M40 running issues,test bulbs fitted....

[daimlerman]

Last week I swapped out the M20 2.7 that is going into my cabbie project.In it's place I put the M40 that came in the cabbie.
M40 started second attempt in it's new home,after I had swapped the fuel lines over.
Ran perfectly around the city all last week on short shopping trips,did perhaps 30 miles.Took it to work last night,about 20 miles each way.Ran perfectly going,then half way home cut out.This was at 5.30am...still dark then...coasted to a halt,spun the engine over and noted the rev counter failed to move,no joy.
half a minute later engine burst into life and ran perfectly.
This pattern continued for the next ten miles,getting steadily worse,now the thing will run for maybe a minute,perfectly,then cut out.When it stops,the rev counter drops to zero immediately.
I have swapped the coil,swapped the DME relay,fuel is circulating,what am I missing?

[sihooker]

Have you checked the AFM flap to see if it's sticking?

[daimlerman]

Have you checked the AFM flap to see if it's sticking?

Have now,thanks,and it was,nt!
Will only run for 30-40 seconds at a time,now

[daimlerman]

Found that the dizzy cap was brokenmbut still no better with a new one fitted.
Starts perfectly,runs for a minute or so perfectly,then stops.
When stopped,I am reasonably certain there is no H/T...

[320Touring]

Its not a fuel supply issue? like a clogged filter or somesuch?

Have you replaced the king lead?

[daimlerman]

Its not a fuel supply issue? like a clogged filter or somesuch?

Have you replaced the king lead?

Certain it is not fuel related,rev counter drops to zero with car in gear and moving...
I have tried running it in the yard on three cylinders,No1 lead attached to a spare plug,when running it sparks properly,when it dies and I crank it the plug shows no spark,leading me to believe that I have a H/T fault...
Or,something is shutting down the ingnition to the ECU...
No doubt that the dizzy cap was cracked/broken,but a new replacement makes no difference.
Will buy a set of H/T leads tommorow,on the basis that heat soak is causing a break,but would like to be certain of just what is the issue,rather than random replacement of suspects!
This is just meant to be a 'tide us over until the cabbie is finished' car,now,then I can sell/weigh in!

[essexe30]

try the idle control valve if they are blocked or sticking it will cut out when coming to a stop

[capri_rob]

Do these have a separate distributor or is the dizzy cap on the end of the cam ?

I had an identical problem with both my Golf GTi and my Audi 2.3GT - engine would run fine one minute and then stop and not restart without warning the next - then after a few minutes would start and run fine again.

Cause was a worn distributor ( not the cap - the actual distributor ) you could feel the play in the driveshaft - replaced and all worked perfect.

[daimlerman]

try the idle control valve if they are blocked or sticking it will cut out when coming to a stop

But it will still spark when being cranked over.....
Engine starts and runs perfectly for 40-60 secs,then dies with no spark...if when cranking it starts spaarking,it runs for 40-60 secs then dies,with no spark...

[engine_ear]

Crank sensor wire rubbing on the fan pulley? Might be shorting and causing it to loose the spark.

[daimlerman]

Dizzy is a cap on the end of the cam,Rob,like a facelift proper engine.
I have now tried a replacement coil/dizzy H/T lead with no improvement.
Crank sensor wire is undamaged.
When cranking,fuel is entering the fuel rail and leaving it.
Only earth point I have disturbed is sound and tight.
Later today I will try a different rotor arm....
Crank sensor wire vanishes under the inlet manifold,can it's connector be reached with the mani on?Thinking I could try swapping that as well!

[Brianmoooore]

Sounds like classic crank sensor failure to me!

[daimlerman]

Removed and tested CPS,showed 615 ohms....
Bought a replacement,took it back because the lead was 3'' too short....
Tested replacement at 900 ohms....
Fitted new CPS,now I do not even have a spark...
Shorted out the fuel pump relay to get the pump to run full time,no difference,still no spark.
If I had hair I would be tearing it out...

[SPADGE]

Do you have a spare ecu you can try and maybe a DME relay??

[daimlerman]

Do you have a spare ecu you can try and maybe a DME relay??

Tried a different DME relay,I only have a spare ECU for a proper engine!
Begining to think that I have an ECU problem,this morning it ran for a short time,now bugger all!

[SPADGE]

Do you have a spare ecu you can try and maybe a DME relay??

Tried a different DME relay,I only have a spare ECU for a proper engine!
Begining to think that I have an ECU problem,this morning it ran for a short time,now bugger all!

Do you want me to send you one to try?

