M20 b25 conversion no spark help please?

[Benten]

Hi I'm new to the online site but have been told to out my problem on here and it will be sorted

I have a 82 318 auto cab and I have put an m20 b25 manual in everything's done and ready to fire, but I have no spark

It's running a motronic 1.0 ecu

I have been testing spark from coil, with the king lead connect to coil on one end and spark plug in the other

It turns over, I have power going to coil but seem to be bridging the power to the negative terminal on the coil it doesn't just pulse

I also have found a broken wire by the ecu, iv been told it's the green wire from c104 plug but I can't find the male part to connect them up

Can anyone help please I'm lost ??

[Grrrmachine]

If you don't have a spark, it's essential to ascertain whether your fuel pump is priming. There are a set of faults that will knock out both at once, so let us know whether you've got fuel at crank so that we can diagnose further.

You can also refer to this page if it's quicker for you:

http://www.e30zone.net/e30zonewiki/inde ... oubleshoot

And welcome to the Zone

[Benten]

Hi thanks for the reply, my fuel pump kicks in when I switch on ignition but when iv been cranking it over and take a plug out there's no sign of fuel

[kam-325i]

Which end of the fuel rail is the Fuel supply pipe connected too ?

[Benten]

Iv tried both I connected the feed to the on nearest the bulkhead but when my dad looked he said as far as he knows they usually go through that regulator 1st so I tried that way too

When I put the feed on the one closest to the bulkhead the fuel constantly flows through the rail and back to the return

[kam-325i]

The feed goes to the end near the bulkhead, the return line to the regulator. there is a round connector underneath the inlet manifold, this is the connection for the injectors, might be worth giving this a check....

[Benten]

Should the fuel constantly be flowing through?

I think iv seen this's under the exhaust manifold, I'm sure mines a spade connect and the wires a little shabby too, it's connected but will it show a live to test the connection is good?

[Benten]

Oh sorry under the inlet, I'll give this a check thanks but spark is my biggest problem why is my negative on the coil which goes to ecu giving an ignition live from the other wire marked 15 on the coil?

[kam-325i]

Just noticed you are only up the road from me....

[Benten]

Yh mate a little further than wolves I'm in wednesbury but work at the four ashes

[kam-325i]

Ill stick up the picture of the green wire by the ECU, maybe Brian could help with it...

[Brianmoooore]

Need a lot more details on what exactly you've done with the electrics to do this conversion. You've fitted this B25 to a very old cab., which has significant differences in the wiring from the more usual newer ones.
Does (did) your cab. have the old rectangular engine loom socket, or the round 20 pin one?
What age is the M20 engine loom?
Are you saying the fuel pump runs when you turn on the ignition? It shouldn't.
Do you have crank position sensors mounted on the gearbox bell housing?
Don't worry about your findings for the ignition coil. That sounds normal for an engine that isn't producing sparks, and is nothing to do with the cause.
Fuel should be constantly flowing in a circle back to the tank when, and only when, the engine is turning.

[Benten]

Thanks mate I'm not sure how to do that yet lol n didn't realise it was u lol

[Brianmoooore]

I think iv seen this's under the exhaust manifold, I'm sure mines a spade connect and the wires a little shabby too, it's connected but will it show a live to test the connection is good?

I think this is the oil pressure switch you've found.

[Benten]

Hi glad to hear from you, I heard your the man to speak to.

So it's a k reg cabby with the circular socket and so does the m20 lump

It's all come from the Same doner car and has a motronic 1.0 ecu so from what the net has told me it's around and 85 to 87 car the 2.5 came from I havnt changed much on the c101 if u can bare with me for ten I'll go and lift the bonnet and tell u exactly

It cranks from the key and the fuel pump does constantly flow when ignition is on but if I squash the pipe to stop the flow it cuts off

It has the cps mounted in the gearbox bell housing

Thanks, ben

[Speedtouch]

A K-reg will be a 1992, not 1982, as suggested in your first post - just to clear up any confusion.

[Benten]

Ok just popped the bonnet and checked I havnt altered any wires on the c101 they are just as they wer all colours are the Same from the fuse box end to the engine loom end and the only wire not connected is white which I believe is something to do with airbags

[Benten]

Oh yes sorry didn't realise I clicked wrong button it is a 92

[Grrrmachine]

If your fuel pump is constantly running with ignition on but no cranking, then there's something seriously wrong with your wiring.

With Motronic 1.0, the ECU needs to receive a pulse from the Crank Position Sensor in order to engage the fuel pump, the injectors and the ignition coil. If it's not receiving that pulse then none of those three will work.

