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3.9 V8 Cold Starting Problems

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Budgie:
Hi All,

I need a little assistance to locate a problem on my 1995 3.9 V8.
I had the fuel pump go a couple of weeks ago, just stopped and never went again. That's been replaced and the motor runs but when you start it from cold you need to give is some thottle when it initially fires otherwise it won't keep going, like there's no choke. Now I know the 3.5 had a cold start injector in the plenum chamber but what does the 3.9 have?
Any other ideas what could be causing this?

Another wee problem is the fuel gauge. A couple of days before the pump gave up the fuel gauge started doing all sorts of things. One minute it was reading full to the brim and then it fall to below the red and the warning light would come on. I thought this was part of the pump problem but it still does it with the new pump fitted. Has the gauge gone south or is there something else I could look at?

Cheer for any input. ;)

mentalmoshio sophs V8i:
mite be a poor connection around the fuel tank where the pumps is mines not the best ive ever seen, or a bad earth wire along one of the senders

Range Rover Blues:
The 3.9 uses multiple fuel maps depending on temperature, it's not just hot or cold.  Ity also uses an idle stepper motor on the rear of the plenum to control idle speed, the throttle plate almost suts completely and without the steeper the "base idle" spped is less than 500RPM.

Budgie:
Thanks for that, I've got a spare stepper motor so I'll swap that over and see if it make any difference.
I don't think it's a bad earth as I would have expected it to show the right fuel leave at some point, which it hasn't. Worth checking anyway.  ;)

Budgie:
Well the cold start problem was the stepper motor.
I took it out today, reconnected the wires and turned the ignition on & off once to reset the stepper motor, the plunger should withdraw fully but this one juddered a couple of times and didn't move, remaining about half way out.

So I replaced it with the spare I have and the engine fired first time, as normal. The tickover is very high now but I think that's cos I sealed the plenum chamber properly before swapping the stepper motor and I put new exhaust manifold gasket in as a couple were leaking, so I'll have sort that out.
But before I can do that I have a wee wiring fault to sort out as when I started the motor for the second time it only ran for about 30 seconds, then the fuel pump fuse blew.
I replaced the fuse and as soon as I turn the ignition on the fuse blows again so there's something not right in there.  :roll:

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