Misfiring after new engine.

[Uncle B]

Hi all,
The mechanic finally got the new (to me) engine into the FTO and has discovered that its misfiring on a cylinder.
I also got the decat fitted now too and I'm just wondering would the temp sensor have anything to do with it?

He's going to do a diagnostic that'll hopefully throw up some codes but would anyone be able to enlighten me as to what might cause this?

Would it be coil packs, leads or spark plugs related? I haven't a clue really just want to help narrow it down.
Like I said the engine was changed and a new complete engine gasket kit put in along with a few other bits and pieces.

Any ideas?

[colm_mcm]

Check each plug for spark to figure out if It's that.

[Uncle B]

OK bit of an update...

Plugs fine (Got new ones anyway)
Leads fine (New magnecor ones)
Coils working grand.
Injectors all good.

Did a diagnostic using the shorting method and got no codes.
So we're gonna do a compression test to rule that out...
Then use the MUT-II to see if we can get some live data that might help.

Whats left after that?
Ugh getting sick of this!

[steelroe]

Are the leads on in the correct sequence. Make sure that the leads going to the rear plugs come from the correct coil on the front bank, easy mistake. This will cause a misfire.

[steelroe]

you dont need to go to main dealer for MUT-II level diagnostics. Anyone with a launch X-431 can do live data. Cheaper than main stealer
Also how do you know coils are ok. How did he test them.
I would move the coils around and see if the problem changes cylinder

[Uncle B]

Hey Rory thanks for the replies,

Are the leads on in the correct sequence. Make sure that the leads going to the rear plugs come from the correct coil on the front bank, easy mistake. This will cause a misfire.

Is this the right order/sequence:
Rear: 1 2 3
Front: 4 5 6

Connect 1-5, 2-6, 3-4

Tbh I've no idea how he checked the coils so I'll double check and get him to move them around as you suggest.
Someone else I was talking mentioned it could be the timing? Is that a potential issue?
The same guy said it might be a bent valve either (god I hope not...)

Thanks again guys,
I'll let you know as soon as I get an update.

[mcgon1979]

not to be negaive, but after the first post I though a bent valve or a burned out valve. I only thought this because I had that problem on a previous car after an engine change. one of the valves was damaged. car misfired on a cylinder. took us ages to find it. did everything mentioned above, leads, plugs, swithc them around, compression etc. eventually found it. got a new valve and ground it in. was ok then.

[steelroe]

Cylinder leakdown test will tell you if it is a valve. You can alos get a camera down there. Firstly check compression, if valve is badly bent it will loose compression on that cylinder.
Double and triple check everything, I is very easy to incorrectly connect or overlook something.
Any codes flashing out.

[steelroe]

Was timing belt changed on new engine. If so possibly out, even one tooth on a pulley will cause problems.

[Uncle B]

Hi guys,

Sorry to bring this up again but finally got around to doing a bit (exams/work placement take precedence...)

Got the compression done,180-200 on each cylinder.
Coils and injectors checked again and they're sound too.

Rory, I got a new TB about 5-7k km before she died so yes it has the newer TB fitted, I'll check that ASAP.
Could it be a sensor still?

The error code check using the engine management light technique didn't show up anything but would it be worthwhile to tow it to a main stealer/indy that has the proper diagnostic kit? I suppose it could narrow it down so I'm thinking it'll be worth the trip.

Thanks again,
Paul

[Uncle B]

Was looking on the net for other ideas and someone mentioned that the tappets could be too tight on the High or low speed cams?
Could that be a cause? And how tight is too tight?

Please excuse my ignorance once again!

[RockShox]

If it's isolated on one chamber, it could be a bad intake valve hydraulic adjusters with air inside. Since there's no error code, we can rule out the CAS.

[Uncle B]

Timing is bang on and we changed the CAS with the one from my old engine but the problem still remains.

We're goin to try the CAS from the working engine just to be 100% sure it's not that but any other suggestions?

Cheers,
Paul

[Uncle B]

CAS fine, coils fine...

We're hoping its fuel related now

Here's a video of it at idle, apologies for poor quality of phone

From Youtube.com


It seems to get worse when as you rev it, well it does to me at least.

[steelroe]

Have ye at least identified which cylinder is misfiring at this stage.

[Uncle B]

We've pulled the leads/plugs one at a time while its been running there's absolutely no difference between them, no change in noise or anything else.

Is there another way to isolate which cylinder is missing?

I'm considering towing it to Paul Nolan's if I can't get it sorted in the next two weeks, would that be a smart move or a waste of money?

[Kace]

I'm considering towing it to Paul Nolan's if I can't get it sorted in the next two weeks, would that be a smart move or a waste of money?

Probably best to give him a call and tell him what you've done and ask him for his ideas on what else he may have seen and what he would be trying next himself if you did tow it out to him.

Send him on your YouTube also.

[Uncle B]

Went out to do diagnostics with a different tool and get some live data... The Brainbee ST6000 isn't compatible with an FTO...

I know Rory mentioned a Launch X431, would some Indy's have this? What else would work?
I'll make a few calls tomorrow and see if I can find a place with one.

[RockShox]

from the looks of your exhaust, gray smoke would mean fueling problems too.

[Uncle B]

Going on pulling injector connectors I'm down on 3 cylinders (according to my untrained ear!)

I replaced the fuel rail and the 6 injectors with my breaker car that is working 100% fine.
Unfortunately it made no difference.

I'm calling Paul Nolan again later.
I'm just sick of it at the moment 'cause I have to get a lift out there (no other car) and then either have someone wait for me while I mess about or else get them to come back for me later...

Thanks for all input thus far.

[Uncle B]

Will be trailering the car up to Paul Nolan the weekend after next.
He won't be able to look at it for a while but at least its with an expert!