Fueling too rich, 2.5 Pi

Message

KieranEbbett2500 · Sun Dec 25, 2016 11:13 am

Hi all.

I've got a 1974 2.5 pi running a late green top MU. According to the previous owner it was rebuilt, the butterflys were calibrated and the rest was checked and was said to be ok. But the car in my opinion ran rich. I can confirm the MU had been off as it was spotless...

I am nearly finished rebuilding the engine( loads of new parts too many to list) and in the process removed a lot of carbon, more so than I expected. So I was really wondering what I can do short of sending the MU to the UK (I'm in new Zealand) and having it sorted. Apart from a higher fuel consumption than I would expect and slightly rich behaviour it ran extremely well and had a reasonable amount of poke.

Any help is appreciated

#2 Post by **Alan Chatterton** » Sun Dec 25, 2016 9:13 pm

With all PI systems, it relies on vacuum to give accurate fueling.
Before you start with the MU, everything else must be perfect.
Ignition system, timing and valve clearances all need to be spot on.
Have you checked the vacuum via a gauge to find what hg reading you have?

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KieranEbbett2500 · #3 Post by **KieranEbbett2500** » Mon Dec 26, 2016 6:11 am

Hi Alan

Well no I haven't. The engine isn't currently in the car so I can't check anything but I'll be striving to make sure everything is perfect. I don't have a vacuum gauge.

KieranEbbett2500 · #4 Post by **KieranEbbett2500** » Mon Dec 26, 2016 6:16 am

However what I checked of that (ignition timing, point gap and the rocker clearance was all as per the book.

#5 Post by **Alan Chatterton** » Mon Dec 26, 2016 8:31 am

Ok. Let us know when the engine is back in and running and we can guide you through some checks and tests. It's not that difficult and there are adjustments you can make to get it running correctly. Hopefully the MU won't need replacing.

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KieranEbbett2500 · Mon Dec 26, 2016 11:12 am

Hi Alan.

Thanks for that. The engine is now reassembled and hopefully it'll be back in the car in the next few days.

According to the previous owner it was overhauled and set up on a test right by someone who was familiar with the Lucas injection system so I'm hoping it's not too serious.

tony · #7 Post by **tony** » Mon Dec 26, 2016 9:02 pm

I'm fairly sure there's someone in Auckland who can set up the units. Name escapes me at the moment though.
Tony.

KieranEbbett2500 · Tue Dec 27, 2016 10:37 am

Hi.

Metering unit leaking fuel from tell tale hole upon running pump... bugger

#9 Post by **Alan Chatterton** » Tue Dec 27, 2016 10:41 am

That would suggest the seals need some work at the very least..................

KieranEbbett2500 · Tue Dec 27, 2016 9:07 pm

Yep. Mustn't have liked sitting in the boot for three weeks too much. Must it be sent away now?

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