The green wire being talked about was mentioned in the very first reply I posted. Read about it here:

http://www.e30zone.net/e30zonewiki/inde ... Green_Wire

Perform the tests mentioned in that link and report back.

[Brianmoooore]

I did think '82 was a bit early for a cab, even a Baur.
'92 should be plug and play, except for the possibilities of the pin 20 fiasco (you haven't posted that your wiring loom has melted, so we can assume this is OK), and the need to provide power for ABS brakes.
Might be some problems at MOT time when the car doesn't meet the post 08/91 emissions limits, and you need to prove that the engine is pre 09/91.
If it has the crank sensors in the bell housing, then it's possible to connect these the wrong way around, which (IIRC) can result in the fuel pump running when cranking, but no injector action. Pump shouldn't be running with just the ignition on, though. As Grrr says, there must be something seriously wrong with the wiring. What colour wire is connected to pin 13 of your engine loom plug.

[Benten]

But should a fuel pump prime up so the fuels there ready

Iv only just thought of this, didn't think it would be a problem but when the 2.5 lump was in the other car, the fuel pump was external and the cab I have has the pump in the tank

[Brianmoooore]

FAO Grr. Spotted a small mistake in the wiki article in your link: "At this point there is a two-pin wire with one green, one green/red wire. "
Should read "At this point there is a two-pin socket with one green wire to each pin. If there is an OBC fitted, there will be a plug with one green wire and one green/red wire plugged into it. If there is no OBC and no immobiliser fitted, the socket should have a plug pushed into it with a short loop of green wire between its pins.

[Brianmoooore]

But should a fuel pump prime up so the fuels there ready

Iv only just thought of this, didn't think it would be a problem but when the 2.5 lump was in the other car, the fuel pump was external and the cab I have has the pump in the tank

External or internal pump doesn't make any difference.
Fuel system should hold sufficient pressure to start the engine for many days, and the pump starts running as soon as the crank turns.

[Benten]

I'm not too worried about mot's as long as my friend doesn't decide a career change, if u know what I meen.

I have tried switching these to plugs a few times but no joy there.just had a look and pin 13 on the fuse box side is a thick purple with red stripe and engine loom side it's green with purple stripe

[Benten]

The green ignition wire is fully working inside the car and to the c101 plus the green wire by the coil is showing a live so that's all ok isn't it?

[Brianmoooore]

If the wiring is wrong for one thing, then there's likely to other wiring fault as well. If one wire goes to the wrong place, then the one that should be going there instead will also be wrong.
Green/purple to purple/red is correct for pin 13.
Find the fuel pump relay on the bracket for the air meter (the only one with a green/purple wire going to it) and see if the fuel pump runs with the ignition when it is removed.

[Benten]

Ok I will try this in an hour or so

Will the fuel and spark be coming from the same problem

[Benten]

Hi again Brian just done the check u told me to do and yes the fuel pump still runs without that relay in

[Grrrmachine]

FAO Grr. Spotted a small mistake in the wiki article in your link: "At this point there is a two-pin wire with one green, one green/red wire. "
Should read "At this point there is a two-pin socket with one green wire to each pin. If there is an OBC fitted, there will be a plug with one green wire and one green/red wire plugged into it. If there is no OBC and no immobiliser fitted, the socket should have a plug pushed into it with a short loop of green wire between its pins.

Cheers Brian - updated

[Brianmoooore]

Hi again Brian just done the check u told me to do and yes the fuel pump still runs without that relay in

Try with the engine loom unplugged at the C101.

[Benten]

Yes mate fuel pump running with c101 unplugged

[Brianmoooore]

Now pull out fuse 11 and try it.

[Benten]

So iv just pulled out fuse 11 which was a 15a
The c101 is unplugged and relay out but yes still pumping fuel

[Grrrmachine]

This car's possessed!

You have a serious issue with your fuel pump wiring. You're going to need to trace the route of the green/purple wire and work out how it's getting a 12V feed with IGN-on.

It emerges from the duct from the bottom of the fusebox, behind the steering column on LH drive, goes across to behind the top of the speaker panel, down behind the front of the panel, and then the back of the LH sill to the fuel pump.

How long have you owned the car?

[Benten]

Haha trust me to get it

Iv had it around six months, the 1.8 what was in it had all read been stripped for a replacement head gasket and left to go rusty

I will trace that tonight and let you know how it goes but have just popped back out and if I remove fuse 10 it cuts the live to the fuel pump