Jump to content

Upgraded forum subscription packages are now available here - this costs from just 4p a day so please consider supporting the forum. All discussion boards and technical forums will continue to be visible to all users. Forum software add-ons including the Private Messaging and Photo Uploader systems will be deprecated during August for free members.

New posts in the IB Cars and Parts Classifieds, Marketplace Discussions and Wanted Ads sections are now restricted to supporting members only. Access to the Classifieds, Marketplace Discussions and Wanted Ads section will be supporting members only from September 1st.

Note that the rules on trade adverts have not changed. IB still does not permit trade ads, but I am working on an 'IB Professional' supporter's option which may be of interest.

Recommended Posts

Whilst building my 3.4 upgrade I decided to start looking into how to tune the Motronic system, so I could tune it to match the increase capacity myself and avoid paying someone else to to it.

 

Its taken me a while to understand the chip types, format of the code and suitable kit for reading and writing the Eproms, but as of last weekend I'm now running with my own 'tunes' installed :)

 

Started out by buying one of these programmers from China:

 

IMG_9469.jpg

 

.....no English instructions (I think you pay extra for these!) so took a while to work out how to use it.

 

I picked up ten secondhand Eproms for £10 on ebay:

 

IMG_9464.jpg

 

Then had to get hold of a UV eraser to clear the chips of all existing data - 30 mins under the special UV lamp and they're all blank.

 

Next I needed a way of changing chips in the ECU without taking it apart every time - to do this I copied a mod that I found on a couple of the US tuners websites and made up an Eprom extension lead.

 

Here's the finished lead - put together with a little help from a colleague who's a lot better at soldering than me!

 

IMG_9446.jpg

 

All the parts to make this cost less than a tenner: the ribbon is from old computer hard drive connector, the plug is an Eprom socket (ebay £1.60), the green ZIF socket also from ebay (£4.40) and the black enclosure for £3.

 

The plug fits in the socket in the ECU in place of the Eprom:

 

IMG_9449.jpg

 

Then made a small cut out in ECU lid for the ribbon to exit

 

IMG_9451.jpg

 

And protected the ribbon where it exits the case:

 

IMG_9453.jpg

 

Finished - with quick change Eprom socket attached on the ECU lid with some 3M mounting tape:

 

IMG_9455.jpg

 

I've got the ECU pulled out into the passenger footwell for now - takes 30 seconds to change chip, just need to make sure its the right way around each time:

 

IMG_9477.jpg

 

So far I created 'back ups' of my two existing chips (OE Porsche and 3.2 'custom tune') and I've written a couple of my own.

 

I've started with fairly small and safe changes so far; the first one being to increase the fueling where I've got a lean 'stumble' at light throttle. After this I've had a go at my first 3.4 tune, starting with the OE Porsche calibration, and adding the following mods:

 

- First cut 3.4 WOT fuel curve by taking my custom 3.2 fuel curve and increasing it by 6% (the capacity increase)

- Slightly more aggressive ignition map - but not a far as the custom tune... don't want to risk this until I can get it on a rolling road

- Increased the rev limit to ~6750 rpm

 

Had my first chance to take the car out yesterday and drive it with the different chips - tried the chip with the correction for the light throttle stumble first and this has pretty much sorted this (a new set of injectors helped too!). Also tried the second chip with full load mods and this definitely gives an extra 'kick' at high rpms :steering:

 

Next step is to get the car on a rolling road and record some data to I can make some more informed updates to the tune and hopefully unleash a few more hp.

 

When I get a bit more time I'll post some more details on how I've modified the data that's on the chips.. it helps to have teenage son who's into programming!

Edited by MaxDiesel

Share this post


Link to post
Share on other sites

Bloody 'ell Matt, did you happen to attend the Harry Potter school of wizardry?!! I'll doff my hat to you sir, well done and on a very modest budget to boot! Sure will be interesting exploring different curves and tweeks.

 

Regards,

David.

Share this post


Link to post
Share on other sites

Bloody 'ell Matt, did you happen to attend the Harry Potter school of wizardry?!! I'll doff my hat to you sir, well done and on a very modest budget to boot! Sure will be interesting exploring different curves and tweeks.

 

Regards,

David.

 

Cheers David - I'll post some of the original fuel and ignition curves on here when I get a chance. Everything I'm doing is on based on the 1987 24pin Eprom and calibration, if anyone's got an stock Porsche '84 - '86 chip (24 pin) or an '88 -'89 chip (28pin) and is willing to lend it to me for a a couple of days it would be great to download the maps from those to compare.

