M20 smoking issues with more pics and videos

[daimlerman]

Your engine build seems wrong to me.

2.7 eta pistons with an 885 head will give poor combustion,they really should be used with a 320/323 (200/720?)type head casting.

325 pistons,with the block 'decked' to suit may well have been a better option.

What head did Hartge originaly supply for these engines?

[HairyScreech]

IIRC the H27 used modified M50 pistons, sop they were nearly flat topped.

It seems up to about 10:1 and with conservative timing then its not such a big deal.
Its hardly ideal, leaves dead areas for high emissions and leaves a lot of power on the table but was certainly ok in the H27 or the super ETA.

If this is an oil problem then you should be going through oil fairly quickly.
If you are 100% sure the oil is not going down too fast then we need to consider the fueling, (and if its an oil consumption issue it's strip down time so better to cover the external issues first).

First thing is: Is the oil smelling of fuel? pull the dipstick and give it a sniff.
Does the oil seem thinner than it should be?
Does the car stink of fuel when running? (just spotted above- Yes.)
Is your fuel consumption high?

Might be worth getting your friendly mot tester to stick the emissions probe up the pipe and check the emissions.
Trouble with that is it will only tell you that hydrocarbons are being burned so it wont eliminate oil.

Does the car have a lambda sensor in the exhaust? I don't think the H27 does.
What AFM is fitted? Should be a part number on the top.
What injectors are in there? as someone has fitted an adjustable pressure regulator I can't help but think there has been some pikey tuning at some point.

[SilverShadow]

Sorry guys was meaning to update this over the weekend.

From what I understand Hartge never built all engines in the same way. They were a mish mash of parts and had different technicians working on. Some had port/polished heads and some didn't etc etc.

Just to reiterate when I initially brought the engine it had one of those adjustable FPRs that i quickly removed and replaced with a standard 3.0bar oem unit.

At first oil consumption was high but I'm sure this is not the case now.

Over the weekend I took the car to a garage to get an emissions test done, before I released i walked to the car and the so called mechanic had started to adjust the AFM I am aware that these are set from factory and should NOT be adjusted. However the mechanic said that adjusting it does not make any difference to the readings??

The AFM looks like to be a 325i unit however I can see some sealant around the black cover which would indicate that it has been pissed with at some point. Theres no lambda sensor.

Heres a pic of the readings as when I left the garage:



Also to mention is that when I done the rebuild I had the injectors rebuilt by injectortune and there is a definite smell of fuel in the oil - checked from the dipstick and oil filler cap this weekend, it also smells when the engine is running.

[Speedtouch]

Over the weekend I took the car to a garage to get an emissions test done, before I released i walked to the car and the so called mechanic had started to adjust the AFM I am aware that these are set from factory and should NOT be adjusted. However the mechanic said that adjusting it does not make any difference to the readings??

Why did he touch it in the first place then?

[SilverShadow]

Over the weekend I took the car to a garage to get an emissions test done, before I released i walked to the car and the so called mechanic had started to adjust the AFM I am aware that these are set from factory and should NOT be adjusted. However the mechanic said that adjusting it does not make any difference to the readings??

Why did he touch it in the first place then?

He quoted that the CO level should be at around 0.22 and after adjusting it he said that there was hardly no movement.

Just another money mechanic that doesnt now the M20 engines...

[SilverShadow]

What AFM is fitted? Should be a part number on the top.
What injectors are in there? as someone has fitted an adjustable pressure regulator I can't help but think there has been some pikey tuning at some point.

looks like a 325i afm but as I said the black cover has sealant around that would suggested its been messed around with:



heres a pic of one of the injectors before i had them cleaned:

[SilverShadow]

So I have been doing some further investigation in way the oil would smell of fuel.

Obviously the fuel is getting through the cylinders, past the rings and into the crankcase - I’ve stopped driving the car know as I understand this could cause bore wash.

Is there a way to test the fuelling system to check/test whether the right amount of fuel is being put out when the engine is running?

At this stage I’m not convinced that I may have leaky injectors as I had them rebuilt by injectortune.

Could this also be caused by timing issues? Just think out load of maybe the fuel is being injected a little late for the spark?

Can anyone confirm the readings of the emissions , do they look about right?

Any help appreciated!

[HairyScreech]

So I have been doing some further investigation in way the oil would smell of fuel.

Obviously the fuel is getting through the cylinders, past the rings and into the crankcase - I’ve stopped driving the car know as I understand this could cause bore wash. Bingo. Good idea, that's why I was asking about the oil, this does seem to point to an massive overfueling issue.

Is there a way to test the fuelling system to check/test whether the right amount of fuel is being put out when the engine is running?

