EML warnings & Warm Idle Low Oil pressure.....MAF? VANOS?

[NabsNabsNabs]

So about 300 miles into my new Z3 I've encountered my first unexpected issue!

I started up the car yesterday - It stalled ( I thought user error ), but then started and drove fine..... About 15 mins in, I gave the engine a bit of a blast from the lights, about 20 seconds later I felt the engine revs stutter a bit, then it felt a little down on power and the yellow EML light appeared....Was taking the car to storage at the time so continued to drive it sheepishly for another 10mins.

Just plugged her into my newly arrived C310+ fault reader with the following errors.

The car is a 2.2L ( M54) , 69k on the clock

Incidentally have also noticed a somewhat 'sticky' rev counter, it may be a red herring or related to engine issues...I am not sure. When coming off the gas, sometimes the RPM indicator stays high ( but the engine sounds like its decreasing ), other times I will accelerate and the RPM does not move then suddenly jumps. Again, the engine feels like it it gradually increasing not jumping.

Oh, also I have a low oil pressure lamp which appears intermittently in neutral when I bought it. I phoned the garage who recently did the MOT/Service for the prior owner and they had said they noticed at the MOT and did an oil pressure test which seemed inline with expectations, but were not asked to investigate further.

Any help much appreciated!

Cheers,

Billy

 

[colb]

Fuel trims exceeding limits are usually down to air leaks after the Maf in the intake rubbers or any of the other vaccum lines and hoses across the engine. Check all for holes or splits, replace any that are found holed or split. Smoke test would find any leaks in the system that you can't find visually. Take the Vanos out and clean the solonoid, sound like its gummed up. Once you have attended to these clear the codes and test drive followed by a rescan to see if any codes have returned. Might be worth renewing the oil pressure sensor to see if that makes a difference.

 

[Althulas]

Fuel trim errors could be possible vacuum leak so a check of all hoses and a smoke test would be best to help elimination if you can’t see anything obvious visually.

misfire could be spark plus or coil, as for the rough running you can try unplugging your MAF to see if there is any improvement in idle.
You can also swap coil pack positions to see if the fault jumps to another cylinder.

Has the vanos seals been change recently? I would look at the other things first before looking at the vanos but you could visually check the wiring from the solenoid to the circuit board to make sure the connection is sound. Also just check your oil level is correct as you need oil pressure for the vanos to work. Also check to see if the cam position sensors have been recently been changed for some eBay specials.

I would try these cheap checks first before throwing money at a new maf, cam sensors, vanos seals.

so try maf, coil pack, leaks, vanos wiring. There are YouTube vids on checking cam sensors voltages. If the maf makes a difference try clearing the codes to see what errors come back. Hope it’s not too much waffle.

 

[NZ00Z3]

You need to have a look at the fuel trims on both banks. Bank 1 may be setting the codes and Bank 2 is all right, showing that problem is only on bank 1. Or, bank 2 may be just behind bank 1 and not yet setting a code, showing a problem common to both banks.

I find this thread very good is looking a fuel trim problems. While it is for the E46, they use the same engine as your Z3. https://www.e46fanatics.com/threads/fuel-trims-lean-codes-misfires-and-how-to-diagnose.1284608/

Your VANOS problem may be solved by the advise from @colb. If it's still there, do some research on the inlet camshaft sensor failures. If the sensor is soft failing, the DME may be loosing track of where the Cams are (VANOS wise speaking). I can't remember where the Rev's signal comes from. It could be the inlet camshaft sensor or the crank sensor. If tis the inlet camshaft sensor, then the Hanging Rev meter may tie in with a soft failing sensor.

 

[NZ00Z3]

If you low oil pressure light is yellow, it either because your oil level is low or the sensor is stuffed. The sensor is on the bottom of the oil sump/pan and is best changed when you do your next oil change.

It the low oil pressure light is red, then that's a bit more serious. You should have about 10 PSI oil pressure at hot idle. I think the red light comes on at about 6 PSI.

 

[NabsNabsNabs]

Fuel trims exceeding limits are usually down to air leaks after the Maf in the intake rubbers or any of the other vaccum lines and hoses across the engine. Check all for holes or splits, replace any that are found holed or split. Smoke test would find any leaks in the system that you can't find visually. Take the Vanos out and clean the solonoid, sound like its gummed up. Once you have attended to these clear the codes and test drive followed by a rescan to see if any codes have returned. Might be worth renewing the oil pressure sensor to see if that makes a difference.

Yeah I was certainly hoping the oil sensor is the issue here, seems a relatively simple £10 ish fix if the case. Will have a good investigation for leaks!

