Triumph 2.5 PI troubles
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anything a try. I've got a 1970 Mk2 Triumph 2.5PI that's misbehaving with
only 15mpg and less than crisp power delivery, black plugs blah blah...
For the history of this subject read the earlier thread on Triumph Acclaims,
drill right down to current date.
I understand the system very well now, after checking most of it, and
reading all the things available on the net.
Check PRV pressure - reset to 106psi from 120psi.
Fuel pump is okay, no hot weather woes, cooling coil fitted.
Fuel filter okay, no crud in any of the bits I've had apart.
Breathers and return pipes are clear.
Engine vacuum is 15Hg at 850rpm, no determinable vacuum leaks.
Throttle spindle bushes replaced, butterflies synchronised as near as
dammit - small variance in one twinned-pair, one flap opening slightly ahead
of other.
All excessive mechanical lost motion removed from throttle assembly - idling
stable at 850rpm.
Recent KMI injectors fitted, two returned as dribbling too much, -
replacements have less than conical spray but query how much of a problem
this is.
Metering unit was recon in 1988, but car has only done a few hundred miles
since this.
Metering unit springs changed back to standard blue 132bhp saloon, from TR6.
Metering unit adjusted to smoothest fastest idle, and all points around this
(trying everything).
Engine compression excellent with 170psi per cylinder, valve clearances on
the button.
At this point, I'll take any comments on board, on the basis that if I
haven't already tried something I'll give *anything* a whirl.
I'd like to keep it as a PI, but a necessary fallback will be to fit 2500s
manifold and HS6 carbs - the 2500s had a lower compression and 106bhp, would
I be reasonable in assuming more bhp than this with the PI engine and these
carbs - maybe just a tad more?
Over to you chaps and chapettes,
Ta, Ken.
--
Ken Davidson
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J
--
J
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"DocDelete" <docd...@removehotmail.com> wrote in message
news:z0K_a.3419$z7.5...@wards.force9.net...
Jim Warren
<snip to here>
> Recent KMI injectors fitted, two returned as dribbling too much, -
> replacements have less than conical spray but query how much of a problem
> this is.
This could be a problem. My PI has 5 injectors with a conical spray, and
one with what is best described as a bow tie pattern. There is a slight
misfire under load a low revs (no sign above 1500) and one plug looks
slightly different to the rest. The plug that looks different moves when I
move the odd injector.
> Metering unit was recon in 1988, but car has only done a few hundred miles
> since this.
They wear out quickly if you over rev them. Have you been kind to this
unit?
> Metering unit springs changed back to standard blue 132bhp saloon, from
TR6.
> Metering unit adjusted to smoothest fastest idle, and all points around
this
Get everything really warmed up (drive at least 10 miles) and *then* check
your adjustments. Mine runs best when it needs just a touch of choke to pick
up from idle (500rpm) without hesitation until the temperature gauge is
almost up to normal running temperature.
> (trying everything).
Have you checked that the pipes from metering unit to injector are not
getting soft? The pulse of fuel needs to get straight to the injector and
not be damped by elasticity in the pipe wall.
Jim
DocDelete
news:a7a59a1e936a0239...@news.teranews.com...
> Ken - where in the world are you and what's your budget for fixing this?
I'm in Solihull, budget? Christ knows - given that I'm holding off from
installing 2500s carbs that I've already got then the budget has got to be
controlled. Under £150? Also because I've already spent in the region of
£250 on the fuel system.
Canley Classics? I'm certainly aware - and have visited - tried to get some
bodywork done with no luck.
What's your suggestion? ;-)
DocDelete
news:v20%a.4548$yK4...@news-binary.blueyonder.co.uk...
> > Recent KMI injectors fitted, two returned as dribbling too much, -
> > replacements have less than conical spray but query how much of a
problem
> > this is.
> This could be a problem. My PI has 5 injectors with a conical spray, and
> one with what is best described as a bow tie pattern. There is a slight
> misfire under load a low revs (no sign above 1500) and one plug looks
> slightly different to the rest. The plug that looks different moves when
I
> move the odd injector.
I'm strongly believing this now - which leaves me with the prospect of a
nice conversation with that nice Mr Witor. Hope he agrees. Twice in the last
fortnight the car has literally surprised by running well - sh*t off a
shovel. On both occasions I beleive some "blockage" was momentarily blasted
away. The injectors are coming out on Sunday for a peak.
