Bad engine misfire

[francoishensen11]

Possibly the filter but could even be a fuel pump/pressure issue with your lines running empty hence when you swing,it takes time for the fuel line to run full again, might be wrong but worth having it checked.

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[zippy320]

I did replace the pump, just a day before the fuel injector issue, is there a way to prime the lines so that the pressure goes up again?

Possibly the filter but could even be a fuel pump/pressure issue with your lines running empty hence when you swing,it takes time for the fuel line to run full again, might be wrong but worth having it checked.

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[francoishensen11]

Have the fuel pressure tested by someone who has a fuel pressure tester (should get a reading of 3 bar,correct me if I'm wrong here) quickest way to check for air in the fuel line is to remove that little screw cap on top of your injector rail,once off there's a like a little ball inside use a thin screwdriver or paperclip to press that ball, to do it: if car has been switched off for a while unscrew the cap and be ready to push the ball, have someone put the ignition on (don't swing) you should hear the pump prime, at that moment press it, be warned that the fuel will come out fast so less than a second should suffice,make sure there's no open flames or sparks nearby when doing this, other than that short of reading the codes I'm stumped.

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[zippy320]

Thanks francoishensen11 ,

I have this Fuel pressure tester, Thing is, its very old though has never been used, by old I mean it once cost R6.99 from Hyperama . Will see what it reads.

Do I plug in the from before it goes to the fuel rail or from before it goes to the fuel filter?

Have the fuel pressure tested by someone who has a fuel pressure tester (should get a reading of 3 bar,correct me if I'm wrong here) quickest way to check for air in the fuel line is to remove that little screw cap on top of your injector rail,once off there's a like a little ball inside use a thin screwdriver or paperclip to press that ball, to do it: if car has been switched off for a while unscrew the cap and be ready to push the ball, have someone put the ignition on (don't swing) you should hear the pump prime, at that moment press it, be warned that the fuel will come out fast so less than a second should suffice,make sure there's no open flames or sparks nearby when doing this, other than that short of reading the codes I'm stumped.

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Found the Little screw on top of the fuel rail ? < looks like a cleaner version of the caps I have on the tyres, in fact, looks like the same cap.

I had parked the car off about 3 hours ago, so it was a little warm. pushed in the little ball and for a second or less I could hear an air sort of sound. Pressed it in again and a little fuel came out.

I will try it again when the cars completely cold , following your procedure.

Have the fuel pressure tested by someone who has a fuel pressure tester (should get a reading of 3 bar,correct me if I'm wrong here) quickest way to check for air in the fuel line is to remove that little screw cap on top of your injector rail,once off there's a like a little ball inside use a thin screwdriver or paperclip to press that ball, to do it: if car has been switched off for a while unscrew the cap and be ready to push the ball, have someone put the ignition on (don't swing) you should hear the pump prime, at that moment press it, be warned that the fuel will come out fast so less than a second should suffice,make sure there's no open flames or sparks nearby when doing this, other than that short of reading the codes I'm stumped.

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[francoishensen11]

Yep that's the location where the tester goes on aswell, there shouldn't be air at all in there as you press that ball fuel should instantly come out, how does it start now with that air out?

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[zippy320]

Haven't started it yet, waited for the car to cool, Im going to try your method in the morning as well , then try and start it.

How would air get trapped in there? after driving it for the day, wouldn't it get pushed out by the flow of fuel?

On a side note, I visited a "junk yard" today looking for some screws and plastic bolts for my E30 and mentioned the problem to the guy there, He tells me that it could be as I had the 1 fuel injector replaced, the others might not be flowing at the same rate as the new one , I should look at having the other 3 injectors cleaned. Whats your thoughts on this? Can the others be cleaned out? Could they also be on their way out ? Will it be safe for the car?

Will keep you updated.

Yep that's the location where the tester goes on aswell, there shouldn't be air at all in there as you press that ball fuel should instantly come out, how does it start now with that air out?