Fuel trim errors could be possible vacuum leak so a check of all hoses and a smoke test would be best to help elimination if you can’t see anything obvious visually.

misfire could be spark plus or coil, as for the rough running you can try unplugging your MAF to see if there is any improvement in idle.
You can also swap coil pack positions to see if the fault jumps to another cylinder.

Has the vanos seals been change recently? I would look at the other things first before looking at the vanos but you could visually check the wiring from the solenoid to the circuit board to make sure the connection is sound. Also just check your oil level is correct as you need oil pressure for the vanos to work. Also check to see if the cam position sensors have been recently been changed for some eBay specials.

I would try these cheap checks first before throwing money at a new maf, cam sensors, vanos seals.

so try maf, coil pack, leaks, vanos wiring. There are YouTube vids on checking cam sensors voltages. If the maf makes a difference try clearing the codes to see what errors come back. Hope it’s not too much waffle.

I've no idea if the VANOS seals have been changed. I doubt it to be honest....at what kinda mileage would I expect them to be done? ( I'm on just under 70k )

Also, I would need to do the work back at mine, will this be safe to drive back home ( 25mins across traffic ) without causing further damage?

 

[NabsNabsNabs]

If you low oil pressure light is yellow, it either because your oil level is low or the sensor is stuffed. The sensor is on the bottom of the oil sump/pan and is best changed when you do your next oil change.

It the low oil pressure light is red, then that's a bit more serious. You should have about 10 PSI oil pressure at hot idle. I think the red light comes on at about 6 PSI.

So the seller had just changed the oil in late March, but yeah its the amber lamp not red...at least for now. The level is fine on the dipstick, so was thinking I don't want to waste the fresh oil so might give it a few months before I look at it, unless the sensor can be changed without wasting the oil?

 

[NabsNabsNabs]

You need to have a look at the fuel trims on both banks. Bank 1 may be setting the codes and Bank 2 is all right, showing that problem is only on bank 1. Or, bank 2 may be just behind bank 1 and not yet setting a code, showing a problem common to both banks.

I find this thread very good is looking a fuel trim problems. While it is for the E46, they use the same engine as your Z3. https://www.e46fanatics.com/threads/fuel-trims-lean-codes-misfires-and-how-to-diagnose.1284608/

Your VANOS problem may be solved by the advise from @colb. If it's still there, do some research on the inlet camshaft sensor failures. If the sensor is soft failing, the DME may be loosing track of where the Cams are (VANOS wise speaking). I can't remember where the Rev's signal comes from. It could be the inlet camshaft sensor or the crank sensor. If tis the inlet camshaft sensor, then the Hanging Rev meter may tie in with a soft failing sensor.

great link!

 

[Althulas]

To be honest I’ve seen recommended at 50,000 to 100,009 miles to change the seals. I would look at the other stuff first if it was running fine before vanos seals gradually wear and you would notice the lower torque dropping off. You can get the service kits at a reasonable price from https://x8r.co.uk/bmw/bmw-vanos-repair-kits.html and http://www.beisansystems.com/products.html on the latter has guides on how to change them.

I changed my solenoid seals, filter as I was unsure my vanos covers had the new longer and stronger cover bolts as there had been some issues on the S50 bolts letting go so while I was there I installed the M5 seals as they were the latest at the time. I’ll be having an overhaul by Mr Vanos eventually to get rid of the growl which develops on the S50 engine.

 

[Pingu]

If you low oil pressure light is yellow, it either because your oil level is low or the sensor is stuffed. The sensor is on the bottom of the oil sump/pan and is best changed when you do your next oil change.

It the low oil pressure light is red, then that's a bit more serious. You should have about 10 PSI oil pressure at hot idle. I think the red light comes on at about 6 PSI.

There is a test done in the first few seconds and if the sensor is not working, the light glows amber for a few seconds, then switches off.

The sensor is a heating element that needs to be kept cool by the oil.

Apparently, the most common reason for sensor failure is turning on the ignition with the oil level too low. This is often done during a service when things are checked as the oil is being drained.

It's an expensive, non-essential component. Unless you can get a cheap one, I'd just ignore it and trust the dipstick.

 

[NabsNabsNabs]

Ok, so after a little hiatus, I today started to try pinpoint the issue with my EML light to start with.

I actually reset the codes yesterday to see what would happen, and after a drive only three codes returned.....

It was a surprise that the misfire codes disappeared, but hey I'm not holding out that it won't return.

