Fueling E30 Dramas (I think)

[Forrest 35]

Made this thread because there is too much crap to sort through on the internet and I have had a google.

E30 PFL 325i M20 Motronic 1.1

So on Sunday I had problems starting my car. Left it a while and later on it started again fine.

Drove it on Tuesday all is well. Tuesday night I go to a BMW workshop to get my headlights aligned. As I arrive, the car dies. Spent all night trying to fix it. While it was being looked at, we can confirm:

- The fuel pump relay works and was clicking, even replaced with another one from a car that started fine.

- The fuses associated to the fuelling are fine.

- The ECU is fine, it was swapped into another e30 and started up fine.

- There is plenty of fuel in it.

- It is getting spark.

- When it is going the fuel pump seems to be pulsing fine.

- We couldn't manage to get the test light to light up while the key was turned in the ign to the on postition or while trying to start it.

Eventually gave up and left it at the workshop with a flat battery.

Come back in the morning and the battery has miraculously re-charged itself and it starts first pop and has done until about ten min ago when it died while going round the block and is now parked up in a church parking lot. Lol.

I have heard that fuel pumps be stubborn and then work then not work etc when they are on their way out, so that is a possibility, but doesn't explain the no power issue.

Also with further research have found that when the ign is turned on the fuel pump turns on for 3-4 seconds. It might not be related, but last week I had a wire short out under the dash and caught fire to my ign switch wiring I had installed, is there a possibility that the melting of those wires has shorted the wire that goes from the steering column to the fuel pump?

Also thought maybe the plug the fuel pump relay goes into maybe dirty and causing a bad connection, thoughts?

Hope there is enough info there for someone to go from.

Any help is appreciated, I have already had to re-book my LVV cert test once because of the car not going, so I am hoping to sort this asap.

Cheers, Nathan

Edited April 29, 2010 by Hellpina

[*Glenn* 854]

Did you replace the ignition switch as well when all this shorted out ??

[Lucan 196]

Mine doesn't start randomly, i leave it 30min and it'll start up stright away...i thought it might have been the starter playing up though?

[Forrest 35]

After ringing Glenn I am now on the tangent to see if the ignition switch has correct voltage and if it needs to be replaced. Thinking the electrical fire may have melted the terminals on the switch, not allowing the car to start properly etc. Towing the car home soon so can do some investigating.

[huff3r 347]

this is oli here.. allans car did this before we got rid of the m20, he used to get stuck in all sorts of places.... never figured it out though, but make sure that you injector relay is not sticking sometimes, and just check earths and the common things like that.

[hotwire 352]

Nathan, surely should have been simple enough for a garage to diagnose the problem. Fuel pump either has power to it or it doesn't. It should prime for a couple of seconds with ign on then start again while cranking.

If voltage is leaving the fuel pump relay (green/purple wire from memory) & not getting to pump - obviously a fault in wiring/plugs between.

Ign switch also a simple check - is correct voltage coming out on ign wire (also while cranking)? Will be 10ish volts while cranking

[Forrest 35]

^ Cheers Grant, Lets just say he is a recommended local BMW mechanic and didn't know where the fuel pump relay is on a E30 and leave it at that. I am glad I wasn't paying anything.

I haven't got the car back yet to check the voltage etc, your recommendations mirror what Glenn said to me on the phone so you guys must be right

Will keep this updated with any findings.

Edited April 29, 2010 by Hellpina

[Forrest 35]

Okay so I managed to take the ign switch off, it volt tested fine but had a couple dodgy looking kinks in the main ign wire so I replaced it. Managed to find a near new one off a car at pick a part even with the BMW part sticker etc still attached. Installed it, now I can get the lights etc on the dash to light up fine, but can't get it to crank. WTF has gone wrong/what is next tangent to follow?

Just about ready to push it off a cliff

[flake 0]

Okay so I managed to take the ign switch off, it volt tested fine but had a couple dodgy looking kinks in the main ign wire so I replaced it. Managed to find a near new one off a car at pick a part even with the BMW part sticker etc still attached. Installed it, now I can get the lights etc on the dash to light up fine, but can't get it to crank. WTF has gone wrong/what is next tangent to follow?

Just about ready to push it off a cliff

let me know when you wanna push it off a cliff cause we can do mine at the same time

[antil33t 90]

Thirded. though mine will require towing.

[_ethrty-Andy_ 2132]

^+2

[Hartage 0]

let me know when you wanna push it off a cliff cause we can do mine at the same time

\\Come on now, There not that bad!

Just keep at it, you will get there!