Share this post


Link to post
Share on other sites

No end to your talents is there!

Share this post


Link to post
Share on other sites

Wayne has competition! Max is a legend....

Share this post


Link to post
Share on other sites

Ha, ninja skillz! You seen the ostrich on the fly stuff?

 

https://www.moates.net/ostrich-20-the-new-breed-p-169.html

 

A few more ££ but means you can map as you drive instead of coolect data then map then test results?

 

Yep - seen the Ostrich kit and very tempted by it - it would be much more like the development kit I used to use at work. As I'm only tuning one car I decided to stick with the budget approach for now and see how far I can get... will take a bit longer this way but most my projects end up doing that !

Share this post


Link to post
Share on other sites

Good effort!

 

Looks like you're doing fine but if you ever get stuck with any of the electronics stuff, give us a shout.

 

Where did you get the info on how to interpret the EEPROM contents?

Share this post


Link to post
Share on other sites

I've got spare ecu from my 88 that I happy for you to fiddle with.

Share this post


Link to post
Share on other sites

MD that's like so far over head i feel I'm not worthy

I know how to do tap washers ;-))

Great work

Share this post


Link to post
Share on other sites

I've got a stock 3.6 964 chip if that's any help?

You're welcome to copy the map and play from there..?

Share this post


Link to post
Share on other sites

Cheers David - I'll post some of the original fuel and ignition curves on here when I get a chance. Everything I'm doing is on based on the 1987 24pin Eprom and calibration, if anyone's got an stock Porsche '84 - '86 chip (24 pin) or an '88 -'89 chip (28pin) and is willing to lend it to me for a a couple of days it would be great to download the maps from those to compare.

I have another 87. It's my old stock 24 pin 87 chip, pre Steve Wong. Been in my desk draw in a nice black plastic box . PM me your address if you want it.

 

VT

Share this post


Link to post
Share on other sites

Next step is to get the car on a rolling road and record some data to I can make some more informed updates to the tune and hopefully unleash a few more hp.

 

When I get a bit more time I'll post some more details on how I've modified the data that's on the chips..

:bowdown: :bowdown: :bowdown:

 

Mark

Share this post


Link to post
Share on other sites

You really clever guys are just going to have to stop...well...being clever. If it isn't TeaBoy with welding, it's SilverWT with fibreglass. And then Jonny Hart gets in on the game with electrics. And now this! Just stop it. I know my skills are pretty limited without you lot constantly rubbing my nose in it. Now, where did I put my meds....I am going for a lie down and read one of those self help esteem books...

 

Great effort by the way, and loving the 'under a tenner' 'man in a shed' approach.

Share this post


Link to post
Share on other sites

Matt

 

Awesome.

 

I bet you can now order a Chinese t/a in the native tongue as well?

 

SW nicked my 24pin when he sorted my the ECU the naughty boy - if you are really stuck I could request that he sends it back pronto?

 

Cheers

Share this post


Link to post
Share on other sites

Good effort!

 

Looks like you're doing fine but if you ever get stuck with any of the electronics stuff, give us a shout.

 

Where did you get the info on how to interpret the EEPROM contents?

 

Thanks Jonny - I may well take you up on that at some point - especially if I ever get back onto my MAF project.....

 

Re interpreting the Eprom contents - this is still a bit work in progress: for basic map variable updates I'm using some free US software called 'Tunerpro' (http://www.tunerpro.net/) - this relies on someone having created an accurate description file ('XDF') for a particular vehicle model and Eprom data format. The description file basically identifies the key maps and conversions into engineering units. I found a number of these description files on US tuning sites - some are better than others giving more or less access to maps and variables. In parallel I'm trying to decipher the original 'BIN' hex data file myself so I don't need to rely on someone else's description file; converting the data from hex is straight forward but locating the various maps, multipliers is taking longer - should provide more options for tuning the calibration though.

 

 

I've got spare ecu from my 88 that I happy for you to fiddle with.

 

Nige that would be great - particularly if ts a 28Pin ECU, I'm told they're interchangeable with the earlier ECUs but it would be good to try this and also downlaod the data from the chip.

 

I've got a stock 3.6 964 chip if that's any help?

You're welcome to copy the map and play from there..?

 

Yes - it would be interesting to compare the ignition maps on a twin spark engine - more data the better :ani_nerd:

 

I have another 87. It's my old stock 24 pin 87 chip, pre Steve Wong. Been in my desk draw in a nice black plastic box . PM me your address if you want it.

