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Injector driver

Andy123abc

Dec 28, 2022
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Hello I am new here who can help me to make injector driver for 6 cylinder engine whitch has two injectors banks controlls by engine ECU motronic1.3 3.5L engine that driver not working and all injectors spraying together at the same time. I would like to make one injector driver whitch will controll 6 injectors by two banks the each bank has 3 injector connected together and another bank has 3 injectors connected same. I would like to pick up signal from RPM crank shaft sensor and connected to the disign driver which will control one bank for 3 injectors for 60m/s then another bank of 3 injectors for 60m/s at engine idle speed 800RPM ones the engine speed encrease then m/s time decrease. One bank of the 3 injectors should be turn on for 60m/s and another bank of 3 injectors should be on hold for 60m/s and so on. Injectors will be running ON and OFF depends on engine speed. Thanks in advance for your answer !
 

Bluejets

Oct 5, 2014
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Think you will find this is not a forum which offers free design and testing services.
You might be lucky and find someone willing to go down that path but be prepared to have very deep pockets with payments up front.
 

kellys_eye

Jun 25, 2010
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whitch has two injectors banks controlls by engine ECU motronic1.3 3.5L engine that driver not working and all injectors spraying together at the same time.
Then your ECU is faulty....... the injector control should be a functioning part of the ECU and needs to be investigated properly if it's not working as it should.
 

Alec_t

Jul 7, 2015
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There are serious safety concerns with controlling a 3.5L engine. Will your insurer be happy knowing the injection is controlled by a home-brew bit of electronics?
Have you checked if there are strict vehicle requirements in your country to comply with?
How will you control the injector timing in response to such variables as throttle position etc handled by the ECU?
 

kellys_eye

Jun 25, 2010
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There are serious safety concerns with controlling a 3.5L engine. Will your insurer be happy knowing the injection is controlled by a home-brew bit of electronics?
Have you checked if there are strict vehicle requirements in your country to comply with?
How will you control the injector timing in response to such variables as throttle position etc handled by the ECU?
I've often wondered myself..... there are loads of very effective DIY replacements for ECUs on t'internet and they are as credible as the OEM stuff as far as capability is concerned. AFAIK all you have to do is be within the emissions spec of your relevant country for the ECU to 'pass' muster - otherwise it's a totally transparent fit in any vehicle.

Insurers, as you'd expect, can nullify your policy if you change the ECU 'parameters' but if you tell them you have then there's no problem - much as you're supposed to tell them even if you fit new wheels/tires.
 

Andy123abc

Dec 28, 2022
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Then your ECU is faulty....... the injector control should be a functioning part of the ECU and needs to be investigated properly if it's not working as it should.
Yes the engine ECU not working properly as it should. The engine ECU can be by-pass not everything just injectors timing by disconnected pins 16 and 17 which is two banks of injectors and connected modified injectors driver to those 6 injectors which will control two banks of the injectors on 6 cylinder engine that is all. Who can help me to make a drew electronic diagram with electronic parts and soldered on small circuit board and who will make it correct diagram I can pay. Let me know how much it will cost approximately ? Thanks !
 

kellys_eye

Jun 25, 2010
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Yes the engine ECU not working properly as it should.
How are you testing this? By pure observation or by using some form of electronic monitoring device like an oscilloscope? Which model of ECU are you using? What technical details can you post here? (links etc). Can you show the actual injector arrangement? Are you 100% certain the injector side is working as it should and is in accordance with the specs the ECU manufacturers demand of it? Have you wired/powered the injectors correctly i.e are they a 'pull down' or 'pull up' power arrangement; is the power side capable of delivering the required energy? etc.

Your claim that the ECU is faulty might not be as true as you think it is - unless you have correctly eliminated all other potential issues.
 

Andy123abc

Dec 28, 2022
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Then how do you know it will provide the correct signals for controlling any home-built injector driving arrangement?
Module will be controling ground circuit on/off of the injectors only the positive side will be always powered with 12v. It would be better if module firing all injectors separately same like spark plugs then the engine could not get any misfire and emissions would be better.
 

Alec_t

Jul 7, 2015
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Module will be controling ground circuit on/off of the injectors only
That may be so, but the correct timing information (pulse start time and duration) would nevertheless have to come from the ECU which you say is not working properly.
 

Andy123abc

Dec 28, 2022
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I am saying that the engine ECU turns on all injectors at the same time. The engine ECU has 2 pins. One pin is fo 3 injectors and another pin is for another 3 injectors. I don't know how the engine ECU should working on those injectors. It should firing all injectors at the same time or it should firing 3 injectors and after next 3 injectors. 3 injectors ground connected together and goes to th engine ECU.
 

kellys_eye

Jun 25, 2010
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It fires three on one part of the engine cycle and three on the other. The fact that it fires into a 'non-ignition' port is irrelevant as that fuel is drawn in on the next 'cycle' - the time difference between each cylinder cycling through an 'intake' is so short it doesn't make any real difference to the injection cycle itself. Yes, you can improve efficiency by using more ports on the ECU (ideally drive each injector individually) but the savings versus cost compromise is pretty hard to discern for most users.

If you were running a high powered sports car (on track) then you'd clearly want control over each injection cycle and fit an ECU that actually has the appropriate number of injector control outputs but for a daily driver......

If it's firing both sets of three together then you need to check either the ECU settings (have you configured it for the right number of cyclinders?) or look for shorts (unlikely).
 

