Fires and tries to run but will not!
Discussion
Hi
Well we started working on the ex press car today, know this car is a barn find which been in there for four or five years!
We removed 8 galls of very stale Fuel. The fuel gague was reading nearly 3/4 full so the gague reads about correct!
Whilst looking around the car in more details and it has 15" 7J wheels no wonder it looked a bit different!
Well we fitted a new slim battery as the battery hole is the same as a 280i hole!
The fuel filter was changed plus the plugs and we had a very health spark!
Then we got fuel up to the new secondary fuel filter!
So we tried to see if it would run it fired but would not keep running, we tried a few more times and the same thing happened. It was running only on the fuel from the cold start injector, the main injectors were not openning!
Further investegation found the AFM top was lose as was the power resistor box lid.
This is were we think the problem lays but time was against us today as we had other cars to ready for this weekend!
Has anybody else got any thoughts on this?
Andy
Well we started working on the ex press car today, know this car is a barn find which been in there for four or five years!
We removed 8 galls of very stale Fuel. The fuel gague was reading nearly 3/4 full so the gague reads about correct!
Whilst looking around the car in more details and it has 15" 7J wheels no wonder it looked a bit different!
Well we fitted a new slim battery as the battery hole is the same as a 280i hole!
The fuel filter was changed plus the plugs and we had a very health spark!
Then we got fuel up to the new secondary fuel filter!
So we tried to see if it would run it fired but would not keep running, we tried a few more times and the same thing happened. It was running only on the fuel from the cold start injector, the main injectors were not openning!
Further investegation found the AFM top was lose as was the power resistor box lid.
This is were we think the problem lays but time was against us today as we had other cars to ready for this weekend!
Has anybody else got any thoughts on this?
Andy
adam quantrill said:
Good idea - do clean the connector on the end of the loom though. The earth strap to the pack doesn't do that much as the earth return goes back through the loom for each injector anyway.
That earth braid is only there for interference suppression, there's no internal connection to earth in the resistor pack.I feel for you Andy after my recent break down which resulted in non firing injectors!
When you say the lids on the AFM and resistor pack are loose, do they look like someone has been fiddling trying to diagnose a fault? Do you know if the car was laid up after a break down?
If the throttle pot is connected and working (simple to test with a voltmeter) and the resistor pack is OK I'd start looking at the ECU.
At least you have a few known good bits available to swap out!
Have you checked the earth to the injection loom? On my S1 it's on the nearside of the bell housing, without it the injectors won't fire as I discovered after some clutch work.
If you end up with a completely dead ECU you don't want I'd be interested as I'm trying to build a working spare.
When you say the lids on the AFM and resistor pack are loose, do they look like someone has been fiddling trying to diagnose a fault? Do you know if the car was laid up after a break down?
If the throttle pot is connected and working (simple to test with a voltmeter) and the resistor pack is OK I'd start looking at the ECU.
At least you have a few known good bits available to swap out!
Have you checked the earth to the injection loom? On my S1 it's on the nearside of the bell housing, without it the injectors won't fire as I discovered after some clutch work.
If you end up with a completely dead ECU you don't want I'd be interested as I'm trying to build a working spare.
Hi
The car was laid up because it failed its MOT on the exhust
what a surprise!
The AFM top was lose and has been removed before and it looks like it had been done some time ago as there is a bit of silicone around it, I have a spare so I will replace that! The same goes for the resistor pack. the one on the car has been opened, what they used to undo the small bolts, correction more like mullerd them open!
We will be replacing that!
The throtle sensor was the next thing we were going to look at if replacing the resistor does not work! At present its complete and has no signs of being tampered with!
We will look at it again at the show over the weekend!
Andy
The car was laid up because it failed its MOT on the exhust
what a surprise!The AFM top was lose and has been removed before and it looks like it had been done some time ago as there is a bit of silicone around it, I have a spare so I will replace that! The same goes for the resistor pack. the one on the car has been opened, what they used to undo the small bolts, correction more like mullerd them open!
We will be replacing that!
The throtle sensor was the next thing we were going to look at if replacing the resistor does not work! At present its complete and has no signs of being tampered with!
We will look at it again at the show over the weekend!
Andy
Is the AFM signal to the fuel pump working, the fuel pump will run while cranking (which could explain the initial firing) and should also run when the AFM flapper is open beyond a certain point. If that signal was duff or if the AFM has been tampered with then there will be no fuel.
There is also that funny wire from the dizzy to the ECU (black on white) that may be used for firing the injectors, on my 390 there is a connector for this wire just under the AFM which I have on occasion forgotten to reconnect.
Russ
There is also that funny wire from the dizzy to the ECU (black on white) that may be used for firing the injectors, on my 390 there is a connector for this wire just under the AFM which I have on occasion forgotten to reconnect.
Russ
MrPicky said:
Is the AFM signal to the fuel pump working, the fuel pump will run while cranking (which could explain the initial firing) and should also run when the AFM flapper is open beyond a certain point. If that signal was duff or if the AFM has been tampered with then there will be no fuel.
There is also that funny wire from the dizzy to the ECU (black on white) that may be used for firing the injectors, on my 390 there is a connector for this wire just under the AFM which I have on occasion forgotten to reconnect.
Russ
Both good points. The diode steering module (the 'red relay') could be at fault (rarely) or plugged into the wrong socket (it has happened).There is also that funny wire from the dizzy to the ECU (black on white) that may be used for firing the injectors, on my 390 there is a connector for this wire just under the AFM which I have on occasion forgotten to reconnect.
Russ
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