M20 b25 conversion no spark help please?

[Benten]

Could this problem also be the cause of my spark issues

[Grrrmachine]

As I said in my very first reply, there is a fault that will disable both the fuel pump and sparks. However, there is no known fault that will make the fuel pump run when its relay has been removed, unless the previous owner has been messing about with the wiring.

If Fuse 10 cuts the fuel supply, then you really need to look at the underdash wiring. If you pull out the glovebox/LH speaker panel, I expect you'll find bodged wiring aplenty.

[Benten]

Ther is an immobiliser on there, it say bmw part but the wiring looks too messy for bmw factory fit and there has been something scotch locked in the fuse box

Will get on it when kids are in bed and see what I come up with thanks

[Brianmoooore]

Check if pulling out relay K7 in the fusebox kills the fuel pump.
This is unlikely to be directly the cause of the spark issues, but it will help with solving that problem if the pump is connected as it should be.
K7 is next to fuses 24 - 26.

[Benten]

Ok so I'm outside now messing

Tried pulling k7 out it's still flowing but that scotch locked wire in the fuse box below fuses is the green and purple connected to green with white stripe

Got a pic but don't know how to upload it

[Brianmoooore]

but that scotch locked wire in the fuse box below fuses is the green and purple connected to green with white stripe

That will be it then. Remove the scotch lock and make good. Fit a 7.5A fuse in position 11, and check that F10 is 7.5A also.
With this car clearly previously owned by an idiot, it will be a good idea to find the fuse diagram (in the wiki?) and check that all the fuses are the correct rating.
Back to the original problem: Pull out the fuel pump relay, and link pins 30 and 87 of its base (marked on the relay) with a piece of wire to ensure that the fuel pump circuit is all OK and the pump runs.
Put the relay back in, and see if the fuel pump runs when you crank the engine. You can do this by connecting a bulb between any point on the green/purple wire and earth.

[Benten]

Checked all the fuses couple were wrong got rid of the scotch lock and tidied that
Iv pulled the relay out and there's two pins marked 87, so I connected both with 30 and fuel pump has came on just from putting the battery back on with ignition off

[kam-325i]

Got a pic but don't know how to upload it

Send to me on facebook, ill stick it up on here for you.

[Benten]

Thanks kam sent it through

[kam-325i]

[Brianmoooore]

Checked all the fuses couple were wrong got rid of the scotch lock and tidied that
I've pulled the relay out and there's two pins marked 87, so I connected both with 30 and fuel pump has came on just from putting the battery back on with ignition off

With the link in place, the pump should run continuously, with or without the ignition on, but it's worrying that you say there's two 87s. Five pin DME relay next to it should have two 87s, but the pump relay (usually orange) should have four pins, marked 30, 85, 86 and 87.

Scotchlok in the pic. explains the pump shenanigans! Well hidden away.

[Benten]

Just had a look fuel pump is a white relay

DME is green and both relays read the same, if kam doesn't mind putting some pics up I'll show you in a min

[kam-325i]

[Benten]

Thanks mate

[Grrrmachine]

The white relay has 5 pins, but you can see that only 4 wires go into the base, and one of them is the green/purple wire to the fuel pump. You've bridged those wires and confirmed the fuel pump works, so that's one point checked on our troubleshooting list, but you've got the wrong relay fitted there. Don't think a 5-pin relay in a 4-pin socket will do any harm though.

With the fuel pump relay and Fuse 11 fitted, can you confirm that the fuel pump spins when the engine is cranked? You need C101 connected for this test. If it DOESN'T spin, we're closer to diagnosing why you have no spark.

[Brianmoooore]

This thread is going to be fun!
Fuel pump relay should be four pin, and was originally orange.
The DME relay should be five pin, and was originally white. IIRC, a new DME relay from BMW is a pale green colour.
The white relay in your pic. does NOT have the correct pin configuration for an E30 DME relay - pins 86 and 30 are transposed. It does, however have the same configuration as an E30 fuel pump relay, albeit with an extra 87 in the middle, so will probably work as one.

Let's have a pic. of the base of the green relay.

[Benten]

Ok that's good to know I'll get that changed

Just done the test and no there's no live there when cranking, tested it engine loom side if the c101

[Benten]

Haha glad your enjoying it

Those two pics are both of the relays 1st pic is the pale green

[Brianmoooore]

Those two pics are both of the relays 1st pic is the pale green

So both relays have the same pin configuration.
30 and 86 are the wrong way around for an E30 DME relay, BUT 30 and 86 are linked directly together on the relay's base by a piece of wire in the E30 application*, so this doesn't matter.

*My wiring diagrams are for a later version of Motronic. I'm pretty sure yours is the same in this area, but it may be worth you double checking that a wire runs between 30 and 86 on the base.

Not having fuel pump activity as well as no sparks is a much better state of affairs than just having no sparks. In fact, it seems that at the moment, your whole management system is doing nothing at all.
Does the DME relay click if you pull it out and push it back in with the ignition on?

