Technical Immobiliser Bypass Help

[Communicator]

I didn't know what a wax stat was but having read up on it I wouldn't have thought so either.

I had a thought lastnight though and hope this will be the problem. Directly above the solenoid box is a bleed nipple on the fuel pump. This was in the way of the multi tool so we temporarily swapped it for a short bolt to give us more room and I reckon it's drawn in some air. This seems to be the only thing we did that no one else has mentioned doing and they've had successful bypasses.

@bugsymike I appreciate your explanation on how to bleed the injectors but I'm not confident I've done it 100% correctly and wonder whether it also needs bleeding from the filter and the nipple we removed. I have a mobile mechanic coming this afternoon to bleed the system so I will report back whether it makes a difference.

I hope that you temporary bolt was not inserted too far causing damage.

As consolation, in my younger days I had a diesel Land Rover. I could bleed from two nipples on the pump with the engine running on level ground, to no avail, because as soon as the vehicle was on a slight tilt the engine stopped. Another small bubble of air out, and all was then OK.

 

[Jmj89]

I hope that you temporary bolt was not inserted too far causing damage.

As consolation, in my younger days I had a diesel Land Rover. I could bleed from two nipples on the pump with the engine running on level ground, to no avail, because as soon as the vehicle was on a slight tilt the engine stopped. Another small bubble of air out, and all was then OK.

It was a small bolt with about 10mm of thread so hopefully not.

Ah that sounds annoying. It is on a slight decline so hopefully he can still bleed it ok and I won't have that problem.

 

[Jmj89]

So that didn't go very well. He bled the system and no joy. After some investigating he said while it is receiving fuel it's not getting enough and it doesn't know when to start. He said it's 100% an immobiliser fault even though it's been bypassed and the solenoid gets power. He showed us fuel coming out of the injectors when cranking, then disconnected the bypass and cranked again and exactly the same amount of fuel was coming out. He thinks we've messed something up and said best option is to buy a new fuel pump and immobiliser and have them coded in - basically do it properly.

My thoughts now are that we either damaged the PCB while it was still connected and it's messed something up (there was a tiny bit of damage to to PCB by the multi tool). Or we've blown the yellow box (perhaps by accidentally sending 12v down the communication wire to the box) before bypassing it which has kind of locked it into key not regonised mode. The reason I think this is from reading up, The CODE light is provided by the yellow box and I no longer get one. There is 12v supply to the box so it's getting power but perhaps not drawing any.

@Communicator I know you explained this process and why there is nothing to start the process off, but the bypasses I've read people seem to still get a CODE light until the yellow box is unplugged. Unless it's because they left the chip in and soldered onto it rather than removing it and soldering straight to solenoid.

I cant help but think if that box was replaced the light might come back on. Even if it failed to communicate with the immobiliser because there isn't one, I'd still expect a CODE light and to then have to unplug the box to get rid of it.

Does anyone know if the yellow box is interlinked with anything else other than the immobiliser?

 

[Communicator]

So that didn't go very well. He bled the system and no joy. After some investigating he said while it is receiving fuel it's not getting enough and it doesn't know when to start. He said it's 100% an immobiliser fault even though it's been bypassed and the solenoid gets power. He showed us fuel coming out of the injectors when cranking, then disconnected the bypass and cranked again and exactly the same amount of fuel was coming out. He thinks we've messed something up and said best option is to buy a new fuel pump and immobiliser and have them coded in - basically do it properly.

My thoughts now are that we either damaged the chip while it was still connected and it's messed something up (there was a tiny bit of damage to to PCB by the multi tool). Or we've blown the yellow box (perhaps by accidentally sending 12v down the communication wire to the box) before bypassing it which has kind of locked it into key not regonised mode. The reason I think this is from reading up, The CODE light is provided by the yellow box and I no longer get one. There is 12v supply to the box so it's getting power but perhaps not drawing any.

@Communicator I know you explained this process and why there is nothing to start the process off, but the bypasses I've read people seem to still get a CODE light until the yellow box is unplugged. Unless it's because they left the chip in and soldered onto it rather than removing it and soldering straight to solenoid.

I cant help but think if that box was replaced the light might come back on. Even if it failed to communicate with the immobiliser because there isn't one, I'd still expect a CODE light and to then have to unplug the box to get rid of it.

Does anyone know if the yellow box is interlinked with anything else other than the immobiliser?

