Recuring Problems with my e39

[WTCooperman]

Dear SifusI have introduced myself in the newbie section a few weeks back. I have been following this forum on/off for the past many years and find it very informative and useful.I own a 1998 e39, 523i single Vanos, ~280k mileage and I have been driving it for ~10 years, it has served me very well and I have taken very good care of herSorry for this very lengthy post to describe my problem.This problem first happen about a year ago during my outstation trip back to KL, and for some strange reasons, recurs under similar condition until now.I.e. when I encountered very bad start/stop traffic congestion during long distance trip (e.g. during festive seasons), my car would lose power (and sometimes stall or going to stall e.g. like someone who is out of breath and trying to grasp for oxygen) when I am stuck in the very bad traffic crawl. I would have to restart my car and it moves, but very slowly, literally at “snail pace” (no power at all when I press the accelerator… the RPM would go up, but car moves very slowly). If the traffic crawl is very bad, literally start and stop, I had to pull it to the side, turnoff the ignition, and restart and to get it going (in this case, I have no choice but to drive on the emergency lane to keep my car moving so that it won’t stall – sorry I do not encourage this and please do not flame me: -). Again, as long as the car moves, it’s OK. Somehow I managed to get to my destination, spent a few days driving around there and back to KL as though the problem has not happened in the first place.After the first occurrence, I sent it to my regular workshop in KL. The O2 sensor error (can’t remember the code, sorry) was diagnosed, they cleared it and I drove (around town and regular short trips to KLIA etc.) it for the next few months without any problems.Then consistently, the same problem recur over my next 3 other outstation trips under similar very bad start/stop traffic conditions during the journey i.e.1) After the second recurrence, I sent it to my workshop, no error was diagnosed, but I changed the O2 sensor (comes in a pair), fuel filter, Vanos seals, cleaned my MAF and checked all the hoses for possible leakages. Thereafter, drove it for a couple months in KL (very bad start stop traffic at times) and some short trips without any problems whatsoever.2) Problem recur when I did my next outstation trip. Again no error was diagnosed, however, I replaced my cam shaft sensor and oil separator (this is thru Google-ling). Happily driving it around in KL and short trips to Bukit Tinggi, Bentong and regular trips to KLIA without any problems for the next few months.3) Took another long distance trip some 3 weeks back. Same problem recurred under similar conditions and again no error code was detected. I have not replaced anything yet as the folks from my workshop are at a lost. But I am still driving around in KL until now without any problems (touch wood). I am not sure what else to do or replace, could it be the MAF? “going-to-be” faulty fuel pump (which I have changed 1-1/2 year ago) ? Idle control valve? Etc. I have lost all confidence taking my car on long trips for obvious reasonsFyi and in summary:-a) There is no overheating issues. I take good care and service my car religiously. b) When I drive it around KL for months and under similar very bad start stop traffic crawl, there is no such problem. c) If I drive outstation and if there is no bad start/stop traffic crawl in between, the problem does not recurd) The problem always recur when I get caught is very bad start/stop traffic crawl during my long distance tripThe other “unexplained” theory is that my car is getting “old” and does not like to go on long distance trip and get stuck in very bad traffic crawls during the journey anymore But seriously I hope some Sifus here can offer some advice and help.Thank you in advance and much appreciated.Rgds WTCooperman

 

[jarance]

Have you change your ATF for your Gearbox before?

 

[haywire]

Errr....your MAF might be due for a change and a cleanup may not be sufficient. As you have changed the O2 sensor might as well change the MAF since these two works together.

 

[WTCooperman]

Hi Jarance

Sorry for the noob question, if ATF = Auto Transmission Fluid, yes, I changed it approx. every 30,000 km or thereabouts. My next schedule change is another 5,000km away.

FYI my gear shift has been rather smooth, but last weekend when I sent my car for wheel alignment, I noticed that the area around my gear box is oily, but there is no oily patch on my car porch yet.

Thanks for the quick response.

 

[initialM]

Have you send to mechanic for diagnostic at your regular workshop?

 

[WTCooperman]

Errr....your MAF might be due for a change and a cleanup may not be sufficient. As you have changed the O2 sensor might as well change the MAF since these two works together.

Haywire

Ok that could be my next change.

By the way, is there any 'scientific' or trial and error method to confirm if it's the MAF as there is no error code reflected during the diagnostic?

Thanks in advance.

 

[WTCooperman]

Have you send to mechanic for diagnostic at your regular workshop?

Yes I did but no error was found, except the O2 error when the problem first happen. Thanks.

 

[wuzzles]

Haywire

Ok that could be my next change.

