E30 320 to 325 engine conversion issue

[E30ibz]

Hi there everyone,

I hope you're all well

I have recently joined and posted in the new member section but was told to post in the technical section so here goes!

A few years back I blew the head gasket on my 320 convertible, at which point I saw it as an opportunity to upgrade and purchased an engine and ECU out of a 325 (M20 B25)
The garage that I took it to at the time swapped the engines and ECU but was unable to get it started and claimed that the issue is there is no spark at the plugs.

I ended up taking the car back home as I no longer wanted that garage working on it and seeing as we are in lock down thought its about time to get it going.

I have been told that the immobiliser may be the issue or it may be some kind of wiring issue, so I wanted to check in with you all to see if anyone has encountered this before and where to start?

Please see below for some pictures of the car and engine bay, if you need better pictures or anything else let me know.

I also recognise that the battery isn't in at the moment as I'm currently charging one up so i know that isn't the reason why I have no spark lol

Any advice would be appreciated!

Stay safe and well
Ibz

[Cloggy Saint]

Welcome to the zone! Have a look at the troubleshooting page on the wiki https://www.e30zone.net/e30wiki/index.p ... oubleshoot

[mark_i]

the engine is a later 2.5 running on motronic 1.3 which makes your dads job easier.
Get him to down load the wiring diagram from the Wiki to check for 12 volts at the ignition coil.
However you also have a rag stuffed into the throttle body and the round connector between the engine and main looms has not been properly attached.

[E30ibz]

Thanks for the advice Mark, I’ll be sure to pass the info on to dad and see how we get on.

I’m pretty sure he also stuffed the rag in the throttle body the other day when we were giving it a clean .

[Ukhozi]

And while it's out get some rust killer on the battery tray and paint it, then fit a rubber mat before installing the battery.

[Brianmoooore]

Before you go any further, take the 20 pin c101 engine loom plug and socket apart and check the wires going to pin 20 of each half. If there's a red/yellow on one side and a brown on the other, come back here for further advice before even connecting the battery.

Connect a 12 volt lamp between the + terminal of the ignition coil and a good body earth, such as the terminal on top of the RH suspension turret. Switch on the ignit rect AFM with your new engine? A 325 will start and run on a 320 AFM, but it will never run properly - and get fuse 11 changed for the correct 7.5A (brown) one.

[E30ibz]

So quick update, there is power going to the coil, but no power coming out of the coil and my dad seems to think its not the coil that needs changing and that it is the cam sensor, does that make sense to you guys as I'm about to order it

Should I order a coil as well?

[tha881]

No cam sensor on m20 engines, only a crankshaft pulse sensor

[Brianmoooore]

Hang on a bit! Ordering random parts without knowing if there's anything wrong with them is a good way to make E30 ownership expensive.
There's nothing wrong with your coil. They don't fail.
Next thing to check is whether the fuel pump runs when the engine is cranked. The fuel pump lives under a black cover under the RH side of the rear seat cushion, and you can hear if its whirring away if you get close enough. Rear seat cushion pulls up at the front, out of two clips, then slides out.
If the fuel pump runs, then there is probably nothing wrong with the crank position sensor.
If you can't hear it run, pull off the two pin plug, and connect the 12 volt lamp to it, and crank the engine again.

[E30ibz]

UPDATE

So crank sensor has been changed but still no spark.

C101 - not all the pins line up, there wasn’t a pin 20 on the car loom but there is on the engine side. Also a brown wire has been cut (see pictures below)

As for the fuel pump there isn’t any sound coming from it when I crank the engine and no power going to the 2 pin plug.

I have also attached picture of the ECU if this helps

Any ideas?

Thanks
Ibz

[Brianmoooore]

164 is the early early Motronic 1.3 ECU, and considering that one has been messed about, albeit professionally, it would be good to try the later 173 or 380 ECU. ECU failure is extremely rare, but borrowing a substitute might possibly save some time and head scratching in this particular case.
Where are you located?
You could check that the engine relays have been fitted in their respective correct places. They live under the cover on the inner wing beside the AFM.
You will probably have only two of the three sockets occupied by a relay, unless your car has emissions equipment fitted.
There should be a five pin relay, usually white, which must be in the socket that has a wire connected to the centre pin, and a four pin orange relay, that must be in the socket that has a green/purple wire going to one of the pins.
The number of pins in the C101 refers to the number of locations there are for pins, not the actual number fitted. The cut brown wire on the body side shows that someone in the past has read one of my posts! This is an earth wire, which in the original designs was used as the earth return for the brown coolant temperature sensor, but, in later models pin 20 was used to feed an ignition switched 12 volts+ to the ABS system, so if the engine loom from one of these later cars is fitted to a body that has the brown wire connected and the ignition switched on, you are rewarded with plumes of smoke from under the bonnet and melted wiring.

