350i Starting Problems
Discussion
What happens if you put 12v across all the injectors on one bank with a pressurised fuel rail for a couple of seconds? Should be enough to get the car started and prove that some (or all) of the injectors are working. If it doesn't start then it should be enough to soak the plugs and prove that some (or all) of the injectors are working. If no start and the plugs remain dry then almost certainly injectors not passing fuel.
Never tried it myself, so risks are unknown to me. Possible hydraulic issues?
Never tried it myself, so risks are unknown to me. Possible hydraulic issues?
V8 Fettler said:
What happens if you put 12v across all the injectors on one bank with a pressurised fuel rail for a couple of seconds? Should be enough to get the car started and prove that some (or all) of the injectors are working. If it doesn't start then it should be enough to soak the plugs and prove that some (or all) of the injectors are working. If no start and the plugs remain dry then almost certainly injectors not passing fuel.
Never tried it myself, so risks are unknown to me. Possible hydraulic issues?
Think flapper injectors are not 12v, that is why there is a resistor pack.... more like 3v?Never tried it myself, so risks are unknown to me. Possible hydraulic issues?
Rob
350zwelgje said:
V8 Fettler said:
What happens if you put 12v across all the injectors on one bank with a pressurised fuel rail for a couple of seconds? Should be enough to get the car started and prove that some (or all) of the injectors are working. If it doesn't start then it should be enough to soak the plugs and prove that some (or all) of the injectors are working. If no start and the plugs remain dry then almost certainly injectors not passing fuel.
Never tried it myself, so risks are unknown to me. Possible hydraulic issues?
Think flapper injectors are not 12v, that is why there is a resistor pack.... more like 3v?Never tried it myself, so risks are unknown to me. Possible hydraulic issues?
Rob
3v = 2 AA batteries?
Firstly thank you one and all for your replies!
I have just spent a little time tinkering and the cold start injector is definitely firing as it should.
I swapped the harness from cylinder 4 and 6 and tried it on the cold start injector and it doesn't fire so we have progress!
Wedg1e you mention the importance of the earth, one of the initial problems was that the fuel pump and coil weren't earthed, we found one thick black wire and two thinner black and white wires that came out of the bulkhead we attached to the back of the cylinder heads. Are these one and the same or should we be looking elsewhere on the loom for the earth wires?
I have just spent a little time tinkering and the cold start injector is definitely firing as it should.
I swapped the harness from cylinder 4 and 6 and tried it on the cold start injector and it doesn't fire so we have progress!
Wedg1e you mention the importance of the earth, one of the initial problems was that the fuel pump and coil weren't earthed, we found one thick black wire and two thinner black and white wires that came out of the bulkhead we attached to the back of the cylinder heads. Are these one and the same or should we be looking elsewhere on the loom for the earth wires?
Benjamico said:
Firstly thank you one and all for your replies!
I have just spent a little time tinkering and the cold start injector is definitely firing as it should.
I swapped the harness from cylinder 4 and 6 and tried it on the cold start injector and it doesn't fire so we have progress!
Wedg1e you mention the importance of the earth, one of the initial problems was that the fuel pump and coil weren't earthed, we found one thick black wire and two thinner black and white wires that came out of the bulkhead we attached to the back of the cylinder heads. Are these one and the same or should we be looking elsewhere on the loom for the earth wires?
Does "black and white" wires mean wires that are both black and white? Or one black wire and one white wire? A black/white wire carries the signal from the ignition amp to the ECUI have just spent a little time tinkering and the cold start injector is definitely firing as it should.
I swapped the harness from cylinder 4 and 6 and tried it on the cold start injector and it doesn't fire so we have progress!
Wedg1e you mention the importance of the earth, one of the initial problems was that the fuel pump and coil weren't earthed, we found one thick black wire and two thinner black and white wires that came out of the bulkhead we attached to the back of the cylinder heads. Are these one and the same or should we be looking elsewhere on the loom for the earth wires?
I'll try and describe how I've wired it best I can...
The white wire wire with a black stripe is connected from the ignition amp to a connector on the loom just by the air flow meter and resistor pack.
The two wires I meant are black with a white stripe and come out through the bulkhead into the engine bay both go into a single crimped ring connector.
Hope that makes sense or have I shorted the signal?!!