By the way, is there any 'scientific' or trial and error method to confirm if it's the MAF as there is no error code reflected during the diagnostic?

Thanks in advance.

The next time your car losses power, pull out the MAF sensor wire. See if the car come back to normal. If it does, put back the wire and if it starts to misbehave again, you might have found your culprit. I was having similar issues like you... just that it didn't take A LONG distance drive only for the car to slow down to snails pace. This is how my mech zoomed down for my problem. Hope this helps...

 

[jarance]

you can use a diagnostic and get to read the live data of the MAF with and without the AC at idling speed.

 

[jarance]

Hi Jarance

Sorry for the noob question, if ATF = Auto Transmission Fluid, yes, I change it approx. every 30,000 km or thereabouts. My next schedule change is another 5,000km away.

FYI my gear shift has been rather smooth, but last weekend when I sent my car for wheel alignment, I noticed that the area around my gear box is oily, but there is no oily patch on my car porch yet.

Thanks for the quick response.

the reason i ask is because the mechanic might use the wrong type of atf. i am sure you are fully aware that the gb is very sensitive to the brand of atf. but i doubt it is your atf since you have covered 25k with the same atf.

you might like to check on the atf temperature with the live data for the gb as i suspect it could be due temperature issue.

also check the thermostat at the bottom of the radiator located near the heat exchanger for the atf.

 

[seewai]

Sounds like something intermittently overheat (during slow traffic after long drive) or the cooling power of that device is inefficient when it's too hot in there.

My ride has been having O2 sensor fault for more than a year now, everytime I clear the error, the next ignition they would come back. So far no issue driving around long or short distance.

Could you confirm all fans operate normally when you detect the problem?

 

[WTCooperman]

Sounds like something intermittently overheat (during slow traffic after long drive) or the cooling power of that device is inefficient when it's too hot in there.

My ride has been having O2 sensor fault for more than a year now, everytime I clear the error, the next ignition they would come back. So far no issue driving around long or short distance.

Could you confirm all fans operate normally when you detect the problem?

The fans seems to be working and no overheating. Actually, I am quite puzzled as at times I get caught in similar very bad crawl in KL, but no such problem, touchwood.

Thanks for the advice

 

[huskar3399]

Sounds like something intermittently overheat (during slow traffic after long drive) or the cooling power of that device is inefficient when it's too hot in there.

My ride has been having O2 sensor fault for more than a year now, everytime I clear the error, the next ignition they would come back. So far no issue driving around long or short distance.

Could you confirm all fans operate normally when you detect the problem?

Similar like my case. My morning routine now is clearing the CEL off. But it comes back after driving for a while in next reignition. Sometimes it behaves ok but some other times it leads to misfire.

The fans seems to be working and no overheating. Actually, I am quite puzzled as at times I get caught in similar very bad crawl in KL, but no such problem, touchwood.

Thanks for the advice

U can try unplug your MAF and drive without it. If your car behaves ok than that's the real culprit. Just like wuzzle had mentioned earlier.

Sent from my LT26i using Tapatalk

 

[pussy]

what a coincidence.. i m having the same nightmare as yours, only thing my car is a e32 V8 engine! but my gear box is the same as yours 5HP18...

till today i can't find out the problem since last saturday.

 

[macgy]

another possible culprit, d fuel pressure regulator, hv u replaced it?

 

[WTCooperman]

what a coincidence.. i m having the same nightmare as yours, only thing my car is a e32 V8 engine! but my gear box is the same as yours 5HP18...

till today i can't find out the problem since last saturday.

I will get my workshop to try out the MAF as suggested by Wuzzles and Huskar in the next couple week when I am back to KL and see if that is the real culprit, will monitor thereafter and update you all. By the way do advise if you find a solution to your problem. Thanks.

 

[WTCooperman]

another possible culprit, d fuel pressure regulator, hv u replaced it?

No I have not, by the way what are the symptoms of a soon to be faulty fuel pressure regulator? I have changed my fuel pump about 1-1/2 years though. Thanks

 

[macgy]

like what u hv described, also at time it take longer to start d car.

 

[WTCooperman]

like what u hv described, also at time it take longer to start d car.

Ok I will get my workshop to check that too. I have no problem, my car will start up at first crank almost immediately. Thanks.

 

[macgy]

I assume u hv replaced d fuel filter located underneath d car, there is also a fuel regulator attached to it, that is similar to d one on d engine, in fact u may be able to reuse it if u still keep d part, pls chk w ur mech.
In ur case when this happen, try to re start d car, it has to start at 1st crank & immediately....does d car back to normal?, from my experience the failing throttle body replicate same symptom but CEL light will came out but urs don't.