Jim K
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Re: JK 24v 3liter ..at last!

Post by Jim K »

Hi Festy, nice to see ya here!
Ok guys, here's how I ended up with 4 bad ecu's (p/n 0261203301): The original one that came with the engine, was damaged by the garage guys, when they kept switching batteries, having installed the engine in my mechanic's car for break-in ...trying to find a good battery, strong enough to start the car. Thinking the batteries were good, they ended up playing around with the relays... :roll: . With all that boosting and sparking around, ultimately, the ecu died (that's #1). I then bought one from German ebay and ran the car (that's #2). A friend sent me another one which was inoperative (that's #3). I sent the two bad ones to Germany for repair, but only one was repaired. So, at this point I had 1 bad and 2 good ones. Upon returning from a track weekend, one died inexplicably -the only mystery death so far imo. That left me with only one good one. I figured I should have one spare for each engine (the 3liter and the still-to-be 3.2) so I looked around and found one more in Holland (#4). At this point, I decided to give the only two good ones to a friend who does chipwork so that he would copy the dyno-chip on both. ....When I got them back, none worked; dead in the water! :evil: Once more, I found another one in Holland (#5) albeit p/n 0261203834 (the one with the immobilizer but modded to non-immo by Squadra Tuning). So now the car has a std ecu and the 4 bad ones are in Holland. When they come back, I'll take them to my dyno/mapping guy so that he can copy and install the chip he made on them all. Sorry to cram all this stuff on you all but maybe some of you guys needed a laugh! :roll: Believe me, I'm not in the least amused; you can imagine all this has cost a serious bundle! As a sideline, I also got an Emerald K6 and will sometime have this wired in also -not in a hurry though at this time to play with it.Like I said, summer is still here and things are moving very slowly.
Festy, you may have something there with this LDA stuff. Its in the manual but that's all the info there is. Your reasoning sounds plausible but I won't try any inputs to the LDA pin until I have 4 good ecu's again....get my drift? :twisted:
In the meantime, I'll try to scrounge 600€ for the 24v cams with M3 profiles. I want to see what it'll take to have them fit in the spare heads. Its not just a bolt-on thing...I suspect issues with guides and springs for starters...When I have something, you'll hear about it!
Jim K.
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Re: JK 24v 3liter ..at last!

Post by festy »

I can't find much information on the LDA line, but it's function seems to be related to limiting engine braking on decelleration, to prevent the rear wheels locking up.
The signal would either be a digital on/off (i.e. the ABS ECU would pull the pin high or low) or a PWM signal to request an amount of LDS to apply.
If the ECU pin has been left floating, it could be triggering the LDS mode.

If you had access to a Q4 and a scope, it would be easy to work out, but I gather that's not an option...

But I came across a thread last night where a q4 owner was having problems with the fuel cut not working, and engine flooding - http://www.alfisti.net/alfa-forum/newti ... macke.html
Google translate is a bit hit and miss, but from what I can gather the cause turned out to be a bad connection to the coolant sensor.
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Re: JK 24v 3liter ..at last!

Post by Jim K »

In his case that would probably explain the high idle speed although these advanced Motronics don't accept sudden NTC changes and go into safe mode.
If by the time I get the ecu's back no other info appears re the cutoff, I may just give up and use my own cct to do it, as I've said before -in essence a two-input comparator with a relay placed in series with the injector 12v line (pin 87 of the Motronic relay). I would prefer a simpler factory solution but unfortunately, commonly available literature doesn't help much. As a last try, I may drop a line to the Bosch Technical Dept. but I suppose it would be like the proverbial needle in the haystack thing... Can I really expect an answer? Truth be said, its a rather specialized question outside the intended use of their product! However, there are some race teams in Europe using these ecu's in 2wd cars...I just have to find who they are and talk to them... :roll: Yeah, yeah..by the time I get around to actually solving this, there will be no more fossil fuels... :lol:
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Re: JK 24v 3liter ..at last!

