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Discussion Starter #1
Right i have an issure with my 1999 316i with the later 1.9 engine. With the MAF sensor plugged in, it starts and runs for 2-3 seconds then cuts out. If i unplug it, it runs very rough, nothing like before the issue. Ive used a brad new MAF sensor and the same problem persisted. I did notice the emission pump casing split, a fee people said it could be that, so i replaced that and still nothing. Now im stuck for ideas what it could be.
Maf sensor replaced
Emission pump replaced

Its runs really rough unplugged and cuts out almost instantly if i plug it back in

Any ideas what this could be.
Cheers
Luke
 

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unplugged it should run to some degree as it reverts to a backup fuel map within the ECU,i think the engine has other issues like compression or lambda issues or summat but without diagnostics data its hard to give an accurate diagnosis...

i suggest a scan with INPA or similar software....


cold starting the engine relys on engine temp and MAF data (open loop) until the engine warms up and the lambdas start sending data (closed loop)
 

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Discussion Starter #3
Okay, i have no way of plugging into a computer at the moment. But before it cut put the other day it was running fine. Now it only running with a rough idle with maf unplugged. I dont know much abput engines and under the bonnet stuff. My step dad reckons it what ever the wire is connected to at the other end of the maf sensor
 

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Okay, i have no way of plugging into a computer at the moment. But before it cut put the other day it was running fine. Now it only running with a rough idle with maf unplugged. I dont know much abput engines and under the bonnet stuff. My step dad reckons it what ever the wire is connected to at the other end of the maf sensor
as daily dogger says, if its the maf sensor, it would run fine if unplugged as it will go to default ecu settings,maybe run a bit rich
 

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check you throttle body and flap inside of it. the flam could be worn and its not getting constant position as result it may hunt for idle speed. to cure this, adjust bolt for the throttle flap to pass worn area on throttle body
 

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Discussion Starter #6
Right so my mate and his dad have had a look. Plugged in there computer and figured the rough running and eliminated what it could be.
Its only running on 3 cylinders. The done a compression test on no.4 and its fine, plugs fine, but dry and they say it should be soak in fuel if its missing. So injector. They checked that the signal is being sent to the injector by the cable and it is so im guessing its a blocked or faulty injector.

Going onto the maf sensor being plugged in and out running wise, they've traced the wire back and its fine, could that be some thing to do with the injector with fuel and air mix.
 

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swap injector but also the coil blocks on M43 engines are notorious failures...
 

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Discussion Starter #8
I took it to bmsport garage and they sorted the misfire by changing leads and plugs, which if i knew i would have done myself but theres still a airflow problem with the maf sensor. The one i tried was 75 pound, which i took back. Is it woth spending the 140 on a bosch one to see if that one works. I know all the wires are fine for itso unsure what that problem could be
 

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cheap mafs are false economy...and a notorious failure on the m43 engine...
 

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The ecu burns out on these cars then they miss fire

We do replacement DME ecu's for these cars and have 10 in stock if needed

If you can get the car down I can look at if for you

Before you waste any more money


Sent from AutoGuide.com Free App
 

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Discussion Starter #13
I got the misfire sorted now. Just changed plugs and leads snd viola, all good. With the same mag sensor plugged in to. Now just gotta repair or get a new pipe that i found has a split.
 
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