bi22le
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| posted on 25/10/14 at 11:55 AM |
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why would the leaky injectors prevent it from starting?
If the pressure is there and they are working under normal cranking conditions then I am not sure you are looking down the right alley.
I still think checking the injectors is a god shout. You have everything else but no bang.
When it does start does it run rough? Does is rev freely?
Now you have fuel in it you can actually start diagnosing again!!
We have all made that mistake. My mate unplugged a crank sensor without telling me and it took me days to find out why my completely faultless engine
has suddenly decided to stop firing.
I saw the funny side of it. . . . .just.
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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rodgling
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| posted on 25/10/14 at 04:47 PM |
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quote:
Originally posted by bi22le
why would the leaky injectors prevent it from starting?
If the pressure is there and they are working under normal cranking conditions then I am not sure you are looking down the right alley.
I still think checking the injectors is a god shout. You have everything else but no bang.
When it does start does it run rough? Does is rev freely?
Thanks for the tips. Some more testing today:
Pressure is dropping *fast* (about a second to go to zero pressure) as soon as the pumps stop (it should stay at > 4.5 bar for half an hour
according to BMW specs). This means that when starting, fuel pressure isn't where it should be which I think is what's stopping it from
starting. The sequence is, turn the key halfway, pumps prime for a few seconds then stop, turn the key all the way and start the car - but pressure is
already dropping by the time I begin starting the car and so it can't quite start.
I bought a couple of one-way valves to put in-line with the fuel pumps. On the first attempt these did the job and it started and ran fine. Then on
subsequent attempts it didn't.
Then took out the injectors and swapped for a set of spares - no improvement, so obviously not leaking fuel pressure via the injectors.
Finally discovered that 5 bar of pressure had turned my one-way valves into two-way valves... which would explain why it worked the first time but not
subsequently. Pretty sure this is where the problem lies now, so bought some higher-spec valves and will see if they fix it.
Meanwhile the injectors are out of the car so may as well get them cleaned and flow tested before putting them back. Confident everything will be fine
in time to do Bedford next Saturday...!
I reckon that is quite funny about the crank sensor? I can see that it wasn't at the time though... :-)
[Edited on 25/10/14 by rodgling]
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rodgling
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| posted on 28/10/14 at 10:46 PM |
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Bought some proper valves (Sytec one way fuel valves) which appear to hold fuel pressure at 4 bar when the pumps aren't running. Problem solved,
car starts first time, every time :-)
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bi22le
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| posted on 28/10/14 at 11:37 PM |
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The saying I use in triumphant times like this is:
Get the f♡ck in there sun shine!!!
Normally quite loudly.
Ahem. . Well done sunny, enjoy Bedford.
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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rodgling
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| posted on 1/11/14 at 11:56 PM |
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Yeah there was a bit of swearing throughout the process :-)
Bedford was good, fuel valves did their job nicely and the sun stayed out - great day until I lost brakes (pads got too thin so started overheating
too easily) and throttle (cable snapped)! Easy fixes though, and still a fun day.
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coyoteboy
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| posted on 2/11/14 at 10:45 AM |
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If you're struggling with a sticking injector and blowing fuel through the area will /stink/ of fuel and your sump may well have a higher level
now. Even a slight misfire from my running engine coats the garage door in fuel and stinks for days.
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