BX16 GTi export model wiring/crankshaft sensor

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Jori_fin
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My Cars: Citroen BX 16 GTi, 1990, export model
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BX16 GTi export model wiring/crankshaft sensor

Post by Jori_fin »

Hey guys! I really hope you could help me, I am in a dead end. I have a bx16 gti 8 valve sohc, the exported model, model year 1990. On the engine, there is a crankshaft position sensor, but I have no place for it to plug in on the main wiring harness/loom. Am I missing a harness or should this model even have a crankshaft position sensor?

I also am having trouble recognizing the ignition system I have. Some sources say it is LU3 jetronic, some say later gtis had motronic and some that it's the magneti marelli. I have the ignition coil on left side firewall, I have a distributor (so I guess it isnt jetronic?), but I cant find MAP sensor or air/fuel mixture from the places they should be according to Haynes. Also the wiring diagrams dont exactly match this car. I have a Bosch ECU 0280000340 under the right side front seat. And there is integrated ECU in the MAF sensor.

Here is a clip on Youtube that I made for you -

Hope you can help me! I am really falling in love in this car, and would like to get running and restored properly.

Cheers, Jori

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Jaba
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Re: BX16 GTi export model wiring/crankshaft sensor

Post by Jaba »

Quick reply here. There is no crank position sensor on this model with an airflow meter. Crank timing is done by the distributor. That connector you have found is some sort of diagnostic plug and is on all petrol BXs as far as I know. It is never used though.
Since you seem to have a fuel supply problem then a quick test for fuel pump operation, no need for cranking, is that when you turn on the ignition the pump runs for a short time and then stops, this gives fuel pressure at the inlet for starting. Whether this is relay controlled or just ECU controlled I am not sure. So test the fuel pump electrics to see if it is getting any voltage as a first step.
The Joy of BX with just one Citroën BX to my name now. Will I sing Bye Bye to my GTI or will it be Till death us do part.

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David
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Re: BX16 GTi export model wiring/crankshaft sensor

Post by David »

I had a lot of trouble getting a 1.9 GTi engine running a few years ago. It looked like there was an harness missing, but eventually I got it running and I put it all in a post on this forum.

The crankshaft position sensor isn't used on this engine, it's only there for diagnostics, so it's not plugged into anything.

That wire that comes out of the bulkhead isn't used either; it connects to the ABS &/or the 4X4 wiring harnesses, if fitted. It looks like your car has neither.

Essentially you need an ignition live and neutral to the coil to work the spark. The distributor works out when it should be sparking, along with the electronic controller or points on the distributor; it has nothing to do with the Ecu.

The fuelling is controlled by the ecu and it has a wire connected to it from the coil to tell it when to open the injectors and let the fuel in, so if you make sure the engine has a spark and then make sure that they're connected together correctly, it should start. If you're unsure, then find my post on here. It's from around 2016. It goes into great detail of what wires connect where, although I was working with a different coil. They all function the same.

Hope that helps.
1992 Citroën BX 1.9 Diesel Meteor 4x4 - The Project.

1992 Citroën BX 1.9 TXD (with GTI engine; Mulleys old car) - Parts car.

2004 Citroën Xsara Desire. (Now gone).

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Jaba
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Re: BX16 GTi export model wiring/crankshaft sensor

Post by Jaba »

Just had a further look at your video and I confirm that there is something amiss as you appear to have two different ignition systems installed. The engine with distributor is used in the earlier GTi before July 1990 and is Jetronic LE3 (according to Haynes). What I assume has happened is that a replacement engine from an earlier car has been installed together with the engine loom and ancillaries for that car.
The later Motronic 3.1 Has a large loom connector that screws on to its counterpart near the alternator that disappears into the front wing and then down to the ECU under the seat. This ECU also controls the fuel pump as well as everything else. A conversion would entail duplicating the functions of this ECU, tricky but not impossible.
You have a challenge on your hands I think. A nice summer time project for you.
The Joy of BX with just one Citroën BX to my name now. Will I sing Bye Bye to my GTI or will it be Till death us do part.

Jori_fin
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My Cars: Citroen BX 16 GTi, 1990, export model
Audi A4 B8 2.0tdi, 2008
Opel Astra 1.6L ecotec, 1996

Re: BX16 GTi export model wiring/crankshaft sensor

Post by Jori_fin »

Hey guys! Thanks for the replies, I am loving the support! I was cheering out loud for the first two replies, but the third took me down fast :D

David - I will look into your post for sure, thank you!

I tested the fuel pump with a separate battery, it works and I get clear fuel to the fuel rail, so the fuel lines are complete with no leaks. So it's not clearly getting voltage from cars own wiring. I ditched all the further plans as I found the crankshaft sensor/diagnostic unplugged, because I was sure (haha :D) it would prevent the fuel and ignition systems working properly.

Jaba - are you 100% sure. My video was really messy, I could make a new one or take pics and check for parts that would make it even more clear that there truly is a replacement engine installed. What should I check to make this easier? I guess the engine code would be one the tell it straight away?

