Xantia 1.8 16v petrol - Bosch injection.
Starts fine every time if used every day. However, if left idle for a day or two, starts first time but then cuts-out just as engine reaches fast-idle speed. (after 3-5secs running with throttle untouched) Once this has happened, restarting is extremely difficult.
Found out it's a fuel-supply problem. No voltage measurable at the yellow lead on the fuel pump. -Which I assume is the positive, as always the manual is about as much use as...<fill blank>
Anyone know how the fuel-pump is fed with power? I think it might be via the separate relay in the ignition ECU box.
Edited by - IanR on 02 Jan 2003 12:52:22
Xantia cut-out after starting.
Moderator: RichardW
Definitely a case of fuel pump not running. Car has now decided to quit completely, so it's down to finding the cause.
Discovered that the fuel pump is controlled by one of two relays in a separate small box alongside the main Bosch ECU. Relay isn't being energised. Relay itself doesn't appear to be faulty, unfortunately.
Removed and checked the deceleration cut-off device, appears to be working fine as confirmed by ohm-meter.
-Any ideas what contols the relay? is the relay-coil fed from the injection ECU, or elsewhere? difficult to trace, as there are several identically-coloured leads, and the plug is moulded.
Any help (or anywhere I can get a decent circuit diagram) welcome.
It's a Bosch MP5.1.1 unit.
-One other point: does anyone know the logic of these things, does the fuel pump relay go in when the ignition is turned-on, or only when the engine starts to crank? (Just thinking if the latter, the problem might be to do with ignition sensors)
Edited by - IanR on 02 Jan 2003 16:56:43
Discovered that the fuel pump is controlled by one of two relays in a separate small box alongside the main Bosch ECU. Relay isn't being energised. Relay itself doesn't appear to be faulty, unfortunately.
Removed and checked the deceleration cut-off device, appears to be working fine as confirmed by ohm-meter.
-Any ideas what contols the relay? is the relay-coil fed from the injection ECU, or elsewhere? difficult to trace, as there are several identically-coloured leads, and the plug is moulded.
Any help (or anywhere I can get a decent circuit diagram) welcome.
It's a Bosch MP5.1.1 unit.
-One other point: does anyone know the logic of these things, does the fuel pump relay go in when the ignition is turned-on, or only when the engine starts to crank? (Just thinking if the latter, the problem might be to do with ignition sensors)
Edited by - IanR on 02 Jan 2003 16:56:43
HI.is the 'K' light come on when turning switch on ?if yes,ask someone to switch, try listen doble click. if you hear the ecu and the doble relay is ok,the problem is ignition or fuel delivery(pump).if you hear one click the problem is the doble relay or its conector or imobilizer coded or engine speed sensor located infront of g/b.
<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>
HI.is the 'K' light come on when turning switch on ?if yes,ask someone to switch, try listen doble click. if you hear the ecu and the doble relay is ok,the problem is ignition or fuel delivery(pump).if you hear one click the problem is the doble relay or its conector or imobilizer coded or engine speed sensor located infront of g/b.
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>
I've carefully removed the cover from the relay box. (Which is just lightly glued-on) One relay (Ignition I presume) activates when the keycode is entered, the other (which is definitely fuel pump) doesn't. The immobiliser gives a green light so I presume that's OK.
If you manually engage the pump relay you can hear fuel hissing through the injector-rail regulator, but it still won't fire. I suspect the injectors aren't operating either. Problem is obviously more fundamental than just the relay.
I was wondering an o/c flywheel sensor might be a possible cause, perhaps this is the next line of attack for tomorrow. Weather permitting!
BTW, to save me pulling it all to pieces, does anyone know what's in the box underneath the inlet manifold? Another mystery-box that doesn't even exist as far as Haynes is concerned!
I assume the main Bosch ECU cotrols ignition as well as injection? Or is this other under-manifold box involved?
HI.is the 'K' light come on when turning switch on ?if yes,ask someone to switch, try listen doble click. if you hear the ecu and the doble relay is ok,the problem is ignition or fuel delivery(pump).if you hear one click the problem is the doble relay or its conector or imobilizer coded or engine speed sensor located infront of g/b.
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>
I've carefully removed the cover from the relay box. (Which is just lightly glued-on) One relay (Ignition I presume) activates when the keycode is entered, the other (which is definitely fuel pump) doesn't. The immobiliser gives a green light so I presume that's OK.
If you manually engage the pump relay you can hear fuel hissing through the injector-rail regulator, but it still won't fire. I suspect the injectors aren't operating either. Problem is obviously more fundamental than just the relay.
I was wondering an o/c flywheel sensor might be a possible cause, perhaps this is the next line of attack for tomorrow. Weather permitting!
BTW, to save me pulling it all to pieces, does anyone know what's in the box underneath the inlet manifold? Another mystery-box that doesn't even exist as far as Haynes is concerned!
I assume the main Bosch ECU cotrols ignition as well as injection? Or is this other under-manifold box involved?