M5 lost power - check engine on - The Unofficial BMW M5 Messageboard (m5board.com)

JohnL · 14th October 2004, 18:02

This weekend, while out on a drive, I went to pass a slower car. I was in 6th gear. I believe that I had the sport mode on. As I gave it gas, it just didn't seem to have any power. I then downshifted to 5th gear and punched it and the car just lost power. Didn't seem to miss but acted like the fuel was cut off as if I had redlined it (which I hadn't). Fortunately the car I was passing reduced speed and the oncoming traffic moved to the right avoiding a collision so I could squeeze back into my lane. Then the check engine light came on. I pulled to the sided of the road and shutdown the engine. After checking the fuel cap and looking under the hood for anything obvious and not finding anything, I started the car back up. The check engine light was now off and the car acted fine. Since then all has been fine. But the situation could have been much worse. You don't expect a car to lose power in a situation like passing. Any ideas as to what could have happened?

1badm5 · 14th October 2004, 18:47

My car was doing that too. THE EXACT SAME THING. "limp Mode" during hard acceleration. Not all the time, but often...too often! Did it for months actually. BWM said "your not using the right gas...BLAH BLAH BLAH". Anyway, I finally took it to BMW service WHILE IT WAS IN THAT "LIMP MODE" and let the Service Manager drive (still in the "limp mode") WITH ME IN THE CAR TOO. I left it with them for about a week. FINALLY they replaced the MAF sensors. The car now drives LIKE A BAT-OUT-OF-HELL! It is wonderful!

Although I told BWM Service I believed the problem to be the MAF Sensors(from reading of otheres on this board with the same problem!), they refused to believe me initally.

Anyway, the problem you described will continue and actually start effecting the computer and the car will run WORSE & WORSE (even when NOT in "limp mode").

Get the MAF sensors replaced and watch the car GO FAST again!

robert

SC'dKellenersM5 · 14th October 2004, 19:18

had same problem...did same cure.

stumbo · 15th October 2004, 11:46

I had same symtoms.

Took to Hexagon BMW Kentish Town.

They said 1 day >> had the car for a week.

They said they would tell me unfront what costs were as they grew >> they doubled it when I turned up (but hacked it down when I nearly fainted).

I said MAF or O2 sensors 9based on this board) >> They said doubt it.

They said Catalytic convertor was on the way out and took it off to test >> it passed all tests.

They decided on one of the O2 sensors (pre cat).

They swapped the coils and spark plug in cylinder 5 (missfire on 5 was one of the symtoms) over to other bank >> problem remains where it was.

They replaced the O2 sensor and drove for a day. Then swapped the coils and plug back, and drove for a day >> No problems.

Handed the car back, tried to charge me double what we agreed with on the phone. Came to an agreement.

Cars been good since. I only same *good* because I suspect the MAF's may also need cleaning/replacing.

JohnL · 15th October 2004, 19:37

Quote:

Originally Posted by 1badm5

My car was doing that too. THE EXACT SAME THING. "limp Mode" during hard acceleration. Not all the time, but often...too often! Did it for months actually. BWM said "your not using the right gas...BLAH BLAH BLAH". Anyway, I finally took it to BMW service WHILE IT WAS IN THAT "LIMP MODE" and let the Service Manager drive (still in the "limp mode") WITH ME IN THE CAR TOO. I left it with them for about a week. FINALLY they replaced the MAF sensors. The car now drives LIKE A BAT-OUT-OF-HELL! It is wonderful!

Although I told BWM Service I believed the problem to be the MAF Sensors(from reading of otheres on this board with the same problem!), they refused to believe me initally.

Anyway, the problem you described will continue and actually start effecting the computer and the car will run WORSE & WORSE (even when NOT in "limp mode").

robert

Get the MAF sensors replaced and watch the car GO FAST again!

What type of air filter are you/were you using at that time? Standard factory or K&N (or similar).

JohnL · 15th October 2004, 19:37

Quote:

Originally Posted by RennSportSC'dKellenersM5

had same problem...did same cure.

What type of air filter are you/were you using at that time? Standard factory or K&N (or similar).

1badm5 · 15th October 2004, 20:23

OEM filters.....

Robert

Quote:

Originally Posted by JohnL

Get the MAF sensors replaced and watch the car GO FAST again!

What type of air filter are you/were you using at that time? Standard factory or K&N (or similar).