The white wire wire with a black stripe is connected from the ignition amp to a connector on the loom just by the air flow meter and resistor pack.
The two wires I meant are black with a white stripe and come out through the bulkhead into the engine bay both go into a single crimped ring connector.
Hope that makes sense or have I shorted the signal?!!
One simple one to stop it running - if the wires onto the ignition amp are the wrong way around.
So no spray through the cold start injector when connected to the No4 plug - that is odd as all the firing clicks etc seemed to indicate all was good with the signals.
Hmmm... thinking cap back on.
So no spray through the cold start injector when connected to the No4 plug - that is odd as all the firing clicks etc seemed to indicate all was good with the signals.
Hmmm... thinking cap back on.
V8 Fettler said:
A black/white wire carries the signal from the ignition amp to the ECU
[Pedant head on] It's a White/Black for the ignition coil & ECU trigger - white wire with a thin black tracer. The earths are black with a thin white tracer. 
As an aside, the white of these wires can discolour with age and heat to appear pink/black!
Wedg1e said:
V8 Fettler said:
A black/white wire carries the signal from the ignition amp to the ECU
[Pedant head on] It's a White/Black for the ignition coil & ECU trigger - white wire with a thin black tracer. The earths are black with a thin white tracer. As an aside, the white of these wires can discolour with age and heat to appear pink/black!
I should have said: see wiring diagramI'm not an auto-electrician, to me a cable that is black and white is also white and black. Should really use the time honoured technique of tugging cables on cars that have a history, you never know who has been butchering.
I've never seen the white tracer on the black earths on my 350i, must be the decades of oil/dirt!
adam quantrill said:
From here I can see that the AFM air hose is not connected.
All together now... it won't run without it....
Perhaps some close-ups of the engine bay?
Sorry I should have been more specific, that is a picture of it before work began!All together now... it won't run without it....
Perhaps some close-ups of the engine bay?
Since that picture we have made some progress... Here are the highlights!
All coolant / air / fuel hoses have been connected / replaced.
Alternator / pulleys / starter motor / exhaust manifolds / engine mounts installed.
I will get some pics at the weekend and post them up for all to see
Benjamico said:
I swapped the harness from cylinder 4 and 6 and tried it on the cold start injector and it doesn't fire so we have progress!
adam quantrill said:
So no spray through the cold start injector when connected to the No4 plug - that is odd as all the firing clicks etc seemed to indicate all was good with the signals.
Hmmm... thinking cap back on.
The CSI runs on 12 volts and the injectors use approx 3 volts via the resistor pack. The CSI will not activate when connected to ane injector plug.Hmmm... thinking cap back on.
Thanks that explains it - I always assumed they were the same part but looks like not - I wonder why they didn't use the same part and put a resistor in series? It would have been more sensible...
So forget that test it's pointless. Looks like we are back to the blockage theory then....
So forget that test it's pointless. Looks like we are back to the blockage theory then....
Further progress has been made...
I'll start with the good news, we took the injectors out and they are also firing as they should.
We reset the timing and still nothing.
Next up we removed the rocker cover to double check we were on the right cycle... Then came the bad news, as we cranked the engine the rockers weren't rocking on three out of four cylinders!
Back to the drawing board!
I'll start with the good news, we took the injectors out and they are also firing as they should.
We reset the timing and still nothing.
Next up we removed the rocker cover to double check we were on the right cycle... Then came the bad news, as we cranked the engine the rockers weren't rocking on three out of four cylinders!
Back to the drawing board!
Benjamico said:
Further progress has been made...
I'll start with the good news, we took the injectors out and they are also firing as they should.
We reset the timing and still nothing.
Next up we removed the rocker cover to double check we were on the right cycle... Then came the bad news, as we cranked the engine the rockers weren't rocking on three out of four cylinders!
Back to the drawing board!
At first glance that would suggest the cam lobes are somewhat worn... but it might also appear that the lifters are completely empty of oil, although you'd still expect some movement as otherwise the valves would never open and the engine would never start...I'll start with the good news, we took the injectors out and they are also firing as they should.
We reset the timing and still nothing.
Next up we removed the rocker cover to double check we were on the right cycle... Then came the bad news, as we cranked the engine the rockers weren't rocking on three out of four cylinders!
Back to the drawing board!
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