Andy123abc

Dec 28, 2022
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It fires three on one part of the engine cycle and three on the other. The fact that it fires into a 'non-ignition' port is irrelevant as that fuel is drawn in on the next 'cycle' - the time difference between each cylinder cycling through an 'intake' is so short it doesn't make any real difference to the injection cycle itself. Yes, you can improve efficiency by using more ports on the ECU (ideally drive each injector individually) but the savings versus cost compromise is pretty hard to discern for most users.

If you were running a high powered sports car (on track) then you'd clearly want control over each injection cycle and fit an ECU that actually has the appropriate number of injector control outputs but for a daily driver......

If it's firing both sets of three together then you need to check either the ECU settings (have you configured it for the right number of cyclinders?) or look for shorts (unlikely).
Yes I also think so that 3 injectors firing when at the same time firing 3 spark plugs. When injectors 1-3-5 is firing then 3 spark plugs firing in firing order 1-5-3 then next injectors 2-4-6 firing with firing spark plugs in firing order 6-2-4.
 

Andy123abc

Dec 28, 2022
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Do you mean one part of the engine cycle that is 360 degrees of the crankshaft. One rotation of the crankshaft is 360 degrees for 3 injectors and 3 spark plugs to fire ? 720 degrees will be 6 injectors and 6 spark plugs fired. 3 injectors and 3 spark plugs it takes 60 m/s to fire and next 3 injectors with spark plugs also 60 m/s. Two full turns of the crankshaft is 720 degrees and 120 m/s time than measurement taken from engine speed at idle 800RPM when engine speed will increase then m/s time will be decrease. For example if engine speed will be 1500RPM then time will be 40 m/s for 3 injectors and 3 spark plugs to fire.
 
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kellys_eye

Jun 25, 2010
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In the first rotation (360 deg) three cylinders will fire off in their appropriate sequence (1,5 and 3 for example), the other three (2, 4 and 6)in the next 360 degree rotation. For each rotation you therefore only need to inject fuel to the three cylinders that are GOING to fire so you fire off those three injectors simultaneously.

ONE of the three cylinders will be on the intake/compression cycle and draw the fuel in to be burned. The remaining fuel in the other two (yet-to-fire) intake runners can sit there and 'wait' until that cylinders intake valve opens an sucks the mixture in (has to wait a full revolution though) - but it's far too short a time for anything untoward to happen to the fuel/air mix (it ain't going any where!) and the actual amount (fuel/air ratio) won't need to change as the throttle response is far, far too long in comparison to the actual firing sequence.

The two sets of injectors are each therefore fired only ONCE per revolution (sequentially) at a time determined by the ECU which gets its timing from the crankshaft sensor and then calculates the BTDC timing depending on load/revs etc.

As you should be able to see, there is no need to fire the injectors 'individually' (i.e. at each intake/compression/firing cycle) - charging three intakes at the same time has little effect on the end result.

Compare this to a standard carb setup where the fuel/air mix is available to ALL cylinders at the same time (for a single carb setup) or for two lots of three cylinders in a dual carb setup. All the injectors do is a better job at atomising the fuel mix and placing it where it's needed rather than it having to travel convoluted intake pipe routes (just the air does in an injector setup).

Consequently your ECU should have a pulse on one of the injector drivers, then the other. If you could connect a light to both outputs you'd see them both flashing but never at the same time - just alternately. Each pulse would only appear once every TWO revolutions of the crankshaft.

If you had an oscilloscope you could check these pulses quite easily (a dual channel scope would show the pulses and their relationship i.e. no overlap).

The time period between one set of injectors firing and the second set is just 150mS at only 800rpm!!!! (i.e. as near as dammit 6 times/second). Quite how you can tell they are firing 'together' rather than individually is rather mystifying to me - you must have VERY fast eyeballs!
 
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Andy123abc

Dec 28, 2022
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Firing all six injectors together without cut-off one group of the three injectors. Cylinder identification sensor should disconnect one group of the three injectors when number six cylinder is firing. Also when ignition is ON the engine ECU should have present 5v at connector of cylinder identification sensor there is no 5v present. When cylinder identification sensor disconnected or connected nothing change the engine misfire same.
 

kellys_eye

Jun 25, 2010
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You still haven't indicated which make/model ECU you're using. It might help if we could reference the datasheets/manual to see what might be causing it.

Also when ignition is ON the engine ECU should have present 5v at connector of cylinder identification sensor there is no 5v present.

Have you eliminated wiring issues? programming/setup issues? If so the the ECU might have a software problem (try reprogramming it) or the port delivering the supply might be defective - it could be repairable, depends on the make/model - which we STILL don't know.....
 

Andy123abc

Dec 28, 2022
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BMW 735i E32 1990 engine ECU motronic 1.3 and software number 55376215. I didn't do any reprogramming
 

kellys_eye

Jun 25, 2010
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Tried another ECU? Have you considered opening the one you have and executing any necessary repairs? It's not impossible!

the engine ECU should have present 5v at connector of cylinder identification sensor there is no 5v present.

Sourcing another 5V signal should be easy enough - many of the other ports will output 5V. Find one that is present when the ignition is on and parallel off it. Is the cylinder identification sensor working properly or is it shorted? (thus dragging the 5V down to zero).

Bottom line is that it is quite possible to design and build an interface that bypasses the issues you're faced with but in comparison to repair/replacement of the existing unit (not to mention the cost) it's not a path worth going down. Indeed it would be cheaper and (probably) more useful to buy one of the DIY ECU's on the market and just replace the OEM one altogether. I wouldn't be surprised if someone hasn't already used one on that make/model of engine and will have the data necessary to program a DIY ECU straight off the bat - I'm told such ECU's come with basic software that allows an out-of-the-box setup that will get an engine working.
 
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