Engine chugs when power is taken off

Talk about the E-Type Series 1

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Denycegeoff
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Australia

#1 Engine chugs when power is taken off

Post by Denycegeoff » Sun Jan 13, 2019 8:17 am

Engine runs fine with power on, pulls hard plenty of torque delightful to drive under power. However when foot is off the accelerator and car is still in gear engine chugs and car lurges particularly at low revs. Timing is 9 deg advanced and other than this the car runs fine. Any thoughts appreciated.🤨

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Tom W
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#2 Re: Engine chugs when power is taken off

Post by Tom W » Sun Jan 13, 2019 8:38 am

It’s difficult to diagnose without more info. How low revs are you talking? What speed are you going? Does it do it in all gears? What condition is your car in? Has it always done this, or is this a new thing?
Tom
1970 S2 FHC

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Denycegeoff
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#3 Re: Engine chugs when power is taken off

Post by Denycegeoff » Mon Jan 14, 2019 2:35 am

When slowing down using the gears. For example when coming to an intersection using gears to slow the car. The vehicle condition is in excellent condition ( concours winner in 2011). It has always been a bit jerky at low revs after a ground up reso in 2007

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Simonpfhc
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#4 Re: Engine chugs when power is taken off

Post by Simonpfhc » Mon Jan 14, 2019 6:22 am

Could be many things, but I’ve seen this happen when the mixture is wrong. Could be running too lean.
Simon
62 3.8 FHC
91 Porsche 928GT
Find me on Instagram and Facebook @oldcarfixer

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cactusman
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#5 Re: Engine chugs when power is taken off

Post by cactusman » Mon Jan 14, 2019 7:51 am

I'd agree with Simon......something amiss with the carbs set up.
Julian the E-type man
1962 FHC
1966 MGB....fab little car too

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Series1 Stu
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#6 Re: Engine chugs when power is taken off

Post by Series1 Stu » Mon Jan 14, 2019 4:52 pm

Insufficient or incorrect oil in the dashpots causing over-rapid dropping of the piston?

Regards
Stuart

If you can't make it work, make it complicated!

'62 FHC - Nearing completion
'69 Daimler 420 Sovereign
'78 Land Rover Series 3 109

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madjack4
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#7 Re: Engine chugs when power is taken off

Post by madjack4 » Mon Jan 14, 2019 11:26 pm

Hi tight spark plug gaps cause that problem try gapping them slightly wider than they should be and see if it improves the problem
Rob 1972 s3 roadster
Aston Martin DB9 Volante

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chrisfell
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#8 Re: Engine chugs when power is taken off

Post by chrisfell » Tue Jan 15, 2019 9:47 am

I only know one of the causes of just this kind of symptom because my neighbour told me about it. In this case it was a Ford Escort, but the cause was the same. A recently cashed up young chap who always wanted to own the car his Dad used to drive, bought one fully restored. And on his first few drives, had just this symptom. He took a mate, who 'knew about classics cars' with him on a drive.

His mate told him to shut the choke off.

Problem solved.
Chris '67 S1 2+2

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Simon P
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#9 Re: Engine chugs when power is taken off

Post by Simon P » Tue Jan 15, 2019 10:25 am

There's a similar story years ago about a lady complaining to the garage that her Morris Minor was running rough. The car went in and out several times but the garage couldn't detect any problem. Eventually when she came back yet again they suggested she drive one of their mechanics and see if she could point to what she meant. They both duly got in the car, she pulled out the choke ready to start the engine, and then hung her handbag on it......

:lol:
1969 S2 FHC - 1R20258
1993 Lancia Delta HF integrale Evo II

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Moeregaard
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#10 Re: Engine chugs when power is taken off

Post by Moeregaard » Tue Jan 15, 2019 12:56 pm

All great suggestions, so here's one more: check for a stuck distributor breaker plate.
Mark (Moe) Shipley
Former owner '66FHC, #1E32208
Former owner '65FHC, #1E30036

Planning on getting E-Type No. 3 as soon as possible....

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Grayjay66
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#11 Re: Engine chugs when power is taken off

Post by Grayjay66 » Wed Feb 13, 2019 6:35 am

Mine 66 would start obviously misfiring and keep misfiring. Finally realized front float bowl ball bearing in the jet was sticking and front carb was starving. Pipe brushed and all well until

A month ago started running rough again, this time it was a plugged front float carb intake screen. Although it did not seem to be particles more like a varnish as I could see through the filter but fluid would not pass through. Sitting for 4 months could be a cause.

Once cleaned is much better but still has a constant misfire at all constant rpm range to 50 mph. Very smooth when accelerating. Not sure about this new symptom.

Years ago I had a misfire that was traced to the distributor, a plastic piece had failed on the points.

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