[daimlerman]

Do you have a spare ecu you can try and maybe a DME relay??

Tried a different DME relay,I only have a spare ECU for a proper engine!
Begining to think that I have an ECU problem,this morning it ran for a short time,now bugger all!

Do you want me to send you one to try?

Oh yes please!
Will have to be 'sale or return'!!
Do you have an address for me,still?

[fowler]

an odd shot have a look in plastic poly box around inlet as its known place for water to find may have been disturbed during engine transplant

[SPADGE]

Tried a different DME relay,I only have a spare ECU for a proper engine!
Begining to think that I have an ECU problem,this morning it ran for a short time,now bugger all!

Do you want me to send you one to try?

Oh yes please!
Will have to be 'sale or return'!!
Do you have an address for me,still?

PM me your address and the number/colour off the ecu please mate.

Jules..

[Brianmoooore]

Sounds like classic crank sensor failure to me!

In spite of what I said here, and in spite of the fact that ECU failure is very rare, the last M40 I came across with symtoms like yours was eventually cured, after replacing the CPS, the DME relay, and much voltage monitoring, by replacing the ECU!
Perhaps we have a new 'common' fault here!

[daimlerman]

Sounds like classic crank sensor failure to me!

In spite of what I said here, and in spite of the fact that ECU failure is very rare, the last M40 I came across with symtoms like yours was eventually cured, after replacing the CPS, the DME relay, and much voltage monitoring, by replacing the ECU!
Perhaps we have a new 'common' fault here!

Can I send you the bill for the CPS then?
(only joking!)
Seem to have tried everything else,and it is a 'creeping' failure,whatever it is!

[E30BeemerLad]

If for any reason you should have an AFM problem Malcolm I have one here you can have for nowt from the 316i touring. Managed to get the princely sum of £10 for the ECU on ebay

[daimlerman]

Managed to get the princely sum of £10 for the ECU on ebay

Thanks,I'll point that out to Spadge when he bills me ...
AFM seems fine,all of the engine related bits came out of project cabbie,which does appear to have had a Mr Bodgeit type owner in it's not too distant past...I found the handbrake shoes retained by a bit of twisted wire,for example!
Big box of goodies arrived from Cotswold this morning,should be able to progress the cabbie this weekend..

[SPADGE]

Malcolm

I won't be billing you as this is a gift from me to a loyal customer and i just hope it cures your problem!

Cheers Jules..

[daimlerman]

Malcolm

I won't be billing you as this is a gift from me to a loyal customer and i just hope it cures your problem!

Cheers Jules..

Thanks,mate....
Unfortunately I still have no spark...
So;
1, Dizzy cap changed
2,Coil awapped
3,rotor arm swapped
4.Coil h/t lead swapped
5,CPS swapperd
6,ECU swapped
What have I missed

[E30BeemerLad]

I'm purely fumbling in the dark here, but what is the deal with that thread Brian started concerning some wires that sometimes are present and sometimes not when engine swaps are done?

[daimlerman]

Lee,the thing started and ran perfectly for a week.
I checked that issue out before inserting the motor,the warning concerns a potential fire risk,just at the moment the matches are out.....
I have a huge bruise from banging my head against the wall as well...

[sihooker]

Is it an automatic?
If so,has the start inhibitor switch thingy in the selector come loose?

Edit. Actually,thinking about it again,i believe that switch stops the car from turning over so wouldn't affect the spark.

[Speedtouch]

Try fitting an additional engine to body earth strap - they only cost a couple of quid.

[Brianmoooore]

Simple engine, with simple management! Assuming it hasn't self destructed internally, all it needs is fuel injected and a spark and it will run.
All it needs to produce these is power on the appropriate terminals of the ECU, a working fuel pump, power to the coil, a working ECU, and a working crank sensor.
So which haven't you checked?

[daimlerman]

Simple engine, with simple management! Assuming it hasn't self destructed internally, all it needs is fuel injected and a spark and it will run.
All it needs to produce these is power on the appropriate terminals of the ECU, a working fuel pump, power to the coil, a working ECU, and a working crank sensor.
So which haven't you checked?

Power to the ECU terminals is the only thing there,Brian,as you are aware I am not an electrician!
Engine ran perfectly for a week,now there is no h/t....
Tell me what to check,just off to earn some more E30 parts chits!

[Brianmoooore]

Stick a 12 volt bulb between the coil + terminal and earth for a start.

[daimlerman]

Stick a 12 volt bulb between the coil + terminal and earth for a start.

Bulb nice and bright,meter shows battery voltage with ign on.