My opinion of your mobile mechanic is on a downward slope. He obviously knows little about immobilisers, and the availability of spares for 25 year old vehicles. You could perhaps buy a new or refurbished pump, but it would be expensive. I doubt that you would be able to purchase an immobiliser, for which the design life is probably 20 years. Perhaps an automotive locksmith would be able to reprogramme, but again I am sceptical as there will be little if any demand for such service.
However the bit about equal fuel flow with the solenoid (bypass) disconnected is interesting. It suggests a problem in the fuel pump head or solenoid valve. There should be no fuel flow with the solenoid disconnected.

I think you are attaching too much importance to the missing code light. I have never seen any diagrams for the immobiliser on mechanically controlled injection systems similar to yours, so cannot comment with absolute certainty. I believe that is similar to that on x244 vehicles, but instead of the pump pcb, you have to substitute a section of the engine computer. I do have a diagram for that system which applies to my vehicle, and I will attach for discussion. The code receiver has an 3 way, and a 8 way connector. The former has only two pins connected for the aerial, and the latter (8 way) has only 5 pins used on diagram. The latter 8 way has 5 pins connected on the diagram. Pin 5 connects to the EOBD port (E8010) for programming.
Does your yellow box have the same connectors?
If so not much room for other connections.

If you look at the ECU (M010 ) it only has 3 connections for this purpose, ign on, data, and earth. This matches the connections on your pump pcb, if you exclude the output to the solenoid.

 

[jackwhoo]

I too think the mobile person possibly did not understand your pre-common rail injection pump. It is possible he had no idea how to bleed the system.

To energise the stop solenoid to its run position it just requires battery +ve to the solenoid no pcb at all , no yellow box at all.

The injection pump draws fuel from the tank via the fuel filter .

There may or may not be an in tank fuel lift pump too help.

There are threads with photos on forum how to remove the immo from pump. Try and find those to check what you have done.

 

[jackwhoo]

 

[jackwhoo]

Stop solenoid is number 8 on that pic

On your pump it will be covered by some kind of box possibly integral with the pump immo parts.

 

[jackwhoo]

Post a photo of the "bleed screw" you removed and replaced

 

[Jmj89]

My opinion of your mobile mechanic is on a downward slope. He obviously knows little about immobilisers, and the availability of spares for 25 year old vehicles. You could perhaps buy a new or refurbished pump, but it would be expensive. I doubt that you would be able to purchase an immobiliser, for which the design life is probably 20 years. Perhaps an automotive locksmith would be able to reprogramme, but again I am sceptical as there will be little if any demand for such service.
However the bit about equal fuel flow with the solenoid (bypass) disconnected is interesting. It suggests a problem in the fuel pump head or solenoid valve. There should be no fuel flow with the solenoid disconnected.

I think you are attaching too much importance to the missing code light. I have never seen any diagrams for the immobiliser on mechanically controlled injection systems similar to yours, so cannot comment with absolute certainty. I believe that is similar to that on x244 vehicles, but instead of the pump pcb, you have to substitute a section of the engine computer. I do have a diagram for that system which applies to my vehicle, and I will attach for discussion. The code receiver has an 3 way, and a 8 way connector. The former has only two pins connected for the aerial, and the latter (8 way) has only 5 pins used on diagram. The latter 8 way has 5 pins connected on the diagram. Pin 5 connects to the EOBD port (E8010) for programming.
Does your yellow box have the same connectors?
If so not much room for other connections.

If you look at the ECU (M010 ) it only has 3 connections for this purpose, ign on, data, and earth. This matches the connections on your pump pcb, if you exclude the output to the solenoid.

He was recommended by a few people but I'm not confident either. I've found a few immobilisers but as you say the programming could be a bit tricky.

I understand what you're saying about the fuel thing, it makes no sense how it could pump fuel when the solenoids not connected to anything. He put a voltmeter on the three cables that used to go onto PCB and said there's an earth and two lives. It may be that he connected both lives separately and it was the same fuel flow. I will have to check with my friend who was watching as I was cranking and couldn't see what he was doing, maybe I misunderstood him.

Re the key light, I could well be but after checking so many things and there not being many other possibilities I thought its something else to look into. Especially as others don't usually lose the light.

Thanks for the diagram, it's the same connections on mine a 3 and (from memory) an 8 way.

At the end of the day and as everyone has said, if fuels pumping through and it's getting air and compression it should start so I'm trying to think if there is anything that could prevent a start when these things are present.

 

[Jmj89]

I too think the mobile person possibly did not understand your pre-common rail injection pump. It is possible he had no idea how to bleed the system.