> > Metering unit was recon in 1988, but car has only done a few hundred
miles
> > since this.
> They wear out quickly if you over rev them. Have you been kind to this
> unit?
Yes, but please define "over-rev" - I never blip the throttle (certainly
from cold) like many less-mechanically-sensitive Sunday morning mechanics -
and the car rarely gets over 4500 rpm or needs to. The car was idle for ten
years - only started periodically by the previous owner. To his credit
though, he kept up with sensible servicing and warming up.
> Get everything really warmed up (drive at least 10 miles) and *then* check
> your adjustments. Mine runs best when it needs just a touch of choke to
pick
> up from idle (500rpm) without hesitation until the temperature gauge is
> almost up to normal running temperature.
I can echo this, and yes I did my adjustments when warmed up.
> Have you checked that the pipes from metering unit to injector are not
> getting soft?
They're hunky dory - good strong pulses in all - at least when I check, I
get the distinct impression that the act of getting back in the car causes
one or more injectors to go back to sleep :-(
Thanks Jim - any more comments anyone? I'll report the injector situation
next week...
J
> "J" <I...@it.again> wrote in message
> news:a7a59a1e936a0239...@news.teranews.com...
> > Ken - where in the world are you and what's your budget for fixing this?
>
> I'm in Solihull, budget? Christ knows - given that I'm holding off from
> installing 2500s carbs that I've already got then the budget has got to be
> controlled. Under £150? Also because I've already spent in the region of
> £250 on the fuel system.
>
> Canley Classics? I'm certainly aware - and have visited - tried to get
some
> bodywork done with no luck.
>
> What's your suggestion? ;-)
>
> --
Well there seems to be only two places that get a good press - Canley
Classics and Prestige Developments, get your cheque book out for Prestige
though! Canley's aren't a body shop although they will do that sort of work.
Why not try an email to Canley's - mark it FAO Dave and see what you get.
From the little I know of errant PI systems a lot of problems seem to trace
down to crappy fuel supply - O rings in metering units can disintegrate and
block injectors, filters can fail and the all important fuel pressure can be
tricky. Injector spray patterns are critical and often temperamental.
DocDelete
> From the little I know of errant PI systems a lot of problems seem to
trace
> down to crappy fuel supply - O rings in metering units can disintegrate
and
> block injectors, filters can fail and the all important fuel pressure can
be
> tricky. Injector spray patterns are critical and often temperamental.
FYI I pulled the injectors and gave 'em another blast through. The patterns
aren't that neat with most exhibiting a bias or "lean" to the conical spray.
Bit the bullet and pulled the (recent) fuel filter in the boot. Evidence of
some crud but on the tank side of the filter. Still, bunged in a new one -
and Weheeeeeyy! If I were to guess I've gone from around 75 horses to 125!
Still not 132 but better. Just shows you - don't necessarily trust a £3
paper filter.
It's been okay for three days now, even managed to lean the mixture off a
bit and dial in some more advance on the dizzy. Time will tell, but fuel
consumption is still an issue - I might have improved it to 16mpg.
There's still less-than-crisp power delivery low down, and the engine runs
out of puff (like hitting a rev limiter or bouncing valves) at around
4000rpm. I think I'll have to adjust the maximum fuel adjustment on the
metering unit out a bit. Anyone got any opinions on this last bit?
Thanks all, Ken.
--
Ken Davidson
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Andy Luckman
<URL:mailto:docd...@removehotmail.com> wrote:
> Bit the bullet and pulled the (recent) fuel filter in the boot. Evidence of
> some crud but on the tank side of the filter. Still, bunged in a new one -
> and Weheeeeeyy! If I were to guess I've gone from around 75 horses to 125!
> Still not 132 but better. Just shows you - don't necessarily trust a £3
> paper filter.
I wonder if you have a blocked breather to the fuel tank? That could give
rise to the symptoms you mention. Changing the fuel filter would have
equalised the pressure for a while, until the pump creates enough of a
vacumm again.
