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Trying to get the ECU to cooperate


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#21 Chickenman

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Posted 28 June 2016 - 09:09 AM


 

 

If I do go for a stand alone system how do you get the new wiring harness to match up with the existing sensors and control units, or do they have to be replaced as well?

There are lots of Options for making a new harness. 

 

You use a new bare harness that comes with your Stand alone system. ECU side is terminated with proper Terminals and there is usually a sub- harness for a Relay box ( Fuel pump, ECU Main Relay, Cooling Fans, Nitrous etc ) The sensor ends, injector, etc  are bare pigtails and you attach what ever terminal ends you need. Bosch terminal ends are widely available on the internet. DIY Auto Tune carries any terminals and parts you need.

 

https://www.diyautot...ing-components/

 

You can also order the new Harness pre-terminated with all the correct ends from DIY Auto Tuning ( or any other supplier ) for additional money.

 

One of our members ( Fric Frac ) makes beautiful custom made harnesses. He also supplies the bare Bosch connectors ( new style with spring release ) for a reasonable cost. Kit includes enough EV1 connectors for all injectors and sensors, TPS and AFM ( if needed ). Terminals come with unwired terminal pins so you can crimp on the pins to your harness. I find that much easier than soldering wires together and then heat shrinking etc.


Edited by Chickenman, 28 June 2016 - 09:34 AM.


#22 Chickenman

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Posted 28 June 2016 - 09:41 AM

^ And of course if you already have the BMW harness routed and all connected, you can leave it in place and just change the ECU side connector. All standalone ECU's use standard electronics grade connectors which are easily sourced



#23 Chickenman

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Posted 28 June 2016 - 09:53 AM

I don't know the BMW cars very well or their service manuals, but it looks like they were using L-Jetronic for quite a while.  I found a manual and downloaded (I save all old documentation on the off-chance I might actually get one in the future).

 

Could it be the fuel injection relay that's the problem?  Looks like they were doing the same as Nissan, a separate pump relay and an EFI system relay.  Could be that one powers the other.  Nissan started using a control relay to power a relay on their fuel systems in 1978.  I don't know if the EFI relay needs to work to run the pump relay, but I do know that my 76 car wouldn't start when the EFI relay started to die sporadically.  I had a fuel pump switch, kind of like where you ended up before the starter problem, so never figured out if the pump was working when the EFI relay went bad.

 

Here's a link and a picture (page 163).  Things were probably similar for the M6.  It's a big file. http://www.mediafire...r_manual_v7.pdf

 

ZH has a very good point. German manufacturers like to use Multi function relays instead of individual relays. They have multiple sets of contacts inside controlling power to different circuits, such as Fuel Pumps, Ignition and Injectors. One set of contacts can fail while another still works. Might be an idea to get a new ECU relay or at least test the old one to make sure all the contacts are working correctly.

 

Sometimes it's faster just to pop the cover off and give it the old " Sniff " test. Burnt out coils have a distinctive odor.... and you can usually see any discoloration of the windings.  Pitted or corroded contacts can be viewed with a mgnifying glass.



#24 grannyknot

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Posted 28 June 2016 - 02:35 PM

I don't know the BMW cars very well or their service manuals, but it looks like they were using L-Jetronic for quite a while.  I found a manual and downloaded (I save all old documentation on the off-chance I might actually get one in the future).

 

Could it be the fuel injection relay that's the problem?  Looks like they were doing the same as Nissan, a separate pump relay and an EFI system relay.  Could be that one powers the other.  Nissan started using a control relay to power a relay on their fuel systems in 1978.  I don't know if the EFI relay needs to work to run the pump relay, but I do know that my 76 car wouldn't start when the EFI relay started to die sporadically.  I had a fuel pump switch, kind of like where you ended up before the starter problem, so never figured out if the pump was working when the EFI relay went bad.

 

Here's a link and a picture (page 163).  Things were probably similar for the M6.  It's a big file. http://www.mediafire...r_manual_v7.pdf

NZ, your right, the main relay powers the ECU, the injectors and the fuel relay, the fuel relay powers the fuel pumps, O2 sensor and the ICV. I did try some new relays when I first started testing but I hadn't sorted out the anti theft wire or the starter yet,

so now would be a good time to try new relays again.

