11 replies to this topic

[Cooper1999]

I'm hoping someone on here has the answer!
After a run on the motorway yesterday, my MPi started misfiring, running rough. Getting home I started to diagnose by pulling each plug lead off in turn which showed a weak/no spark on No. 2 & 3 cylinders.
So I bought new leads today which gave a similar result, and it still wouldn't run properly. So I put on another coil pack I have (unknown history) which seemed to give a more even spark across all four cylinders but now it won't run at all!
I've recharged the battery, dryed, cleaned and checked the plugs and still no go. It hiccupped a couple of times but still nothing.
So, anyone got any ideas? Haynes suggests a major mechanical failure e.g. cam drive. I'm pretty sure it's not, but could be wrong I suppose .
Tomorrow I'm planning on getting a new set of plugs (and a set of HD jump leads to attach to a big diesel vehicle) 'cause I can't think of anything else!
I should maybe add, it's got a big valve head, running about 11:1 CR, BPR7ES plugs.
Thanks in advance!
Graham

Edited by Cooper1999, 16 December 2009 - 09:49 PM.

[danie garry]

do u have any compression in them 2 cylinders?
i found a guy and his mini on the side of the road last week and the car ran -badly- good spark but we towed it to the garage, no compression in 1st and 2nd cylinder, head gasket musta gone between the 1st and 2nd

hopefuly u'r aint as bad but a compression test should tell ya

[L400RAS]

I'm hoping someone on here has the answer!
...Getting home I started to diagnose by pulling each plug lead off in turn which showed a weak/no spark on No. 2 & 3 cylinders...

Hi Graham,

pulling plug leads off does not diagnose a weak spark, it diagnoses the cylinder at fault - the spark plug could still be sparking well, just there is no compression to burn the fuel. Seen as it is cylinder 2 & 3 i would say head gasket - very common to blow over these cylinders as opposed to any of the others.

Ryan.

[Paul Wiginton]

Usually a miss on 2 and 3 is a blown head gasket. has it been set up on the rolling road with that high compression?

Paul

[Sprocket]

What fuel are you using with 11:1 CR?

[Cooper1999]

Yes - it does indeed look like head gasket failure! Just done a compression test:
No. 1 - 14 bar No. 2 - 4 bar No. 3 - 4 bar No. 4 - 13 bar
Sprocket, I use 97 Superunleaded, and there is one garage not too far which has 98 octane. I resist going to Castle Coombe for the 101 (I think) octane stuff!
Paul, yes it was on Slarks rollers when I fitted the head - no sign of detonation, and 74.1bhp from a 1275 MPi set up.
The gasket is a Payen BK450. Shortly after I fitted it I heard they'd moved the manufacture overseas, and producing bad gaskets! Hopefully this has been rectified!

[L400RAS]

...and producing bad gaskets! Hopefully this has been rectified!

Yes it has - all new gaskets bought from minispares are guaranteed to be from a "good" batch. Unfortunately it looks like you were one of the unlucky ones

Ryan.

[Sprocket]

Yes - it does indeed look like head gasket failure! Just done a compression test:
No. 1 - 14 bar No. 2 - 4 bar No. 3 - 4 bar No. 4 - 13 bar
Sprocket, I use 97 Superunleaded, and there is one garage not too far which has 98 octane. I resist going to Castle Coombe for the 101 (I think) octane stuff!
Paul, yes it was on Slarks rollers when I fitted the head - no sign of detonation, and 74.1bhp from a 1275 MPi set up.
The gasket is a Payen BK450. Shortly after I fitted it I heard they'd moved the manufacture overseas, and producing bad gaskets! Hopefully this has been rectified!

I would suggest you find a Shell garage and pay just a little more for the Vpower, not only is it gauranteed to be 99 octane (dropped one point from 100, about 2 years ago I think) at the pump but it does actualy clean and lubricate the upper cylinder amazingly well!!!

The reason I say this is that the 97, 98 and even the tesco 99 could be asmuch as 1 point less that the advertised value. This is due to storage, and transportation methods. Basicaly, Shell use one tanker for Vpower and another for regular 95 unleaded

[Cooper1999]

And the problem was:

[Sprocket]

That is one of the dodgey ones. You can see where the fire rings between the bores have splayed out. I made that assumption earlier in the year, based on what I had seen on the gaskes i have used and cut up, when the gasket issues were highlighted, but apparently that was not the fault with them. I am still not convinced.

Use Vpower with the standard ECU and 11:1 compression, that should help keep knock in a slightly better place, as even with 97 octane it would have been knocking.

Edited by Sprocket, 22 December 2009 - 11:04 PM.

[Cooper1999]

Use Vpower with the standard ECU and 11:1 compression, that should help keep knock in a slightly better place, as even with 97 octane it would have been knocking.

Will do! I've put another Payen in - hopefully they've cured the problem!

[Cooper1999]

Hmm - so it ran last night (got up to temperature, the fan kicked in a couple of times) and yet this morning it wouldn't!
So whats changed?
The only thing I can think of is the temperature! It was -5 degrees last night (the dregs in the bottom of the tea cup I left in there last night was frozen!), and I don't think the car likes the cold too much with such a high CR.
I've bought some new plugs - these ones may have been flooded once too often now! It's meant to be milder tomorrow, so I'll try again then. But any other ideas or suggestions are welcome!