15mpg

[suchy]

Right then, bit long-winded this!
I know the Sport needs looking at by someone who really knows E30's properly but wondering what I can check before doing this to eliminate any possible faults/problems?

Quick outline of history and engine;
M20B25, possible mild headwork, Piper cam, Emerald ECU, ITG induction, stainless 6 branch & full system
Bexley Motor Works did an air mass meter conversion, fitted the vernier and installed a Unichip 6yrs ago.
196.8bhp@5951rpm - 191.1lb/ft

5yrs ago car wasn't running right (not a daily driver so faults take a while to become apparent) so it was taken to a local performance garage. Car was massively overfueling so had Unichip taken out and an Emerald ECU fitted. They admitted to having trouble mapping the car properly.
185.7bhp@5400rpm - 185lb/ft
Trouble is this was with fuel pressure set to 4Bar with injectors running 100% rate cycle!!!

Recently have had the car on the rollers again to check fuelling as power drops at 5K so wanted to check it wasn't leaning out at top end.
181.5bhp@5500rpm - 185lb/ft
No voltage drops and AFR is 16.2
Car runs lumpy (bogs down at low revs), stinks of fuel and is more fuel efficient on the motorway at 90mph than it is at 60mph (did tank of each!)

Urban tank 15mpg
Combined tank 18mpg
Motorway tank 20mpg

So what can I check first before the inevitable happens and it gets looked at properly? All input gratefully received

[daimlerman]

Check out the blue temp sensor.

Using a meter set to ohms,you are looking for a big difference in readings between hot and cold.

[suchy]

New blue & brown fitted!!

[daimlerman]

Then check the readings at the ECU end to make sure the information is reaching the ECU....

Have you had the injectors cleaned/serviced recently?

[suchy]

Stand alone ECU Malc- have no idea how to!! Injectors were brand new 5yrs ago (standard Bosch)

[Gwynleym10]

just being devils advocate, but new parts don't always mean correctly working parts...

[daimlerman]

You will have to trace the wires then!

Point is that if the ECU thinks the engine is always cold,it will just keep on chucking fuel at it,your 'improved' consumption at speed seems to back this up.

May also be worth a PM to Gunni,he 'live-mapped' my 2.7 late spring and it has been very much more economical since.He will be able to check and adjust fueling if the ECU is wrongly set,but you need to be sure of the simple bits first,as his time will cost to trace faults not directly connected to a re-map.

[suchy]

just being devils advocate, but new parts don't always mean correctly working parts...

True! So if anyone knows how to check an Emerald ECU for blue/brown sensor readings? And in the meantime I can check sensors themselves. I'm guessing to test reading on startup and then when up to running temp?

[suchy]

[quote="daimlerman"]You will have to trace the wires then!

Point is that if the ECU thinks the engine is always cold,it will just keep on chucking fuel at it,your 'improved' consumption at speed seems to back this up.
quote]

Could this also be some fault with the air mass meter doing something odd??

[suchy]

May also be worth a PM to Gunni,he 'live-mapped' my 2.7 late spring and it has been very much more economical since.He will be able to check and adjust fueling if the ECU is wrongly set,but you need to be sure of the simple bits first,as his time will cost to trace faults not directly connected to a re-map.

Someone else has suggested him. I also have Fowler's number but wanted to check the simple things first for the exact reason you mentioned- hence this thread

[daimlerman]

Brown sensor can be ignored,it feeds the dash gauge.Blue sensor wire colours can be checked at it's plug,then look for the same colour popping up at the ECU.

I guess that the colours could change somewhere,but they should pass through C101(engine loom/body loom connector,mounted close to the fusebox)

Check direct at the blue sensor before starting a cold engine,and again when at normal running temp.

[Jhonno]

Mapping...?

Does it run a lambda?

TPS?

[Ilkorin]

Pretty confident it's a cal issue. 100% duty at peak power at 4bar rail pressure? Doubtful that is correct at your power figures.

