It could be your ecu. The AAV, Thermo time switch, AFM.... several of your FI components are monitored or receive voltage or ground from the ecu.
Also have a look at the thermo time switch. He is also looking a bit guilty right now...
Open up the BMW 528i L-Jet schematic I attached for reference. It's a bit easier to read than the Italian L-Jet translation.
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AussieGTV6
- Silver
- Posts: 9
- Joined: Mon May 16, 2005 4:02 am
- Location: Australia
Hi all. Well i went back and tried everything again and went over all the things that i have already done like checking for vacume leaks and running an OHM meter over the sensors.
The AFM seems to be ok as i have tried swapping it with another one off a 2.5 Milano and it didnt make any difference. The fuel pump is definitely working as i have installed a brand new one with new fuel lines and a new filter. I have checked that the fuel return line is not blocked, and have used a fuel pressure gauge to check that the fuel pressure is not dropping when the motor faulters.
It started perfectly again when i tried it yesterday morning. Ran on all six cylinders smooth as silk, for about 45seconds, then did its usual trick of dropping cylinders and finally stalling.
As far as i can tell it is only firing on cylinders 2 and 3 after it faulters. All the other cylinders are getting spark, they are getting a pulse to the injectors because i used a tester to make sure that they are pulsing, but for some reason they are just are not firing. Either these cylinders are getting too much fuel or they arent getting enough, or the fuel is getting introduced at the wrong time. The spark is dictated by the distributor so one would assume that if cylinders 2 and 3 are getting it at the correct time then all the others should be as well.
The point at which the engine faulters is very pronounced. It happens quickly. One moment it is firing on all 6 and the next it is falling in a heap and is rough as guts.
Im seriously starting to consider selling this car for whatever i can get for it. It is in beautiful condition, full genuine Zender body kit, Zender wheels, Sparco race seat, Sparco pedals, Momo steering wheel and gear knob, cross drilled rotors, 27mm front torsion bar and sport springs in the rear, Koni dampers, fully re-built limited slip diff with extra locking plates, power steering from Milano/75, and the list goes on. Anyone interested? I simply dont have the time anymore to chase this problem.
The AFM seems to be ok as i have tried swapping it with another one off a 2.5 Milano and it didnt make any difference. The fuel pump is definitely working as i have installed a brand new one with new fuel lines and a new filter. I have checked that the fuel return line is not blocked, and have used a fuel pressure gauge to check that the fuel pressure is not dropping when the motor faulters.
It started perfectly again when i tried it yesterday morning. Ran on all six cylinders smooth as silk, for about 45seconds, then did its usual trick of dropping cylinders and finally stalling.
As far as i can tell it is only firing on cylinders 2 and 3 after it faulters. All the other cylinders are getting spark, they are getting a pulse to the injectors because i used a tester to make sure that they are pulsing, but for some reason they are just are not firing. Either these cylinders are getting too much fuel or they arent getting enough, or the fuel is getting introduced at the wrong time. The spark is dictated by the distributor so one would assume that if cylinders 2 and 3 are getting it at the correct time then all the others should be as well.
The point at which the engine faulters is very pronounced. It happens quickly. One moment it is firing on all 6 and the next it is falling in a heap and is rough as guts.
Im seriously starting to consider selling this car for whatever i can get for it. It is in beautiful condition, full genuine Zender body kit, Zender wheels, Sparco race seat, Sparco pedals, Momo steering wheel and gear knob, cross drilled rotors, 27mm front torsion bar and sport springs in the rear, Koni dampers, fully re-built limited slip diff with extra locking plates, power steering from Milano/75, and the list goes on. Anyone interested? I simply dont have the time anymore to chase this problem.
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AussieGTV6
- Silver
- Posts: 9
- Joined: Mon May 16, 2005 4:02 am
- Location: Australia
Hey Dave, yes i am going to swap over the ECU and if that doesnt make a difference then the car is going down to a local fuel injection specialist who i have used before. He specialises in Porsches but can diagnose the L-Jetronic in the Alfa with no problems. He is expensive but i am at the stage where i am out of ideas and simply dont have the time anymore to chase this problem.
When the culprit is identified i will be sure to post the remedy.
When the culprit is identified i will be sure to post the remedy.
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AussieGTV6
- Silver
- Posts: 9
- Joined: Mon May 16, 2005 4:02 am
- Location: Australia
SOLVED!!!
Well it has taken a while and ive been a bit slack over Christmas, BUT the Gtv6 is back to its former self and running perfectly again.
I ALMOST had it from the very beginning but one vital piece of information eluded me. There is a fine gauze filter in the fuel tank that filters the fuel prior to it entering the pump. The first thing i went for when the car wouldnt run was the fuel pump and filter, followed closely by the injectors. As there was no debris in either the pump or fuel filter i thought that the tank was clean. BIG MISTAKE!!
The gauze filter in the fuel tank (reachable from under the car via the large bolt holding the fuel line to the tank) was completely clogged with rust and other debris. I have now flushed the tank and cleaned the filter and the car is running better than ever before.
I ALMOST had it from the very beginning but one vital piece of information eluded me. There is a fine gauze filter in the fuel tank that filters the fuel prior to it entering the pump. The first thing i went for when the car wouldnt run was the fuel pump and filter, followed closely by the injectors. As there was no debris in either the pump or fuel filter i thought that the tank was clean. BIG MISTAKE!!
The gauze filter in the fuel tank (reachable from under the car via the large bolt holding the fuel line to the tank) was completely clogged with rust and other debris. I have now flushed the tank and cleaned the filter and the car is running better than ever before.
GTV6GPTT, The job of getting to the in - tank filter and cleaning or replacing it is not a hard one but the "side effects" can be really nasty.
In my case I decided to do this as preventative maintenance and have regretted it ever since
As it turned out my in tank filter was fine after 240k miles and didn't need replacing.
In removing the large fitting I created pinhole leaks in the gas tank.The tank sits on a foam pad which collects moisture over time and rust had started to weaken the metal.The torque required to undo the fitting was sufficient to cause small holes.Obviously I didn't notice this until everything was back together and I smelled gas.At that point I had to remove the tank to have it repaired.That went fine but once I put her all back together My fuel pump failed (twice
) It turned out that by manipulating the fuel line under there I had dislodged disintegrating plastic inside the hard plastic outgoing line (I'd already replaced all the rubber fuel lines).These bits of plastic jammed the fuel pump.
I've since recovered from this experience -however my desire to drink lots of beer has not yet gone away
But to make a long story short - "if it ain't broke - don't fix it"
In my case I decided to do this as preventative maintenance and have regretted it ever since
As it turned out my in tank filter was fine after 240k miles and didn't need replacing.
In removing the large fitting I created pinhole leaks in the gas tank.The tank sits on a foam pad which collects moisture over time and rust had started to weaken the metal.The torque required to undo the fitting was sufficient to cause small holes.Obviously I didn't notice this until everything was back together and I smelled gas.At that point I had to remove the tank to have it repaired.That went fine but once I put her all back together My fuel pump failed (twice
) It turned out that by manipulating the fuel line under there I had dislodged disintegrating plastic inside the hard plastic outgoing line (I'd already replaced all the rubber fuel lines).These bits of plastic jammed the fuel pump.I've since recovered from this experience -however my desire to drink lots of beer has not yet gone away
But to make a long story short - "if it ain't broke - don't fix it"
1986-GTV6
1989-75 Twinspark very sadly sold-remarkable sedan !
2014 Audi Q5 3.0l TDI - torque MONSTER
1989-75 Twinspark very sadly sold-remarkable sedan !
2014 Audi Q5 3.0l TDI - torque MONSTER