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[francoishensen11]

Only way that air could get in there was when the injector was replaced,air was introduced into the system,as for the cleaning of them what I used to do on my e30 325i was to use a compressed air, connected the air hose with a clamp on the fuel intake side of the injector and slowly open the air of the compressor that being done while the injector itself was clamped down into a bench vice obviously all visible dirt I saw before hand in the injector I cleaned out with a paper clip and knocked it gently on a block of wood to ensure most dirt was out,that said in my experience injectors either work or they don't,meaning I once had a car that was difficult to start and when it did it didn't want to rev up properly(miss and flat spot) then I saw it had the wrong injectors(this was a e36 323i) in 4 of the 6 cylinders(4 injectors was from a e30 320i) changed them out car was perfect, also do check your fuel pressure,I'm still not sure what reading is correct for that engine if it's off it can be only 1 of 3 things namely the fuel pressure regulator possibly faulty (located on the fuel filter) fuel pump or a fuel line that possibly has a kink and is restricting fuel flow ever so slightly also make sure the little air pipe is connected to the fuel pressure regulator.

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[zippy320]

Hi Francoishensen11

So , this morning I had the same issue, car took 4 turns before it started, Drive ability seemed to have changed a little, It feels slightly rougher, and "irritated?" while in traffic, and there is a lot of traffic now with the load shedding causing most of the robots to switch off. I tried checking the fuel pressure but I must have been doing something wrong or maybe the gauge I have wasn't sealing properly onto that little piece on the rail, the rail seems to have a screw piece where as my gauge has a conical shaped rubber tip , I will take it to a garage and have them check it for me tomorrow.

With the above in mind I decided to take your advice and change the fuel filter , I thought , well the pumps new , 1 injectors new , I might as well replace the filter , it cant hurt the car in any way. So I replaced it this evening. I cant say if it solved the problem , but after a few turns it did start up .( I guess that's normal as the pump has to prime/fill the filter and lines with fuel) So I cant tell as yet if this worked. I will know in the morning . I haven't checked the old filter,I plan on checking it for dirt/blockages, I fitted a Mahle Filter, Depressing to find older E46s filters are so much cheaper then the one fitted to my car. R200 as apposed to my R650 for the Mahle .

I checked all the lines , everything is straight, All lines are still perfectly clipped onto their plastic holding clips . The cars never had any of its lines replaced so im not sure if a bend or crimp could occur anywhere else?

How many bars of pressure should my cars fuel system have? Iv been told 3 , 3.5 , and 6 by various people. I did purchase the right Bosch pump, I hope the guy over at Diesel Electric gave me the correct part . Part number 0986580132 , I cant seem to find its pressure rating anywhere.

Regarding the Fuel pressure regulator , I believe this part is built into the fuel filter on my car so with a new filter comes a new regulator. Hence the little pipe ? connects to the filter as well.

Lets see, If this does not work, Will look into cleaning the remaining injectors.

Will keep you updated.

Only way that air could get in there was when the injector was replaced,air was introduced into the system,as for the cleaning of them what I used to do on my e30 325i was to use a compressed air, connected the air hose with a clamp on the fuel intake side of the injector and slowly open the air of the compressor that being done while the injector itself was clamped down into a bench vice obviously all visible dirt I saw before hand in the injector I cleaned out with a paper clip and knocked it gently on a block of wood to ensure most dirt was out,that said in my experience injectors either work or they don't,meaning I once had a car that was difficult to start and when it did it didn't want to rev up properly(miss and flat spot) then I saw it had the wrong injectors(this was a e36 323i) in 4 of the 6 cylinders(4 injectors was from a e30 320i) changed them out car was perfect, also do check your fuel pressure,I'm still not sure what reading is correct for that engine if it's off it can be only 1 of 3 things namely the fuel pressure regulator possibly faulty (located on the fuel filter) fuel pump or a fuel line that possibly has a kink and is restricting fuel flow ever so slightly also make sure the little air pipe is connected to the fuel pressure regulator.

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[francoishensen11]

Yeah I think it should be around 3.5 bar, with the correct fuel pressure tester connected,put ignition on as the pump primes you should get a reading of about/close to 3.5 bar then put ignition off,leave tester connected for about 10mins and check what the pressure reading is, if there's a significant drop on the gauge you have a possible leaky injector or the built in valve(check valve I think the yanks call it) of the fuel pump is messing about

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[zippy320]

Update:

After replacing the fuel filter, the starting issue is still there, It still takes about 3 to 4 turns before it starts up , This only happens after the cars been sitting for a while , though I noticed if I press the acc down, the car starts up quicker.

If I switch it off and after staring it with the issue, the first time and restart it , it will start almost instantly. And it does this all the time thereafter. Its only after its been parked for a while does it give a problem.

