and it started and idled fine.

Given above issues experienced and below update (30/07) is there a specific wiring loom that connects the lighting system which said rodents could have nibbled, causing the leccy problems? Also, just re-reading @Gazza's comment - could it be worthwhile changing the coil packs? I believe it still has the originals on. (2001 car).

Cheers

Tom
thomasbrown92 wrote:
Thu 30 Jul, 2020 11:42

Was out driving last night and under normal load at 25-30mph the engine coughed and cut out momentarily, before coming back to life (kind of like a mini stall).

One thing I should mention is when I went to retrieve the car from winter storage at the beginning of June, I found evidence of mice nesting in external crevices of the intake manifold. They had chewed at a few bits - plastic conduit mainly - but didn't seem to have caused any mainline damage. I'm hoping they didn't manage to find their way into the cylinder head!
Tom
2001 BMW Z3 2.2 Hellrot Red
2011 BMW 320d M Sport [E92] Space Grey

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rayboy
Joined: Sun 05 Nov, 2006 07:54
Posts: 73

  Z3 roadster 1.8
Location: erpingham

Re: Engine Mgt Light (2.2i)

Post by rayboy »

Bought 2.2 this Summer from dealer
On way home EML came on.
Returned to dealer. They spent a lot of money replacing the mixture sensors Lamda?
Got it 100 miles home and light came on again
Went to my local indie Herring and Palmer in Norwich
Tim immediately diagnosed the problem . A split large inlet rubber!
Led to weak mixture so sensor was enrichening the mix until it gave up.
MPG was down to 19 too.
Tiny hole big problem
The hose was replaced and no more EML I’ve got lovely new sensors too
This may not have been your problem but it might others. Check that pipe first.
Indies rock!

Rayboy

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