sprouts-car
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| posted on 7/5/15 at 07:07 AM |
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Engine starts but won't run. Help!
Morning all,
Firstly let me give you the background. I was driving the 7 about 20miles to move it to its new garage. This involved a few miles at motor way speeds
on the A303. (All good so far). When I exited the A road and was going down the slip road the engine cutout. Not noise, messy or fuss, just dead.
I stopped and took the bonnet off and found the water level was low, the engine was hot and the radiator wasn't. (Oh crap)
When I tried to start it again, it would start fine and cutout 1sec later. So we towed it the rest of the way and tucked it up for the day.
Last night I went to try and start it again (now that its cooled down). But exactly the same thing happens, starts fine and cuts out after a
second.
I removed a plug to watch the spark. It sparks strongly until 1sec then the spark stops and the engine therefore stops too ( but it does seem that way
round).
So I'm not sure what the problem is?
If I'd badly overheated it then either it wouldn't turn over or wouldn't start at all. So I'm hoping I haven't done
that.
All I can think is that the ecu isn't happy with what the sensors are saying and shutting the engine down? But I'm not aware that
that's even a thing this ecu does.
Any ideas? Suggestions? Magical fixes?
Chris
Spec:
1.8 ford cvh engine using all the original wiring sensors ecu ect.
[Edited on 7/5/15 by sprouts-car]
Build blog
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ianm67
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| posted on 7/5/15 at 07:23 AM |
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Dead coil pack perhaps? Have you checked for spark on all 4 leads?
Always biting off more than I can chew.....
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r1_pete
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| posted on 7/5/15 at 07:33 AM |
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Agree I'd look to the coil 1st, the ECU may imitate the old ballast resistor setup, whereby a lower voltage coil is used and at startup the full
battery voltage is applied to the coil but when running it drops to the coil's design voltage, this was done to overcome lack of current at the
coil during cranking.
It may be your coil still works with the high voltage whilst cranking / initial startup, but, will not run at the operating voltage.
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cliftyhanger
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| posted on 7/5/15 at 07:37 AM |
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After my car breaking down last night  but an excellent AA man arriving and helping me fault-find and fix, I would urge you to check power supplies
to the ecu etc etc. Mine was a wire just pulled off the inertia cutout, and that meant the problem started as engine dying then restarting instantly
at 70mph, getting worse very fast and I just managed to get to a lay-by. However, my thougts are the starter may be giving power to the ECU when
starting, but then the ignition circuit not giving power. Just a thought. Or maybe does the ecu override stuff during starting??
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sprouts-car
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| posted on 7/5/15 at 07:39 AM |
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quote:
Originally posted by r1_pete
Agree I'd look to the coil 1st, the ECU may imitate the old ballast resistor setup, whereby a lower voltage coil is used and at startup the full
battery voltage is applied to the coil but when running it drops to the coil's design voltage, this was done to overcome lack of current at the
coil during cranking.
It may be your coil still works with the high voltage whilst cranking / initial startup, but, will not run at the operating voltage.
Interesting! I assume that getting too hot could cause this?
Is there a way to test that theory? By supplying 12v direct to the coil maybe?
[Edited on 7/5/15 by sprouts-car]
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mark chandler
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| posted on 7/5/15 at 10:57 AM |
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Check the fuel filters, new tank a bit of debris blocking the inlet, worse when low on fuel
Start car, it draws enough fuel for it to cough into life then dies quickly as the debris blocks the pipes, turn off and the debris now has nothing to
hold it in place so falls away from the inlet allowing it to draw enough fuel to start again.
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r1_pete
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| posted on 7/5/15 at 11:49 AM |
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quote:
Originally posted by sprouts-car
quote:
Originally posted by r1_pete
Agree I'd look to the coil 1st, the ECU may imitate the old ballast resistor setup, whereby a lower voltage coil is used and at startup the full
battery voltage is applied to the coil but when running it drops to the coil's design voltage, this was done to overcome lack of current at the
coil during cranking.
It may be your coil still works with the high voltage whilst cranking / initial startup, but, will not run at the operating voltage.
Interesting! I assume that getting too hot could cause this?
Is there a way to test that theory? By supplying 12v direct to the coil maybe?
[Edited on 7/5/15 by sprouts-car]
I wouldn't like to say, not knowing the inner workings of the electronic units.
There is a coil on ebay at the moment for £15 inc post, which is probably little more than what Royal Mail would charge to deliver it, might be worth
a punt??
LINK
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britishtrident
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| posted on 7/5/15 at 12:15 PM |
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What engine and ignition system and what fuel system?
On cars with a ballast resistor in the ignition circuit if the ballast is blown or disconnected the engine will only run with the ignition in the
start position.
On a lot of systems the ignition and injection is supplied when the starter is initially activated but is cut off for safety and or security reasons
unless the electronics see that the engine is running normally.
For example on old Rovers and some Land-Rovers the oil pressure switch had to get a few psi oil pressure or the ignition and fuel pump supply would
be cut off.
The other thing that will do this is a security or immobiliser problem.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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big_wasa
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| posted on 7/5/15 at 04:36 PM |
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There is no safety thermal cut with a ford ecu that I've found. My dad (86) had the rad hose burst on the mondeo. When it started to nip up he
dropped it a cog and gave it a boot full. He did this in all five gears until it stopped. It got so hot the valve seats fell out wedging the valves
open and the engine with no compression, but still it never seized.
So it's a cvh but what fuel and spark set up ?
I am sure the 1.8 had front mounted trigger wheel with a single coil and distributer and a carb. I am sure only the 1.6 got the cfi single point
injection.
So if it's not fuel related.......
My money is on the dodgy rotor arms, most have one clip missing, the dizzy cap, the coil, crank sensor.
I converted mine to run full Dis with a coil pack and the ecu from a fiesta.
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scott h
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| posted on 7/5/15 at 10:23 PM |
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I have a diesel Mondeo that just stopped one day. It would start fine but run for 3 seconds then stop. It made no difference if I let it idle or rev
it, always 3 seconds then stop. It turned out to be a duff diode located in the fuse box. I know it's diesel and your car is petrol but the
symptoms sound the same.
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rusty nuts
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| posted on 8/5/15 at 06:04 PM |
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The old 1 .8 CVH engines suffered from the fuel pump push rod wearing causing the fuel pump to not work as it should. Once had a Sierra that suffered
very similar symptoms
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sprouts-car
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| posted on 11/5/15 at 05:25 PM |
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quote:
Originally posted by rusty nuts
The old 1 .8 CVH engines suffered from the fuel pump push rod wearing causing the fuel pump to not work as it should. Once had a Sierra that suffered
very similar symptoms
That could be interesting!
I'm currently going down the "try different electrics" route. But would be quite easy to test that idea.
Thanks
Build blog
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adithorp
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| posted on 11/5/15 at 05:53 PM |
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quote:
Originally posted by sprouts-car
quote:
Originally posted by rusty nuts
The old 1 .8 CVH engines suffered from the fuel pump push rod wearing causing the fuel pump to not work as it should. Once had a Sierra that suffered
very similar symptoms
That could be interesting!
I'm currently going down the "try different electrics" route. But would be quite easy to test that idea.
Thanks
If you remove the pump and pull the push rod, if it is worn you can usually see rings (like tree rings) on the worn end.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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