AFR at full load is pretty meaningless, even though it's looking a tad lean. The car is never really driven at full load. From what you say if your MPG is good on the motorway and it's bogging down in town, your transient cal needs to be looked at.

Get plugged in to the ECU and do some logging on the road and work out if your part load AFR looks good and look out for transient spikes.

[suchy]

Check direct at the blue sensor before starting a cold engine,and again when at normal running temp.

Will do Malc

[suchy]

Mapping...?

Does it run a lambda?

TPS?

Mapping yes in a way but it's mapped 'correctly' to it's setup which has a sneeky problem- it's like it's been mapped to overcome a problem without fixing the problem (which they couldn't work out!). It pretty much needs the fuel as it runs lean without it, and burns most of it anyway (gases aren't too bad, bad but not tragic as should be expected). They did admit to not being able to set the cold start mapping properly (they tried for an entire week to do that!!) but at the time I needed the car back as it'd been two weeks.

Lambda - pretty sure not.

TPS - wouldn't know what to look for, any clues?? I know where it is and that's about it!!

[daimlerman]

TPS should give an audible 'click' as it moves off the throttle stop.

Think that the ECU sees only closed and wide open throttle.

[suchy]

Pretty confident it's a cal issue. 100% duty at peak power at 4bar rail pressure? Doubtful that is correct at your power figures.

AFR at full load is pretty meaningless, even though it's looking a tad lean. The car is never really driven at full load. From what you say if your MPG is good on the motorway and it's bogging down in town, your transient cal needs to be looked at.

Get plugged in to the ECU and do some logging on the road and work out if your part load AFR looks good and look out for transient spikes.

Cal issue?
It is running 4Bar pressure @ 100%!! I know it shouldn't be!! That was the only way when the Emerald was installed to get enough fuel in!! Hence underlying problem

MPG isn't exactly good on the motorway! 20mpg at max efficiency isn't good for an M20!!

Oh it does need mapping, I agree but it needs a problem sorted also and I wanted to try to eliminate any daft obvious issues before taking to someone to sort out properly

[suchy]

TPS should give an audible 'click' as it moves off the throttle stop.

Think that the ECU sees only closed and wide open throttle.

Kool, that sounds easy!!

[Jhonno]

TPS works in a 0-5v range iirc..

Speak to Dave Walker?

[suchy]

Speak to Dave Walker?

Yeah but he's up in East Anglia iirc?!!? I know he's Mr.Emerald but figured a proper E30 specialist would diagnose a quirky fault far easier? Two local performance garages have been stumped, have no wish to pour £ down the drain experimenting with different people
But I will eliminate/check the other things kindly posted up here first!!

[Jhonno]

He is.. It's not THAT bad a trip, and seeing as he knows these things like the back of his hand, he might be able to offer a solution! Ring him to begin with perhaps? He is Mr Emerald, and knows his engines!

[suchy]

He is.. It's not THAT bad a trip, and seeing as he knows these things like the back of his hand, he might be able to offer a solution! Ring him to begin with perhaps? He is Mr Emerald, and knows his engines!

Close to 400mile round trip @20mpg max (hopefully would be far more fuel efficient for return journey though?!!?)

Worth a call though when all the other boxes ticked.

[Motorhole]

It does sound like the ECU either isn't receiving a key piece of information from one of the sensors or is receiving the wrong information. This has probably been the case since it was originally mapped and it's been mapped "around" the problem.

As Jhonno's said, Dave Walker's your man.

[pacerpete]

Speak to Dave Walker?

Yeah but he's up in East Anglia iirc?!!? I know he's Mr.Emerald but figured a proper E30 specialist would diagnose a quirky fault far easier? Two local performance garages have been stumped, have no wish to pour £ down the drain experimenting with different people
But I will eliminate/check the other things kindly posted up here first!!

The issue is undoubtably related to all the after market bits that you have.