[Brianmoooore]

*My wiring diagrams are for a later version of Motronic. I'm pretty sure yours is the same in this area, but it may be worth you double checking that a wire runs between 30 and 86 on the base.

A little bit of further investigation suggests that it may NOT be the same, and looking at your pic. of the wires on the base, although the pic. isn't big enough to be certain, it looks like the wire colours may be those of the alternative wiring I've found.
On the five pin relay, can you tell me the colours of the wires and what pins they connect to on your relay.
I think I may have found the problem!

[Benten]

That's good news then and Sorry, how do I check if they are linked together with the wire?

And iv checked and the DME does click with ignition on but also clicks with the ignition off

[Benten]

Ok so the solid red goes to 86

Green goes with 30

Red with blue stripe goes in centre 87

Thick red with white stripe and thin red with white stripe goes in the other 87

And brown goes in 85

[Brianmoooore]

With that configuration, the relay will be energised all the time it's plugged in, and will drain the battery.
The solid red should come from the battery (one of the smaller wires on the + terminal), and should be 12 volts live all the time.
Pins 85 and 86 are the coil of the relay, and the brown wire is earth, so the relay will be drawing power all the time, (unless it's one with a diode connected in series with the coil, which happens to be reverse biased.)
You definitely have the wrong relay fitted here as well, but with green (switched ignition live) going to pin 30, that would substitute for the permanent live that should be on this pin, albeit with overloading of wires and excessive voltage drop.

Does your battery go flat if left connected?
Check whether the relay clicks when you pull it out and push it in.
Check that there is 12 volts all the time on the red wire at the DME relay base.
Check that there is 12 volts on the green wire at the DME relay base when, and only when, the ignition is on.
Do you have the DME and fuel pump relays from your old M40 engine?

[Benten]

Ok so iv just been doing the test u told me to do

I don't leave the battery on, I take it off when not messing so I don't know about anything draining it

The 5 pin relay click with ignition on or off and iv found the m40 relays.

My battery was giving me a read of 11.3 which I know is low but it's on charge now

The solid red is giving me 11.3 also

But the green one gave me nothin and going back to the wire I found loose by the ecu ( kam put the pic up earlier in the thread) I thought I'd try putting a live to that and it worked, it lit the green up by the relay but still no spark though

[Grrrmachine]

The green wire should be going into Pin 1 of the ECU - no idea why its disconnected, but you need to to reconnect it.

What we're trying to ascertain is whether there's a problem with your ignition system (coil, dizzy etc) or a problem with your engine management. Judging by the bodged wiring, it seems to be the engine management that's at fault, and the previous owner knew that and made some really shonky repairs. With a non-functioning engine management system, you won't get spark OR fuel, so we need to undo the bodgework to find out where the problem really is.

Just to confirm, this setup should have two sensors in the gearbox that connect to the engine loom, correct?

[Benten]

Pin 1 on the ecu has a thick black wire going in to it

I'm testing spark through putting a spark in the end of the king lead connected to the coil at the min so won't be dizzy I don't think
And yes there's two sensors coming from the gearbox bell housing

[Speedtouch]

Which ECU do you have - the early 0 261 200 073 or 153 one with the 35 pin socket?

You should check the power and earths on the ECU socket - see the pinout diagram in this Wiki link:

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

[Benten]

I will check that now and it's a motroni 1.0 there is a pic of numbers on 1st page

[Speedtouch]

Yes, it appears to be an 0 261 200 073. You should see an ignition switched live (+12V) from the DME relay on pin 20.

[Grrrmachine]

What I'm suspecting is that one of your gearbox sensors has failed (or the reference pin on the flywheel fell off), so all this bodgework has been done to give you permanent spark and fuel instead, which will kill your battery.

For starters, the wires for pins 30 and 86 on your 5-pin relay have been swapped over.

[Grrrmachine]

Pin 1 on the ecu has a thick black wire going in to it

Confirmed - my mistake. What colour wires have you got on pins 8 and 24 of the ECU? I think 8 should actually have two wires coming out of it.

[Benten]

Ok there's only 1 black wire in pin8 but comes from a loom of 3, the others are yellow and transparent

And 24 is a thin brown

[Benten]

What I'm suspecting is that one of your gearbox sensors has failed (or the reference pin on the flywheel fell off), so all this bodgework has been done to give you permanent spark and fuel instead, which will kill your battery.

For starters, the wires for pins 30 and 86 on your 5-pin relay have been swapped over.

Is there anyway of testing these sensors

And should I swap those two wire back around?

[Grrrmachine]

There's no guaranteed way to check those sensors without serious equipment. If you've got a multimeter handy, you can do a resistance test across the two wires of each sensor; you should get about 500 ohms. If you don't then the sensor is probably duff, but if you do it doesn't guarantee the sensor is working.

As for wiring, I'd wait for Brian's input on whether to rewire the DME relay, as his wiring knowledge is infinitely better than mine. But I do think that loose green wire ought to be going into pin 8 of the ECU, alongside the black one.

[Benten]

I have a multimeter, I'll do a quick check now

The pins on my ecu with no wires connected are 12,18,30,31,32