Fueling too rich, 2.5 Pi

[KieranEbbett2500]

Right. I changed the two seals in the pedestal and reassembled it back on the car and it started. And runs but I'm still not happy with how it's running fueling wise. Still seems far too rich. What can I do about it

[Alan Chatterton]

Remove the black plastic rectangle from the front. 4 screws.
Inside you will see the datum track and rollers.
Measure gap between roller and track with engine off, should be 2 thou.
Next remove the top of the metering unit. 4 screws.
Remove springs and replace the top. This will allow you to lift the cam up to measure the top clearance between the rollers. This should be 56 thou. I'll bet this one is too wide.
Adjustment is by the full load screw and locknut under the MU. Adjust to 56 thou.



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[KieranEbbett2500]

Thanks Alan.

I will look at that tomorrow, other than that and an electrical issue with the overdrive it turned out quite well

[wwt338j]

One thing you might try before altering the settings inside the metering unit is to alter the phasing of the metering unit in relation to TDS on no 1 piston. I drive a TR6 which was running v rich (CO around 6% at idle, plugs sooty black). The phasing of the metering unit was initially spot on as per the workshop manual. Whilst messing around with the distributor fitting an pertronix ignitor I inadvertently changed the phasing of the metering unit. I didn't realise at the time but the effect has been to reduce the CO to around 2% and the plugs look actually a bit lean now.
I'd read that phasing of the metering unit wasn't very important and recently in the TR register forum there was a post which mentioned that altering the phasing affected emissions. Not sure why this should be the case but it will be less expensive than recalibrating your metering unit.
David

[KieranEbbett2500]

Me and a friend attempted to check those the best we could and it doesn't really seem to have helped.

It runs on 6 but it sort of feels like the choke is out until above 2000 or so rpm where it gets better but it still sounds too rich. It just sounds very cammed at idle and up to 2000 + rpm. What can I do? I don't have access to vacuum gauge.

Is there anyone in NZ I can get recalibrated properly by? The seals are all new now so it would be nice if it could just be adjusted properly

[Alec]

Hello Kieran,

go back to square one first, and double check all the engine settings. If you have a compression gauge or can borrow one, ensure the compressions are good and even for all six cylinders. Set the ignition timing by road testing rather than using the book figure. (Advance the timing until it pinks then retard just a shade so it doesn't). Ensure the distributor mechanical advance is free and lubricated and the vacuum advance works (if it has one).
Two other things with the injection, pull the injectors one by one with the engine running and check for a good spray cone and no dribbling and that the air cleaner is clean.

Alec

[KieranEbbett2500]

I've tried a few things but it all still points to fueling issue. Should it use more fuel than a carbed 2.5?

Is there anywhere in NZ that specialises in Pi gear? Surely the Tr guys are looked after.

Any help is appreciated

[tony]

Keiran,
Where about's are you? I seem to remember that P.I.'s are thirstier than carbed models. Used to be Collett and Fleming in New Lynn but don't know if they still exist.
Tony.

[KieranEbbett2500]

Hi.

I'm in Dannevirke which is near Palmerston north.
It uses a noticeable amount more than my other one

[johnnydog]

Should it use more fuel than a carbed 2.5?

A correctly set up PI should return a better mpg figure than a carb'd 2500.
It will also out-perform a carb'd 2500!
However, when a PI is running well, you tend to use its performance more (well I have always done when my PI's have been on the road!) which obviously doesn't help the consumption!