At this stage I’m not convinced that I may have leaky injectors as I had them rebuilt by injectortune. unlikely to be leaky but the wrong flow rate is likely. What was the flow rate the injectors tested at when injectortune did them? they provide before and after flow rates.
I am wondering if someone has put bigger injectors on and used an adjustable regulator to wind the fuel back down, cause that's tuning, innit bruv.

Could this also be caused by timing issues? Just think out load of maybe the fuel is being injected a little late for the spark? shouldn't make that much difference, the injectors are fired in batches of 3 so 4cyl out of 6 are always out of time

Can anyone confirm the readings of the emissions , do they look about right?

Any help appreciated!

[/b]

[Speedtouch]

The 0 280 150 715 injector, as pictured, is standard for the 325i, with 14.5lb/hr flow rate:

http://www.gomog.com/allmorgan/InjectorRatesBosch.html

[HairyScreech]

Thanks Speed touch, that puts paid to that one then.

At least we can confirm that the injectors are the correct size and there's now a stock regulator in it.

Time to start thinking electrical.

[HairyScreech]

Ok, AFM is a 325i one by part number.

One quick check is the blue temp sensor, both at the blue plug and the ECU.

Test the resistance of the air temp sensor in the AFM and while your there do the AFM check for varying resistance.

I have come across these bosch ecus running massively rich due to oil/crap caked air temp sensors or in one case the thermistor had dropped off and it was rattling around!

Need to eliminate everything before tearing deeper into the engine really.

[SilverShadow]

Ok, AFM is a 325i one by part number.

One quick check is the blue temp sensor, both at the blue plug and the ECU.

Test the resistance of the air temp sensor in the AFM and while your there do the AFM check for varying resistance.

I have come across these bosch ecus running massively rich due to oil/crap caked air temp sensors or in one case the thermistor had dropped off and it was rattling around!

Need to eliminate everything before tearing deeper into the engine really.

Thanks guys.

I will load the flow rates of the injectors regardless.

As per my previous post blue temp sensor has been checked at the ecu and sensor and is fine.

Will look at testing the AFM as soon as i find out how to.

Do the emissions results look ok?

[HairyScreech]

They don't look toooo bad. To give some perspective a misfiring A series lump gives 1500 ppm of HC!

Your lambda says your a little lean at 18:1, but there is no guarantee that the probe is accurate.
If you were actually that lean there would be bigger issues, more likely your exhaust is pulling air in through a leak.

Was that result taken at idle or revved up a bit? If it was on idle and passed then not much can be read into it, your not smoking at idle so what ever is burning (fuel or oil) is only bad when revved or under load.

I know its quite subjective but can you compare the oil in your sump at the moment with some fresh stuff of the same type.
You smoke more when your hot, and its bad.
I can't help but wonder if the oil is being thinned to the point of getting passed the rings, likely by fuel.

Did it smoke as soon as the oil was changed or is the smoking recent?

You will need to change that oil anyway so swap it out, compare the old and new for viscosity and then see if it is any better with new oil in.

Without the full Hartge spec it is likely the car is overfueling in the higher rpm range and higher loads due to decreased airflow through the engine.
This might have been enough to contaminate the oil to the point that it starts getting past the rings when hot.

[SilverShadow]

Quick update on this”¦

Was that result taken at idle or revved up a bit? If it was on idle and passed then not much can be read into it, your not smoking at idle so what ever is burning (fuel or oil) is only bad when revved or under load.

To confirm that the readings were taken at idle.

Ok so yesterday I dropped the oil and it was black (only having done approx 500miles) and it smelled of fuel. The viscosity seemed much thinner in what it should be, however this time around I have opted for 15w 40 semi.

I managed to get hold of a AFM and ECU of a 325i and am running that this week hoping to clear out all the crap in the exhaust.

Will keep you updated.

[HairyScreech]

It should run ok on a stock ecu, I would just keep out of the throttle, you will be lean at high rpm and advanced on the timing, so detonation is likely.
Just go easy.

Mid range/low throttle it should be able to fuel enough to run ok, the AFM will indicate its pulling more air than normal.

Timing will still be out regardless of the load/speed. So watch out for detonation.

[SilverShadow]

After a week of driving on a borrowed AFM and ECU from a 325i there was no positive difference in the smoke.

I have been trying to establish when the smoke appears and its defiantly at higher RPMs, during idle and normal driving it seems fine.

If it is decreased air flow would that mean to investigate the map on the chip or have a live remap done?

Without the full Hartge spec it is likely the car is overfueling in the higher rpm range and higher loads due to decreased airflow through the engine.
This might have been enough to contaminate the oil to the point that it starts getting past the rings when hot.