Black smoke Series 3 2+2

Talk about the E-Type Series 3
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Djerome60
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#1 Black smoke Series 3 2+2

Post by Djerome60 » Thu Oct 18, 2018 11:24 am

Hi everybody,

since i have finished my restoration on my Series 3 2+2 from 1972 i have enjoyed al lot of good ride but i have a little issue that annoys me and i idon't find a fix.
In fact mainly at idle but also when i accelerate i have black smoke coming from the Left hand side of the exhaust = engine B cylinders row.
Please see what i have done so far with no success:
-Adjust mixture to a much leaner setting with current metering needle ==> No change
-Review all hoses connection ==> No change
-Ran tests with ail filter==> no change
-Control float heights = 17mm ==> No change
- Adjust timing ==> No change.
- Remove the ball and spring from the fuel non return valve to make sure i did not have too much pressure ==> No change
-Replace the metering needle by brand new B1BH ==> Notested yet

What is strange is that the Raw 1 is ok, the spark plug are having the right expected color (good mixture) but All 6 of the Rax B are black even if i adjust the mixture to the leaner setting.
The engine is running very good, no power loss, quite stable at idle,.... but the fuel consumption seems a bit too high even for a V12.

DO you think this could be caused by an internal broken pipe in 1 or both of the Left hand side carburator? Vaccum issue?,....
Thanks in advance for your usual gret support.

Regards
Jerome
Regards
Jérôme

E type Series 3 - 2+2 1972
Peugeot 304 Cab 1971

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Ole-xke1974
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#2 Re: Black smoke Series 3 2+2

Post by Ole-xke1974 » Fri Oct 19, 2018 2:05 am

Jerome,
Have you checked that the choke on the B cylinder bank isn't stuck in one way or an other ?
That's the only thing I can think of that would be common to the two carbs and one bank only.
Otherwise, it looks like you checked everything else.
You know that the two carbs on each side share the choke system of only one of the carbs ?
Cheers and good luck .......... Ole
1974 SIII E-Type w. XJ S2 4sp w. O/D

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Djerome60
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#3 Re: Black smoke Series 3 2+2

Post by Djerome60 » Fri Oct 19, 2018 6:40 am

Ole,

thanks. I forgot to mention it but yes i have already checked that the ckoke was not stuck on that bank and it's not. There is only 1 carb which has a choke.
Regards
Jérome
Regards
Jérôme

E type Series 3 - 2+2 1972
Peugeot 304 Cab 1971

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PeterCrespin
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#4 Re: Black smoke Series 3 2+2

Post by PeterCrespin » Fri Oct 19, 2018 10:58 am

You could try removing the connecting pipe to see if three cylinders return to normal after isolating from choke. Do all floats float? Try swapping carb bowls or eventually complete pairs between A & B bank.
1E75339 UberLynx D-Type; 1R27190 70 FHC; 1E78478; 79 S2 XJ12L; 97 XJ6L

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jagwit
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#5 Re: Black smoke Series 3 2+2

Post by jagwit » Fri Oct 19, 2018 1:47 pm

Someone has recently found that the disc with the holes inside the choke mechanism was installed the wrong way round. Better check yours.
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

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Djerome60
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#6 Re: Black smoke Series 3 2+2

Post by Djerome60 » Fri Oct 19, 2018 4:29 pm

Peter, Philip,

thanks for your idea, i'll do it and let you know.
I have already check the choke disc and looked ok to me but did not have any drawing to compare. I'll do it.
In parallel i have found 2 second hand Carb that i'll rework and swap them with my current one if i do not have any improvements with the last tests i'll make.

Keep you posted
Thanks
Jérôme
Regards
Jérôme

E type Series 3 - 2+2 1972
Peugeot 304 Cab 1971

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Djerome60
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#7 Re: Black smoke Series 3 2+2

Post by Djerome60 » Fri Nov 09, 2018 12:11 pm

Hi,

sorry for not getting back earlier but i could not do the tests as i have faced a fuel pump failure and i just received the parts to rework the pump this week.
I'm just wondering if my smoke issue could not be linked to the fuem pump!?
I explain my reasoning: when i disassemble the pump i found out that the pump was almost stuck and i think the full pressure was much lower than it should. In consequnce the Band A was supplied probably with enough pressure but not the band B as supplied after the A. Therefore if the pressure was not high enough for band B the fuel flow was perhaps not good enough to fill the float chamber quick enough and therefore close the needle as it should. This could potentially create an fuel overfilling in the band B and explain the smoke.
Does my reasoning make sense? OR not?
I'll try to run some testing in the coming days to see whether or not my theroy is completely stupid or not.

Thanks in advance for your comment.
Jérôme
Regards
Jérôme

E type Series 3 - 2+2 1972
Peugeot 304 Cab 1971

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jagwit
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#8 Re: Black smoke Series 3 2+2

Post by jagwit » Fri Nov 09, 2018 1:20 pm

Jérôme

The only ways OVERfilling can result (that I can think of now) is if:
1) the fuel pump pressure is WAY too high - so high that it can push fuel THROUGH the needle and seat. It is rather unlikely that a non-EFI fuel pump can do this;
2) the needle does not close fully (floats not set correctly, debris in the needle/seat).
But then you should see fuel flowing out the main jets with fuel pump running and engine stationary.

With fuel pressure too LOW, its really hard to predict what will happen but I would guess the RH bank is likely to get more fuel than the left. If you tuned the carbs in this situation, its likely that the LH carbs will run richer once proper fuel pressure is restored.

Regardless, I still think you should check the choke assemblies first, even if only to know for sure that they really ARE OK.
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

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