Diagnosing the fuel trim bank, I did a smoke test and couldn't find any vacuum leaks...

I'm guessing next I should try the O2 sensor and then MAF....with this being fuel trim bank 1 would this mean it's more likely the O2, as wouldn't the MAF throw out both Banks?

Also, when reattaching the MAF and boot after the smoke test I noticed a piece below. Seems to be a rubber plastic hose with an open hole....I have no idea if this is meant to be open? Or covered? Sits directly under the boot after MAF and is attached to a chamber seemingly connected to the MAF air intake (my finger nail is just touching inside)


Any advice appreciated

 

[colb]

That hole in the underside of the upper intake rubber is the connection for the sound generator if its fitted. If it isn't then a different rubber without that hole is fitted. If you havn't got a sound generator fitted that hole after the maf will be letting unmetered air in which will be a cause of dodgy fuel trims. Maybe that wrong hose has been fitted in the past or a sound generator removed if it was fitted at all?

 

[Althulas]

I didn’t realise the z3 had a sound generator I thought they were on the z4.

 

[colb]

That's why I think it's the wrong top inlet hose oem parts for a 2.2 shows no bottom hole. Had this with mates 2.2 he has a sound generator on his Z3 2.2 replacement rubber didn't have bottom hole to link it so surmised sound generator had been added before he owned it. He fitted the new rubber without the bottom hole and did away with the sound generator, made no difference to engine noise

 

[NabsNabsNabs]

That hole in the underside of the upper intake rubber is the connection for the sound generator if its fitted. If it isn't then a different rubber without that hole is fitted. If you havn't got a sound generator fitted that hole after the maf will be letting unmetered air in which will be a cause of dodgy fuel trims. Maybe that wrong hose has been fitted in the past or a sound generator removed if it was fitted at all?

So maybe my picture is a little bad, but the hole is not in the underside of the upper boot, but in another rubber duct/boot on the upper side, directly beneath the upper boot ( the nail side of my finger is in the hole ). So I don't think this is unmetered air bypassing the MAF. This part seems to join the intake muffler, which joins the MAF and upper boot. So somehow there are two branches coming out the intake muffler, 1 to MAF, 1 to this other mystery part with a hole maybe 4cm in diameter.
Looking on real oem, I can't seem to find this part for a 2.2 either.....

Meanwhile, I would be interested in making adjustments to improve sound if such devices exist. Will look at that post sorting the issues tho!

 

[colb]

oem diagram for 2.2 here

RealOEM.com - Online BMW Parts Catalog

BMW parts Z3 E36 Z3 2.2i Hot-film air mass meter

www.realoem.com

 

[colb]

Think that hole you have your finger in is a sound generator as fitted to E46 models if it was the upper intake hose would have had a connecting pipe to it, as yours hasn't I would assume it was replaced with the correct part and the sound generator left unconnected. The E46 set up is here showing the parts used

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[NabsNabsNabs]

Think that hole you have your finger in is a sound generator as fitted to E46 models if it was the upper intake hose would have had a connecting pipe to it, as yours hasn't I would assume it was replaced with the correct part and the sound generator left unconnected. The E46 set up is here showing the parts used

Genuine BMW Rubber boot (13547510315) -- Worldwide delivery

emiauto.eu - Genuine BMW parts online. Worldwide delivery. Low prices! Order BMW 13547510315 now! Directly from Germany!

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So should I replace it? Is it doing any harm as is?

 

[colb]

Shouldn't do any harm as it is its not connected to anything if its not branched off the upper intake boot, back to your fuel trims have you considered smoke testing it from after the Maf. Sorted a mates 2.2 out by smoking it and finding leaks on the inlet side, sucking jet valve was leaking just alongside the idle control valve, sorted that then resmoked to find a leak over on the cam cover around No4 plug well, found the actual cover was cracked at that point and had started crumbling. Only soloution was to fit a good used cam cover with new gaskets. That sorted it and fuel trims were restored to normal and his visits to the petrol station decreased!!
Air leaks are the bane of these engines, check all inlet and vaccum pipes and hoses, cam cover and the dipstick hole O ring for leaks, smoke is your freind.

 

[NabsNabsNabs]

The seller had some receipts for 'Air intake pipes' done in 2017. It didn't say which, but they looked ok to the eye.
I went down the home made smoke device route earlier today, using a soldering iron, sock, baby oil and jar. I only attached on the boot just after the MAF and couldn't detect any leaks....Should I have done more?
If not, my next port of call was to suspect the O2 sensors given its only 1 bank and I understand there is a separate sensor for each bank, but these look super fiddly to access...