[E30ibz]

Thanks Brian, I’m located in Harlow, Essex.

I guess my first point of call from what you have said will be to try and source another ECU.

Does anyone here have one for sale or know where best to source one?

[E30ibz]

In response to your point on checking the relays, I’ve located them and there seems to be 2 there.
As for whether or not they are in the correct places I’m not sure

[Brianmoooore]

The little tabs on the relay bases, at the bottom of your pic., release the relay bases from the plastic back plate, so push the tabs back and pull the bases up, so that you can see underneath them. The bases can be clipped back in any order, which is why I can't tell if they are right just by looking at the order they are in.
Can you pull the blue relay out, please, and post a close up in focus pic. of the internal wiring diagram of it, which should be printed or embossed on one side.
Pics. of the underside of the relay bases would be good as well.
Hold off on the replacement ECU for now.

[E30ibz]

Okay another day, here we go!

Brian please find attached a copy of the pictures you requested.

Separately me and dad found a diagram for the loom and decided to check everything is going where it’s meant to be and we have got to the crank position sensor and it seems to fit into two sockets (as seen below) one of the sockets has a cable with a yellow tag and one doesn’t but we aren’t sure which one it goes into?

Thanks
Ibz

[mark_i]

Looks like you've discovered the issue.
The main relay is missing ! the relay socket that has the red/brown/red-blue/red-white cables needs a white relay.

Others will confirm if the blue relay can be used instead of white as a temporary troubleshoot.

Pretty certain you are on the home straight now.

[E30ibz]

Lovely! Just on route to pick up the relay, will let you know how I get on

Thanks!

[Brianmoooore]

A few posts back, tha881 stated that there was no cam sensor on a M20 engine, which is true, in the conventional sense, but they do have a primitive type of cam sensor in the form of an inductive sensor on one of the plug leads, and I can see it in one of your engine bay pics, near the distributor cap. For some reason, BMW chose an identical plug on this to the one on the crank sensor, and then decided to fit the two sockets very close together, as you have found. When it's all fitted up, it's reasonably obvious which goes where by the way the wiring lies, but that's no help to you at this stage.
I've never noticed the yellow sleeve on the wiring in one socket before, because I don't think I've ever looked under the rubber boot on this socket. If this turns out to be the case on every loom, then you have made a contribution to the E30 database of knowledge.
The usual way of finding out which is which is to plug them in and see which way works.
As to why your engine doesn't run, we're getting somewhere! You have two relays in three sockets, the relays you have are in the right sockets BUT it's the wrong one that is empty.
The empty socket is the one for the DME relay, without which your engine will never run, because the ECU and injectors will not be powered up!
The blue relay is for the lambda sensor heater, which you probably don't have. Look on the RH end of the battery tray, and you should see the small black plastic retaining tag of a socket that is mounted underneath the tray. Reach under the tray and see if there is anything plugged into this socket.
The DME relay is a white 5 pin relay, and a second hand one is perfectly acceptable. Can be from a M40 or M20 engine.
In the meantime, you can easily bypass the relay for testing purposes with a couple of bits of wire, pushed into the socket.
You need to link together pins 30, 87 and 87a. Pin 30 is the one that is at right angles to the other pins, and the other two are the one in the middle and the one opposite - three in a row.

[Brianmoooore]

Looks like you've discovered the issue.
The main relay is missing ! the relay socket that has the red/brown/red-blue/red-white cables needs a white relay.

Others will confirm if the blue relay can be used instead of white as a temporary troubleshoot.

Pretty certain you are on the home straight now.

Looks like I spent too long typing my reply (eating lunch at the same time). Blue relay cannot be used as a sub. for the DME relay. It's a pin short. It can be used in place of the orange fuel pump relay, however.

[kdevitt]

I'm personally excited for the OP's response where the car fires into life

[E30ibz]

Okay update, relay is in and we have spark! I’m literally dancing around the garage

Only issue now is the fuel pump doesn’t seem to be coming on.