Post by festy »

JimGreek wrote: If by the time I get the ecu's back no other info appears re the cutoff, I may just give up and use my own cct to do it, as I've said before -in essence a two-input comparator with a relay placed in series with the injector 12v line (pin 87 of the Motronic relay).
I hate to say it, but I don't think that will work too well :cry:
This ECU maintains an in-memory table for injector trims - so if an injector gets a bit lazy, it can compensate.
To accomplish this, it monitors the return voltage on each injector pin, to determine how much current each is drawing as it fires.
If you cut the 12v supply to the injectors, the ECU will see 0v and either a) compensate by slashing the injector opening times, or b) go into a limp-home mode because the return voltage is below the minimum threshold, or c) reboot because it thinks the output driver has failed. I would expect c or possibly b (it's too smrt for scenario a), but regardless, none of them are good outcomes :(

If it is LDA working against you - do you happen to have a matching ABS ECU by any chance? You could wire it up with just the clutch pedal switch hard-wired on, which from what I can tell should prevent LDA being activated.

re: sudden sensor changes and safe modes - if the coolant sensor is determined to be faulty, the first thing they do is check the inlet air temp sensor.
If it's within a specific range, it uses the air temp value for coolant temp (and logs a fault). If it can't use the IAT value, it uses a fixed value for the coolant (usually around 80*) and a fixed value for air temp too - and logs a fault.
So with a faulty coolant sensor but a working air temp sensor it will sort-of run, but as the decel fuel cut table is RPM vs engine temp, it will cut fuel a lot later than it should with a warm engine.
It will also idle a bit faster, as idle speed is determined by engine temp as well.
Your ECU might do things a bit differently to this, but Bosch jumped through all sorts of hoops trying to guess appropriate sensor values to keep the engine running.
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Re: JK 24v 3liter ..at last!

Post by Jim K »

:shock: You just had to shoot me on this Friday morning, didn't ya? :D I hope the ecu isn't reading this... I have no other Q4 parts so I'll have to chance it with the cct. Tell you what: how about I send you one of the good ones (when they're back) and you play with it? You get it going and you'll have a huge bottle of Ouzo coming to Oz.. :wink:
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Re: JK 24v 3liter ..at last!

Post by festy »

Think how I feel, delivering news like that on a friday afternoon over here :oops:

Even with a broken ECU I'd have a fair chance of figuring out a way to make it do what you wanted for that matter.
I've had a few looks at the eprom dump you sent me a while ago - but without a schematic of the ECU or hardware to trace out, I can't begin to guess what's going on inside.
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Re: JK 24v 3liter ..at last!

Post by Jim K »

Allright sir...! As soon as I receive my ecu's back from Holland I'll send one to OZ and wait for the outcome of brain surgery! That said, I don't think the moderators will object to your status being upgraded to 'honorary site ecu genius' :lol:
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Re: JK 24v 3liter ..at last!

Post by fedezyl »

JimGreek wrote:Allright sir...! As soon as I receive my ecu's back from Holland I'll send one to OZ and wait for the outcome of brain surgery! That said, I don't think the moderators will object to your status being upgraded to 'honorary site ecu genius' :lol:
Jim K.

I second that Jim!! :D
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Re: JK 24v 3liter ..at last!

Post by slyalfa »

grant just got a 24V if you tell me the pins I might be able to put a scope on it the next time he is over.
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Re: JK 24v 3liter ..at last!

Post by Mats »

fedezyl wrote:
JimGreek wrote:Allright sir...! As soon as I receive my ecu's back from Holland I'll send one to OZ and wait for the outcome of brain surgery! That said, I don't think the moderators will object to your status being upgraded to 'honorary site ecu genius' :lol:
Jim K.

I second that Jim!! :D
Hear! Hear!!
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Re: JK 24v 3liter ..at last!

Post by PietereQ »

I hope Jim won't mind, I wanted to share dyno graph one guy posted on a local forum. I think you might find it interesting especially the 'v-tak' kick ;) KM=HP



Image

Engine is sourced from 916 GTV, electic throttle retained, overhauled, new headers, but other than that stock engine. Tuned with EMU.
Jim K
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Re: JK 24v 3liter ..at last!

Post by Jim K »

Nice shape! But what is V-tak? :?:
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Re: JK 24v 3liter ..at last!

Post by 75evo »

V-TAK is Polish for V-TEC :D
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Jim K
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Re: JK 24v 3liter ..at last!

Post by Jim K »

You put the cams in yet? GET BUSY!! 8)
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Re: JK 24v 3liter ..at last!

Post by PietereQ »

Jim K wrote:Nice shape! But what is V-tak? :?:
Jim K.
http://www.urbandictionary.com/define.php?term=V-TAK

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