Why won't my Rangy pick up ?

I'm desperate for some help....I own a 1991 3.9 SE Vogue (pretty but
juicy !) I've had it for a fair while, but recently it's been not
starting, needless to say, plugs, distributor cap & roter arm were
replaced. Turns out the distributor itself was broken ! So new one of
those on and now it starts and idles OK. When you put the engine under
load though, it doesn't like it. It sounds like it's missfiring and
goes all lumpy. The timing has slipped twice...and been put right..but
it's still not picking up. Any one got any ideas ? Not being that
technical minded, I took it to my local garage, and they said the ECU
may be on the way out. What's that then ?
Ta for all/any help.

<[email protected]> wrote in message
news:[email protected]...
> I'm desperate for some help....I own a 1991 3.9 SE Vogue (pretty but
> juicy !) I've had it for a fair while, but recently it's been not
> starting, needless to say, plugs, distributor cap & roter arm were
> replaced. Turns out the distributor itself was broken ! So new one of
> those on and now it starts and idles OK. When you put the engine under
> load though, it doesn't like it. It sounds like it's missfiring and
> goes all lumpy. The timing has slipped twice...and been put right..but
> it's still not picking up. Any one got any ideas ? Not being that
> technical minded, I took it to my local garage, and they said the ECU
> may be on the way out. What's that then ?
> Ta for all/any help.

Sounds like the timing is out, again. Now, if the dizzy body is clamped
tight and the timing moves, it has to be due to mechanical wear
unfortunately.
I've only ever seen it the once, but if the timing chain is so badly
stretched that it jumps a tooth, that will knock out both the camshaft and
dizzy timing, making it run like an absolute pig, if at all.
Garages blame ecu's (the fuel injection system's "brain") when they can't
understand what is wrong, they blame the controlling item rather than
isolate the cause. In your case, the ecu has NO control over the ignition or
distributor timing on a 1991 3.9, it merely takes an input from the ignition
coil so that it (the ecu) knows what speed the engine is running at, so as
to work out the correct ammount of fuel to inject.
I'd suggest they start by rechecking the ignition timing, thyen check for
excessive slack in the timing chain by turning the engine clockwise by hand
ensuring that the dizzy is turning with it, then backwards, noting how far
it turns before the slack is taken up and the dizzy turns backwards with it.
Any more than 5 degrees free movement at the crank and there is serious
internal wear.
BTW, it's always a good idea when posting on this NG with a problem to tell
us where you are.... you never know what help may then be offered?
Good luck.
Badger.

Badger wrote:

> BTW, it's always a good idea when posting on this NG with a problem to tell
> us where you are.... you never know what help may then be offered?
> Good luck.
> Badger.

At a wild guess from the antipodes I'd say Brentford, Middlesex.



--
EMB

Oops...Thanks..A close guess...Middlesex yes, Brentford...no !
Shepperton is where I am, the car is in a garage in Byfleet, Surrey.
(only 6 miles away)
And thanks for all the help so far. )
EMB wrote:
> Badger wrote:
>
> > BTW, it's always a good idea when posting on this NG with a problem to tell
> > us where you are.... you never know what help may then be offered?
> > Good luck.
> > Badger.
>
> At a wild guess from the antipodes I'd say Brentford, Middlesex.
>
>
>
> --
> EMB

<[email protected]> wrote in message
news:[email protected]...
> I'm desperate for some help....I own a 1991 3.9 SE Vogue (pretty but
> juicy !) I've had it for a fair while, but recently it's been not
> starting, needless to say, plugs, distributor cap & roter arm were
> replaced. Turns out the distributor itself was broken ! So new one of
> those on and now it starts and idles OK. When you put the engine under
> load though, it doesn't like it. It sounds like it's missfiring and
> goes all lumpy. The timing has slipped twice...and been put right..but
> it's still not picking up. Any one got any ideas ? Not being that
> technical minded, I took it to my local garage, and they said the ECU
> may be on the way out. What's that then ?
> Ta for all/any help.
>
Does it always misfire underload?
Mine intermittantly misfired under load, mainly on initial pull away.
Changed the usual leads, plug, coil, even the airflow meter from a friendly
donor Range Rover.
The actual culprit turned out to be the fuel pressure regulator located at
the back of the engine behind the EFI chamber. It is a 15 mins job to swap
if you have friendly Range Rover owner who is willing to lend it for
testing. Otherwise i think they are £40-50 new.

Just my experience.

Martin

Thanks for all the info you gave me, needless to say, the garage now
thinks the cam is buggered ! They are having to retard and increase the
timing by up to 40 (yes fourty) degrees to get the damn thing
running...which it does, but now really quickly !
I got the car back (unfixed) yesterday, so me & the other half are
going to reset the whole thing get it to TDC then work on the basis
that the timing chain is worn. Is there anything else I should be
looking for ?

<[email protected]> wrote in message
news:[email protected]...
> Thanks for all the info you gave me, needless to say, the garage now
> thinks the cam is buggered ! They are having to retard and increase the
> timing by up to 40 (yes fourty) degrees to get the damn thing
> running...which it does, but now really quickly !
> I got the car back (unfixed) yesterday, so me & the other half are
> going to reset the whole thing get it to TDC then work on the basis
> that the timing chain is worn. Is there anything else I should be
> looking for ?
>

It's worth taking no. 1 spark plug out and using a small screwdriver or
piece of stiff wire, find the true TDC position, I had a 3.9 in the workshop
back in the summer that had running issues, apparently needing about 30
degrees static advance on the ignition just to run without backfirng, the
std timing marks can be a considerable ammount out, but that was the
excepttion rather than the rule. Might be worth checking though....
Badger.