Odd loss of power.

[rare]

Okay this is weird, I had a very similar problem with my 318iS. Now with my sport sometimes the car can be reluctant to start again if its just been used (ie, go out for drive, turn it off, come back a small while later). It will run rough for about 10 mins before it smooths out.

This happened this afternoon, and then while I was driving only having just restarted the car, I accelerated in 2nd gear and for a breif second there was a complete loss of power. And then it came back again.

Any ideas?

[Widge]

This has happened to mine too, only twice though.
Bothe times was when it had been started from stone cold, and had not been started for a couple of days cos I had been working on it.
Accelerating in 2nd gear complete loss of power for a very very short time. Huge jolt obviously like if someone had turned the engine off for a micro second.

Just dosen't like being neglected I suppose

[rare]

Sounds like the exct same problem :/ It really is odd. At first I thought it might be due to loss of air or something, but I really have no idea:/

[Widge]

As I say it has only happened twice, but hell is it scary thought the timing belt had snapped. Dunno, air, electrical, dodgy ecu earth? Think it hsa somthing to do with air in the fuel pipes cos only happened when I haven't use it for 2 days or more.

[dazleeds]

mines been doing this too most fookin annoying
dosent do it everyday and done 200mile trip today cruisin at 110plus with no probs but like you say seems to be in 2nd and not even under hard acceleration

if anyone finds out what it is let me know cheers Daz leeds

[rare]

Im pretty sure there will be more people. It must be a common fualt.

[Jackle]

My old 325 did this, cutting out for an instant when accelerating in 2nd, the cure was to replace the DME relay(frontmost (small white) relay in the set of three just infront of the left suspension strut).

[Widge]

Got a boot ful of spare relays, I'll try this in the morning. Won't really be able to tell the difference though! Only seems to do it every coupla months.

Cheers though mate, How did you discover that was the problem

[Jackle]

To be honest I can't really remember, it was a couple of years ago now, I think it might have been suggested on this forum. The garage I got the car from knew about the problem but couldn't solve it - they thought it was the coil..

[Widge]

Ok guys my odd loss of power has developed, but not in the way you would have liked Got in it today after 3 days of not using it and it wouldn't start. Took 5 min's of cranking to get it going. Never done that before. I have had difficulty starting it before but only when warm??? Ok so I went in to town and when I got back to the car, it started but it did churn for a good 20 seconds, and this is with the car hot/warm.

It's never been this bad before, when it used to refuse to start it would churn for 20 secs then fire at about 100rpm for the ecu kicked in an it went to 1000rpm, and as I say it only did this when warm.

It also some times has an odd smaell of petrol around, dut this is infrequent and it doesn't drip. It's had new plugs, rotor cap and arm too in the past couple of months.

Is it possible that ther could be a tiny tiny hole in one of the fuel pipes so that when it's left to stand air gets in and means it has to be cranked to get it going?

Any help appreciated guys, I'll try the relay thing now but won't know the results till I start it in the morning, if ever!!

[Andy_magic]

The next time the car wont warm start straight away, stop cranking, open the bonnet and pull the fuel pump relay under the black box by the near side wing (middle one I think) and then try re starting, if it fires up almost immediately and then dies again due ot no fuel you could be looking at the blue temperature sensor problem.

My car would do this all the time when I picked it up, start a cold engine, drive down the paper shop about a mile away (lazy git that I am), buy some woodbines, come out and try and restart. Usually having to crank it for 20-30 seconds.

It turned out to be the blue temp sensor and the wiring to the ECU being dodgy.

I fitted new sensor and sorted the wiring and the car hasn't done it since, I can re-introduce the problem too by disconencting the blue sensor under the bonnet so it's not a fluke.

Everyone must be gettin pi55ed off with me going on about blue temp sensors

[Widge]

I keep meaning to put 2 new sensors on, I'll do it at the bank holiday now, cheers mate.

[Andy_magic]

It also used to drop power, but only very occasionally. It was almost like a hiccup, like someone flicking the key off and then back on again. fook knows why a temp sensor would affect it though....

[Widge]

My old 325 did this, cutting out for an instant when accelerating in 2nd, the cure was to replace the DME relay(frontmost (small white) relay in the set of three just infront of the left suspension strut).

I think it's a combination of problems, the flick on off one, the warm start one, and the leave it for 2 days and won't star problem. I con't think 1 thing will fix it all.

[Andy_magic]

When left for 2 days, does it start with a bit of black smoke, you need to actaully watch the exhaust while its being started, if so this sounds like leaky injectors.

Does it sort of fire, then die, then catch on a few cylinders and sort of grumble a bit then chime in on all pots and act fine??

I love my techy descriptions

[Widge]

It fires once then turns at about 1-200 rpm for a second or 2 before the ECU kicks in and it then idles at 1000 rpm fine and then goes fine. Dunno about the exhaust.

[johnono]

probably obvious but look at the fuel line into the fuel rail, and see if there is any shineyness around in that area, cos mine takes a few seconds to come about and i recently found fresh smelling fuel in that area so....

i reckon its loosing pressure in the fuel rail and is charging pressure via the pump, thats why it takes a little chug to get it running.. and the delay may be due to the fuel leaking rather than being fed into the rail under pressure. but this is only a guess dude and is in no way based on anything factual

may have 2 n half thousand posts but i still dont know shit

[Widge]

This is what I thought it was firs Johnono, I think I may check them cos somtimes I get a whiff of fuel, and my mates rubber fuel pipes gave up and squirted fuel all over his engine bay recently. Don't want that happening at 95mph on the A1

[johnono]

go for it dude, iԚ´ve had this weird start up "tradition" since i got her.. never changed always the same , as if its correct op. procedure or summin

changed

sparks
ign cables
diz cap
diz rotor
temp blue
temp brown
fuel pres. regulator
air filter

and i cant seem to shift it, so after finding the shiney smelly patch yesterday, im convinced its coming , or at least related to that

but ill keep on lookin anyway

[Andy_magic]

Mine does it too, but I'll be swapping injectors from the donor car that didn't do it.

I'll let you all know where I can be bothered to do it.

[Gwynleym10]

My m10 does this sometimes as well, think its a vacuum leek as i put some electrical tape over one of the pipes and it ran far better. I'm going to get new pipes very soon!

[amit325i]

loss of power or sudden jolt could be a loose earth strap, crank position sensor wiring is a potential weak spot on these cars aswell.

[pete325i]

My Car suffers from the hiccup of power problem, it starts fine, but every so often, usually when warm and you give it some "beans" usually on a change down, the power cuts out for a second. I think its an electrical problem but thats all I can work out. I've chnaged the plugs, dizzy cap and rotor arm, but it's still happening, even more frequently now.

Could this been anything to do with the ECU? I've had it out to put a chip in. Would a sensor cause this problem?

Thanks


Pete