Replacing the filter has helped with drive ability , all the previous issues seem to have gone now. Engine is smooth at idle , stopped in traffic its fine, no rough engine. So it wasn't waste replacing the filter. Surprisingly though the old filter wasn't that old, I replaced the original that was on the car from new with this one last year , and had done just a few thousand Kms with it. This was a Bosch filter.

I decided to take the old fuel pump apart . Tested it before taking it apart and it wouldn't spin, So took it apart to see if there was anything in it. It was pretty clean, no dirt or damage. I checked for wear and it didn't seem worn out at all everything looked pretty newish. This is the original fuel pump that was on the car from new. I did find some white, dusty thin layer of sediment on some of the parts... What could this be? It was on the plastic mesh filter as well. Iv cleaned up all the pieces and will reassemble it to see if it works after the clean.

I didn't have time to have the fuel pressure tested on the car, this load shedding is killing me, everything gets delayed by at least 3 hours each day because of it.

When testing the old fuel pump previously (non start issue) , While using a test light , I noticed that the pump will only get power (that is my test light will only flash) when the engine turns over. Unlike my E30 when put into ignition position two which primes the lines , the light wont come on and I don't hear it buzzing.

On the E46 N42 , should it also prime at position two before turning over? Mine seems to only "pump" when the engine turns, Is this normal?

Yeah I think it should be around 3.5 bar, with the correct fuel pressure tester connected,put ignition on as the pump primes you should get a reading of about/close to 3.5 bar then put ignition off,leave tester connected for about 10mins and check what the pressure reading is, if there's a significant drop on the gauge you have a possible leaky injector or the built in valve(check valve I think the yanks call it) of the fuel pump is messing about

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[Ratslaaf]

It does sound like you have a slow leak somewhere, hence the car needing to crank a few times when left for a while.

 

[Charlie Brown]

Howzit, I suggest you take the car to Eddie at Pumprite in Pinetown.

This oke is sharp and will assist you in getting this sorted.

 

[zippy320]

Thanks guys, I'm starting to believe that it could also be the non priming of the lines in position 2 that's causing the hard start?

It does sound like you have a slow leak somewhere, hence the car needing to crank a few times when left for a while.

 

[zippy320]

Update: I reassembled the old pump after taking it apart and cleaning it, and guess what , it works, Spins freely, no noise.

Thanks guys, I'm starting to believe that it could also be the non priming of the lines in position 2 that's causing the hard start?

It does sound like you have a slow leak somewhere, hence the car needing to crank a few times when left for a while.

 

[francoishensen11]

It should prime,at least that's what happens on ALL n42's pre or facelift that I've worked on, Maybe a fuel relay issue?

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[zippy320]

Hi Francoishensen11

This evening after a drive out , I replaced the fuel relay with a new one , the green relay that sits way behind the fuse box under in the cubby.

Turned the ignition and the car does start , though I expected it to as it only has the hard starting issue after the car sits for a while.

I did hear a noise though when putting the car into ignition position 2 , outside it sounds like a bzzzt for around less then a second.

Will know tomorrow morning if this worked. I did this twice, and the sound stopped after the 3rd time (that is putting it in position 2)

I then started the car there after , tried it again and I get the noise again.
Im hoping that this is priming the lines.

I wonder , if this does work, could it have been the old pump that stopped , causing extra load on the fuel relay to cause it to malfunction like that. (That is if it does solve the problem)
The old relay looks almost new, its never been removed from the car since new so I know nobody's touched it.

Will keep you guys updated.

Regards

It should prime,at least that's what happens on ALL n42's pre or facelift that I've worked on, Maybe a fuel relay issue?

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[francoishensen11]

Yep that bzzzzt you hear is the pump priming, so when cold or parked off for an hour or so,before you swing let the pump fully prime(bzzzzt sound until it stops while ignition is on) before you swing and see what happens.

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[zippy320]

Just an updated

Replaced the fuel relay , the car seems to be working well now. Seems to be driving normally,Starting normally as well. It did give me an issue with 4 3 and 2 swings after I replaced the fuel pump relay . but now starts on the turn. I just have to wait for the pump to prime and it turns over on the first spin

Thanks for all your help guys! This really really helped! Special thanks to Francoishensen11! You are awesome! Thanks for all your advice!

Hope this thread can help someone else in the future
Next step , replacing my front shocks.

 

[francoishensen11]

Glad you're sorted and that I could be of help,now enjoy the sheer driving pleasure

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