[Forrest 35]

Well guess who's the pinhead forgot to connect the black and yellow wire that goes from the ign switch to the starter motor. I slammed my head in the drivers door as punishment lol. It starts now, just need to see if the troubles mentioned above continue. So it's bittersweet.

The ign switch that came off the car before I replaced it with the new one looked all corroded and was shorting off another wire..so could be the cause. Fingers crossed !

Edited April 30, 2010 by Hellpina

[huff3r 347]

Well guess who's the pinhead forgot to connect the black and yellow wire that goes from the ign switch to the starter motor. I slammed my head in the drivers door as punishment lol. It starts now, just need to see if the troubles mentioned above continue. So it's bittersweet.

The ign switch that came off the car before I replaced it with the new one looked all corroded and was shorting off another wire..so could be the cause. Fingers crossed !

Good luck!! You of all people seem to need some

Next: Lets get Anthonys car going...

[mark247 39]

Well guess who's the pinhead forgot to connect the black and yellow wire that goes from the ign switch to the starter motor. I slammed my head in the drivers door as punishment lol. It starts now, just need to see if the troubles mentioned above continue. So it's bittersweet.

The ign switch that came off the car before I replaced it with the new one looked all corroded and was shorting off another wire..so could be the cause. Fingers crossed !

Ha good stuff. We were both pretty stumped before.

I should of read this first, I just pm'd you a convo I had with Troy and I'm pretty sure he mentioned that you should check that you plugged that in! Good to see ya one step ahead.

Kudos to ya for sorting that out.

[Forrest 35]

^ Cheers for your help yesterday Mark anyway

Edited April 30, 2010 by Hellpina

[Forrest 35]

So to add another chapter in the saga...it is still dying at idle.

I think it is air related as it initially idling at 500rpm then dropping to 250rpm which is far too low.

Will try cleaning out the idle control valve with throttle body cleaner and the associated plugs with electrical cleaner, then moving onto cleaning the AFM sensor with sensor cleaner.

Anyone else have any pointers? Is there anyway to adjust idle speed? Hopefully if it is able to be raised, it will stop it dying. It has only ever died when it is idling, so I don't think it is the fuel pump, surely something to do with air. As I have said before we have tons of spark, 12v everywhere.

Help is appreciated.

[tire 10]

Yes you can raise the idle by adjusting a little screw on the tb with an allen key, it just opens up the throttle. Its meant to be wound on so that there is a specific gap between the throttle plate and the throttle body. I'm not sure what this spec is but Glenn knows.

[huff3r 347]

So to add another chapter in the saga...it is still dying at idle.

I think it is air related as it initially idling at 500rpm then dropping to 250rpm which is far too low.

Will try cleaning out the idle control valve with throttle body cleaner and the associated plugs with electrical cleaner, then moving onto cleaning the AFM sensor with sensor cleaner.

Anyone else have any pointers? Is there anyway to adjust idle speed? Hopefully if it is able to be raised, it will stop it dying. It has only ever died when it is idling, so I don't think it is the fuel pump, surely something to do with air. As I have said before we have tons of spark, 12v everywhere.

Help is appreciated.

Mine did this when the rocker-cover breather wasnt attached, are all the hoses secure? In good condition?

[Forrest 35]

^ Yeap they are all brand new. I might try cleaning the TPS plug too.

[pureboiracer 0]

as said above, either air leak or tps or afm or iac valve. if its not hunting too bad and cleaning sh*t doesnt fix it i would just wind that throttle plate screw up a lil. thats my 2c

[Forrest 35]

Cheers Oli, Paul and Max.

Will try all those things. It also goes from starting fine, to idling as per normal then droping to 0 RPM and dying to not starting at all, hence why I have been stranded a few times. Quite frustrating.

I have seen similar symptoms in a M20 that got pressure washed and wouldn't start. Ended up being water somewhere around the AFM and eventually dried out etc. I will note on one of the days it died whilst it was like monsoon season down here, maybe it is an after effect of that?

Edited May 2, 2010 by Hellpina

[pureboiracer 0]

^yeah i feel your pain... my latest e30 has got me stranded it fair share of times too, something to do with blowing apart right rear tyres. and mysterious flat batterys..

My race car would hardly run the other day, it went from kelson to almost at interpart before it would go over 3000rpm, paul thinks its because something under bonnet got wet. said he had simillar problem with geoffs car, can only asume its the afm thats the problem

Edited May 2, 2010 by e30li

[Forrest 35]

^ Yeah the E30 that got pressure washed that I mentioned was Geoff's. I might be onto something.

P.S got no credit, bring those rear springs Thursday along with some biers, we can give em a go

[pureboiracer 0]

^sweetbix