Author Topic: to see data log in stock ECU.. possible? (Read 7402 times)

ReSuL · « **on:** September 25, 2012, 04:52:47 AM »

hi guys.. I wanna learn that whether is it possible to see data logs in stoch ECU 175?? and it yes, how??

I know I have a problem in my car but couldnt figure it out for a long long time.. it doesnt pull good enough.. we have checked almost everything but no solution.. so I wanna see the datas that the ECU logged..

by the way what is the proper engine compression psi for each cylinder for a "stock" m42??

thanks in advance for your help...

bmwconnect · « **Reply #1 on:** September 25, 2012, 07:22:23 AM »

No you cannot log data via the stock 175 DME. The only lines of communication are fault codes for problematic sensors.

190-210psi is good compression for that motor

All the best

DesktopDave · « **Reply #2 on:** September 25, 2012, 07:25:38 AM »

BMW did have a diag computer that could log through the diagnostic port, but it didn't use the stock Motronic and couldn't be taken on the road.

If you've eliminated all the other causes, maybe consider a WBO2. They're cheap, maybe $200-ish, and it might be a real help to you. Logging units are only a bit more and they use generic laptops - no need for BMW DIS any more!

romkasponka · « **Reply #3 on:** September 25, 2012, 11:10:17 AM »

As I know it is possible to do it with EDIABAS programming API, but you have to be a programmer. I dont know how to do it....

http://www.youtube.com/watch?v=duAvoOfvZiI

and found now http://forums.bimmerforums.com/forum/showthread.php?p=24257983#post24257983

DesktopDave · « **Reply #4 on:** September 25, 2012, 01:52:24 PM »

Lemme see if I can get my buddy's little DIS up & running...that gives me a few ideas.

bmwconnect · « **Reply #5 on:** September 25, 2012, 04:35:13 PM »

There is no ALDL data stream in early OBD1 Motronic units

ReSuL · « **Reply #6 on:** September 26, 2012, 01:16:52 AM »

thank you for the answers friends.. my compression is about 150-155 psi which seems to be the problem.. I dont know where but I read somewhere that the factory specs for stock m42 compression should be between 142-156 psi.. is t correct???

another question is it possible for a sensor which does not function well but pretty enough not to give an error code?? I mean it doesnt work properly but still doesnt give an error code?? because I dont have an error code in stomp test...

ReSuL · « **Reply #7 on:** September 26, 2012, 01:52:44 AM »

here boys... the manual says...

DesktopDave · « **Reply #8 on:** September 26, 2012, 07:03:34 AM »

Well, looks like your compression is good. I'm assuming that with a 175 you're running an e30 - so you should be seeing a 1444 code, right?

The DME doesn't understand the fuel pressure, and tends to ignore the coils. Testing the fuel pressure and flow might be a good idea. If you have a bad FPR or fuel pump the car will tylically lean out at higher rpm and you'll note running problems once the car warms up.

A flaky coil can also demonstrate odd problems, like only when it's warmed up or only when it's cold & wet outside. Like a lot of newer BMWs, the 175 DME has issues with coil drivers - even if a bad coil was replaced, the DME driver transistor could have been damaged. The damaged driver either won't work well or can even eventually destroy the newer coil.

I'd also test your temp sensors to be sure the car is properly getting to 'closed-loop' operation. If it's running open-loop all the time due to a CLT sensor you'll have poor fuel economy and the car will run badly when it's warmed up.

5m1dy · « **Reply #9 on:** September 26, 2012, 05:48:47 PM »

Hmm. I ran a compression test on mine over the weekend and got;
1. 200 2. 240 3. 220. 4. 200
All in PSI

Way to high?

DesktopDave · « **Reply #10 on:** September 26, 2012, 07:21:02 PM »

Higher is better...but I was always under the impression that those numbers should just be reasonably close to each other...if they're within 5% or 10% of each other you're OK. That #2 reading seems a bit high, maybe you have a bit of carbon buildup? Can you get some SeaFoam down your way? I'd hesitate to tear it all apart based on one reading.

OTOH, I've always had troubles with compression gauges. I suspect one of two things - either my skills are marginal or the cheap gauges I buy aren't all that accurate. Likely it's both!

5m1dy · « **Reply #11 on:** September 26, 2012, 07:44:50 PM »

Ive looked into seafoam before. Pretty unavailable down here.

Im certainly not pulling anything appart, its running well at the moment.

Apparently the PO had the head rebuilt before he sold it. Could decking the head for a rebuild increase compression this much?

DesktopDave · « **Reply #12 on:** September 26, 2012, 08:25:50 PM »

I don't know for sure, but I'd assume that's the case.

bmwconnect · « **Reply #13 on:** September 26, 2012, 08:49:13 PM »

Also when doing the test you should allow the engine to turn over at least three full revolutions before stopping to check the compression numbers

ReSuL · « **Reply #14 on:** September 27, 2012, 01:40:49 AM »

Quote from: DesktopDave;116247

Well, looks like your compression is good. I'm assuming that with a 175 you're running an e30 - so you should be seeing a 1444 code, right?

The DME doesn't understand the fuel pressure, and tends to ignore the coils. Testing the fuel pressure and flow might be a good idea. If you have a bad FPR or fuel pump the car will tylically lean out at higher rpm and you'll note running problems once the car warms up.

A flaky coil can also demonstrate odd problems, like only when it's warmed up or only when it's cold & wet outside. Like a lot of newer BMWs, the 175 DME has issues with coil drivers - even if a bad coil was replaced, the DME driver transistor could have been damaged. The damaged driver either won't work well or can even eventually destroy the newer coil.

I'd also test your temp sensors to be sure the car is properly getting to 'closed-loop' operation. If it's running open-loop all the time due to a CLT sensor you'll have poor fuel economy and the car will run badly when it's warmed up.

thank you for the reply.. yes, I am running an E30 and no I have no error code

which means 1444 and I have had a mechanic test the fuel pressure and he said no problem.. the problem is that it pulls better at higher rpm (which I think it must be better than this anyway) but the lower rpms are real torture.. and by the way I have no starting problem at any time whether hot, cold or warm.

we have checked the ignition system and have changed the sparking plugs and sparking plug cables and checked the ignition and all 4 cylinder has sparking/ignition but still if there is a way to see if the coil driver transistor in DME working or not I really wanna know it...

another thing is that we have changed the tempetarute sensor which is on the engine block two times.. and especially it started to pull better (not better enough) in the second change. and I am using a termic not a radiotor fan for coolant.. and I think the fuel economy may be a bit better than now..

just to add something: as you said my car pulls better if the weather is cold and pretty better when the car is cold.. when it gets warmer or hot, it starts to die..

one question: assume that I am having a temprature sensor problem which leads me a problem of running the car rich or lean (correct me if I am wrong) I will be able to see it on my AFR wideband gauge which I will mount in a couple of days.. right?

and again assume that I am having a coil driver transistor problem in DME.. does this mean the fuel is not burnt because of for sparking not good enough, again will this show up in AFR??