 CM, good info on the stand alone FI controller, I'm not feeling so intimidated now. I did a bunch of reading last night about Mega squirt, alot of guys love it but there also seems to be a lot guys who despise it. I'll keep an open mind but hopefully I'll get the bmw unit working first.

Thanks for the advice boys, I really appreciate it.

Chris



#25 grannyknot

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Posted 30 June 2016 - 03:01 PM

Okay, I did some more testing with new and known working used relays for the main and fuel relays, same old story, so I'm done with Motronic, I'll save the wiring harness and convert it to use with Megasquirt.

There sure is a lot to read with MS, so far it looks like I will order,

MS2 extra board,

V.3.0,

a relay board,

Glen's Garage adapter for the 3 wire TPS,

a JimStim,

a GM intake air temp sensor,

a 60-2 wheel harmonic balancer from a m30b35 engine

and an old laptop with a serial port



#26 Chickenman

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Posted 01 July 2016 - 10:43 AM

MegaSquirt is really nice to work with. And they have a ton of support on their forums. I don't know if I've mentioned this already, but this is an excellent book to buy for people building and tuning any Stand-alone EFI system. Highly recommended!!

 

Performance Fuel Injection Systems by HP Books. DIYAutoTuning developers Matt Cramer and Jerry Hoffman are the Authors.

 

https://www.diyautot...stems-hp-books/

 

Amazon.com and all online book retailers can get it.



#27 Chickenman

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Posted 01 July 2016 - 10:57 AM

I think the comments form the guys who despise it are  from the ones who don't properly understand any EFI systems. The capabilities of modern stand alone EFI systems are pretty similar. The differences are in the User Interfaces. Some GUI' are better than others.

 

There's also the issue on the build it yourself kits is that some people just don't have the necessary electrical and soldering skills to assemble the kits. There's a heck of a lot of difference from soldering automotive wires or house plumbing and electronics soldering. Unfortunately those people tend to over estimate their skills, and then end up with problems. Human nature being what it is, they then blame the manufacturer for their own lack of skills

 

The kits are really for those who are experienced in working on electronic circuit boards and soldering small scale electronic components. If you are not experienced with that, then you are far better off spending the extra money and buying the professionally built units. Just my .02c beermug.gif



#28 Chickenman

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Posted 01 July 2016 - 11:12 AM

The Jim Stim is a handy little device. It is also very helpful to to run a Bench Test  with all of the sensors connected and Calibrated, then play with the program and Load and Modify some tunes. You can get a good idea of how the GUI works before installing it on the car. Most of the developments at DIY Autotuning is done by simulation. Haltech, SEM and all the manufacturers all run simulations first.

 

DIYAutoTuning likely has a stock tune ready to go for that engine. Juts put in a request in the appropriate forum and they'll usually fire one off to you. You could even ask them to include the BMW when you buy the Hardware. They can easily throw it on a CD or send by E-Mail.

 

Ideally you can have all the sensors calibrated. The stock base tune loaded. All the Ignition sett-up and timing Maps svaed and loaded. Then you can install it on the car. Turn the key and have it fire on first crank. That really impresses your buddies!!

 

BTW, if you run into any issues, there are lots of people on the DIY Forums who can help you and and even  remotely tune in Real Time. All you need is to make sure that you have a good wireless connection available to your Laptop when connected to your car. An have a Remote Connection program like " Team Viewer " installed and running. It's free for Home users:

 

https://www.teamview...pF2_hoCgwXw_wcB



#29 Chickenman

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Posted 01 July 2016 - 11:23 AM

Juts a note on Coolant and Air Temperature sensors. If ordering the GM style, make sure you order genuine GM or AC Delco sensors. I've found that aftermarket ones vary considerably in the values. Even Standard Blue Streak was nearly out of GM's allowable tolerance range. The GM/AC Delco sensors were dead nuts accurate ( Temperature vs resistance ) .



#30 grannyknot

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Posted 01 July 2016 - 11:36 AM

I'm definitely in the non electronic camp, I have started talking to Peter Florance of http://www.pftuning.com/ about putting a system together for me. He owns an M5 of the same era as mine and is well thought of on the MS and 5 series forums.

Thanks for all the info.

Chris



#31 Chickenman

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Posted 01 July 2016 - 09:58 PM

^ Had a quick look at the above site. Some very good info there. I think you're in good hands with Peter. I've added his site to my Chip Tuning Library. Thanks for the link. GL.

 

Richard






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