To energise the stop solenoid to its run position it just requires battery +ve to the solenoid no pcb at all , no yellow box at all.

The injection pump draws fuel from the tank via the fuel filter .

There may or may not be an in tank fuel lift pump too help.

There are threads with photos on forum how to remove the immo from pump. Try and find those to check what you have done.

Yes you could be right. I understand that, and you can hear it click on ignition. I've also ran direct from battery + and it's the same click so it seems to be operating correctly.

Before attempting it I spent a week reading through posts and looking at pictures so I am confident we have done the correct solenoid. Just to confirm as it was at the beginning of the thread, we did not completely remove the security casing so did not reveal the solenoid. We took off the plastic end cover, removed the silicone and multi tooled a bit off the top of the box to allow us to get behind the PCB and gently prise it out. This left the small wire from solenoid that used to connect to PCB poking out the top left corner of the security casing. There wasn't enough wire or any slack on it so we multi tooled the corner around the wire off the box and then soldered the ignition switch live of the 3 old cables onto it. So there is no PCB present now and the earth and code box wire are not connected to anything. We have tried connecting the earth but no difference.

I will take some pictures in daylight tomorrow.

 

[Communicator]

There are threads with photos on forum how to remove the immo from pump. Try and find those to check what you have done.

See post #29 on this thread.

 

[Jmj89]

@jackwhoo this is not my image but this is the bleed screw.

 

[Communicator]

I have a memory of @bugsymike removing the inards of a solenoid valve in order to keep a customers vehicle running. Stopping the engine was by stalling it. Temporary fix only. It may have been due to either a faulty solenoid, or a faulty valve. I cannot remenber which. Mike will have retired for the night.

 

[Jmj89]

I have a memory of @bugsymike removing the inards of a solenoid valve in order to keep a customers vehicle running. Stopping the engine was by stalling it. Temporary fix only. It may have been due to either a faulty solenoid, or a faulty valve. I cannot remenber which. Mike will have retired for the night.

He did mention the possibility of doing that as a temporary fix to hopefully get it off my friends drive. If it doesn't start with the solenoid forced open at least i'd know it wasn't that and the bypass was more than likely working.

 

[Jmj89]

@jackwhoo this is what we've done. Obviously the plastic cover and PCB were removed.

 

[bugsymike]

I have a memory of @bugsymike removing the inards of a solenoid valve in order to keep a customers vehicle running. Stopping the engine was by stalling it. Temporary fix only. It may have been due to either a faulty solenoid, or a faulty valve. I cannot remenber which. Mike will have retired for the night.

Very true, I like my sleep.
Bang on the nail as usual though @Communicator .
It was about 1987 on a Peugeot 305 XUD diesel, solenoid magnet was weak and wouldn't hold pintle/valve open to allow fuel into injector pump, so as owner was desperate to use the vehicle I simply removed the spring and pintle/valve from end of solenoid which obviously meant he could only stop the vehicle by stalling it until a new solenoid arrived from local Lucas/diesel specialist.
Small point, that was a 1.9 diesel, stalling a 2.8 Sofim engine may be a bit harder, so advise take a spanner to fit injector pipe unions to stop engine, just in case.

 

[jackwhoo]

@jackwhoo this is not my image but this is the bleed screw.View attachment 468950

That is not a bleed screw.

It is a fueling adjustment screw.

 

[Jmj89]

That is not a bleed screw.

It is a fueling adjustment screw.

This was it! We hadn't put it in far enough, screwed in a bit more and started straight up!

@Communicator, @jackwhoo and @bugsymike please send me your PayPal if you have it. I would like to send you a drink.

 

[jackwhoo]

This was it! We hadn't put it in far enough, screwed in a bit more and started straight up!

@Communicator, @jackwhoo and @bugsymike please send me your PayPal if you have it. I would like to send you a drink.

Hi,

I am ecstatic you have got it started (-:

We all need a win now and again.

The more the screw is in the more fuel is injected. If when driving there is a lot of black tail pipe smoke unscrew say a quarter turn then retest.
If power well down screw in quarter turn then retest.

Well done .

Jack

 

[Greasytrucker]

This was it! We hadn't put it in far enough, screwed in a bit more and started straight up!

@Communicator, @jackwhoo and @bugsymike please send me your PayPal if you have it. I would like to send you a drink.

i’m just pleased for you that you didn’t go down the mobile mechanics route of putting it all back to how it should be with second hand bits and recoding etc. Where would you be now? Glad you sorted it mate