BMW Forums : BimmerForums banner

1 - 12 of 12 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
Hi all - my first post on Bimmerforums but you might have seen my tale of woe on e46zone.

My car - 2002 e46 Touring with M54 2.2Litre 6-cyl engine. Manual. 154,000 miles.

Over the last few months I got a mis-fire at low rpm, and a slight lack of low speed power. Engine also drinks oil (1 litre per 600 miles). I recently changed the plugs and that cured the misfire, but not the slight lack of power at low speed.

Drove to Bristol a couple of weekends ago (son to Uni...) - this is about a 120 mile journey. As I drove, the power loss got worse and worse and the CEL came on. Stopped for fuel and for a while it was ok, but then started getting bad again to the point where I was at wide-open-throttle in first gear at 3 mph!

Each time I would pull over and the car would idle ok. After a few minutes I could drive away again, but only for a mile or so before it lost power again.

The AA said it was coils, so after they carried me home, I put a new set of six coils in - no different. I checked all the intake ducts and vacuum lines for leaks but they were all ok. Then I replaced the CCV and the four plastic hoses but again, no different.

I have INPA software, and I cleared the codes and drove around the block and got 'Burn Fail' cyls 4,5 and 6. cleared the codes and repeated the run and got the exactly the same result.

So at this stage I'm thinking it's a massive vacuum leak somewhere, so I rechecked for vacuum leaks by spraying brake cleaner around all the joints and seals but it had no effect on the engine idle speed. I tried unplugging the MAF, and this made a very slight difference (better), but it was really very slight in comparison to the terrible loss of power. When the power was down, and my foot was on the floor, the intake made a very loud howling noise. This might be normal but usually drowned out by the mechanical noise of the engine, so I can't say whether it was an issue or not...

Then I thought it could be a fuel starvation issue. So I replaced the fuel filter but again, no different. I'm not sure what to do now. I've had to buy another car so that I can get to work, but I don't want to give up on my lovely old E46!

A colleague suggested it could be something to do with fuel pressure - perhaps the tank not venting and creating a vacuum in the tank preventing the fuel being pumped up to the engine. Does this sound plausible?

Does anyone have any suggestions as I'm now at my whit's end.

Many thanks for any advice you can provide.

David
 

·
Super Moderator
Joined
·
12,946 Posts
post up the fuel trim data page from inpa...


you changed the fuel filter/regulator????
 

·
Registered
Joined
·
6 Posts
Discussion Starter #3
Hopefully a screenshot of both the fuel trims, and the lambda sensors is attached to this post.

The fuel trims are a bit surprising. This was only a couple of minutes after a cold start, but I thought fuel trims were stored in the Keep Alive Memory (KAM) so that they were immediately available next time you use the car. I have seen them with slightly different numbers on them in the past, but never anything far from the zeros they show here.

Clearly only the pre-cat lambdas were up to temp when I snapped the second screen. Howver, this shows (and I have seen before) that the values are right at the bottom end. Am I right in saying that Lambda-1 (stoic or ideal mixture) should be at around the middle of the green bars? These figures seem to be much lower - perhaps showing very lean mixture. Have I got this logic right?

Regarding the fuel filter - yes, I replaced the cylindrical aluminium filter under the passenger floor that has two hoses going in, and one coming out. It also has a vac line attached that runs up to the purge valve just under the front edge of the inlet manifold. I think this filter is a regulator too...?

David
 

Attachments

·
Super Moderator
Joined
·
12,946 Posts
it fliters the fuel and maintains the fuel pressure by regulating/venting the return fuel to the tank...
 

·
Super Moderator
Joined
·
12,946 Posts
your fuel trim data for long and short trim is all zero which sez to me you or somebody have been resetting your ECU adaptions, you need to drive doin mixed driving for at least 20-30 miles...and repost trim figures....
 

·
Registered
Joined
·
6 Posts
Discussion Starter #6
That's a bit difficult now as the car will only go about 2 miles before it dies.

I don't know why these adaptives have gone to zero as I don't think I have changed them (at least not deliberately...). When I looked at them previously, they each had low values - just off the centre of the green bar - nothing drastic.

What do you think of the lambda values?

David
 

·
Registered
Joined
·
165 Posts
Have you checked for a blocked CAT? Try taking out the pre-cat lambda sensor and see if the problem is improved. ( leave it connected though ).

TT
 

·
Super Moderator
Joined
·
12,946 Posts
if there is no definitive fault codes ide take it a garage and get the fuel pressure checked....
 

·
Registered
Joined
·
6 Posts
Discussion Starter #10
Would INPA be able to tell me fuel pressure? I've read some stuff on forums that suggests it does, but I can't see how to do in on mine...

Thanks
 

·
Super Moderator
Joined
·
12,946 Posts
no it will not AFAIK there is no fuel pressure sensor...it would prolly throw codes pointing or giving clues towards fuel tho....


only way is a gauge plumbed into the fuel rail....

have you tried driving it with MAF unplugged????
 

·
Registered
Joined
·
6 Posts
Discussion Starter #12
Yes, tried it with MAF unplugged. It was marginally better (but I mean someone not used to the car would not notice the difference), but it still fell flat on its face when I tipped into the throttle.

I really hope it's the fuel pump because I'm sick of throwing money at it now. Any members in north London willing to lend me a fuel pressure test gauge for a couple of hours?

David.
 
1 - 12 of 12 Posts
Top