No oxygen sensor !!!

Car : BMW 525i 1993 manual gear, M50 without Vanos.

I've been getting very poor fuel economy (compared to every other car I've owned upto this one) I filled up a full tank 5 days ago I assume it's close to 17 gallons cause I paid 81 Dirhams (local currency here Dirham:USD = 3.75:1, and petrol is approx. 4.95/gallon) and it gave me a total of 382 kilometers on it thats 4.7 kms/litre, the worst car I've driven previously was a friends 1988 500SEL which gave me about 6 kms/litre which I thought was ok considering it's a very heavy 8 cylinder vehicle with an prehistorical type of fuel injection (CIS), my 1994 V6 Camry (owned only for 2 months) normally came close to 9-10kms/litre, is this figure normal or could it be something is wrong with this car, I've changed plugs, oil+filter, fuel filter, exhaust with one from a 1989 750i from the second muffler to the exhaust tip (old one was leaking in too many places and when taken out and shaken sounded like full of carbon or something ???) also ran injector cleaner through the tank 3 times, fuel consumption is the only concern here otherwise idle is smooth, I could be wrong and this kind of figure could be normal for this car (time to start thinking about a 1995-96 318i ?)

One more thing related or not I don't really know, I think a "stomp" test (I've been reading about these a lot over here) does not work on my car it does check the speedo and tacho guage and give some figures in german including last 7 characters of my Chassis No i.e. BG50725 and some fuel index but no codes, my car does not have an obc just a normal analogue clock, also all cars here (until the last 4-5 years) didn't come normally with a cat unless u specified it, I know for sure mine doesn't have one and maybe not even a oxygen sensor (don't know where else to look in the absence of a cat). Would the absence of this give me a bad fuel economy wouldn't it throw some sort of an error code even without an obc, also is it very difficult to do the complete wiring to install (one what does it connect to) if it is not there without screwing up somewhere.

Also my car on exceeding 120kmph gives an message of "speed limit on the dash can I do something to make this come on at a higher speed like 160kmph for example or ending it for good.


Ali

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Originally Posted by Ali

One more thing related or not I don't really know, I think a "stomp" test (I've been reading about these a lot over here) does not work on my car it does check the speedo and tacho guage and give some figures in german including last 7 characters of my Chassis No i.e. BG50725 and some fuel index but no codes, my car does not have an obc just a normal analogue clock, also cars here didn't come normally with a cat unless u specified it, I know for sure mine doesn't have one and maybe not even a oxygen sensor (don't know where else to look in the absence of a cat). Would the absence of this give me a bad fuel economy wouldn't it throw some sort of an error code even without an obc, also my car on exceeding 120kmph gives an message of "speed limit on the dash can I do something to make this come on at a higher speed like 160kmph for example.

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Your car should have the oxygen sensor even if it doesn't have a cat. Oxygen sensor controls the mixture thus largely affecting performance and fuel economy.

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Originally Posted by Interceptor

Your car should have the oxygen sensor even if it doesn't have a cat. Oxygen sensor controls the mixture thus largely affecting performance and fuel economy.

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Could it have been removed sometime in the past and where would it be installed in a vehicle which didn't come with a cat as there was almost no emission contol regulations here until recently, we just moved on to all unleaded fuel it used to be an alternative used by owners of american made cars like ford, chevrolet etc. which are the only cars here that have come from the early 1990s with cats.

If it was removed can I rewire and fit a new one in correctly ?.

Just love my vehicle's sound after changing the exhaust :D .

Thanks for the reply Interceptor

Ali

The stomp test wont work unless you have US spec car,mine is Japan import and doesnt have this function,so only way is to to use the dealers Modic3 or other available tools like PEAK brand.

The O2 sensor could be a cause,and it would be interesting if you could do a general check on the fuel lines,start from the tank cap,or the hoses coming out from the tank all the way to the fuel rail of engine,sometimes cracks can be found.When was the last time you inspected for injectors? are they functioning as they should?any leaking injector? when was the last time you replaced the plugs,and do they look in god shape?do you smell from the exhaust that it is gasoline rich?any other related issues of driveability?

Just checking the basics won`t cost a thing,and you`ll get to know your car better.Having a bentley manual would be interesting and useful, but i always ask this forum then i MIGHT refer to my manual :D

keep the forum posted

jj

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Your car should have the oxygen sensor even if it doesn't have a cat.

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not necessarily :cars sold in markets with leaded petrol ie 1990 the uk,australia and new zealand for starters had leaded petrol so cars came without cats or o2 sensors just runs on a preprogrammed map......you can fit one i think but i dont know for sure...I definetly think you have a problem i get around 13 l 100 ks(7.7km/l) at worst but my driving is not much stop start.The previous was around 17 l 100 ks(5.88 km/l km) but this would be pretty bad stop start traffic and this is a manual 535...You should have a few buttons to push and LIMIT is the one where you can set the speed alarm....

