Mongrel badly misfiring post quarter mile racing

[devonutopia]

Here's a rough video....  Any idea?  Car at low revs is misfiring/bucking like no ones business.  I could only drive it keeping revs above 2500rpm.  :(  I will try and get a better video tomorrow.  I am fearing a broken injector, or worse potentially a failed camshaft.

 

 

[Dark_Hero]

Sounds like it's firing on 3 cylinders.

Is it vibrating through the car?

My brother had an injector fail and it made a similar sound

[devonutopia]

It's SHAKING the whole car (when trying to use low revs and a bit of juice)

 

The journey home was actually OK, but I bailed out of doing more drag runs when I noted one run went to 3.0 bar boost and I felt a slight misfire at the top end of 4th gear.

 

I think what finished it off was me deciding to blat up a dual carriageway about 6 miles from home as once I got to the top I could feel the misfire developing real quick and within 2 miles I was fighting the car home.

 

The car has been / was smoking slightly on tickover - a sort of bluey but more grey haze/wisps - I had been wondering if a bit too much fuel was being injected by one unit and wasn't all being combusted properly....

[devonutopia]

The sad thing is, I think this writes off my chances of doing the Combe sessions....

[jays]

Is it down on power if so id go for piston/rings

[mr rooney]

Have you done a fault code read?

Could be a faulty injector?

[TeflonTom]

sounds like it's only running on 2 mate, head gasket?

[Dark_Hero]

You can passenger with me at Combe if you can't fix your car Jason. As mentioned sounds like an injector sadly

[silky16v]

cam timing

[BossFox]

The sad thing is, I think this writes off my chances of doing the Combe sessions....

 

I doubt it, you've got two weeks yet and anything injector/headgasket etc... is easily fixable in that time.

 

Get cracking.

 

Can't have you turning the power up to 11, breaking it first time out and then not taking part at Combe.

 

If you need anything off the ones I'm breaking, let me know.

[sepulchrave]

sounds like it's only running on 2 mate, head gasket?

 

+1

[SKYHAWK]

my bet it the cam mine sounded like that and it had worn through the buckets no power until boost sounded terrible and smoked alot

[@Lee]

please fix it, I'm rather looking forward to my passenger ride :(

 

Good luck and get cracking

[rover220]

I would be worried about pistons and rods if you hit a real 3bar of boost.

[devonutopia]

Rods are forged so not concerned about them. As the misfire is much worse under low load at low revs than at tickover or low load at higher revs, I'm thinking loom first culprit. It's the only weak consumable part in the injection system.

[merrett07]

This is what mine is like but I've got stupid amount if smoke, at 2500rpm is that where yours comes into boost. As mine drives at around 2000rpm when it comes into boost and missing goes.

[Phil-J]

No faults logged?!

[jays]

Sounds like piston slap to me had the same thing on a R5 GTT

Edited 13 April, 2014 by jays

[rover220]

Rods are forged so not concerned about them. As the misfire is much worse under low load at low revs than at tickover or low load at higher revs, I'm thinking loom first culprit. It's the only weak consumable part in the injection system.

Ive seen forged rods fail just the same as cast especially when subjected to massive over boost.

[bilun777]

Sounds like it's only running on 3 cylinders to me .

Possibly only 2 ?

[TeflonTom]

Ive seen forged rods fail just the same as cast

 

cast conrods?? thats a new one on me

[sepulchrave]

Ive seen forged rods fail just the same as cast especially when subjected to massive over boost.

 

Seriously, and the engine still ran and ticked over afterwards, really?

[sepulchrave]

cast conrods?? thats a new one on me

 

I think he's getting pistons and rods mixed up.

[TeflonTom]

i have seen cast conrods but they are rare, stuff like chainsaws have them, the overwhelming majority of oem connecting rods in cars are forged, you can tell a forged rod by the wide parting line on the sides where the flash has been squeezed out from between the forging dies during  manufacure, some rods in low stress applications are sintered instead ( its basically powdered metal that has been squashed) a sintered rod will normally have a fracture split at the big end rather than machined flat surfaces..

 

anyway enough about all that, come on jason get the spanners out and fix it

[Guest BigJase88]

Camshaft