We have taken the cover off under the back seat and there isn’t any sound coming from it or power going to it.

Do your thing E30 wizards!

[mark_i]

Double check fuse 11. Also verify 12volts is present at the fuel pump connector while cranking

[E30ibz]

Fuse 11 is okay, we’ve taken the pump out and put power to it and it’s not making any noise

[E30ibz]

I’ve ordered an new pump which is coming tomorrow but in the meantime dad is saying there still isn’t power going to the pump.

As I said, fuse 11 has been checked, so what is the next point of call?

[E30ibz]

Update, power is in fact going to the pump, will have to wait until tomorrow for the new one to arrive

[E30ibz]

Oh and so you guys know for future reference, the lead with the yellow tag is for the HT lead

[Brianmoooore]

If the car's been parked up for a while with E5 petrol in it, the internals of the pump will have lightly rusted together because of the water that comes dissolved in the bl**dy stuff. If you can get it to free up, it usually stays working, unless it was worn internally with age anyway.
I've noticed that the fuse 11 in your fusebox appears to have been replaced with a 15A one. This usually happens when the pump starts to stall intermittently with age, but, of course, your pump might already have been replaced, and the over rated fuse left in place.
Duly noted about the yellow sleeve.

[mark_i]

I reckon that once you get a working fuel pump and pressure in the injector rail, the engine will start first time.

Note that the correct rubber boot to connect airflow meter and throttle will be needed to allow proper idling and engine speed increase. Don’t be tempted to fiddle with the throttle stop screw yet.

[Brianmoooore]

Don’t be tempted to fiddle with the throttle stop screw yet.

Or at any time, unless there's evidence it has been moved. Throttle stop, the internals of the AFM, and AFM bypass only have one correct setting, and that's where they were set at the factory.
Engine will start and idle normally with the large convoluted hose not fitted, as long s the AFM is plugged in. Leaving the actual AFM unplugged makes no difference, but the inlet air temp. signal also passes through the plug.

[E30ibz]

Good evening everyone! Quick update - so we fitted the new fuel pump but not getting any fuel at the engine and the pump is definitely working

Any idea guys?

[Brianmoooore]

Good evening everyone! Quick update - so we fitted the new fuel pump but not getting any fuel at the engine and the pump is definitely working

Any idea guys?

Disconnect both fuel hoses at the engine and see if fuel comes out of one when you crank the engine, and which one.
The fuel supply hose goes directly to the fuel rail, not the pressure regulator, as some think.

[E30ibz]

Okay so the I think we wired up the pump wrong but we managed to solve the issue and get fuel to the engine and after a few cranks she started for the first time in 5 years haha!

Still a lot of work to do but thank you all so much for your help thus far

Now The next step is getting it ready for an MOT, for some reason the reverse lights aren’t coming on when I put it into reverse.

The clutch seems to struggle getting into gears so my dad has asked how to drain the clutch fluid so we can change that, it looks dark and contaminated.

Also, can anyone point me in the right direction to source a reasonably priced isolator switch for the windows?

Thanks a million

[Tzantushka]

Watching this thread from the sidelines - a great result and all thanks to the E30 zone community.

Have drink to celebrate.
My shout!

[Brianmoooore]

Lucky that I had the afterthought about the relays, and edited it into my first post on the 19th - the one where I suggested you source another ECU.
There's no window isolator switch fitted on a cab. It's a small square switch, and is only fitted on four door saloons with rear electric windows.
I suspect you mean the thermal cut out, which is a rectangular device with a lightning symbol on top, and is fitted to all models with electric windows, but it is neither a switch, nor an isolator. It's a resettable thermal fuse and should only be touched when the button has popped up, exposing a red band.
The clutch fluid problem is common on RH drive cars. The service schedule requires the replacement of brake fluid every two years, and the reservoir is shared with the clutch on LH drive models, so the clutch fluid gets changed as well. Unfortunately, on RH drive cars, although the brake fluid may have been changed many times, it's quite common for the clutch fluid to be the original, and when you replace the tar like substance in the system with nice new thin fluid, you'll find that the seals in both the master and slave cylinder leak like a sieve, and both will need replacement.

[E30ibz]

Okay so she’s up and running, passed the MOT, when I left the garage I started getting a loud squeaky noise from what I imagine is one of the belts.
Only does it when it is in gear, any idea what it could be and how to get rid of it? I’m getting looks when I drive by people for the wrong reasons