Sounds like a (expensive) job for Mr Walker. The problem is , it's not a 'standard' E30 anymore


At the risk of sounding like that other miserable old bloke who gets excited by tourings BMW spent thousands of hours developing the optimum COMPROMISE when 'mapping' these cars , and a good job they did. The cars start all the time, every time, -20 or +40, they idle smoothly , they pull cleanly whilst adhering to all relevant emission standards. Then a geyser appears out of his shed with a laptop ............

Don't get me wrong, I am sure there are cars out there running after market management that behave just like factory whilst also improving power/ torque and driveability, just a shame I haven't seen one !

[Jhonno]

Mapped right there are Peter.. However, it says much about your clientbel me thinks. Tight arse bodgeartists..

[pacerpete]

Mapped right there are Peter.. However, it says much about your clientbel me thinks. Tight arse bodgeartists..

I don't get involved in bodged up half breeds, I tell the owners the truth and send them on their way

[HairyScreech]

have you had the injectors tested at any time? could it have been mapped with old/bad/320 injectors in it?

[suchy]

@Pete

Absolutely the sum of the parts and (reason) being someone has f**ked up along the way and hasn't left a trail to work back from! I'm under no illusion about it being a cheap, quick fix, but that's why I'm asking what to cross off the list so as to minimise collateral damage

[suchy]

have you had the injectors tested at any time? could it have been mapped with old/bad/320 injectors in it?

Brand spankers Bosch ones 6yrs ago (about 15-20k miles) but not had them cleaned or tested since. Worth doing or just better to stick M30 injectors in and be done with it?

[HairyScreech]

the stock injectors should be fine for 185hp, especially at 4bar.
the most logical upgrade would be m50/52 2.5/2.8 ones.

so its unlikely to be that then.

there must be some underlying reason as your fuel consumption is 10mpg down on the average and nearly worse than an m30.

[suchy]

Never been happy with them at 4Bar and 100%rate!! Shouldn't be, and yes deffo an underlying reason!

[punko]

maybe your looking a bit to hard at what might be a simple problem there are many things you can do yourself before taking it to a garage id start by general servicing if its been stood for a while. plugs, leads, cap and rotor arm, oil n filter, fuel filter give that air filter a clean,
check for air leaks including exhaust, check and adjust tappets checking cam lobes at the same time.
personally then id do a continuity test to make sure every sensor is actually connected to the ecu, if you know anybody who has autodata or it may tell you how to test each sensor in the haynes manual with a multimeter etc, id look a bit into the air flow meter mod thats been done id be interested in seeing a picture of it
if i did all these checks and it was still not right it may be time to take it to a garage and id be having them check that the engine is dialled in correctley on the vernier (another thing to look at is the timing belt hasnt gone slack).
only then would i be putting a set of m50 2.5 (green) injectors in and taking it to emerald themselves and have it LIVE mapped.
You say the head has been ported and polished if it has not been used much an incorrect port flow could create a carbon build up disrupting the fuel economy the m20 head is a tricky one to port id like never to do another one
hope this helps

[suchy]

Oh it does need looking at- there is something wrong!
I will be checking for air leaks/ manifold leaks, but not sure what other sensors to check (apart from the blue temp one) oh and the TPS and the big one that's hard to reach. Re: checking the air mass meter, have no idea what it should or should not be doing- hence me having to ask these idiot questions!! I've always wondered if the vernier was dialled in slightly incorrect, but again I have no idea on that- that's for someone who knows what they're doing to check, not me
Re: headwork, not sure really as I've not had the head off but have a receipt in the folder from previous for machine work and head refittment- could be something simple like valve replacement or skimming, that's why I said possible.

I've done the usual servicable items recently after being laid up for a while so that's ok. Just want to check anything that I can myself before specialist help.

Oh the joy

[hongkongfuey]

If i remember rightly, this has a non standard, tps, i think it is a 5 pin one, its deffo not standard, it has maf too, also the off has a filter on it, and the throttle bellows has been blocked off, a photo would help here,

As i understand 4 bar is only needed for 300 bhp+

[hongkongfuey]

One further point i was told m50/52 injectors shouldnt be put in as someone suggested, m30 ones would be the upgrade same impedience