running on 2 cylinders???????
Turbo Mini Forums

hi chaps

wen the engine is running and i remove the ht leads from cylinder 1 and 2. ( 1 being closest to the thermostat) it doesnt effect the engine wot so ever.
i bought a Gunson compression tester and have checked each cylinder and all seems fine, checked the resistance of leads, changed coil pack and edis modual. also had new plugs.
wen i take the lead off and hold it away from the plug, im getting quite a good arcing spark tho.
could this be caused by the jolt ecu in anyway?
the engine doesnt sound right, more like a helicopter but wen i have been driving it, it hasnt felt like it has been running on 3?
markgtt is coming round on sunday with his ecu to give that a try. any more suggestions would be much appreciated.
cheers
jamie

'always keep a spare shot for a stray bird'

Hi mate, if you bring the revs up slightly to about 1500, does it change tone as if its firing on all four?

I'd come over and give you a hand but I have a lot on this weekend

i dnt think so mate, seems to be the same tone all of the time.
cheers hope changing the jolt will sort it, if not then im stumped.

'always keep a spare shot for a stray bird'

you will find the head gasket has blown

i know you have compression tested it

ok,

how about swapping leads 1&4 and leads 2&3, then see if its still 1&2 mis firing.

apart from that i'd say a burnt exhaust valve but this isnt the case if the comp test was ok.

could have spat the manifold gasket on the port for 1&2?

ive tried swopping the leads around but this just makes it run like a bag of shite.
ive changed the head gasket a while back to try and cure this, but wen ran again was still the same.
thanks for the help guys keep them coming

'always keep a spare shot for a stray bird'

Edited by Turbo Tel on 2nd Jan, 2009.

website:- http://www.terryhunt.co.uk

Im no expert, but if you can get a good spark off the plug lead with the engine running on the affected cylinders then the spark must be at the wrong time, particularly as you say it has good compression.Does your ignition system have a fault inthe timing for the affected cylinders ?Failing this, it must be a massive air leak in the induction system for cyls 1 and 2, as has already been suggested

Are you sure the firing order is right?

Paul

I seriously doubt it!

thanks turbo tel, i have tried jiggling the plug but has had no effect.
the mega jolt ecu is the only thing left in the system, excluding the wiring, that i havent changed so by changing this is should eliminate any problems if it is the ignition system.
paul im pretty sure the firing is right, i have tried every other combination. how else can i tell?

'always keep a spare shot for a stray bird'

The megajolt shouldn't affect things as the car should run without it even being connected.

as im not running a turbo at the moment, would this have any effect?
cant see as it would just want to make it as clear as possible for you all.
thanks again for all the suggestions

'always keep a spare shot for a stray bird'

As said, the ECU should not prevent it from running "reasonably" OK at tickover as EDIS will just take over at a fixed (10 degree ?) advance.

What is more interesting is that taking 3&4 off has no effect compared to 1&2.....
.....wasted spark means the current flows through plugs 4 and 1 simultaneously (as it does through 2 and 3).

There are only two coils in a coilpack.....

Schrödinger's cat - so which one am I ???

Hi,
It should run on all 4 even if the MJ is at the other end of the country.
Has it ever ran on all 4?
Cheers,
Gavin :)

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I'm not sure what trigger wheel you have, i had a similar problem and it was the timing. my trigger wheel had slipped and needed re positioning. imo check your timing

im using my original pulley thats been machined.
im going to check the distance of the VR sensor to the wheel, think it should be around 0.8mm if i remember.

'always keep a spare shot for a stray bird'

As well as ignition, is worth checking the fueling as well? Abit of crap in the carb etc...........

Edited by Jason G on 3rd Jan, 2009.

i have put a timing gun on the trigger wheel and found that the missing tooth is about 11 oclock with my sensor at 9 oclk.
could this be the cause??

'always keep a spare shot for a stray bird'

Is that with the MJ disconnected (best place to start such diagnostics) and where is TDC (ie, what mark on your timing light) relative to the missing tooth ???

Schrödinger's cat - so which one am I ???

that was with the jolt connected.
right have found a few things, from my coil pack which is numbered 1,2,3,4, on marks these go to the corresponding cylinders. i.e 1 to 1 and 2 to 2 and so on. on mine they go 1 to 2, 2 to 1, 3 to 4, and 4 to 3. marks way just wont have it then back fires.
also using the timing gun, have found that the original timing mark on the pulley is sitting at about 30 degrees before TDC.
my pulley has been machined with the missing tooth in line with the key way.
is this position right?

'always keep a spare shot for a stray bird'

To start, you need to know your missing tooth relative to ACTUAL TDC, not just random marks which may well be wrong.

Using the timing light withOUT MJ connected will give you a good estimate (if it will run) as there is a fixed advance from EDIS when it has no input.

The fact your plug leads are all wrong is probaly just masking the actual problem.

Whether or not your missing tooth should be aligned with the keyway has nothing whatsoever to do with the keyway..... it's all relative to where your VR sensor is mounted.

Schrödinger's cat - so which one am I ???

well when i had the pulley machined i was told that wen the key way in the crank is at 12 oclock, this is TDC for no 1 cylinder.so had the missing tooth removed in line with this.
my sensor is at 9 oclock.
so what should i expect to see on the timing with the Mj disonnected then?

'always keep a spare shot for a stray bird'

right without MJ, its running at 16 degrees BTDC.

'always keep a spare shot for a stray bird'

Hi,
Not right but close enough for now :)
It should be 10 BTDC.
However that wouldn't cause it to run on 2 cylinders.
Plug leads should go 1 on coil pack to plug no 1, 2 to 2, 3 to 3...
If it doesn't run like that swap the two trigger wires round on the coil pack multi-plug ( the 2 outer wires of the three)
Cheers,
Gavin :)

VEMs Authorised Installer / Re-seller. K head kits now available!

WB/EGT gauges. Click here for customers write-up

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My Mini build diary

Someone will correct me if I'm wrong, but I think it's 10 degrees BTDC on EDIS alone.... (sorry, I'm building megasquirt and there are a few fundamental differences to megajolt that I'm not familiar with).

However, it sounds close enough, but, are you sure of your timing marks that you're shining the timing light at, are actually showing you 16 degrees ???

If it is 16 degrees, ie, close enough to 10 degrees, the problem is not with your trigger wheel position as the 6 degrees out can easily be dealt with in the map (or offset in megasquirt, possibly the same in MJ).

If you are that close with the timing, your problems are elsewhere, not MJ.

EDIT - Bat beat me to the 10 degrees, I must learn to type faster.....

Edited by Rod S on 4th Jan, 2009.

Schrödinger's cat - so which one am I ???