Jetronic used a ignition coil located under the intake manifold, am I correct? And mine has the coil on the left side firewall.
The Bosch ECU 0280000340, it was used on a Motronic 3.1.? Jetronic has a different earlier ECU?

Million thanks to you all!

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Jaba
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Re: BX16 GTi export model wiring/crankshaft sensor

Post by Jaba »

Jori_fin wrote:
Sun May 22, 2022 9:34 am

Jaba - are you 100% sure. My video was really messy, I could make a new one or take pics and check for parts that would make it even more clear that there truly is a replacement engine installed. What should I check to make this easier? I guess the engine code would be one the tell it straight away?

Jetronic used a ignition coil located under the intake manifold, am I correct? And mine has the coil on the left side firewall.
The Bosch ECU 0280000340, it was used on a Motronic 3.1.? Jetronic has a different earlier ECU?

Million thanks to you all!
So sorry, I misread and assumed you have a 1.9GTi whereas in fact you have the 1.6, presumably monopoint injection. So you have not had an engine transplant and your lack of fuel must be due to some other problem and not engine transplant related.
Going back to basics, you say there is no fuel injected. Have you checked that the pump runs while cranking ? If it does then is there a 12v pulse to the injector. Poor connections are common as are broken wires inside the insulation. ECUs can fail as well but they are pretty robust and long lasting.

As this model was not sold in UK I am not up to speed with diagnosing faults. I do have a wiring diagram for a 1.6 Jetronic but this does not show the under the seat ECU and has four injectors so is not much use. I think you have probably got a Motronic system fitted. This site may have some info: https://citroen.tramontana.co.hu/

Additionally the engine was fitted to the Peugeot 206 GTI so there may be more help in that direction.

Once again sorry for the bad info and good luck with getting it going.
The Joy of BX with just one Citroën BX to my name now. Will I sing Bye Bye to my GTI or will it be Till death us do part.

Jori_fin
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My Cars: Citroen BX 16 GTi, 1990, export model
Audi A4 B8 2.0tdi, 2008
Opel Astra 1.6L ecotec, 1996

Re: BX16 GTi export model wiring/crankshaft sensor

Post by Jori_fin »

Okay! And no problem, loving the advice you're giving! I have four injectors and a ECU under the seat. If it was Motronic, wouldn't it have TDC sensor providing info to ECU?

There is no pulse to fuel pump, I assumed it was because of the unplugged crankshaft sensor. But as it seems to be just a diagnostic port, I will check the timing, clean all the connectors and ground points, put it all back together and try again. If it's not a success, I will look into replacing relays and sensors one by one.

By the way, where do you get the spare parts from? Is there a dedicated car parts store that would have online shopping available?

Cheers!
BR, Jori

Jori_fin
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Location: Finland, Oulu
My Cars: Citroen BX 16 GTi, 1990, export model
Audi A4 B8 2.0tdi, 2008
Opel Astra 1.6L ecotec, 1996

Re: BX16 GTi export model wiring/crankshaft sensor

Post by Jori_fin »

Bit of an update!

I put the engine back together, cleaned electrical connectors and grounding points. Now I get fuel to the rail with a proper pressure, I tested spark, I got a bright spark from all the plugs in normal 1-3-4-2 firing order. I when I crank the car, it tries to run (ignition happens). I checked the timing, I assume the timing is ok if I can fit a 10mm drill/pole/whatever, into timing holes on both cam and crankshaft pulley? The engine spins with a hand tool. There is plenty of oil in the engine.

I am thinking I would next drain the oil to see if there are bits of metal or something else alarming. Also I would do compression test for all four cylinders. What else to check?

Haven't had spare hands yet to try to start the car by spraying brake cleaner into intake manifold. I didn't test the injectors when they were off the engine, but I had some gas on the plugs after cranking. If the injectors wouldn't be working properly, what electrical component would be able to cause that? Faulty injector relay?
Edit: I think I will look into your earlier post, David, to make sure injectors are connected properly.

Seems that the injection system is Motronic ML4.1.

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Re: BX16 GTi export model wiring/crankshaft sensor

Post by xantia_v6 »

Does the ignition have a distributor? If so, you should check that the ignition timing is not 180° out from the valve timing.

Jori_fin
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Audi A4 B8 2.0tdi, 2008
Opel Astra 1.6L ecotec, 1996

Re: BX16 GTi export model wiring/crankshaft sensor

Post by Jori_fin »

Yes, distributor cap and rotor arm are in correct position.
Edit: got it running with brake cleaner. Next I am going to clean the injectors. If it helps, great - if not, I will be looking into electrical problem.
Edit: cleaned the injectors, seems like a electrical problem. Do the impulses to injectors come from the coil?
Edit: haha :D as you have suggested multiple times, I will now make sure the ECU gets the pulse from coil and injectors the pulse from ECU.