S52 check engine light problem

[jdehaan]

I just dropped an S52 out of a 97 M3 into a 96 TI. The check engine light keeps coming on. My mechanic thought it was teh gas tank sensor, which the 96 lacks. He jerry-rigged a solution, which worked for a while, but as soon as I got it home the light came back on. Any ideas about what else could be causing the check engine light to come on? My license is going to be suspended on Dec. 20th due to emissions, so help me out!

[snuggz]

Originally Posted by jdehaan

I just dropped an S52 out of a 97 M3 into a 96 TI. The check engine light keeps coming on. My mechanic thought it was teh gas tank sensor, which the 96 lacks. He jerry-rigged a solution, which worked for a while, but as soon as I got it home the light came back on. Any ideas about what else could be causing the check engine light to come on? My license is going to be suspended on Dec. 20th due to emissions, so help me out!

Have you tried a code reader? Just "I have a CEL" is kinda vague...

The fuel evap relay code is pretty common in swapped ti's; I'd look in that direction first. But a code reader will tell you exactly what's causing it...

[1996 328ti]

I had NickG write it out of the software on mine.
I don't understand why other OBD-II swaps don't have this problem.

[Keach]

There is a possibility the car won't fail just because the light is on, however if the code is related to anything dealing with emissions they will fail it. I'm in a simular situation with a cam sensor needing to be replaced and most likely a cat. Emissions suck when all they do is look at a light and say it fails! In those cases when the light is on they should just manually test the car to see what the outputs are. I know my car is putting out far less than a lot of older cars they pass. Anyway sorry I can't be of more help but felt this as an oppourtunity to vent. I have till the 30th of Dec. Good luck though. I would go to the emissions station and see if it actually fails or not. Then go from there.

[J!m]

I'm in a similar situation at the moment.

I have not had any problems with the car at all, but when I went fo testing, they got a laundry list of problems...

I re-set the codes, and drove it around for the day (at least three re-starts) and some of the codes "magically dissapeared", but some remained.

If it's not snowing, next week I go to the dealer to have them check it, as some of the codes are a bit vague.

To be replaced: Cam sensor and vehicle speed sensor. That should do it... The array of codes I was getting for the second lamda sensor and secondary air pump were expected, the re-set (and temporary instalation of the air pump) eliminated these codes (after I bought the oxygen sensor, naturally...). I have an idea to eliminate the secondary air pump for little money. I have to run some tests AFTER I go through emissions... I'll let you guys know if my idea works. If it doesn't, Nick may be writing some software for me (on the dyno).

I also agree that if the code check fails, a pipe sniff should be next (perhaps both should be done on every car?). I am baffeled that "emissions testing" does not actually check the emissions of the car any longer... With today's computer-savvy car geek, it could run a sub-routine for testing that indicates all is well, and the cat could be gutted out and spewing filth across the countryside. Not cool...

[bullmand]

J!m,
I'm resurrecting an old thread here, but I found it while searching. I've got an S52 swapped ti (engine and car are OBDII) with no secondary air pump currently installed. The CEL is on, but the only code I'm getting is P0135 which is for the o2 sensor heater circuit. Is there a separate code for the pump or does the pump's absence throw this code? I'm open to any suggestions.

[Marv17]

and what was done to fix the issue??

[bmwconnect]

also curious

[bullmand]

I just checked the code last night, so I haven't had a chance to do anything yet. Pending the advice I get here, I'll probably just go ahead and replace the o2 sensors. I don't know how old they are anyway. I do intend to install the pump in the not too distant future.

[J!m]

The errors should be re-set, and it should be driven until the light comes back on (or not) and re-scan.

The air pump sends it's own code(s) so if the lambda heater is bad, that code will come back.

I suggest writing out the air pump- I had Nick do this for me in the end. I detail this in the manual these days because there are different ways to take the pump out.

[bullmand]

That's a good suggestion. I'll clear that code and see what happens. I was pretty sure the pump should set its own code, that's why the scan confused me. I was surprised to not see the air pump code and now I'm concerned that there may be other problems. I'll be able to get it scanned with a better code reader in the next week or so. That may give me some more information. What effect does the absence of the air pump have on the car? I've noticed that it idles a bit high on cold mornings. I'm assuming that's related. Will the pump not being there shorten the life span of the o2 sensors?

[J!m]

The air pump only rund for a few minutes at cold start to help increase exhaust temps to light off the cat faster. Once the engine is warm (the way it must be for all emissions testing) the pump is off.

If you re-start a hot engine, the pump does not start either.

The engine, and lambda sensors will last just as long with it there or not.

[bullmand]

That's what I thought. So, at this point I guess I'll clear the codes and see what happens. I am concerned that I'm not getting a pump code at all but I'm not sure what to make of that at this point.

[J!m]

Try pulling the battery for five minutes, reconnect it and then reset all the codes.

remember to record the codes, re-set AGAIN and then check the codes a second time.

Recurring codes are what I call "real" and the others are "ghost" codes, often caused by other things in the data stream.

[bullmand]

Did the battery trick and drove it home. One code....P0135. Weird. I'm going to see if I can get a deeper scan with some professional tools and see what happens. But in the meantime I guess I'll order some o2 sensors.