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#1 1293clubby

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Posted 10 January 2006 - 09:22 PM

Hello. My mini is misfiring throughout the rev range. Have to use it for work so its a bit of a problem. Have changed the plugs, leads, dizzy cap, coil, condensor and points and it is getting worse. Have tried the wd40 spray test to see if i have leaky inlet manifold but that is ok too. Almost sure the head gasket has not gone.
Have bought a new fuel pump which i am gonna try. Any other ideas would be welcome.

#2 Jammy

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Posted 10 January 2006 - 09:49 PM

Have you changed anything recently like carb, air filter, manifold?

Have you checked timing? Do you have a colourtune? Have you/are you able to complete a compression check on the cylinders?

#3 miniboo

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Posted 10 January 2006 - 09:54 PM

Timing is a good place to start i reckon.

What is the WD40 test you did for a leaky inlet manifold?

Might have to try it on mine.

#4 minidaves

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Posted 10 January 2006 - 10:00 PM

head gasket between 2 and 3

dave

#5 1293clubby

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Posted 10 January 2006 - 10:06 PM

Hi. If you spray WD40 all around the inlet manifold and the engine revs increase at all then you have a leaky inlet manifold. It works because it is highly flammable and if it gets in the engine it raises the revs for a few seconds.
Could be head gasket because i have mayo in the rocker cover. But water is clear and the coolant level has not gone down.

#6 Sprocket

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Posted 11 January 2006 - 12:50 AM

Hi. If you spray WD40 all around the inlet manifold and the engine revs increase at all then you have a leaky inlet manifold. It works because it is highly flammable and if it gets in the engine it raises the revs for a few seconds.
Could be head gasket because i have mayo in the rocker cover. But water is clear and the coolant level has not gone down.

I think that is total tosh.

is this a regular constant missfire or an irregular one

#7 The Matt

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Posted 11 January 2006 - 03:17 AM

Could be head gasket because i have mayo in the rocker cover. But water is clear and the coolant level has not gone down.

If it was the head gasket between 2 and 3 as Dave has said you wouldn't necessarily get oil in the water or loss of water.

These are common symptoms of a gasket failure yes, but your syptoms are the misfire due to the pistons loosing compression to each other (this is common on the A series).

You would only lose water or get oil and water mixing if the gasket had blown between a waterway and a cylinder or between a waterway and oilway.

As for the WD40, it generally aint a good idea to do that as a test.

Have you tried a compression test on all four cylinders yet? :wink:

#8 cooper_shaz

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Posted 11 January 2006 - 08:49 AM

Carb cleaning spray is a better thing to use for Air leak detection,
this will cause the revs to drop off..!

As for the WD40 I have saw this mentioned a couple times here.... don't use it.... being so flammable and spraying it around a hot engine, especially one that is mis-firing (could be an electrical short and you could have stray sparks about)

Safety first folks...!

But I agree with above, timing check then compression check...

#9 miniallsort

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Posted 11 January 2006 - 04:25 PM

check spark plugs

#10 ianbunyan

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Posted 11 January 2006 - 04:39 PM

I'd go with timing check... mine started to misfire so took it to Bill Richards as I don't know how to do these things myself yet, and he adjusted the timing, and while I was there got it tuned for Optimax :thumbsup: Did the trick!

Let us know what it was when you get it sorted!

#11 1293clubby

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Posted 11 January 2006 - 09:48 PM

Right. The misfire is getting really bad. Chugging along all the time now. misfire is not as bad when i can get the revs higher. Over about 50 mph it is not as bad. Have done a compression test. Dont know which cylinder is supposed to be 1,2,3 and 4 but when looking at the engine form the front of the car i count the furthest left cylinder as 1 the next as 2 then 3 and the furthest right is 4. Th figures i got were cylinder 1, 175 psi. Cylinder 2, 165 psi. Cylinder 3, 176 psi and cylinder 4 178 psi. Then did the test again and got 174, 170, 180 and 176.
Any idea whether these are normal figures.

#12 miniboo

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Posted 11 January 2006 - 09:51 PM

those figures are ok.

no 1 is nearest the rad end.

firing order is 1342

dizzy leads should be like that (1342) starting from the top right as you look at it.

#13 minidaves

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Posted 11 January 2006 - 10:03 PM

did u test with all the plugs in or all the plugs out?

dave

#14 1293clubby

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Posted 11 January 2006 - 10:04 PM

Did the test with all the plugs out.

#15 minidaves

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Posted 11 January 2006 - 10:13 PM

ok then its proberly a lead failure or aplug failure as those comprestions aint that terrible, or the exhaust valve in the low comp one is starting to give out

take it to a garage who knows how to fix

dave




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