 

VT

 

Thanks - I think that'll be the same as my OE chip - if you could let me know the code that's on the chip I can check (#1267355301 ?)

 

Matt

 

Awesome.

 

I bet you can now order a Chinese t/a in the native tongue as well?

 

SW nicked my 24pin when he sorted my the ECU the naughty boy - if you are really stuck I could request that he sends it back pronto?

 

Cheers

 

Cheers Nathan - I think yours will also be the same as my OE chip, so no worries.

Share this post


Link to post
Share on other sites

Hi Matt

 

Attached is some text regarding the reason for the change from 24 pin to 28 pin. I asked the question of Steve Wong when I discovered a PO had stuck a 24pin ECU in my 1988. You might know this already but it may be of interest to others.

 

Cheers

 

Nathan

 

ps. can't cut and paste text into IB - even when attempted to use the proper clipboard icons - hence the attachment.

post-3711-0-79166200-1432037351_thumb.jpg

Share this post


Link to post
Share on other sites

Great stuff Matt - you could get a nice little business going what with everything you have taught yourself.

 

Thanks Richard - I keep telling my wife its my early/semi retirement plan to build & tune air-cooled Porsche engines... unfortunately I need to stick with the day job for another 10 years first :cry:

 

Hi Matt

 

Attached is some text regarding the reason for the change from 24 pin to 28 pin. I asked the question of Steve Wong when I discovered a PO had stuck a 24pin ECU in my 1988. You might know this already but it may be of interest to others.

 

Cheers

 

Nathan

 

ps. can't cut and paste text into IB - even when attempted to use the proper clipboard icons - hence the attachment.

 

Interesting - I knew that the 28pin chips had twice the memory capacity of the 24pin ones but not necessarily why. Sounds like the 28pin chips will have multiple maps for ignition & fuel, which are then selected based on a jumper in the engine loom (US v ROW etc.). It will be interesting to download the data from a 28pin chip and see what's there.

Share this post


Link to post
Share on other sites

I'll dig it out tonight and aim to post it before the weekend, PM me your address details.

 

I did omit to say that the ECU is faulty, but that could be numerous things and not necessarily the chip. Keep it on a long term loan but in the VERY unlikely event of my needing it again I may need it sent back.

Share this post


Link to post
Share on other sites

Yep....301 chip Matt. Here if you need it and wouldn't need it back either.

 

VT

Share this post


Link to post
Share on other sites

I'll dig it out tonight and aim to post it before the weekend, PM me your address details.

 

I did omit to say that the ECU is faulty, but that could be numerous things and not necessarily the chip. Keep it on a long term loan but in the VERY unlikely event of my needing it again I may need it sent back.

 

Thanks Nige - that's great, will pm you my address.

 

I recently repaired several cracked solder joints on my ECU - they were on the ignition part of the circuit on the lower circuit board - the cracks were only visible under a microscope though.... I can check if these have gone on yours while I have it. From reading on Pelican these solder joints are one of the most common causes of failure on Motronic ECUs.

Share this post


Link to post
Share on other sites

 

 

 

I recently repaired several cracked solder joints on my ECU - they were on the ignition part of the circuit on the lower circuit board - the cracks were only visible under a microscope though.... I can check if these have gone on yours while I have it. From reading on Pelican these solder joints are one of the most common causes of failure on Motronic ECUs.

 

Whizz kid or what!!!

Share this post


Link to post
Share on other sites

Exactly the same on mine - you can see the failed joints by the black line within the joint.

 

This is apparently caused by a failing (or previously failed) ignition element which overloads that part of the circuit. In my case a failing ignition switch.

 

cheers

 

 

 

post-3711-0-20604700-1432132841_thumb.jpg

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


Gatherings organised via IB

Anyone attending a meet or event organised via ImpactBumpers.com does so at their own risk. ImpactBumpers.com is not responsible in any way for damage or personal injury sustained while attending any such gatherings. Please behave responsibly.

IB & Mighty Motor Media

ImpactBumpers.com is part of Mighty Motor Media Limited: UK company 07983578. The Impact Bumpers name and all logos are ©Mighty Motor Media Ltd. We have no connection to DR. ING. H.C. F. PORSCHE AG or any of its subsidiaries.

Respect Creative Copyright

We do not endorse the sharing of copyrighted images. Individual users are responsible for all content they post. It is impossible for admin to check every upload but we will remove disputed images swiftly to support copyright holders. Contact us anytime.

More JG websites

Using The Sheriff's other websites supports the IB forum! Please share my valuation services with anyone needing assistance.

×
×
  • Create New...