Bosch LE2/LU2 Jetronic Circuit

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WAWAUS Guru Join Date: Aug 2010 Location: Melbourne, Australia Posts: 740 Good Answers: 24	Bosch LE2/LU2 Jetronic Circuit 12/12/2011 11:04 PM
	Wise people, I have scoured the internet and a few libraries for a circuit diagram of a Bosch LE2 or LU2 Jetronic ECU circuit diagram without success. In this unit the single PCB is surface mount on one side and leaded components on the other including two or three proprietry thick film hybrid modules. This is an 'analog computer' using resistor values to 'program' the performance of the fuel injection system. The unit is intended to start open loop and switch to closed loop (via a heated Lambda sensor) as the engine warms up. My objective is to repair a faulty unit I have which does not switch to closed loop operation. A spare unit I have works fine in the same vehicle. I have tried tracing the circuit, but that becomes very difficult very quickly. Bosch are exceedingly unhelpful, simply saying that I should take it to a 'certified repairer' but I want to understand its operation and therefore have discounted that option. I did find a very early Jetronic circuit or a BMW on the internet but it is several generations older than mine and therefore not particularly helpful Could anyone help me to obtain a copy of this circuit?
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SolarEagle Guru Join Date: Mar 2007 Location: by the beach in Florida Posts: 33392 Good Answers: 1817	#1 Re: Bosch LE2/LU2 Jetronic circuit 12/13/2011 3:47 AM
	This is what I could find...What I would do is try car repair forums for any types of cars that use this system, there seem to be several...Also you might try for individual parts or components in the system, rather than the system as a whole, when searching... http://www.diy-efi.org/pipermail/diy_efi/2006-February/002308.html http://www.peugeot-club.ru/pgt.nsf/0/7607362fac066d3cc3256b74003190a5/$FILE/0932-04C.pdf __________________ All living things seek to control their own destiny....this is the purpose of life
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Tobugrynbak Guru Join Date: Oct 2008 Location: Deepest Darkest Rutherford Oz Posts: 951 Good Answers: 145	#2 Re: Bosch LE2/LU2 Jetronic circuit 12/13/2011 3:47 AM
	Bosch are verrrrrry protective of their "IP". Even obsolete legacy IP, there's lots of information on how to connect to the ecu but nothing on the inside. I tinker with cars a bit (Euro stuff) and while it would be handy to repair an ECU its easier to acquire a replacement one. Its the Thick film asics which will stop you from fixing it. My 740 wagon will be getting a B23T transplant but I'm keeping the LH2.4 of the B234F motor, well the wiring any way. I'll replace the B234F ecu for the equivalent Turbo ecu. I do have the B23 T (LH 2.1) in a front cut with everything but I want to update the management system and add the APC from a SAAB 900 Turbo for better control. Your best bet is to lurk on Euro Car forum sites for "hacks" involving the LE2/LU2 ecu. That's how I found out about the APC hack for the Volvo ecu. You don't say what car your playing with, be aware that most wreckers(in Oz) are now culling a lot of "old" stuff that hasn't been moving for a while. You may be able to get a bargain on a couple of ecu's if you talk nice enough.. Sorry I couldn't be more help. __________________ There are two reasons for a man to do a thing, One that sounds good, and the real one...
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WAWAUS Guru Join Date: Aug 2010 Location: Melbourne, Australia Posts: 740 Good Answers: 24	#3 Re: Bosch LE2/LU2 Jetronic Circuit 12/13/2011 5:00 PM
	Thank you SolarEagle and Tobugrynbak the car is a Peugeot 505 Series II GTI 1988/1989. Interestingly, all the documentation that I have seen says that LE2 does not have Lambda and LU2 does, however all the Peugeot 505 Series II GTIs have ECUs labelled LE2, yet they have Lambda sensors and run closed loop .......!
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merc600sec Power-User Join Date: Oct 2010 Location: Torquay England Posts: 202 Good Answers: 4	#4 Re: Bosch LE2/LU2 Jetronic Circuit 12/14/2011 5:20 AM
	You Might try Mercedes Benz forums they used the L2 system.. __________________ Torque is not cheap
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Rockyscience Power-User Join Date: Sep 2011 Location: Near the New Madrid Fault. USA Posts: 269 Good Answers: 1	#5 Re: Bosch LE2/LU2 Jetronic Circuit 12/14/2011 9:23 AM
	My GTV-6 Alfa has L-Jetronic. The Alfa service manual covers it very well. You may be able to fine a car with your system and buy the manual. __________________ It's not Rocket Science
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