--
AJL Electronics (G6FGO) : Satellite and TV aerial systems
http://www.classicmicrocars.co.uk : http://www.ajlelectronics.co.uk
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> I wonder if you have a blocked breather to the fuel tank? That could give
> rise to the symptoms you mention. Changing the fuel filter would have
> equalised the pressure for a while, until the pump creates enough of a
> vacumm again.
That's a damn fine idea - I'm going out to look now. Would this also cause
fuel back pressure at the forecourt?
Wonder how long the vacuum would take to build back up again, I've stuck 40
miles on it since it was "cured".
J
terrible trouble after putting a new cap on a mini, being a lazy chap I left
the price sticker on it, that covered the little vent hole and the car ran
like a dog on the motorway but was fine around town!
--
J
10 countries in a 22 foot long stretched Triumph Herald?
Believe - http://www.canleyclassics.com/10cr
OR how about Plymouth to Dakar in two Triumph Heralds, yes really!
Visit http://www.team-michelotti.org and see how you can help.
"DocDelete" <docd...@removehotmail.com> wrote in message
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Mike K Smith
>
> That's a good idea, is your fuel cap vented? Should it be? I once had
> terrible trouble after putting a new cap on a mini, being a lazy chap I left
> the price sticker on it, that covered the little vent hole and the car ran
> like a dog on the motorway but was fine around town!
occasionally when I open the filler cap to refuel I can hear an inrush of
air. I don't seem to have any performance problems with the car, and it
doesn't happen every time.
Should I be worried?
Mike
DocDelete
"Mike K Smith" <Mike.K...@sun.com> wrote in message
news:3F44CFFA...@sun.com...
> While we are talking about venting fuel tanks, I have a Porsche 924S and
> occasionally when I open the filler cap to refuel I can hear an inrush of
> air. I don't seem to have any performance problems with the car, and it
> doesn't happen every time.
>
> Should I be worried?
My TR7 V8 used to do that all the time, especially after a long drive on a
hot day. I never worried, but then again it was a carb system. Fuel circuit
breathing can present problems to injected systems - is the 924s Bosch K(E)
Jetronic?
I don't think it matters though, as you say there are no performance issues.
Or are there any nasty fuel vapour smells whilst driving?
DocDelete
vapour (distorts the view through air, and stinks) drop out...
Mike K Smith
>
> "Mike K Smith" <Mike.K...@sun.com> wrote in message
> news:3F44CFFA...@sun.com...
>
> > While we are talking about venting fuel tanks, I have a Porsche 924S and
> > occasionally when I open the filler cap to refuel I can hear an inrush of
> > air. I don't seem to have any performance problems with the car, and it
> > doesn't happen every time.
> >
> > Should I be worried?
>
> My TR7 V8 used to do that all the time, especially after a long drive on a
> hot day. I never worried, but then again it was a carb system. Fuel circuit
> breathing can present problems to injected systems - is the 924s Bosch K(E)
> Jetronic?
(Motronic ML3.1?)
> I don't think it matters though, as you say there are no performance issues.
> Or are there any nasty fuel vapour smells whilst driving?
No nasty smells and no performance problems. Just a sharp intake of air
every time I fill the tank. :)
Mike
Jacques Hankin
Check Air fuel mixture to 4000rpm (colourtune or CO meter)
If this is OK, your distributor might be ropey (shaft profile? bearing
wear? not enough advance at higher revs have you looked at the
advance/rev change?)
Or
You might have a duff plug which gives up at high revs.
J.
Jim Warren
Jacques Hankin <jac...@nospam.demon.co.uk> wrote in message
news:ke5akv42kvlttofmj...@4ax.com...
>
> You might have a duff plug which gives up at high revs.
>
One or more plug leads starting to fail. And if you use the wrong length of
lead from coil to dizzy or from dizzy to one of the middle plugs, they rub
on the inside of the bonnet when it is shut (BTDT).
Jim
Robert Pearce
<docd...@removehotmail.com> writes
>Recent KMI injectors fitted, two returned as dribbling too much, -
>replacements have less than conical spray but query how much of a problem
>this is.
In my line of work[1] this would be considered a significant problem,
but that may be more from the emissions point of view than anything
you're worried about. Still, despite the cost, they may be a suspect.
[1] Fuel injection, modern style
--
Rob Pearce
Club Triumph Spitfire and GT6 consultant
The above views and opinions are mine, and do not necessarily reflect Club
Triumph policy.