Early e34 535's

[kiwi535 538]

Mark D seems a very busy man...He will come through.

I am with you scd.I dont think ANY nz new m30 would have had a sensor and or cat,in fact i would say no nz new e34 had a sensor and cat.....we didnt get unleaded petrol till 95 or so.....

I think the sensor and late dme would increase efficiency by always running the car as lean as possible.....the yanks seem to get quite good economy on the "freeway "

[bezzal 1]

ScD, mine is New Zeland New and has no O2 sensor or Cat. My DME # is .179.

So yes I'm guessing that it is running open loop with no feed back!

I have emailed Bosch to find out if the .179 Motronic v1.3 was ever designed or used in the above configuration.

If there was v1.3 with no Cat no o2. I presume it would be a euro, south african spec Eprom. Hence I've been looking to the UK for a new chip to find out the story over there.

Kiwi, open road i get easily 10.5l/100km. That included ripping up and over the crown range through to wanaka from Qtown. Around town 15l/100km. How does this compare to yours? Indeed how does this compare to the US 535's?

Also am I right, when I say, at W.O.T. the o2 sensor is ignored anyway?? Hence on a Dyno power run no o2 sensor would make no difference and nothing would show up??

Incidentally I was talking to a Mech friend on the weekend. He had heard that there was a commodore of the same era that when an O2 sensor was hooked up, improved them immensly, economy and grunt. The problem, running in open loop! Supplied from the dealer with no O2 sensor or Cat.

BTW Scd you weren't down near the Marshlands road round about a few weeks ago? Silver 535i, spotted me and gave it the jandle? (mine is silver 535i also)

[bezzal 1]

Response From Bosch:

From what I understand from the information I have is that your particular model had the option of a cat or not, depending on which country it was being imported too. Versions with no cat (leaded fuel) also had no oxy sensor. The ECU number remained the same however the software version was different. Check your ECU I believe there should be a version number on it. The no cat version software would ignore the pins related to oxy sensor. I believe the software is installed in the factory, in other words you would need to state either cat version or non cat version when ordering an ECU. Which of course is identified by the version number on the ECU.

Theoretically the oxy sensor version would be better on fuel on highway driving, but only slightly.

END:

So there was a version with no Cat no O2. Is it what we have in our cars? I will pull the ecu at some stage and check the version number.

[kiwi535 538]

i can get 10.5 but onlyon flat gentle runs,i can sometimes show instant readngs of 9 something on a flat smooth motorway......I beleive i am quite an economical driver and as i said i struggle to get any thing better than 11 .Every long trip will include at least a couple of serious overtaking runs( ie lots of throttle and third gear) and one italian tune up run...ussually up the mangawekas......the yanks sem to get 25 mpg and thats (us gallons ) on trips

[bezzal 1]

The Yanks would have nice long motorways where there is just constant speed. I know in the Uk we used to go for ever on a tank of gas on the motorways but as soon as you were on B road's similar to what we have here the gas would disappear.

Is your OBC accurate? Mine was out by almost a litre/100km over a tank of around town driving. It was in fact 13.2l/100km instead of 14.7.

Any way I'm going to pull my ECU out when I get a chance and see what Version it has stamped on it. Email the bosch guy again and get him to confirm which it is.

The next thing is where to source a chip that is suitable for our cars? Any suggestions, sounds like EAT are dragging the chain and Turner motorsport got back to me to say they don't have one either. Although it might be worth getting hold of Jim C directly to confirm that about turner.

ScD do you still have the chip that they sent you that was wrong?

[kiwi535 538]

if all three of us fronted up to mark D at EAT he might do something for us....