Not all O2 sensors are alike

[wcdeane]

I had been fighting a serious drivability problem with my SE for several weeks, and one of the first things I did was replace the O2 sensor. I didn’t want to pay the $150 – $200 USD price for an authentic Lotus OE sensor, so I fitted my car with a BOSCH 15704 sensor. This is a 4 lead sensor that costs about $50 USD. When you use this sensor on an SE you need to swap a couple of the wire leads, but for the most part, it’s a quick, no-brainer project. So anyway, the O2 sensor improved the way my car ran, but it still had a bit of a stumble on acceleration at about 2500 - 3000 RPM. The engine would also occasionally stall during warm up and at intersections.

To make a long story short, after weeks of analysis and consternation I ended up replacing the BOSCH sensor with an authentic Lotus OE sensor. The car now runs the way it is supposed to – which is AWESOME ! I am now one very happy Lotus driver.

Moral of the story?...some authentic Lotus OE parts, like the 02 sensor, just might be worth the extra cost. My humble observation.

Walt

[wonderman]

I had the same trouble with drivability and stalling including a pesky engine light that came on from time to time. I did some research into O2 sensors and decided on an AC Delco 4 wire unit that fit the harness exactly. Yes 2 wires had to be switched but it ran perfect after that and has been ever since. My technician confirmed my findings and I saved aprox $120. Sometimes it works.

[RyanSheldon]

I just replaced mine with BOSCH 0-258-003-913, which is what was in the car when I got it. I do not know if this is the stock O2 sensor, I did have to rewire, but that was easy. So far, so good, but I need to drive the car more to determine if this helps. Do you have the AC Delco part number available in case this does not work out?
Thanks,
Ryan

[cnh1990]

I have had mixed results from non OEM O2 sensors.
Some say after much expermenting they work somewhat.
There is a limit, value, and frustration factor we must put on our own labor. This is one of those questions of how much messing around is worth trying to save a few dollars.
Calvin with OEM O2

[wonderman]

The AC Delco part # is AFS 95 , at least that is what it was at the dealer in Canada. I know for sure that it cured my problem because I was getting an engine light and the code was O2 related. Now the O2 is heating up before I start the engine to maintain a constant temp and the code is gone. Definitely the right sensor. Running 100 %

[SwedishSurgeon]

Oh the bloody O2 Sensor problem... not all O2 sensors are alike. When I brought my '87 Esprit I had problems passing strict emission standards. Whether or not the one that was in the car was correct I did'nt know. This seems to be top secret. No mention in any Bosch publications for this sensor. I played with fuel mixture adjustments with no luck so I bit the bullet and brought one from S&J sports cars saying this was for '88 and up. Since my car is an '87 but uses the same system, I put it in... Bosch part number 0-258-003-032. After resetting the fuel mix, per instructions of the Bible, I passed emissions however my exhaust runs
very hot. I checked the timing which is spot on, but wonder why my exhaust manifold back to the turbo glows at night. I played with the mixture again,since I thought it was running too lean, going to a bit richer as I know this could result for the same problem, {too much unburnt fuel} causing this problem. I'm told this is normal after a hard run however I don't have to run her hard and I still get this. Has anyone out there experienced this same problem? When I played with the fuel mixture, I used a dwell meter reading from the frequency valve to get readings and not guessing in the dark.
Robert

[cnh1990]

My manifold glows red if I run mine hard. It also did it one time when a lean condition was induced by a low battery conditions as my EFI sensors failed as the battery died. That was not a good day for me when that happened, backfiring, etc. Robert are the cam gears aligned? I'm sure they are as you changed the belt recently didn't you? I have seen the belt jump a tooth or so. I don't know much about the K Jetronic system, all you 86-88 car guys speak up on this subject.
Calvin 90 SE

[SwedishSurgeon]

Calvin,
When I replaced my timing belt I checked the marks according to the Bible before I removed it. Everything was correct on that point. Also from experience, if the timing is just one tooth off, a car will not run right. Before my car was running too rich failing emissions, I couldn't get the correct part # of the OE sensor at the time so I brought one from Steve @ S&J.
Steve did say this was for '88 and up, which the '88's used the same system as mine. Too lean or rich will cause this however I cannot seem to find that "happy
medium " in between. I have been told there is a distributer up grade, I do get some backfire on decel
which is from an exhaust leak or too much unburned fuel. Since our exhaust sniffer at work crapped out... I have no real way to check the emissions unless my boss breaks down and buys a 5 gas which we really need!
Otherwise, the car runs perfect in everyway. When I first brought it, it wouldn't light at the turn of the key, but I straightened that out. When I take it out next year I know someone with a Snap-On engine flush system for cleaning fuel injection systems and will give that a try.
Robert

[cnh1990]

I don't know much about that Bosch system. Are the injectors spraying alright instead of dripping big drops? I think you can just test with a hand pump. Hopefully you don't have a manifold leak that causes your O2 to misread and dumps mpre fuel in to compensate. When you changed the belt did you adjust valves? You probably did a compression and leak down test right? I know you like G cars but it would be so much nicer to hook a lap top to read what the engine is doing. Maybe a good winter project if the storage place lets you work on the car. I need to get my other garage built soon so I have more room. Tony has nice set up with the easy lift. I need one of those.
Calvin