In reply to a message from Frank Andersen sent Sat 31 May 2014:
I checked all voltages to all that apply… Checked
resistor pack slate/brown wires they both have battery
power. Opened flap on AFM fuel pump comes on stater ,
injector has pulse shorted fuel pump relay white/white and
green still won’t stay running
To clarify absolutely, Daniel;
- does the engine actually start initially, but won’t stay running?
- does the fuel pump run continuously with ign ‘on’; ie the fuel relay
shorted?
The injector test lamp, noid, should blink regularly while cranking - there
is no light with the engine stationary. You don’t state positively that you
were cranking while testing - it’s peculiar that the engine actually starts
when there is no actual injector action…
Another injector check is that you can hear the injectors clicking while
cranking…
You have done very thorough and comprehensive checks - showing no anomalies,
except; you must positively state if the noid, connected to an injector
connector, does or does not blink while cranking. Further voltage checks on
the connectors; with ign ‘on’, both wires on each injector connector should
show 12V…, please confirm…
Hypothetically, the engine may start on the fuel injected by the CSI, but it
is unusual. The CSI seems to work as it should, so you can forget that for
the time being…
There are five distinct different lines of enquiries, depending on symptoms;
The engine wont’ start - sparking should be checked first, no ignition, no
injection…
The engine starts, but dies slowly when key is released from ‘crank’ -
lack of sustained fuel supply,
The engine starts, but quits immediately the key is released from
‘crank’ - typical ign key fault
Immediate restart attempt gives same results - ditto…
Engine won’t restart - typical, it initially starts on the CSI, which is
inactive on immediate restart…
So…?
Overall injector operation; constantly powered from the resistor pack to one
wire on each injector, the sole function of the ECU is to ground the other
wire on each injector. This allows current to flow, opening the injector for
the programmed time. The ign amp makes/breaks coil current at the same time
gives signals to the ECU - which operates all injectors once every engine
revolution. Ie it fires the injectors on every third ignition pulse - and
the noid on a connector will blink each time the injector is grounded…
A specific test of the ign amp is to connect the noid between coil neg and
ground. It should be fully lit with ign ‘on’ and dim and flicker during
cranking/running. The coil neg (actually ign amp neg) black/white wire is
connected to the ECU via the injector resistor pack - and continuity of this
wire can be checked there (#1 on the ECU connector)
Point is that the flickering of the noid during cranking(!) is essential -
with no noid reaction the cause must be pursued to a solution. One point;
voltage checks should also be carried out with a test lamp - there may be
normal voltages, but there is insufficient current flow…
If the noid reaction is normal, and the engine dies slowly after starting -
one cannot exclude the possibility that there is a blockage of the fuel
lines. Fuel pressure tests is then essential…
But clarify engine behaviour…
Frank
xj6 85 Sov Europe (UK/NZ)
checked grounds on injector
harness and all plugs… Maybe it’s main relay checking
it out-----Original Message-----
From: sawyer10702
Sent: Monday, June 02, 2014 5:37 AM
To: xj@jag-lovers.org
Subject: Re: [xj] 1986 jaguar series 3 xj6 starts but wont stay running
===================================================
The archives and FAQ will answer many queries on the XJ series…
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fingers crossed–