Yes, the speed limit is set. have a look at the owners manual. If you do not have one, do a search here, I have posted the link to an online owners manual several times before.
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the worst car I've driven previously was a friends 1988 500SEL which gave me about 6 kms/litre
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Then you have not driven my 750iL V12. Between 2.8 - 4.5 km/Liter is normal. :D
According to the owners manual the fuel consumption of a E32 750iL is 20,2 Liter per 100 km in city traffic.

Have you already bought a PEAKE tool what I recommended? With that one you do not need the shop that much. As you mentioned earlier, there are not that many good service tehnicians. $ 150 investement is really worth the money.
http://www.peakeresearch.com

Shogun,

I was trying to find the Peake tool locally here, I've used my card only once over the net trying to buy a Haynes repair manual for my ex-230CE sent about 18 emails to the supplier and ended up never getting it and being charged twice, some of my colleagues have had similar experiences of getting inferior quality products to what they were promised (or thought they were promised) and with that experience I've decided to stay away from online purchases, I make it a point now to physically inspect anything I buy before I pay for it and make sure I can take it with me not having it sent via P.O. mail or other such means, hope you understand.

Thanks for all ur help once again shogun

Tell me do u think some E34s came without oxygen sensors and if so what can be done to improve the economy.

Ali

Hi Ali,
as already mentioned before, U.K., Australian cars and also first E34 and E32 in Italy were supplied without cat (option) as they were not legally required.
I once read about that on the U.K. E32 register, and as far as I remeber they were without sensor too. (but I am not sure).
Some country specs are really strange. Here in japan we had a problem with a 750 iL E32 some weeks ago. Engine was running in limp mode and only on 6 cylinders. The owner bought a cat from USA, and that one did not have a temperature feeler at the outlet of the cat. So he did not connect it on one side. The other was connected. We were worried that the temp feeler also was influencing the air/fuel mixture in case it was connected also to the DME, and could report always 'cold' to the DME.
But this one is Japan specification ONLY and not in the Bentley or any wiring diagram online for US spec cars.
Maybe someone from Australia or the U.K. can chime in with a car w/o cat and just crawls under his car.
But you can check that too. Just check under your car if there are loose sensor hanging around. But I cannot imagine. If the car was delived without cat, then the oxy sensor makes no sense.
A Peake you cannot get outside the USA, but you can contact them by email. That is not an Ebay deal.

Now that I think about it there was a wire tied to the chassis I thought this was probably related to the reverse light cause whenever I put fuse No. 12 in and start the car the reverse light comes on and stays on in all gears it's somewhere close to the engine / transmission, I asked the garage guy to plug it in if he could find the place it could've popped out of, he said he couldn't see any place he could plug it in, will take a pic with my cam /phone and try to post it maybe it's the same one but somehow I doubt it, didn't look like anything like the Bosch O2 sensor I replaced on my Merc.

Do u think I left out any routine maintainence in my first tune-up - plugs, both oil n fuel filters, new tyres (got a good deal with 17" BBS rims) including the balancing / alignment....etc. Do u think my fuel consumption figure is ok for this kind of vehicle ? - I was kind of expecting better especially since this is a manual. By the way are these oxygen sensors so expensive everywhere when I asked the dealer for it (after getting the part number from realoem) he said "Why do u want that ?, no stock have to order one from BMW Germany", price approx USD 226 / AED 830, pretty expensive for a consumable part ?, yes most probably no O2 sensors in that era for these parts of the world.


Thank u once again shogun for ur timely advice :) ,


Ali

........bump

if your engine temp sensor for ecu is bad this will cause rich running,or if thermostat stuck open car will run cool and therefore rich.....

the oxygen sensors are quite expensive from the dealer. i think you should at least try to use your credit card payment with known companies like Peake research and also with Oxygen Sesnors Co., where you can buy a original Bosch with the right plug (the the universal one) for only about 75 US$
https://www.automedicsupply.com/pictures/13108_.jpg
https://www.automedicsupply.com/cata...91fae326fa78a#
https://www.automedicsupply.com/faqs...091fae326fa78a
If your exhaust does not have a connection: any exhaust shop has threaded pieces for weld on to the exhaust. That is often required when the old one is corroded and when removing it the whole threaded piece sometimes breaks out of the exhaust.

The wire at the end seems to be the one for the reverse light. If it is connected and the reverse light is always on, check the switch which is under the center console (reverse light switch). Maybe it is misalligned or out of order. Use the online spare parts catalog (ETK) to find the correct p/n.
Not very expensive.